Neurorehabilitation and Neural Repair recent issues

ASNR/WFNR News

Tue, 27 Oct 2009 11:29:16 PDT

Aerobic Exercise Improves Cognition and Motor Function Poststroke

Tue, 27 Oct 2009 11:29:16 PDT

Background. Cognitive deficits impede stroke recovery. Aerobic exercise (AEX) improves cognitive executive function (EF) processes in healthy individuals, although the learning benefits after stroke are unknown. Objective. To understand AEX-induced improvements in EF, motor learning, and mobility poststroke. Methods. Following cardiorespiratory testing, 38 chronic stroke survivors were randomized to 2 different groups that exercised 3 times a week (45-minute sessions) for 8 weeks. The AEX group (n = 19; 9 women; 10 men; 64.10 ± 12.30 years) performed progressive resistive stationary bicycle training at 70% maximal heart rate, whereas the Stretching Exercise (SE) group (n = 19; 12 women; 7 men; 58.96 ± 14.68 years) performed stretches at home. Between-group comparisons were performed on the change in performance at "Post" and "Retention" (8 weeks later) for neuropsychological and motor function measures. Results. VO₂max significantly improved at Post with AEX (P = .04). AEX also improved motor learning in the less-affected hand, with large effect sizes (Cohen’s d calculation). Specifically, AEX significantly improved information processing speed on the serial reaction time task (SRTT; ie, "procedural motor learning") compared with the SE group at Post (P = .024), but not at Retention. Also, at Post (P = .038), AEX significantly improved predictive force accuracy for a precision grip task requiring attention and conditional motor learning of visual cues. Ambulation and sit-to-stand transfers were significantly faster in the AEX group at Post (P = .038), with balance control significantly improved at Retention (P = .041). EF measurements were not significantly different for the AEX group. Conclusion. AEX improved mobility and selected cognitive domains related to motor learning, which enhances sensorimotor control after stroke.

The Effects of Repeated Rehabilitation "Tune-Ups" on Functional Recovery After Focal Ischemia in Rats

Clarke, J., Mala, H., Windle, V., Chernenko, G., Corbett, D. — Tue, 27 Oct 2009 11:29:16 PDT

Background. For most stroke survivors, rehabilitation therapy is the only treatment option available. The beneficial effects of early rehabilitation on neuroplasticity and functional recovery have been modeled in experimental stroke using a combination of enriched environment and rehabilitation. However, the impact of a secondary intervention, such as a periodic return to therapy, remains unclear. Objective. This study examines whether a return to enriched rehabilitation (ie, "tune-up") can further promote functional recovery or produce beneficial changes in brain plasticity in the chronic phase of stroke recovery. Methods. Rats were exposed to focal ischemia (endothelin-1 applied to forelimb sensorimotor cortex and dorsolateral striatum) and allowed to recover either in standard housing or in a combination of enriched environment and rehabilitative reaching for 9 weeks. Animals were then exposed to rotating periods of standard housing (5 weeks) and intensive "tune-up" therapy consisting of various sensorimotor/cognitive activities (2 weeks). Functional recovery was assessed using the Montoya staircase, beam-traversing, and cylinder tests, and Golgi—Cox analysis was used to examine dendritic complexity in the contralesional forelimb motor cortex. Results. Although early enriched rehabilitation significantly improved sensorimotor function in both the beam and staircase tests, "tune-up" therapy had no effect on recovery. Golgi—Cox analysis revealed no effect of treatment on dendritic complexity. Conclusions. This study reaffirms the benefits of early rehabilitation for functional recovery after stroke. However, "tune-up" therapy provided no benefit in ischemic animals regardless of earlier rehabilitation experience. It is possible that alternative approaches in the chronic phase may prove more effective.

The Neural Stem Cell Line CTX0E03 Promotes Behavioral Recovery and Endogenous Neurogenesis After Experimental Stroke in a Dose-Dependent Fashion

Stroemer, P., Patel, S., Hope, A., Oliveira, C., Pollock, K., Sinden, J. — Tue, 27 Oct 2009 11:29:16 PDT

Background. This study investigated behavioral recovery in rats following implanting increasing doses of CTX0E03 cells into the putamen ipsilateral to the stroke damage. Postmortem histological analysis investigated possible mechanisms of behavioral recovery. Methods. At 4 weeks after middle cerebral artery occlusion (MCAO), rats were treated with 4500, 45 000, or 450 000 CTX0E03 cells or vehicle implanted into the putamen with testing on a battery of tasks preocclusion and postocclusion. Histological examination of brains included assessment of lesion volumes, implant cell survival and differentiation, changes to host brain matrix, angiogenesis, and neurogenesis using immunohistochemical methods. Results. Statistically significant dose-related recovery in sensorimotor function deficits (bilateral asymmetry test [BAT; P < .0002] in the mid- and high-dose groups and rotameter test after amphetamine exposure [P < .05] in the high-dose group) was found in the CTX0E03 cell implanted groups compared to the vehicle group. In-life functional improvements correlated with cell dose, though did not correlate with survival of CTX0E03 cells measured at postmortem. Surviving CTX0E03 cells differentiated into oligodendroglial and endothelial phenotypes. MCAO-induced reduction of neurogenesis in the subventricular zone (SVZ) was partially restored to that observed in sham operated controls. No adverse CTX0E03 cell-related effects were observed during in-life observations or on tissue histology. Conclusions. This study found that the implantation of CTX0E03 human neural stem cells in rats after MCAO stroke promoted significant behavioral recovery depending on cell dose. The authors propose a paracrine trophic mechanism, which is triggered early after CTX0E03 cell implantation, and which in turn targets restoration of neurogenesis in the SVZ of MCAO rats.

Effect of Treadmill Training on Autonomic Dysreflexia in Spinal Cord--Injured Rats

Laird, A. S., Carrive, P., Waite, P. M. E. — Tue, 27 Oct 2009 11:29:16 PDT

Background. Weight-supported treadmill training is an emerging rehabilitation method used to improve locomotor ability in patients with spinal cord injury (SCI). However, little research has been undertaken to test the effect of such training on other consequences of SCI, such as neuropathic pain and autonomic dysfunction. Objective. This study investigates the effects of chronic treadmill training on the development of autonomic dysreflexia (AD), a form of cardiovascular dysfunction common in patients with cervical or high thoracic injury. Methods. Treadmill training commenced in adult male rats (n = 11) 3 days following complete T4 transection, whereas a sedentary SCI group (n = 9) and an intact group (n = 6) had no intervention. Treadmill training (up to 0.4 m/s) lasted for 10 min/d 5 days a week, for 6 weeks. Weekly measurements of locomotor ability (BBB scale), baseline mean arterial pressure, and heart rate were made, as were cardiovascular responses to training and colorectal distension (to trigger AD). Results. Treadmill training improved BBB scores from 2 weeks post-transection onward (P = .010). However, it increased AD, resulting in augmented pressor responses from 2 to 6 weeks post-transection (P = .029). Comparison of the vascular response to phenylephrine under ganglionic blockade showed an enhanced vasoconstrictor response in the renal vasculature of trained SCI animals. Immunohistochemical comparison of the L1—L6 spinal cord segments showed an increased area of CGRP immunoreactivity in the dorsal horn (lamina III/IV) of treadmill-trained SCI compared with intact and sedentary SCI animals. Conclusions. These results suggest that treadmill training exaggerated AD responses perhaps through a combination of enhanced vascular reactivity and central plasticity.

Brainstem Reflexes Are Enhanced Following Severe Spinal Cord Injury and Reduced by Continuous Intrathecal Baclofen

Kumru, H., Kofler, M., Valls-Sole, J., Portell, E., Vidal, J. — Tue, 27 Oct 2009 11:29:16 PDT

Objective. Plastic changes in the human central nervous system can occur at multiple levels, including circuits rostral to the lesion level in spinal cord injury (SCI). GABA is the most important inhibitory neurotransmitter in the brain. The authors hypothesized that one of the consequences of plasticity in SCI patients could be enhancement of brainstem reflexes, and they investigated the effect of continuous intrathecal baclofen (CITB) on such enhancement. Methods. The authors studied the early ipsilateral component R1 and the late component R2 of the blink reflex (BR), jaw jerk, masseter silent period (MSP), and auditory startle response (ASR) in 9 SCI patients without baclofen and in 8 with CITB. Nine healthy volunteers served as controls. Results. The amplitude of R1 of BR was significantly smaller in patients with CITB than in the other groups. The area of R2 of BR and of the ASR recorded in the orbicularis oculi, sternocleidomastoid, and biceps brachii muscles were significantly larger in SCI patients without baclofen than in controls, whereas there was no difference between patients with CITB and controls. The MSP magnitude was significantly larger in patients with CITB as compared with those without baclofen. Conclusion. The enhancement of brainstem reflexes in SCI patients may be due to plastic changes at the brainstem level after SCI. The significant reduction in response size in patients with CITB in comparison with patients without baclofen suggests that the enhancement of brainstem reflexes may be due to decreased GABAergic activity and that CITB is effective in reducing abnormal brainstem hyperexcitability.

Repeated Maximal Volitional Effort Contractions in Human Spinal Cord Injury: Initial Torque Increases and Reduced Fatigue

Hornby, T. G., Lewek, M. D., Thompson, C. K., Heitz, R. — Tue, 27 Oct 2009 11:29:17 PDT

Background. Substantial data indicate greater muscle fatigue in individuals with spinal cord injury (SCI) compared with healthy control subjects when tested by using electrical stimulation protocols. Few studies have investigated the extent of volitional fatigue in motor incomplete SCI. Methods. Repeated, maximal volitional effort (MVE) isometric contractions of the knee extensors (KE) were performed in 14 subjects with a motor incomplete SCI and in 10 intact subjects. Subjects performed 20 repeated, intermittent MVEs (5 seconds contraction/5 seconds rest) with KE torques and thigh electromyographic (EMG) activity recorded. Results. Peak KE torques declined to 64% of baseline MVEs with repeated efforts in control subjects. Conversely, subjects with SCI increased peak torques during the first 5 contractions by 15%, with little evidence of fatigue after 20 repeated efforts. Increases in peak KE torques and the rate of torque increase during the first 5 contractions were attributed primarily to increases in quadriceps EMG activity, but not to decreased knee flexor co-activation. The observed initial increases in peak torque were dependent on the subject’s volitional activation and were consistent on the same or different days, indicating little contribution of learning or accommodation to the testing conditions. Sustained MVEs did not elicit substantial increases in peak KE torques as compared to repeated intermittent efforts. Conclusions. These data revealed a marked divergence from expected results of increased fatigability in subjects with SCI, and may be a result of complex interactions between mechanisms underlying spastic motor activity and changes in intrinsic motoneuron properties.

Subjective Fatigue, Mental Effort, and Attention Deficits After Severe Traumatic Brain Injury

Belmont, A., Agar, N., Azouvi, P. — Tue, 27 Oct 2009 11:29:17 PDT

Objective. Although fatigue is one of the most frequent complaints of individuals with traumatic brain injury (TBI), its mechanisms remain poorly understood. The objective of this study was to assess the relationships between subjective mental fatigue, mental effort, attention deficits, and mood after severe TBI. Methods and participants. A total of 27 patients with subacute/chronic severe TBI were compared with matched controls. Patients first rated their baseline subjective fatigue on the Fatigue Severity Scale (FSS) and on the Visual Analog Scale for Fatigue (VAS-F). Mood was assessed with the Montgomery and Asberg Depression Rating Scale (MADRS). Then, they performed a long-duration selective attention task, separated in 2 parts. Fatigue on the VAS-F was assessed again between the 2 parts and at the end of the attention task. Patients were also asked to rate on the VAS the level of subjective mental effort devoted to the task. Results. Patients reported a higher baseline fatigue than controls. They performed significantly poorer on the selective attention task. Significant correlations were found in the group with TBI between attention performance, mental effort, and subjective fatigue. Depression did not significantly correlate with fatigue. Discussion and conclusions. These findings suggest that patients with more severe attention deficits have to produce higher levels of mental effort to manage a complex task, which may increase subjective fatigue, in line with the coping hypothesis.

Comparison of Bilateral and Unilateral Training for Upper Extremity Hemiparesis in Stroke

Stoykov, M. E., Lewis, G. N., Corcos, D. M. — Tue, 27 Oct 2009 11:29:17 PDT

Background. Upper extremity hemiparesis is the most common poststroke disability. Longitudinal studies have indicated that 30% to 66% of stroke survivors do not have full arm function 6 months poststroke. One promising treatment approach is bilateral training. To date, no randomized, blinded study of efficacy comparing 2 groups (bilateral training vs unilateral training) using analogous tasks has been performed in chronic stroke survivors with moderate upper extremity impairment. Objective. To compare the effectiveness of bilateral training with unilateral training for individuals with moderate upper limb hemiparesis. The authors hypothesized that bilateral training would be superior to unilateral training in the proximal extremity but not the distal one. Methods. Twenty-four subjects participated in a randomized, single-blind training study. Subjects in the bilateral group (n = 12) practiced bilateral symmetrical activities, whereas the unilateral group (n = 12) performed the same activity with the affected arm only. The activities consisted of reaching-based tasks that were both rhythmic and discrete. The Motor Assessment Scale (MAS), Motor Status Scale (MSS), and muscle strength were used as outcome measures. Assessments were administered at baseline and posttraining by a rater blinded to group assignment. Results. Both groups had significant improvements on the MSS and measures of strength. The bilateral group had significantly greater improvement on the Upper Arm Function scale (a subscale of the MAS-Upper Limb Items). Conclusion. Both bilateral and unilateral training are efficacious for moderately impaired chronic stroke survivors. Bilateral training may be more advantageous for proximal arm function.

13th International Symposium on Neural Regeneration (ISNR)

Tue, 27 Oct 2009 11:29:17 PDT

ASNR/WFNR News

Wed, 16 Sep 2009 16:13:55 PDT

Multicenter Randomized Trial of Robot-Assisted Rehabilitation for Chronic Stroke: Methods and Entry Characteristics for VA ROBOTICS

Wed, 16 Sep 2009 16:13:55 PDT

Background. Chronic upper extremity impairment due to stroke has significant medical, psychosocial, and financial consequences, but few studies have examined the effectiveness of rehabilitation therapy during the chronic stroke period. Objective. To test the safety and efficacy of the MIT-Manus robotic device for chronic upper extremity impairment following stroke. Methods. The VA Cooperative Studies Program initiated a multicenter, randomized, controlled trial in November 2006 (VA ROBOTICS). Participants with upper extremity impairment ≥6 months poststroke were randomized to robot-assisted therapy (RT), intensive comparison therapy (ICT), or usual care (UC). RT and ICT consisted of three 1-hour treatment sessions per week for 12 weeks. The primary outcome was change in the Fugl-Meyer Assessment upper extremity motor function score at 12 weeks relative to baseline. Secondary outcomes included the Wolf Motor Function Test and the Stroke Impact Scale. Results. A total of 127 participants were randomized: 49 to RT, 50 to ICT, and 28 to UC. The majority of participants were male (96%), with a mean age of 65 years. The primary stroke type was ischemic (85%), and 58% of strokes occurred in the anterior circulation. Twenty percent of the participants reported a stroke in addition to their index stroke. The average time from the index stroke to enrollment was 56 months (range, 6 months to 24 years). The mean Fugl-Meyer score at entry was 18.9. Conclusions. VA ROBOTICS demonstrates the feasibility of conducting multicenter clinical trials to rigorously test new rehabilitative devices before their introduction to clinical practice. The results are expected in early 2010.

Randomized Clinical Trial of Balance-Based Torso Weighting for Improving Upright Mobility in People with Multiple Sclerosis

Widener, G. L., Allen, D. D., Gibson-Horn, C. — Wed, 16 Sep 2009 16:13:55 PDT

Background. Torso weighting has sometimes been effective for improving upright mobility in people with multiple sclerosis, but parameters for weighting have been inconsistent. Objective. To determine whether balance-based torso weighting (BBTW) has immediate effects on upright mobility in people with multiple sclerosis. Methods. This was a 2-phase randomized clinical trial. In phase 1, 36 participants were randomly assigned to experimental and control groups. In phase 2, the control group was subsequently randomized into 2 groups with alternate weight-placement. Tests of upright mobility included: timed up and go (TUG), sharpened Romberg, 360-degree turns, 25-foot walk, and computerized platform posturography. Participants were tested at baseline and again with weights placed according to group membership. In both phases, a physical therapist assessed balance for the BBTW group and then placed weights to decrease balance loss. In phase 1, the control group had no weights placed. In phase 2, the alternate treatment group received standard weight placement of 1.5% body weight. Results. People with BBTW showed a significant improvement in the 25-foot walk (P = .01) over those with no weight, and the TUG (P = .01) over those with standard weight placement. BBTW participants received an average of 0.5 kg, less than 1.5% of any participant’s body weight. Conclusion. BBTW can have immediate advantages over a nonweighted condition for gait velocity and over a standardized weighted condition for a functional activity in people with multiple sclerosis (MS) who are ambulatory but have balance and mobility abnormalities.

Mirror Therapy in Complex Regional Pain Syndrome Type 1 of the Upper Limb in Stroke Patients

Cacchio, A., De Blasis, E., De Blasis, V., Santilli, V., Spacca, G. — Wed, 16 Sep 2009 16:13:55 PDT

Background. Complex regional pain syndrome type 1 (CRPSt1) of the upper limb is a painful and debilitating condition, frequent after stroke, and interferes with the rehabilitative process and outcome. However, treatments used for CRPSt1 of the upper limb are limited. Objective. This randomized controlled study was conducted to compare the effectiveness on pain and upper limb function of mirror therapy on CRPSt1 of upper limb in patients with acute stroke. Methods. Of 208 patients with first episode of unilateral stroke admitted to the authors’ rehabilitation center, 48 patients with CRPSt1 of the affected upper limb were enrolled in a randomized controlled study, with a 6-month follow-up, and assigned to either a mirror therapy group or placebo control group. The primary end points were a reduction in the visual analogue scale score of pain at rest, on movement, and brush-induced tactile allodynia. The secondary end points were improvement in motor function as assessed by the Wolf Motor Function Test and Motor Activity Log. Results. The mean scores of both the primary and secondary end points significantly improved in the mirror group (P < .001). No statistically significant improvement was observed in any of the control group values (P > .001). Moreover, statistically significant differences after treatment (P < .001) and at the 6-month follow-up were found between the 2 groups. Conclusions. The results indicate that mirror therapy effectively reduces pain and enhances upper limb motor function in stroke patients with upper limb CRPSt1.

Cortical Activity in Relation to Velocity Dependent Movement Resistance in the Flexor Muscles of the Hand After Stroke

Wed, 16 Sep 2009 16:13:55 PDT

Background. The role of spinal networks in spasticity is well investigated, but little is known about possible cortical contributions to hypertonicity across a joint. Objective. The authors hypothesized that there are cortical activation correlates to spasticity in stroke patients with increased muscle tone of the wrist flexors. Methods. Stroke patients and controls were scanned using event-related functional magnetic resonance imaging (fMRI) during slow and fast passive movements of the hand with simultaneous recording of passive movement resistance (PMR). Results. Control participants had velocity-dependent activity (greater for slow than fast movements) of 2 types, in areas that were also more active in passive movement than rest (eg, relative increase in activation in contralateral S1 and M1 was greater for slow than fast) and in areas that were also more active in rest than passive movement (eg, relative decrease in activation in occipital areas and ipsilateral precentral gyrus was greater for fast than slow). In the patient group, with large interindividual variation of spasticity, we found an association between PMR and the velocity-dependent activity in ipsilateral S1 (area 3b) extending into M1 (area 4a), contralateral cingulate cortex, supplementary motor area (SMA), Brodmann Area 45 (BA 45), and cerebellum. Post hoc testing also revealed a similar correlation in S1 and M1 bilaterally in controls and showed that patients activated ipsilateral S1 and M1 more than controls in the velocity-dependent condition. Conclusions. The findings suggest the possibility of ipsilateral sensory and motor cortical involvement in spasticity after stroke, which warrant further investigation.

Sense of Effort Determines Lower Limb Force Production During Dynamic Movement in Individuals With Poststroke Hemiparesis

Simon, A. M., Kelly, B. M., Ferris, D. P. — Wed, 16 Sep 2009 16:13:55 PDT

Objective. This study’s purpose was to determine if individuals who have had a stroke primarily use sense of effort to gauge force production during static and dynamic lower limb contractions. If relying on sense of effort while attempting to generate equal limb forces, participants should produce equal percentages of their maximum voluntary strength rather than equal absolute forces in their limbs. Methods. Ten stroke participants performed isometric and isotonic lower limb extensions on an exercise machine. Results. When participants attempted to produce equal bilateral isometric forces, there was a significant difference in absolute force between limbs (ANOVA, P < .0001) but no significant difference when force was normalized to each limb’s maximum voluntary contraction (MVC) force (P = .5129). During bilateral isotonic contractions, participants produced less absolute force in their paretic limb (P = .0005) and less relative force in their paretic limb (normalized to MVC force) when participants were given no instructions on how to perform the extension (P = .0002). When participants were instructed to produce equal forces, there was no significant difference between relative forces in the 2 limbs (P = .2111). Conclusions. For both isometric and isotonic conditions hemiparetic participants relied primarily on sense of effort, rather than proprioceptive feedback, for gauging lower limb force production. This outcome indicates that sense of effort is the major factor determining force production during movements. Lower limb rehabilitation therapies should not only train strength in the paretic limb but should also train patients to recalibrate force-scaling abilities to improve function.

Is Visuospatial Hemineglect Longitudinally Associated with Postural Imbalance in the Postacute Phase of Stroke?

Wed, 16 Sep 2009 16:13:55 PDT

Introduction. The purpose of this study was to determine the longitudinal association of visuospatial hemineglect with postural imbalance in postacute stroke patients and to establish whether this relationship is confounded by other determinants. Methods. A prospective cohort study of 53 postacute stroke patients consecutively admitted for inpatient rehabilitation was conducted. Transfers and standing balance were assessed with the Berg Balance Scale (BBS) and walking balance with the Functional Ambulation Categories (FAC). Repeated measurements took place at baseline (36.6 ± 10.4 days after stroke) and after 6 and 12 weeks. Visuospatial hemineglect was assessed by an asymmetry index, derived from the Letter and Star Cancellation Tests. Random coefficient analysis was used to analyze the longitudinal impact of visuospatial hemineglect on the BBS and FAC. The association between hemineglect and outcome was corrected for the following potential confounders: age, severity of paresis of the lower leg, sensory deficits, and presence of hypertonia. A covariate was considered to be a confounder if the regression coefficient of hemineglect on outcome changed by >15%. Results. Visuospatial hemineglect was significantly associated with BBS and FAC. The relation between hemineglect and both BBS and FAC was confounded by severity of paresis of the lower limb. After controlling for severity of paresis, hemineglect remained independently associated with BBS, whereas the association with FAC lost significance. Conclusion. Visuospatial hemineglect is an independent covariate that is longitudinally associated with postural imbalance after stroke. These findings suggest that hemineglect is an important factor for controlling static and dynamic standing balance during the first months poststroke.

The Use of a Biplot in Studying Outcomes After Stroke

Wed, 16 Sep 2009 16:13:55 PDT

Background and purpose. This study aimed to unravel the multidimensional profile of stroke outcomes by investigating the global correlation structure of motor, functional, and emotional problems of patients, as well as their caregivers’ strain, at 6 months after stroke. Potential differential associations based on patients’ level of functioning on admission to the rehabilitation center were analyzed. Methods. Data were collected within the CERISE-study (Collaborative Evaluation of Rehabilitation in Stroke across Europe). Six months after stroke, the Rivermead Motor Assessment (RMA), Extended Activities of Daily Living (EADL), Hospital Anxiety and Depression Scale—Anxiety (HADS-A) and Hospital Anxiety and Depression Scale—Depression (HADS-D), EuroQol—Health State (EQ-HS), EuroQol—Visual Analogue Scale (EQ-VAS), and Caregiver Strain Index (CSI) were administered. Patients were classified into 3 categories according to their Barthel Index (BI) score on admission to the rehabilitation center. Principal component analysis was carried out, and a biplot was constructed. Results. Data were available on 510 patients. One cluster was formed by RMA and EADL, and a second one by HADS-A, HADS-D, and EQ-VAS. EQ-HS was situated between these two. CSI formed a third dimension. Patients with low BI scores on admission to the rehabilitation center had higher HADS-A and HADS-D scores 6 months after stroke. High BI scores were associated with large variations in HADS-A and HADS-D scores. Conclusions. This novel biplot strategy for rehabilitation studies revealed 2 clusters: one of motor/functional problems and one of emotional problems. Patients with mild functional deficit measured on admission to the rehabilitation center can suffer from mild to severe anxiety and depression at 6 months poststroke. Screening for emotional disorders in all patients is recommended.

The Short-Term Effects of Different Cueing Modalities on Turn Speed in People with Parkinson's Disease

Wed, 16 Sep 2009 16:13:55 PDT

Background. Turning has been associated with instability, falls, and freezing in people with Parkinson’s disease (PD). Objective. To investigate the effect of different modalities of rhythmic cueing on the duration of a functional turn in freezers and nonfreezers. Methods. A total of 133 patients with idiopathic PD while in the on phase of the medication cycle participated in this study as part of a subanalysis from the RESCUE trial. The effect of 3 different cue modalities on functional turning performance was investigated, involving a 180° turn while picking up a tray. Time to perform this task was measured using an activity monitor. Tests were performed without cues and with auditory, visual, and somatosensory cues delivered in a randomized order at preferred straight-line stepping frequency. Results. Cueing (all types) increased the speed of the turn in all subjects. There was no difference between turn performance of freezers and nonfreezers in cued and noncued conditions. Auditory cues made turning significantly faster than visual cues (P < .01) but not compared with somatosensory cues, except in nonfreezers. There was a short-term carryover in the final noncued trial. Conclusions. Rhythmical cueing yielded faster performance of a functional turn in both freezers and nonfreezers. This may be explained by enhancing attentional mechanisms during turning. Although no harmful effects were recorded, the safety of cueing for turning as a therapeutic strategy needs further study.

A Comparison Between Electromyography-Driven Robot and Passive Motion Device on Wrist Rehabilitation for Chronic Stroke

Hu, X. L., Tong, K.-y., Song, R., Zheng, X. J., Leung, W. W. F. — Wed, 16 Sep 2009 16:13:55 PDT

Background. The effect of using robots to improve motor recovery has received increased attention, even though the most effective protocol remains a topic of study. Objective . The objective was to compare the training effects of treatments on the wrist joint of subjects with chronic stroke with an interactive rehabilitation robot and a robot with continuous passive motion. Methods. This study was a single-blinded randomized controlled trial with a 3-month follow-up. Twenty-seven hemiplegic subjects with chronic stroke were randomly assigned to receive 20-session wrist training with a continuous electromyography (EMG)-driven robot (interactive group, n = 15) and a passive motion device (passive group, n = 12), completed within 7 consecutive weeks. Training effects were evaluated with clinical scores by pretraining and posttraining tests (Fugl-Meyer Assessment [FMA] and Modified Ashworth Score [MAS]) and with session-by-session EMG parameters (EMG activation level and co-contraction index). Results. Significant improvements in FMA scores (shoulder/elbow and wrist/hand) were found in the interactive group (P < .05). Significant decreases in the MAS were observed in the wrist and elbow joints for the interactive group and in the wrist joint for the passive group (P < .05). These MAS changes were associated with the decrease in EMG activation level of the flexor carpi radialis and the biceps brachii for the interactive group (P < .05). The muscle coordination on wrist and elbow joints was improved in the interactive groups in the EMG co-contraction indexes across the training sessions (P < .05). Conclusions. The interactive treatment improved muscle coordination and reduced spasticity after the training for both the wrist and elbow joints, which persisted for 3 months. The passive mode training mainly reduced the spasticity in the wrist flexor.

Reduced Sway During Dual Task Balance Performance Among People With Stroke at 6 and 12 Months After Discharge From Hospital

Hyndman, D., Pickering, R. M., Ashburn, A. — Wed, 16 Sep 2009 16:13:55 PDT

Background. Cognitive motor interference has been linked to poor recovery and falls. Little is known about recovery of dual-task balance ability poststroke. Methods. In this experimental study, postural sway was examined while standing on a force plate in preferred stance, with feet together, and with eyes closed, at 6 and 12 months postdischarge from hospital. Sway was assessed in isolation and while participants performed a cognitive (shopping list) task. Results . Seventy-six people with stroke (mean age 67 years; range, 21-91 years) took part. Fifty-four completed both assessments. When compared with the single task, sway during the dual-task condition was significantly lower in both the medial lateral (ML) and anterior posterior (AP) directions (both P < .0001). Sway in both directions was influenced by the difficulty of the balance task (both P < .0001). There was a trend of reduced sway at the 12-month assessment compared with the 6-month assessment: significant only in the ML direction (P = .0056). Repeat fallers swayed more than non—repeat fallers, with increases of 48% and 44% in the ML (P = .0262) and AP (P = .0134) directions, respectively. No significant variation in the dual-task reduction in sway was found: the dual-task effect was remarkably consistent over all the conditions tested, particularly in the AP direction. Conclusions. Sway decreased under dual-task conditions and changed as the difficulty of the balance task changed. Stroke fallers swayed more than nonfallers and there was evidence of a reduction in sway over time, particularly in the ML direction.

Grip Force Control in Individuals With Multiple Sclerosis

Iyengar, V., Santos, M. J., Ko, M., Aruin, A. S. — Wed, 16 Sep 2009 16:13:55 PDT

Background. Appropriate regulation of grip force is essential in performance of various activities of daily living such as drinking, eating, buttoning a shirt, and so on. The extent to which individuals with multiple sclerosis (MS) are able to regulate grip forces while performing elements of the activities of daily living is largely unknown. Objective. To investigate how individuals with MS control grip force during performance of functional tasks. Methods. This study evaluated the grip force control in selected individuals with MS (n = 9) and healthy control subjects (n = 9) while they performed the task of lifting and placing an instrumented object on a shelf and the task of lifting the object and bringing it close to the mouth to mimic drinking. The grip forces, object acceleration, force ratio, and time lag were recorded and analyzed. Results. The individuals with MS used significantly larger peak grip force and force ratio than control subjects while performing both tasks and for both hands. In addition, the time lag between the peaks of grip and load forces was significantly longer in individuals with MS. Conclusion. The application of excessive grip force could predispose individuals with MS to additional fatigue and musculoskeletal overuse trauma. Rehabilitation protocols for the MS population may need to account for increased levels of grip force applied during the performance of functional tasks.

Progressive Shoulder Abduction Loading is a Crucial Element of Arm Rehabilitation in Chronic Stroke

Ellis, M. D., Sukal-Moulton, T., Dewald, J. P. A. — Wed, 16 Sep 2009 16:13:55 PDT

Background. Total reaching range of motion (work area) diminishes as a function of shoulder abduction loading in the paretic arm in individuals with chronic hemiparetic stroke. This occurs when reaching outward against gravity or during transport of an object. Objectives. This study implements 2 closely related impairment-based interventions to identify the effect of a subcomponent of reaching exercise thought to be a crucial element in arm rehabilitation. Methods. A total of 14 individuals with chronic moderate to severe hemiparesis participated in the participant-blinded, randomized controlled study. The experimental group progressively trained for 8 weeks to actively support the weight of the arm, up to and beyond, while reaching to various outward targets. The control group practiced the same reaching tasks with matched frequency and duration with the weight of the arm supported. Work area and isometric strength were measured before and after the intervention. Results. Change scores for work area at 9 loads were calculated for each group. Change scores were significantly larger for the experimental group indicating a larger increase in work area, especially shoulder abduction loads equivalent to those experienced during object transport. Changes in strength were not found within or between groups. Conclusions. Progressive shoulder abduction loading can be utilized to ameliorate reaching range of motion against gravity. Future work should investigate the dosage response of this intervention, as well as test whether shoulder abduction loading can augment other therapeutic techniques such as goal-directed functional task practice and behavioral shaping to enhance real-world arm function.

Letter to the Editor

Stokic, D. S., Yablon, S. A., Blicher, J. U. — Wed, 16 Sep 2009 16:13:55 PDT

ASNR/WFNR News

Wed, 26 Aug 2009 09:03:48 PDT

Collaborative Models for Translational Neuroscience and Rehabilitation Research

Dobkin, B. H. — Wed, 26 Aug 2009 09:03:48 PDT

Little formal research has been conducted on strategies to structure basic, preclinical, and clinical research to increase the likelihood of discovering efficacious interventions for patients with neurological diseases. How academic research is organized and funded by government agencies and foundations seems likely to affect the quality and rate of production of valued therapeutic agents. Few models for translational biomedical research, however, have been defined and no strategies have been compared. Given the narrow width of expertise and laboratory capacity of individual investigators, the complexity of identifying and manipulating mechanisms of disease components over time, and the demand for solutions from society, our continued reliance on funding therapeutic discovery through standalone investigators and projects seems counterproductive. Models are described for funding collaborations of basic and clinical scientists to work in iterative, adaptable, cross-disciplinary interactions around key progress-limiting questions. Problem-oriented collaborations require leadership, incentives, trust, ongoing assessment, and an efficient infrastructure that overcomes barriers. These models are as testable as the hypotheses that drive scientific research.

Interhemispheric Competition After Stroke: Brain Stimulation to Enhance Recovery of Function of the Affected Hand

Nowak, D. A., Grefkes, C., Ameli, M., Fink, G. R. — Wed, 26 Aug 2009 09:03:48 PDT

Background and purpose. Within the concept of interhemispheric competition, technical modulation of the excitability of motor areas in the contralesional and ipsilesional hemisphere has been applied in an attempt to enhance recovery of hand function following stroke. This review critically summarizes the data supporting the use of novel electrophysiological concepts in the rehabilitation of hand function after stroke. Summary of review. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are powerful tools to inhibit or facilitate cortical excitability. Modulation of cortical excitability may instantaneously induce plastic changes within the cortical network of sensorimotor areas, thereby improving motor function of the affected hand after stroke. No significant adverse effects have been noted when applying brain stimulation in stroke patients. To date, however, the clinical effects are small to moderate and short lived. Future work should elucidate whether repetitive administration of rTMS or tDCS over several days and the combination of these techniques with behavioral training (ie, physiotherapy) could result in an enhanced effectiveness. Conclusion. Brain stimulation is a safe and promising tool to induce plastic changes in the cortical sensorimotor network to improve motor behavior after stroke. However, several methodological issues remain to be answered to further improve the effectiveness of these new approaches.

The Relationships Between the Unified Parkinson's Disease Rating Scale and Lower Extremity Functional Performance in Persons With Early-Stage Parkinson's Disease

Song, J., Fisher, B. E., Petzinger, G., Wu, A., Gordon, J., Salem, G. J. — Wed, 26 Aug 2009 09:03:48 PDT

Background. The Unified Parkinson’s Disease Rating Scale (UPDRS) is the "gold standard" assessment tool for characterizing impairments in persons with Parkinson’s disease (PD); however, this scale’s ability to predict functional capabilities across different functional tasks has not been adequately assessed in persons with early-stage PD. Methods. Thirty persons with PD within 3 years of diagnosis and without motor fluctuation performed self-selected walking, fast walking, and sit-to-stand and stair-climbing tasks. Pearson’s correlation coefficients were used to calculate correlations with a standard UPDRS examination (P < .05). Simple linear regression models were used to fit each functional performance outcome measure with the UPDRS total predictor scores. Results. The correlations between the UPDRS motor (section III), UPDRS total scores, and all timed functional performance measures were fair to good (range, 0.45-0.57). Conversely, only greater self-selected time to walk 50 ft correlated with a higher UPDRS activities of daily living (II) score ( r = .386; P < .05). Conclusions. The UPDRS motor (III) and total scores may be good predictors of overall lower extremity function in persons with early-stage PD. Understanding the relationships between UPDRS scores and functional capabilities may allow clinicians to better quantify early physical functioning, longitudinally assess disease progression, and assess the efficacy of interventions.

Minimal Detectable Change Scores for the Wolf Motor Function Test

Fritz, S. L., Blanton, S., Uswatte, G., Taub, E., Wolf, S. L. — Wed, 26 Aug 2009 09:03:48 PDT

Background. The Wolf Motor Function Test (WMFT) is an impairment-based test whose psychometrics have been examined by previous reliability and validity studies. Standards for evaluating whether a given change is meaningful, however, have not yet been addressed. Objectives. To determine the standard error of measurement (SEM) and minimal detectable change (MDC) for the WMFT. Methods. Data were collected from 6 university laboratories that participated in the EXCITE national clinical trial and included 96 individuals with sub-acute stroke (3—9 months). Measurements were made by blinded evaluators who were trained and standardized to administer the WMFT, which was completed on 2 occasions 2 weeks apart. No intervention was given between testing sessions. Results. The WMFT Performance Time score has a SEM of 0.2 seconds and a MDC₉₅ of 0.7 seconds. The individual task timed items MDC₉₅ ranged from 1.0 second (turn key in lock) to 3.4 seconds (reach and retrieve) with individual task items demonstrating notablly higher variability than the average WMFT Performance Time. The average WMFT Functional Ability Scale SEM and MDC₉₅ is 0.1 points. Conclusions. When assessing the effect of a therapeutic intervention, if an individual experiences an amount of change equal to or greater than the MDC, then one may be 95% confident that this margin of change is truly larger than measurement error and not a chance result. Thus, the determination of SEM and MDC in outcome assessments allows researchers and clinicians to distinguish which results are actual differences versus which results are simply changes resulting from error or chance.

Rhythm Perturbations in Acoustically Paced Treadmill Walking After Stroke

Wed, 26 Aug 2009 09:03:48 PDT

Background. In rehabilitation, acoustic rhythms are often used to improve gait after stroke. Acoustic cueing may enhance gait coordination by creating a stable coupling between heel strikes and metronome beats and provide a means to train the adaptability of gait coordination to environmental changes, as required in everyday life ambulation. Objective. To examine the stability and adaptability of auditory—motor synchronization in acoustically paced treadmill walking in stroke patients. Methods. Eleven stroke patients and 10 healthy controls walked on a treadmill at preferred speed and cadence under no metronome, single-metronome (pacing only paretic or nonparetic steps), and double-metronome (pacing both footfalls) conditions. The stability of auditory—motor synchronization was quantified by the variability of the phase relation between footfalls and beats. In a separate session, the acoustic rhythms were perturbed and adaptations to restore auditory—motor synchronization were quantified. Results. For both groups, auditory—motor synchronization was more stable for double-metronome than single-metronome conditions, with stroke patients exhibiting an overall weaker coupling of footfalls to metronome beats than controls. The recovery characteristics following rhythm perturbations corroborated the stability findings and further revealed that stroke patients had difficulty in accelerating their steps and instead preferred a slower-step response to restore synchronization. Conclusions. In gait rehabilitation practice, the use of acoustic rhythms may be more effective when both footfalls are paced. In addition, rhythm perturbations during acoustically paced treadmill walking may not only be employed to evaluate the stability of auditory—motor synchronization but also have promising implications for evaluation and training of gait adaptations in neurorehabilitation practice.

Hemisphere Specific Impairments in Reach-to-Grasp Control After Stroke: Effects of Object Size

Tretriluxana, J., Gordon, J., Fisher, B. E., Winstein, C. J. — Wed, 26 Aug 2009 09:03:48 PDT

Background and objective. The authors investigated hemispheric specialization for the visuomotor transformation of grasp preshaping and the coordination between transport and grasp in individuals poststroke. Based on a bilateral model, the authors hypothesized that after unilateral stroke there would be hemisphere-specific deficits revealed by the ipsilesional limb. Methods. Right or left stroke and age- and limb-matched nondisabled participants performed rapid reach-to-grasp of 3 sized objects. The authors quantified grasp preshaping as the correlation between initial aperture velocity and peak aperture, and peak aperture and object diameter. A cross correlation analysis using transport velocity and aperture size was performed to quantify transport-grasp coordination. All statistical tests for hemisphere-specific deficits involved comparisons between each stroke group and the matched nondisabled group. Results. Overall, the right stroke group, but not left stroke group, demonstrated prolonged movement time. For grasp preshaping there was a higher correlation between initial aperture velocity and peak aperture for the right stroke group and a lower correlation between peak aperture and object diameter for the left stroke group. For transport-grasp coordination the correlation between transport velocity and aperture size was higher for the left stroke group and lower for the right stroke group, which also demonstrated a higher standard deviation of time lag. Conclusions. After left stroke, there was deficient scaling of grasp preshaping and stronger transport-grasp coordination. In contrast, after right stroke, grasp preshaping began earlier and transport-grasp coordination was weaker. Together, these hemisphere-specific deficits suggest a left hemisphere specialization for the visuomotor transformation of grasp preshaping and a right hemisphere specialization for transport-grasp coordination.

Progression of Pathological Changes in the Middle Cerebellar Peduncle by Diffusion Tensor Imaging Correlates With Lesser Motor Gains After Pontine Infarction

Wed, 26 Aug 2009 09:03:48 PDT

Background. Wallerian degeneration in pyramidal tract following supratentorial stroke has been detected by some studies using diffusion tensor imaging (DTI), but the Wallerian degeneration in middle cerebellar peduncle after pontine infarction and its potential clinical significance remain to be confirmed. Methods. Seventeen patients with a recent focal pontine infarct underwent 3 DTIs at week 1 (W1), week 4 (W4), and week 12 (W12) after onset. Seventeen age-matched and gender-matched controls underwent DTI one time. Mean diffusivity and fractional anisotropy (FA) were measured in the basis pontis and bilateral middle cerebellar peduncles. Neurological deficit, motor deficit, functional independence, and limbs ataxia were assessed with the National Institutes of Health (NIH) Stroke Scale, Fugl-Meyer scale, Barthel Index, and the second part of International Cooperative Ataxia Rating Scale. Results. FA values at the bilateral middle cerebellar peduncles decreased significantly from W1 to W12 progressively (P < .01). The patients improved on the NIH Stroke Scale, Fugl-Meyer scale, and Barthel Index over time (P < .01). Greater absolute value of percentage reduction of FA at the bilateral middle peduncles, however, was associated with the less absolute value of percentage reduction of the NIH Stroke Scale and less increase in the Fugl-Meyer scale, as well as greater ataxia over time. Conclusions. Wallerian degeneration in the middle cerebellar peduncle revealed by DTI may hinder the process of neurological recovery following a focal pontine infarct.

Comparison of the Effect of Two Driving Retraining Programs on On-Road Performance After Stroke

Wed, 26 Aug 2009 09:03:48 PDT

Background. Several driving retraining programs have been developed to improve driving skills after stroke. Those programs rely on different rehabilitation concepts. Objectives. The current study sought to examine the specific carryover effect of driving skills of a comprehensive training program in a driving simulator when compared with a cognitive training program. Methods. Further analysis from a previous randomized controlled trial that investigated the effect of simulator training on driving after stroke. Forty-two participants received simulator-based driving training, whereas 41 participants received cognitive training for 15 hours. Overall performance in the on-road test and each of its 13 items were compared between groups immediately posttraining and at 6 months poststroke. Results. Generalized estimating equation analysis showed that the total score on the on-road test and each item score improved significantly over time for both groups. Those who received driving simulator training achieved better results when compared with the cognitive training group in the overall on-road score and the items of anticipation and perception of signs, visual behavior and communication, quality of traffic participation, and turning left. Most of the differences in improvement between the 2 interventions were observed at 6 months poststroke. Conclusions . Contextual training in a driving simulator appeared to be superior to cognitive training to treat impaired on-road driving skills after stroke. The effects were primarily seen in visuointegrative driving skills. Our results favor the implementation of driving simulator therapy in the conventional rehabilitation program of subacute stroke patients with mild deficits.

Best Conventional Therapy Versus Modular Impairment-Oriented Training for Arm Paresis After Stroke: A Single-Blind, Multicenter Randomized Controlled Trial

Platz, T., van Kaick, S., Mehrholz, J., Leidner, O., Eickhof, C., Pohl, M. — Wed, 26 Aug 2009 09:03:48 PDT

Background. The study investigated whether passive splinting or active motor training as either individualized best conventional therapy or as standardized impairment-oriented training (IOT) would be superior in promoting motor recovery in subacute stroke patients with mildly or severely paretic arms. Methods. A total of 148 anterior circulation ischemic stroke patients were randomly assigned to 45 minutes of additional daily arm therapy over 3 to 4 weeks as either ( a) passive therapy with inflatable splints or active arm motor therapy as either (b) individualized best conventional therapy (CONV) or ( c) standardized IOT, that is Arm BASIS training for severe paresis or Arm Ability training for mild paresis. Main outcome measures included the following: Fugl-Meyer arm motor score (severely paretic arms) and the TEMPA time scores (mildly affected arms). Pre—post (immediate effects) and pre—4 weeks follow-up analyses (long-term effects) were performed. Results. Overall improvements were documented (mean baseline and change scores efficacy: Fugl-Meyer, arm motor scores, 24.4, +9.1 points; TEMPA, 119, –26.6 seconds; P < .0001), but with no differential effects between splint therapy and the combined active motor rehabilitation groups. Both efficacy and effectiveness analyses indicated, however, bigger immediate motor improvements after IOT as compared with best conventional therapy (Fugl-Meyer, arm motor scores: IOT +12.3, CONV +9.2 points; TEMPA: IOT –31.1 seconds, CONV –20.5 seconds; P = .0363); for mildly affected patients long-term effects could also be substantiated. Conclusions. Specificity of active training seemed more important for motor recovery than intensity (therapy time). The comprehensive modular IOT approach promoted motor recovery in patients with either severe or mild arm paresis.

Biomechanical Analysis of Functional Electrical Stimulation on Trunk Musculature During Wheelchair Propulsion

Yang, Y.-S., Koontz, A. M., Triolo, R. J., Cooper, R. A., Boninger, M. L. — Wed, 26 Aug 2009 09:03:48 PDT

Background. The objective of this study was to examine how surface electrical stimulation of trunk musculature influences the kinematic, kinetic, and metabolic characteristics, as well as shoulder muscle activity, during wheelchair propulsion. Methods. Eleven participants with spinal cord injury propelled their own wheelchairs on a dynamometer at a speed of 1.3 m/s for three 5-minute trials. During a propulsion trial, 1 of 3 stimulation levels (HIGH, LOW, and OFF) was randomly applied to the participant’s abdominal and back muscle groups with a surface functional electrical stimulation device. Propulsion kinetics, trunk kinematics, metabolic responses, and surface electromyographic (EMG) activity of 6 shoulder muscles were collected synchronously. Kinetic, kinematic, and EMG variables were recorded during 3 time intervals (30 seconds each) within a 5-minute trial. Metabolic variables were recorded through the entire 5-minute trial. Results. Participants with HIGH stimulation increased their gross mechanical efficiency (P = .05) during wheelchair propulsion. No differences were found in shoulder EMG activity, energy expenditure, and trunk motion between stimulation levels. Conclusion. Functional electrical stimulation on the trunk musculature has potential advantages in helping manual wheelchair users with spinal cord injury improve propulsion efficiency without placing additional demands on shoulder musculature.

Community-Based Adaptive Physical Activity Program for Chronic Stroke: Feasibility, Safety, and Efficacy of the Empoli Model

Wed, 26 Aug 2009 09:03:48 PDT

Objective. To determine whether Adaptive Physical Activity (APA-stroke), a community-based exercise program for participants with hemiparetic stroke, improves function in the community. Methods. Nonrandomized controlled study in Tuscany, Italy, of participants with mild to moderate hemiparesis at least 9 months after stroke. Forty-nine participants in a geographic health authority (Empoli) were offered APA-stroke (40 completed the study). Forty-four control participants in neighboring health authorities (Florence and Pisa) received usual care (38 completed the study). The APA intervention was a community-based progressive group exercise regimen that included walking, strength, and balance training for 1 hour, thrice a week, in local gyms, supervised by gym instructors. No serious adverse clinical events occurred during the exercise intervention. Outcome measures included the following: 6-month change in gait velocity (6-Minute Timed Walk), Short Physical Performance Battery (SPPB), Berg Balance Scale, Stroke Impact Scale (SIS), Barthel Index, Hamilton Rating Scale for Depression, and Index of Caregivers Strain. Results. After 6 months, the intervention group improved whereas controls declined in gait velocity, balance, SPPB, and SIS social participation domains. These between-group comparisons were statistically significant at P < .00015. Individuals with depressive symptoms at baseline improved whereas controls were unchanged (P < .003). Oral glucose tolerance tests were performed on a subset of participants in the intervention group. For these individuals, insulin secretion declined 29% after 6 months (P = .01). Conclusion. APA-stroke appears to be safe, feasible, and efficacious in a community setting.

Split-Belt Treadmill Adaptation Transfers to Overground Walking in Persons Poststroke

Reisman, D. S., Wityk, R., Silver, K., Bastian, A. J. — Wed, 26 Aug 2009 09:03:48 PDT

Background and Objective. Following stroke, subjects retain the ability to adapt interlimb symmetry on the split-belt treadmill. Critical to advancing our understanding of locomotor adaptation and its usefulness in rehabilitation is discerning whether adaptive effects observed on a treadmill transfer to walking over ground. We examined whether aftereffects following split-belt treadmill adaptation transfer to overground walking in healthy persons and those poststroke. Methods. Eleven poststroke and 11 age-matched and gender-matched healthy subjects walked over ground before and after walking on a split-belt treadmill. Adaptation and aftereffects in step length and double support time were calculated. Results. Both groups demonstrated partial transfer of the aftereffects observed on the treadmill (P < .001) to overground walking ( P < .05), but the transfer was more robust in the subjects poststroke (P < .05). The subjects with baseline asymmetry after stroke improved in asymmetry of step length and double limb support (P = .06). Conclusions. The partial transfer of aftereffects to overground walking suggests that some shared neural circuits that control locomotion for different environmental contexts are adapted during split-belt treadmill walking. The larger adaptation transfer from the treadmill to overground walking in the stroke survivors may be due to difficulty adjusting their walking pattern to changing environmental demands. Such difficulties with context switching have been considered detrimental to function poststroke. However, we propose that the persistence of improved symmetry when changing context to overground walking could be used to advantage in poststroke rehabilitation.

Pneumorrhachis and Pneumocephalus Due to a Sacral Pressure Sore After Paraplegia

Jomir, L., Fuentes, S., Gelis, A., Labauge, P. — Wed, 26 Aug 2009 09:03:48 PDT

Transformational Technologies in Single-Event Neurological Conditions: Applying Lessons Learned in Stroke to Cerebral Palsy (August 14-15, 2008)

Wed, 26 Aug 2009 09:03:48 PDT

ASNR/WFNR News

Wed, 17 Jun 2009 15:49:23 PDT

Influence of Speed on Walking Economy Poststroke

Reisman, D. S., Rudolph, K. S., Farquhar, W. B. — Wed, 17 Jun 2009 15:49:23 PDT

Background and Objective. Walking speed influences energy cost in healthy adults, but its influence when walking is impaired due to stroke is not clear. This study investigated the effect of manipulating walking speed on the energy economy of walking poststroke. Methods. Sixteen persons with chronic stroke underwent a clinical examination, including several lower extremity impairment measures. consumption (VO₂) was measured as they walked at their self-selected speed (Free), 20% slower (Slow), their fastest possible speed (Fastest), and 2 speeds between Free and Fastest speeds. VO₂ was normalized to body mass and speed, resulting in energy cost per meter walked (CW). Results. A main effect for speed was observed (P = .00001), with faster than self-selected speeds showing greater relative economy as a whole. However, for 5 subjects with the fastest walking speeds (>1.2 m/s), there was a trend toward decreasing relative economy at speeds higher than self-selected speed (P = .18). There was a negative correlation between improvement in CW at the most economical speed and (a) Free speed (r = –.857; P < .0001) and (b) lower extremity Fugl-Meyer scores (r = –.653; P = .006). Conclusions. For those poststroke whose fastest walking speed after stroke is below 1.2 m/s, walking economy improves when speed is increased above the self-selected walking speed. The results suggest that for persons poststroke with very slow self-selected walking speeds, improvements in walking speed could be accompanied by improvements in walking economy if faster walking speeds can be attained through intervention.

Swimming as a Model of Task-Specific Locomotor Retraining After Spinal Cord Injury in the Rat

Wed, 17 Jun 2009 15:49:23 PDT

Background. The authors have shown that rats can be retrained to swim after a moderately severe thoracic spinal cord contusion. They also found that improvements in body position and hindlimb activity occurred rapidly over the first 2 weeks of training, reaching a plateau by week 4. Overground walking was not influenced by swim training, suggesting that swimming may be a task-specific model of locomotor retraining. Objective. To provide a quantitative description of hindlimb movements of uninjured adult rats during swimming, and then after injury and retraining. Methods. The authors used a novel and streamlined kinematic assessment of swimming in which each limb is described in 2 dimensions, as 3 segments and 2 angles. Results. The kinematics of uninjured rats do not change over 4 weeks of daily swimming, suggesting that acclimatization does not involve refinements in hindlimb movement. After spinal cord injury, retraining involved increases in hindlimb excursion and improved limb position, but the velocity of the movements remained slow. Conclusion. These data suggest that the activity pattern of swimming is hardwired in the rat spinal cord. After spinal cord injury, repetition is sufficient to bring about significant improvements in the pattern of hindlimb movement but does not improve the forces generated, leaving the animals with persistent deficits. These data support the concept that force (load) and pattern generation (recruitment) are independent and may have to be managed together with respect to postinjury rehabilitation.

Cost-effectiveness Modeling of Intrathecal Baclofen Therapy Versus Other Interventions for Disabling Spasticity

Wed, 17 Jun 2009 15:49:23 PDT

Objective. To assess by simulation the cost-effectiveness of intrathecal baclofen (ITB) therapy compared with conventional medical treatments for patients with disabling spasticity and functional dependence caused by any neurological disease. Methods. Two models were created to simulate therapeutic strategies for managing severe spasticity, one with and one without the use of ITB, to assess various treatment sequences over 2 years based on current medical practices in France. Successful treatment at each evaluation was defined as a combination of: (1) the increased patient and caregiver satisfaction as assessed by goal attainment scaling (GAS), and (2) a decrease of at least 1 point on the Ashworth score. Probabilistic sensitivity analyses were performed using 5000 Monte-Carlo simulations taking into account specific distribution curves for direct costs and effectiveness parameters in each treatment option. Results. The model simulations suggest that including ITB as a first option strategy in the management of function of severely impaired patients with disabling spasticity results in a higher success rate (78.7% vs 59.3%; P < .001). In addition, the ITB therapy model revealed a lower cost (59 391 vs 88 272; P < .001) and an overall more favorable cost-effectiveness ratio (75 204/success vs 148 822/success; P < .001), compared with conventional medical management without ITB. Conclusion. Within the assumptions of our modeling, ITB therapy evaluated by a combination of treatment success criteria at 6-month intervals over a 2-year period may be a cost-effective strategy compared to conventional medical management alone.

Sympathetic Skin Responses Evoked by Different Stimuli Modalities in Spinal Cord Injury Patients

Kumru, H., Vidal, J., Perez, M., Schestatsky, P., Valls-Sole, J. — Wed, 17 Jun 2009 15:49:23 PDT

Objective. By using a combination of physiological and electrical peripheral nerve stimuli, the authors aimed to characterize the expected dysfunction of the circuits responsible for sympathetic skin response (SSR) in persons with spinal cord injury (SCI). Methods. The authors examined SSR induced in the hand and foot in 50 SCI patients and 15 age-matched and gender-matched healthy volunteers. SSR was induced by deep inhalation, unexpected acoustic stimuli, brisk hand muscle contraction, and median and peroneal nerve electrical stimulation (PNS). Results. SSRs to any stimulus modality were absent in hand and foot in patients with complete SCI above the T4 level. They were present in the hand and absent in the foot in complete SCI patients at levels between T4 and T11 for all stimuli modalities except PNS. The elicitability of SSR was lower with peroneal nerve stimulation than the other stimuli in hand and foot. The mean latency difference between SSRs of the hand and foot was significantly longer in patients than in controls, regardless of stimulus modality. The amplitude of SSR was larger in volunteers than in patients. Conclusion . SSR to various stimuli confirms the importance of supraspinal centers and the integrity of sympathetic descending pathways. Simultaneous recording of the SSR in the hands and feet provides information about the degree of sympathetic impairment possibly in the efferent pathway. To monitor spontaneous recovery or the efficacy of a drug or biological therapeutic intervention, changes in the latency delay between the hand and foot may be valuable.

Feasibility of Iterative Learning Control Mediated by Functional Electrical Stimulation for Reaching After Stroke

Wed, 17 Jun 2009 15:49:23 PDT

Background. An inability to perform tasks involving reaching is a common problem following stroke. Evidence supports the use of robotic therapy and functional electrical stimulation (FES) to reduce upper limb impairments, but current systems may not encourage maximal voluntary contribution from the participant because assistance is not responsive to performance. Objective. This study aimed to investigate whether iterative learning control (ILC) mediated by FES is a feasible intervention in upper limb stroke rehabilitation. Methods. Five hemiparetic participants with reduced upper limb function who were at least 6 months poststroke were recruited from the community. No participants withdrew. Intervention. Participants undertook supported tracking tasks using 27 different trajectories augmented by responsive FES to their triceps brachii muscle, with their hand movement constrained in a 2-dimensional plane by a robot. Eighteen 1-hour treatment sessions were used with 2 participants receiving an additional 7 treatment sessions. Outcome measures. The primary functional outcome measure was the Action Research Arm Test (ARAT). Impairment measures included the upper limb Fugl— Meyer Assessment (FMA), tests of motor control (tracking accuracy), and isometric force. Results. Compliance was excellent and there were no adverse events. Statistically significant improvements were measured (P ≤ .05) in FMA motor score, unassisted tracking for 3 out of 4 trajectories, and in isometric force over 5 out of 6 directions. Changes in ARAT were not statistically significant. Conclusion. This study has demonstrated the feasibility of using ILC mediated by FES for upper limb stroke rehabilitation.

Intramuscular Electrical Stimulation for Upper Limb Recovery in Chronic Hemiparesis: An Exploratory Randomized Clinical Trial

Wed, 17 Jun 2009 15:49:23 PDT

Background. Surface electrical stimulation (ES) has been shown to improve the motor impairment of stroke survivors. However, surface ES can be painful and motor activation can be inconsistent from session to session. Percutaneous intramuscular ES may be an effective alternative. Objective. Evaluate the effectiveness of percutaneous intramuscular ES in facilitating the recovery of the hemiparetic upper limb of chronic stroke survivors. Methods. A total of 26 chronic stroke survivors were randomly assigned to percutaneous intramuscular ES for hand opening (n = 13) or percutaneous ES for sensory stimulation only (n = 13). The intramuscular ES group received cyclic, electromyography (EMG)-triggered or EMG-controlled ES depending on baseline motor status. All participants received 1 hour of stimulation per day for 6 weeks. After completion of ES, participants received 18 hours of task-specific functional training. The primary outcome measure was the Fugl-Meyer Motor Assessment. Secondary measures included the Arm Motor Ability Test and delay and termination of EMG activity. Outcomes were assessed in a blinded manner at baseline, at the end of ES, at the end of functional training, and at 1, 3, and 6 months follow-up. Results. Repeated measure analysis of variance did not yield any significant treatment, or time by treatment interaction effects for any of the outcome measures. Conclusion. Percutaneous intramuscular ES does not appear to be any more effective than sensory ES in enhancing the recovery of the hemiparetic upper limb among chronic stroke survivors. However, because of the exploratory nature of the study and its inherent limitations, conclusions must be drawn with caution.

Dimensionality of Nonmotor Neurobehavioral Impairments When Observed in the Natural Contexts of ADL Task Performance

Arnadottir, G., Fisher, A. G., Lofgren, B. — Wed, 17 Jun 2009 15:49:23 PDT

Objective. To examine diverse nonmotor neurobehavioral impairments (NBIs) that impact activities of daily living (ADL) task performance and to verify if such impairments can be viewed as one dimension when evaluated in an ecologically-relevant context. Methods. Rasch analysis was performed on data from 206 individuals diagnosed with dementia or cerebral vascular accident (CVA) who had been scored on 50 standardized NBIs from the A-ONE Neurobehavioral Impairment scale, based on naturalistic observation of ADL task performance. Evaluation of mean square (MnSq) infit and outfit values and principal components analysis (PCA) of residuals were used to evaluate unidimensionality of the items. Two evaluations were implemented: (1) to evaluate if there is a single global dimension common for persons with either dementia or CVA, and (2) to evaluate if the 50 NBIs are unidimensional, but comprised of different diagnosis-specific global hierarchies (dementia, left CVA, and right CVA). Results. The PCA indicated that 56.8% of variance was explained by the global measure (Rasch factor) of NBIs, with 4.9% of the unexplained variance explained by the first contrast. Four items showed outfit misfit to the common hierarchy. Developing diagnosis-specific global hierarchies resulted in improved PCA results for all 3 diagnostic groups (Rasch factor = 79.2% to 85.5%; unexplained variance in first contrast = 1.7% to 3.4%) after removal of 2 to 3 misfitting items. Conclusions. Nonmotor NBIs, when evaluated based on naturalistic performance of ADL, can be considered unidimensional, but the hierarchical structure of the dimension likely varies across diagnostic groups. Further study is needed with larger samples to verify these results.

Training With Virtual Visual Feedback to Alleviate Phantom Limb Pain

Mercier, C., Sirigu, A. — Wed, 17 Jun 2009 15:49:23 PDT

Background. Performing phantom movements with visual virtual feedback, or mirror therapy, is a promising treatment avenue to alleviate phantom limb pain. However the effectiveness of this approach appears to vary from one patient to another. Objective. To assess the individual response to training with visual virtual feedback and to explore factors influencing the response to that approach. Methods. Eight male participants with phantom limb pain (PLP) resulting from either a traumatic upper limb amputation or a brachial plexus avulsion participated in this single case multiple baseline study. Training was performed 2 times per week for 8 weeks where a virtual image of a missing limb performing different movements was presented and the participant was asked to follow the movements with his phantom limb. Results. Patients reported an average 38% decrease in background pain on a visual analog scale (VAS), with 5 patients out of 8 reporting a reduction greater than 30%. This decrease in pain was maintained at 4 weeks postintervention in 4 of the 5 participants. No significant relationship was found between the long-term pain relief and the duration of the deafferentation or with the immediate pain relief during exposure to the feedback. Conclusions. These results support the use of training with virtual feedback to alleviate phantom limb pain. Our observations suggest that between-participant differences in the effectiveness of the treatment might be related more to a difference in the susceptibility to the virtual visual feedback, than to factors related to the lesion, such as the duration of the deafferentation.

Activity-Based Electrical Stimulation Training in a Stroke Patient With Minimal Movement in the Paretic Upper Extremity

Page, S. J., Maslyn, S., Hermann, V. H., Wu, A., Dunning, K., Levine, P. G. — Wed, 17 Jun 2009 15:49:23 PDT

Background. Existing task-specific practice interventions do not increase movement in stroke patients exhibiting minimal distal movement in the paretic upper extremity. Although often used, an important limitation of conventional electrical stimulation is that it does not involve task-specific practice. Objective. To determine the impact of an activity-specific electrical stimulation program on paretic limb impairment, functional limitation, and ability to perform valued activities in a subacute stroke patient exhibiting minimal paretic wrist and hand movement. Method. A female subject exhibiting trace paretic hand and finger movement was administered, 9 months after stroke, the upper extremity section of the Fugl-Meyer Impairment Scale (FM), the Action Research Arm Test (ARAT), and the Arm Motor Ability Test (AMAT). She then engaged in paretic upper extremity, task-specific training incorporating an electrical stimulation neuroprosthesis. Training occurred 3 hours per day, 5 days per week for 3 weeks. The FM, ARAT, and AMAT were again administered. Results. After intervention, she exhibited reduced impairment (evidenced by an FM score change of 22 to 29), decreased functional limitation (evidenced by an ARAT score change of 4 to 10), and increased ability and speed in performing valued AMAT activities. She also reported using the paretic hand and fingers more and new abilities to perform valued activities such as playing piano. Conclusion. Although conventional paretic upper extremity training strategies are ineffective in patients at this level, electrical stimulation training incorporating a neuroprosthesis appears promising.

Forced, Not Voluntary, Exercise Improves Motor Function in Parkinson's Disease Patients

Ridgel, A. L., Vitek, J. L., Alberts, J. L. — Wed, 17 Jun 2009 15:49:23 PDT

Background. Animal studies indicate forced exercise (FE) improves overall motor function in Parkinsonian rodents. Global improvements in motor function following voluntary exercise (VE) are not widely reported in human Parkinson's disease (PD) patients. Objective. The aim of this study was to compare the effects of VE and FE on PD symptoms, motor function, and bimanual dexterity. Methods. Ten patients with mild to moderate PD were randomly assigned to complete 8 weeks of FE or VE. With the assistance of a trainer, patients in the FE group pedaled at a rate 30% greater than their preferred voluntary rate, whereas patients in the VE group pedaled at their preferred rate. Aerobic intensity for both groups was identical, 60% to 80% of their individualized training heart rate. Results. Aerobic fitness improved for both groups. Following FE, Unified Parkinson's Disease Rating Scale (UPDRS) motor scores improved 35%, whereas patients completing VE did not exhibit any improvement. The control and coordination of grasping forces during the performance of a functional bimanual dexterity task improved significantly for patients in the FE group, whereas no changes in motor performance were observed following VE. Improvements in clinical measures of rigidity and bradykinesia and biomechanical measures of bimanual dexterity were maintained 4 weeks after FE cessation. Conclusions. Aerobic fitness can be improved in PD patients following both VE and FE interventions. However, only FE results in significant improvements in motor function and bimanual dexterity. Biomechanical data indicate that FE leads to a shift in motor control strategy, from feedback to a greater reliance on feedforward processes, which suggests FE may be altering central motor control processes.

Is Visuospatial Hemineglect Really a Determinant of Postural Control Following Stroke? An Acute-Phase Study

Wed, 17 Jun 2009 15:49:23 PDT

Objective. The purpose of this study was to determine the independent contribution of visuospatial hemineglect to impaired postural control in the acute phase (<2 weeks) of stroke compared with other possible clinical and biological determinants. Methods. This study was conducted in 4 hospitals in the mid-east region of the Netherlands. A total of 78 consecutive patients with a first-ever acute supratentorial stroke was included. Functional balance was measured with the Trunk Impairment Scale, the Trunk Control Test, the Berg Balance Scale, and the Functional Ambulation Categories. Visuospatial hemineglect was assessed by means of an asymmetry index obtained from the Behavioral Inattention Test. The Motricity Index, vibration threshold, sustained attention, and the presence of hemianopia were registered as other possible clinical determinants. Stepwise backward multiple linear regression analysis was performed introducing all selected clinical determinants as well as age and poststroke time as possible biological determinants. Results. Hemineglect was present in 17 patients (21.8%). The groups with and without hemineglect were different for gender and the proportion of right hemisphere strokes, but not for age, type of stroke, or poststroke time. Neglect patients had on average lower scores on all functional balance tests as well as on the clinical assessments. Multivariate linear regression showed that, besides hemineglect, only muscle strength and age independently contributed to impaired balance explaining 65% to 72% of variance of the selected outcomes. Conclusion. This study showed that hemineglect independently contributes to impaired postural control in the acute phase of stroke.

Transcutaneously Coupled, High-Frequency Electrical Stimulation of the Pudendal Nerve Blocks External Urethral Sphincter Contractions

Gaunt, R. A., Prochazka, A. — Wed, 17 Jun 2009 15:49:23 PDT

Background. Detrusor-sphincter dyssynergia is a condition in which reflexive contractions of the external urethral sphincter occur during bladder contractions, preventing the expulsion of urine. High-frequency stimulation (kHz range) has been shown to elicit a fast-acting and reversible block of action potential propagation in peripheral nerves, which may be a useful technique in the management of this condition. Objective. The aim of these experiments was to see if a newly developed stimulus delivery system, capable of transmitting current transcutaneously to remote peripheral nerves using a passive implanted conductor, was an effective way to transmit high-frequency waveforms to the pudendal nerve to block ongoing sphincter contractions. Methods. High-frequency waveforms were delivered through the skin to the pudendal nerve using a passive implanted conductor in 6 adult cats anesthetized with isoflurane. Five of the experiments were acute, terminal procedures, and the remaining cat was implanted with a permanent electrode system allowing evaluation for 6 months. Typical stimulation parameters were in the range of 1 to 10 kHz and 1 to 10 mA. Results. Complete blocking of external urethral sphincter contractions was achieved in 5 of the 6 animals. High-frequency stimulation was also tested in the chronically implanted animal without anesthesia, and the stimulation was tolerated with minimal aversive reactions. Conclusions. The transcutaneous passive implanted conductor stimulus delivery system is an effective way to stimulate the pudendal nerve at high frequency, leading to sphincter relaxation. This system may provide a simple means to implement this stimulation paradigm in people with detrusor-sphincter dyssynergia.

Connection of Left Corticospinal Tract and Broca's Area in a Patient With Intracerebral Hemorrhage

Jang, S. H. — Wed, 17 Jun 2009 15:49:23 PDT