Neurorehabilitation and Neural Repair recent issues

ASNR/WFNR News

2008-07-28

Augmenting Clinical Evaluation of Hemiparetic Arm Movement With a Laboratory-Based Quantitative Measurement of Kinematics as a Function of Limb Loading

Ellis, M. D., Sukal, T., DeMott, T., Dewald, J. P. A. — 2008-07-28

Background. Kinematic and kinetic measurements used in laboratory settings can quantify upper extremity movement impairment following stroke, but their relationship to clinical methods of evaluating movement impairment is unclear. Objective. To test whether the Arm Coordination Training 3D device (ACT^3D) could provide a repeatable quantitative measurement of range of motion during upper extremity reaching along a range of functional levels of loads on the arm and correlate with clinical assessments of arm impairment. Methods . Work area during reaching along clockwise and counterclockwise hand paths was measured under 9 limb-loading conditions ranging from no load to twice the weight of the upper extremity in 11 individuals with chronic hemiparetic stroke on 2 separate occasions. Participants were given a battery of clinical assessments that included the Fugl-Meyer Motor Assessment, Chedoke McMaster Stroke Assessment, Reaching Performance Scale, Modified Ashworth Scale, and the Stroke Impact Scale, by a physical therapist who did not know the results of the kinematic studies. Results. A reproducible testretest reduction in work area was found when participants were required to support up to and beyond the weight of their limb. Work area was correlated with most upper extremity clinical assessments, suggesting criterion validity. Conclusions . Reaching work area during various loading conditions is a robust measurement that quantifies the effect of abnormal joint torque coupling and provides useful data that can be applied in the clinical setting.

Clinical Assessment of Motor Imagery After Stroke

Malouin, F., Richards, C. L., Durand, A., Doyon, J. — 2008-07-28

Objective. The aim of this study was to investigate: (1) the effects of a stroke on motor imagery vividness as measured by the Kinesthetic and Visual Imagery Questionnaire (KVIQ-20); (2) the influence of the lesion side; and (3) the symmetry of motor imagery. Methods. Thirty-two persons who had sustained a stroke, in the right (n = 19) or left (n = 13) cerebral hemisphere, and 32 age-matched healthy persons participated. The KVIQ-20 assesses on a 5-point ordinal scale the clarity of the image (visual scale) and the intensity of the sensations (kinesthetic scale) that the subjects are able to imagine from the first-person perspective. Results. In both groups, the visual scores were higher (P = .0001) than the kinesthetic scores and there was no group difference. Likewise, visual scores remained higher than kinesthetic scores irrespective of the lesion side. The visual scores poststroke were higher (P = .001) when imagining upper limb movements on the unaffected side than those on the affected side. When focusing on the lower limb only, however, the kinesthetic scores were higher (P = .001) when imagining movements of the unaffected compared to those on the affected side. Conclusions. The vividness of motor imagery poststroke remains similar to that of age-matched healthy persons and is not affected by the side of the lesion. However, after stroke motor imagery is not symmetrical and motor imagery vividness is better when imagining movements on the unaffected than on the affected side, indicating an overestimation possibly related to a hemispheric imbalance or a recalibration of motor imagery perception.

Prevalence of Sleep Disturbance in Closed Head Injury Patients in a Rehabilitation Unit

2008-07-28

Traumatic brain injury (TBI) is a leading cause of disability in young people in the United States. Disorders of arousal and attention are common in closed head injury (CHI). Daytime drowsiness impairs participation in rehabilitation, whereas nighttime wakefulness leads to falls and behavioral disturbances. Sleep disturbances in TBI reported in the literature have included excessive daytime somnolence, sleep phase cycle disturbance, narcolepsy, and sleep apnea. Although well known to the clinician treating these patients, the extent and prevalence of disrupted sleep in patients in an acute inpatient rehabilitation unit has not been described. Objective. To determine the prevalence of sleep wake cycle disturbance (SWCD) in patients with CHI in a TBI rehabilitation unit. Design. Prospective observational. Setting. Inpatient specialized brain injury rehabilitation unit. Patients. Thirty-one consecutive admissions to a brain injury rehabilitation unit with the diagnosis of CHI. Results. Twenty-one patients (68%) had aberrations of nighttime sleep. There was no significant difference in Glasgow Coma Score on admission to trauma nor was there any significant difference in age between the affected and unaffected groups. Patients with SWCD had longer stays in both the trauma center (P < .003) and the rehabilitation center (P < .03). Conclusions. There is a high prevalence of SWCD in CHI patients admitted to a brain injury rehabilitation unit. Patients with SWCD have longer stays in both acute and rehabilitation settings and may be a marker for more severe injury.

An Accelerometry-Based Comparison of 2 Robotic Assistive Devices for Treadmill Training of Gait

Regnaux, J.-P., Saremi, K., Marehbian, J., Bussel, B., Dobkin, B. H. — 2008-07-28

Objective. Two commercial robotic devices, the Gait Trainer (GT) and the Lokomat (LOKO), assist task-oriented practice of walking. The gait patterns induced by these motor-driven devices have not been characterized and compared. Methods. A healthy participant chose the most comfortable gait pattern on each device and for treadmill (TM) walking at 1, 2 (maximum for the GT), and 3 km/h and over ground at similar speeds. A system of accelerometers on the thighs and feet allowed the calculation of spatiotemporal features and accelerations during the gait cycle. Results . At the 1 and 2 km/h speed settings, single-limb stance times were prolonged on the devices compared with overground walking. Differences on the LOKO were decreased by adjusting the hip and knee angles and step length. At the 3 km/h setting, the LOKO approximated the participant's overground parameters. Irregular accelerations and decelerations from toe-off to heel contact were induced by the devices, especially at slower speeds. Conclusions. The LOKO and GT impose mechanical constraints that may alter leg accelerations–decelerations during stance and swing phases, as well as stance duration, especially at their slower speed settings, that are not found during TM and overground walking. The potential impact of these perturbations on training to improve gait needs further study.

Endurance and Resistance Exercise Training Programs Elicit Specific Effects on Sciatic Nerve Regeneration After Experimental Traumatic Lesion in Rats

2008-07-28

Objective. To evaluate the effects of endurance, resistance, and a combination of both types of exercise training on hindlimb motor function recovery and nerve regeneration after experimental sciatic nerve lesion in rats. Methods. Sciatic nerve crush was performed on adult male rats, and after 2 weeks of the nerve lesion, the animals were submitted to endurance, resistance, and a combination of endurance-resistance training programs for 5 weeks. Over the training period, functional recovery was monitored weekly using the Sciatic Functional Index (SFI) and histological and morphometric nerve analyses were used to assess the nerve regeneration at the end of the trainings. Results. The SFI values of the endurance-trained group reached the control values from the first posttraining week and were significantly better than both the resistance-trained group at the first, second, and third posttraining weeks and the concurrent training group at the first posttraining week. At the distal portion of the regenerating sciatic nerve, the endurance-trained group showed a greater degree of the myelinated fiber maturation than the sedentary, resistance-trained, and concurrent training groups. Furthermore, the endurance-trained group showed a smaller percentage area of endoneurial connective tissue and a greater percentage area of myelinated fibers than the sedentary group. Conclusion . These data provide evidence that endurance training improves sciatic nerve regeneration after an experimental traumatic injury and that resistance training or the combination of 2 strategies may delay functional recovery and do not alter sciatic nerve fiber regeneration.

Effects of Electrical Stimulation at Different Frequencies on Regeneration of Transected Peripheral Nerve

2008-07-28

Background. Electrical stimulation of damaged peripheral nerve may aid regeneration. Objective. The purpose of this study was to determine whether 1 mA of percutaneous electrical stimulation at 1, 2, 20, or 200 Hz augments regeneration between the proximal and distal nerve stumps. Methods. A10-mm gap was made in rat sciatic nerve by suturing the stumps into silicone rubber tubes. A control group received no stimulation. Starting 1 week after transection, electrical stimulation was applied between the cathode placed at the distal stump and the anode at the proximal stump every other day for 6 weeks. Results. Higher frequency stimulation led to less regeneration compared to lower frequencies. Quantitative histology of the successfully regenerated nerves revealed that the groups receiving electrical treatment, especially at 2 Hz, had a more mature structure with a smaller cross-sectional area, more myelinated fibers, higher axon density, and higher ratio of blood vessel to total nerve area compared with the controls. Electrophysiology showed significantly shorter latency, longer duration, and faster conduction velocity. Conclusion. Electrical stimulation can have either a positive or negative impact on peripheral nerve regeneration. Clinical trials that combine stimulation with rehabilitation must determine the parameters that are most likely to be safe and effective.

Preserved and Impaired Aspects of Feed-Forward Grip Force Control After Chronic Somatosensory Deafferentation

Hermsdorfer, J., Elias, Z., Cole, J. D., Quaney, B. M., Nowak, D. A. — 2008-07-28

Background. Although feed-forward mechanisms of grip force control are a prerequisite for skilled object manipulation, somatosensory feedback is essential to acquire, maintain, and adapt these mechanisms. Objective. Individuals with complete peripheral deafferentation provide the unique opportunity to study the function of the motor system deprived of somatosensory feedback. Methods. Two individuals (GL and IW) with complete chronic deafferentation of the trunk and limbs were tested during cyclic vertical movements of a hand-held object. Such movements induce oscillating loads that are typically anticipated by parallel modulations of the grip force. Load magnitude was altered by varying either the movement frequency or object weight. Results. GL and IW employed excessive grip forces probably reflecting a compensatory mechanism. Despite this overall force increase, both deafferented participants adjusted their grip force level according to the load magnitude, indicating preserved scaling of the background grip force to physical demands. The dynamic modulation of the grip force with the load force was largely absent in GL, whereas in IW only slower movements were clearly affected. Conclusions. The authors hypothesize that the deafferented patients may have utilized visual and vestibular cues and/or an efferent copy of the motor command of the arm movement to scale the grip force level. Severely impaired grip force-load coupling in GL suggests that sensory information is important for maintaining a precise internal model of dynamic grip force control. However, comparably better performance in IW argues for the possibility that alternative cues can be used to trigger a residual internal model.

Determining the Optimal Challenge Point for Motor Skill Learning in Adults With Moderately Severe Parkinson's Disease

Onla-or, S., Winstein, C. J. — 2008-07-28

Objective. To test the predictions of the Challenge Point Framework (CPF) for motor learning in individuals with Parkinson's disease (PD) by manipulating nominal task difficulty and conditions of practice. Methods. Twenty adults with PD and 20 nondisabled controls practiced 3 variations of a laboratory-based goal-directed arm movement over 2 days. A between-group (PD, nondisabled) 2-factor design compared 2 levels of nominal task difficulty (low, high) and 2 levels of practice condition (low, high demand). Learning was assessed with a no-feedback recall test 1 day after practice. Performance was quantified using a root mean square error difference between the goal and participant-generated movement. Results. All participants improved with practice. Under the low-demand practice condition, adults with PD demonstrated comparable learning to that of controls when nominal task difficulty was low but not high. In contrast, under the high-demand practice condition, adults with PD demonstrated preserved motor learning for both levels of task difficulty, but only if recall was tested under the same context as that used during practice. Conclusions. In general, the predictions of CPF were supported. Together, the level of nominal task difficulty and the inherent demand of the practice condition played a critical role in determining the optimal challenge point for motor learning in individuals with PD. More important, and in contrast to the predictions of CPF, a high-demand practice condition appeared to have a facilitative effect on motor learning. However, this benefit revealed the context specificity of motor learning in adults with PD.

Motor Cortical Disinhibition During Early and Late Recovery After Stroke

Manganotti, P., Acler, M., Zanette, G. P., Smania, N., Fiaschi, A. — 2008-07-28

Background. Functional neuroimaging studies show adaptive changes in areas adjacent and distant from the stroke. This longitudinal study assessed whether changes in cortical excitability in affected and unaffected motor areas after acute stroke correlates with functional and motor recovery. Methods. We studied 13 patients with moderate to severe hemiparesis 5 to 7 days (T1), 30 days (T2), and 90 days (T3) after acute unilateral stroke, as well as 10 healthy controls. We used paired-pulse transcranial magnetic stimulation to study intracortical inhibition and facilitation, recording from the bilateral thenar eminences. F waves were also recorded. Results. At T1, all patients showed significantly reduced intracortical inhibition in the unaffected hemisphere. At T2, in patients whose motor function recovered, intracortical inhibition in the unaffected hemisphere returned to normal. In patients with poor clinical motor recovery, abnormal disinhibition persisted in both hemispheres. At T3, in patients whose motor function progressively recovered, the abnormal disinhibition in the unaffected hemisphere decreased further, whereas in patients whose motor function remained poor, abnormal inhibition in the unaffected hemisphere persisted. No modification of F-wave latency and amplitude were found in patients and controls. Conclusions. During early days after stroke, motor cortical disinhibition involves both cerebral hemispheres. Longitudinal changes in motor disinhibition of the unaffected hemisphere may reflect the degree of clinical motor recovery.

Recovery From Amnesic Confabulatory Syndrome After Right Fornix Lesion

Ruggeri, M., Sabatini, U. — 2008-07-28

Background. Reports of amnesia due to bilateral fornix lesions are rare. A unilateral right fornix lesion is not known to cause an amnestic confabulatory syndrome. Objective. To investigate the role of right fornix lesion in amnesia, the association of confabulation with executive disorders, and to evaluate the long-term recovery of memory and executive functions after surgical removal of a pilocytic astrocytoma in the right orbitofrontal region extending to the right fornix. Methods. Neuropsychological testing was performed 3 and 17 months after surgery. Results. Severe anterograde global amnesia, mild retrograde amnesia, momentary and spontaneous confabulation, and mild executive deficits were found initially and mostly recovered by 17 months. Conclusions. The authors hypothesize that the lesion of the right fornix was sufficient to cause amnesia by disconnecting the hippocampal formations from the anterior thalamic nuclei and mammillary bodies and interrupting the cholinergic efferents to the hippocampus from the medial septum, according to the extended hippocampal system framework. Sparing of the left fornix may be sufficient to ensure a good recovery of memory. Confabulation is strongly associated with the improvement of executive functions, specifically the ability to suppress irrelevant memory traces.

Reinvestment and Falls in Community-Dwelling Older Adults

Wong, W. L., Masters, R. S. W., Maxwell, J. P., Abernethy, A. B. — 2008-07-28

Background. Falls are common in older adults and have many adverse consequences. In an attempt to prevent further incidents, elder fallers may consciously monitor and control their movements. Ironically, conscious movement control may be one factor that contributes to disruption of automaticity of walking, increasing the likelihood of subsequent falls. Objective. The Movement Specific Reinvestment Scale (MSRS), which aims to measure the propensity for movement-related self-consciousness and for conscious processing of movement, was used to try to discriminate elder fallers from non-fallers. Methods. Fifty-two volunteer older adults, aged 65 or above, participated. In addition to the 10-item MSRS, participants completed the Mini-Mental State Examination questionnaire, Timed "Up & Go" test, and Four Word Short-Term Memory test. Demographics including age, gender, and history of falling were collected. Results. Elder fallers scored significantly higher than non-fallers on both the movement self-consciousness and conscious motor processing components of the MSRS. Logistic regression revealed a significant association between the MSRS (conscious motor processing component) and "faller or non-faller" status. Conclusions. Elder fallers may have a higher propensity to consciously control their movements. The MSRS shows potential as a clinical tool with which to predict falls in the elderly, as well as to gain insight into the perception of safety during walking in any impaired patient.

Outcomes With Stroke and Lateropulsion: A Case-Matched Controlled Study

Babyar, S. R., White, H., Shafi, N., Reding, M. — 2008-07-28

Background and Objective . Lateropulsion after stroke has not been tracked using a case-matched controlled study and a standardized lateropulsion scale. Matched pairs of patients with stroke, with and without lateropulsion, were compared for functional outcomes and discharge destination following inpatient rehabilitation. Methods. A retrospective chart review of patients with ischemic stroke at an inpatient rehabilitation hospital matched 36 pairs of patients with versus without lateropulsion. Scores of 2 or greater on the Burke Lateropulsion Scale identified lateropulsion. Matching criteria were side of stroke, sex, age, admission motor Functional Independence Measure (FIM), and interval poststroke. FIM efficiency (change in total FIM/length of stay) and discharge destination were analyzed with Wilcoxon signed-ranks tests. Results. FIM efficiency and discharge FIM scores were lower in the lateropulsion group. Groups had similar mean lengths of stay. Post-hoc analyses showed that only patients with lateropulsion and right brain damage had significantly different FIM efficiency and discharge FIM scores. Lower extremity weakness was greater in the lateropulsion group at discharge; patients with right brain damage accounted for this difference. Patients with lateropulsion required more dependent living situations at discharge, especially if they had right brain damage. Conclusions. Patients with lateropulsion following stroke have a lower FIM efficiency and more dependency at discharge when compared with matched controls with equal functional limitations. Secondary analyses show worse outcomes for the subgroup of patients with right hemisphere stroke; lateropulsion and greater leg weakness may account for differences. Patients with lateropulsion may require longer rehabilitation to reach outcome goals.

Erratum

2008-05-06

ASNR/WFNR News

2008-05-06

The Predictive Brain State: Timing Deficiency in Traumatic Brain Injury?

Ghajar, J., Ivry, R. B. — 2008-05-06

Attention and memory deficits observed in traumatic brain injury (TBI) are postulated to result from the shearing of white matter connections between the prefrontal cortex, parietal lobe, and cerebellum that are critical in the generation, maintenance, and precise timing of anticipatory neural activity. These fiber tracts are part of a neural network that generates predictions of future states and events, processes that are required for optimal performance on attention and working memory tasks. The authors discuss the role of this anticipatory neural system for understanding the varied symptoms and potential rehabilitation interventions for TBI. Preparatory neural activity normally allows the efficient integration of sensory information with goal-based representations. It is postulated that an impairment in the generation of this activity in traumatic brain injury (TBI) leads to performance variability as the brain shifts from a predictive to reactive mode. This dysfunction may constitute a fundamental defect in TBI as well as other attention disorders, causing working memory deficits, distractibility, a loss of goal-oriented behavior, and decreased awareness.

Informing Dose-Finding Studies of Repetitive Transcranial Magnetic Stimulation to Enhance Motor Function: A Qualitative Systematic Review

Hiscock, A., Miller, S., Rothwell, J., Tallis, R. C., Pomeroy, V. M. — 2008-05-06

Objective. Repetitive transcranial magnetic stimulation (rTMS) of the lesioned hemisphere might enhance motor recovery after stroke, but the appropriate dose (parameters of rTMS) remains uncertain. The present review collates evidence of the effect of rTMS on corticospinal pathway excitability and motor function in healthy adults and in people after stroke. Methods. The authors searched MEDLINE and EMBASE (1996 to April 2007), their own collection of peer-reviewed articles, and the reference lists of included studies. They included healthy adults or people with stroke who received rTMS to the primary motor cortex to facilitate or inhibit contralateral corticospinal excitability or movement control. Findings. Of the 625 references identified, 37 studies were included with 455 healthy adults (34 studies) and 69 people with stroke (3 studies). For healthy adults, the effects of rTMS on corticospinal pathway excitability varied within each frequency, for example, 1 Hz rTMS was found to facilitate, inhibit, and have no effect on amplitude of motor-evoked potentials (MEPs). After stroke there was a trend for recovery of MEPs (ie, presence of MEPs) after 10 daily sessions of 3 Hz rTMS (one study). Motor function in healthy adults might be adversely affected by 1 Hz rTMS (two studies), whereas combined frequency rTMS was found to have no effect (one study). Interpretation . There is as yet insufficient published evidence to guide the dose of rTMS to the lesioned hemisphere after stroke to improve recovery of a paretic limb. Moreover, it is apparent that there is variability in response to rTMS in healthy adults. Dose-finding studies in groups of well-characterized stroke patients are needed.

Motor Skill Training, but not Voluntary Exercise, Improves Skilled Reaching After Unilateral Ischemic Lesions of the Sensorimotor Cortex in Rats

Maldonado, M. A., Allred, R. P., Felthauser, E. L., Jones, T. A. — 2008-05-06

Background and Purpose . Exercise and rehabilitative training each have been implicated in the promotion of restorative neural plasticity after cerebral injury. Because motor skill training induces synaptic plasticity and exercise increases plasticity-related proteins, we asked if exercise could improve the efficacy of training on a skilled motor task after focal cortical lesions. Methods . Female young and middle-aged rats were trained on the single-pellet retrieval task and received unilateral ischemic sensorimotor cortex lesions contralateral to the trained limb. Rats then received both, either, or neither voluntary running and/or rehabilitative training for 5 weeks beginning 5 days postlesion. Motor skill training consisted of daily practice of the impaired forelimb in a tray-reaching task. Exercised rats had free access to running wheels for 6 h/day. Reaching function was periodically probed using the single-pellet retrieval task. Results. In young adults, motor skill training significantly enhanced skilled reaching recovery compared to controls. However, exercise did not significantly enhance performance when administered alone or in combination with skill training. There was also no major benefit of exercise in older rats. Additionally, there were no effects of exercise in a measure of coordinated forelimb placement (the foot-fault test) or in immunocytochemical measures of several plasticity-related proteins in the motor cortex. Conclusions. In young and middle-aged animals, exercise did not improve motor skill training efficacy following ischemic lesions. Practicing motor skills more effectively improved recovery of these skills than did exercise. It remains possible that an alternative manner of administering exercise would be more effective.

Nogo-66 Receptor Antagonist Peptide (NEP1-40) Administration Promotes Functional Recovery and Axonal Growth After Lateral Funiculus Injury in the Adult Rat

2008-05-06

Objective. The myelin protein Nogo inhibits axon regeneration by binding to its receptor (NgR) on axons. Intrathecal delivery of an NgR antagonist (NEP1-40) promotes growth of injured corticospinal axons and recovery of motor function following a dorsal hemisection. The authors used a similar design to examine recovery and repair after a lesion that interrupts the rubrospinal tract (RST). Methods. Rats received a lateral funiculotomy at C4 and NEP1-40 or vehicle was delivered to the cervical spinal cord for 4 weeks. Outcome measures included motor and sensory tests and immunohistochemistry. Results. Gait analysis showed recovery in the NEP1-40-treated group compared to operated controls, and a test of forelimb usage also showed a beneficial effect. The density of labeled RST axons increased ipsilaterally in the NEP1-40 group in the lateral funiculus rostral to the lesion and contralaterally in both gray and white matter. Thus, rubrospinal axons exhibited diminished dieback and/or growth up to the lesion site. This was accompanied by greater density of 5HT and calcitonin gene-related peptide axons adjacent to and into the lesion/matrix site in the NEP1-40 group. Conclusions. NgR blockade after RST injury is associated with axonal growth and/or diminished dieback of severed RST axons up to but not into or beyond the lesion/matrix site, and growth of serotonergic and dorsal root axons adjacent to and into the lesion/matrix site. NgR blockade also supported partial recovery of function. The authors' results indicate that severed rubrospinal axons respond to NEP1-40 treatment but less robustly than corticospinal, raphe-spinal, or dorsal root axons.

Short-Term Changes in and Predictors of Participation of Older Adults After Stroke Following Acute Care or Rehabilitation

Desrosiers, J., Demers, L., Robichaud, L., Vincent, C., Belleville, S., Ska, B. — 2008-05-06

Background. Stroke can lead to restrictions in participation in daily activities and social roles. Although considered an important rehabilitation outcome, little is known about participation after stroke and its predictors, and about the differences associated with the types of services provided following stroke. Objective . The aims of this study were 1) to follow and compare changes in participation of older adults discharged home after stroke from acute care or postacute rehabilitation, and 2) to identify the best predictors of participation after stroke from physical, cognitive, perceptual, and psychological ability measures taken shortly after discharge. Methods. Level of participation in daily activities and social roles of 197 older adults who had a stroke was evaluated at 2 to 3 weeks (T1), 3 months (T2), and 6 months (T3) after being discharged home from acute care (n = 86) or rehabilitation (n = 111). Physical, cognitive, perceptual, and psychological abilities were assessed at T1. Results. A significant increase in participation was found over time for both groups, mainly in the first 3 months. The best predictors of participation differed between the groups and between the daily activities and social roles domains. Walking and acceptance of the stroke or fewer depressive symptoms were the best predictors of the level of participation after stroke. Conclusions . Participation was not optimal at discharge because it continued to increase after the return home. The importance of psychological factors in participation after stroke is undeniable. Many predictors are amenable to interventions.

The Influence of Hand Dominance on the Response to a Constraint-Induced Therapy Program Following Stroke

Langan, J., van Donkelaar, P. — 2008-05-06

Background. Following stroke it is common to exhibit deficits in mobility of the upper extremity. Constraint-induced therapy (CIT) is a rehabilitation technique used to promote use of the more affected hand via constraint of the less affected hand. One factor that could impact the outcome following CIT is hand dominance. Years of preferred use of one hand may give individuals with the dominant hand affected by stroke an advantage in improving the mobility of the more affected hand compared to those individuals with the nondominant hand affected by stroke. In addition, the diminished use of the less affected hand during CIT may also create changes. Objective. Our goal was to better understand how hand dominance may influence the response to a CIT program both cortically and behaviorally in both the more affected hand and less affected constrained hand. Methods. A repeated measures design with a double baseline was used to assess changes in clinical tests and functional magnetic resonance imaging (fMRI) in individuals with their dominant or nondominant hand affected by stroke involved in a CIT program. Results. No significant differences were found between groups in their responses to CIT. Overall subjects demonstrated behavioral and cortical changes with the more affected hand and the less affected constrained hand did not significantly change. Conclusion. CIT promotes improvement of the more affected hand particularly on complex tests without decrements to the less affected constrained hand. Cortically, statistically significant changes in activation were noted after the intervention for the more affected hand; no changes were noted with the less affected constrained hand.

Intensive Sensorimotor Arm Training Mediated by Therapist or Robot Improves Hemiparesis in Patients With Chronic Stroke

2008-05-06

Investigators have demonstrated that a variety of intensive movement training protocols for persistent upper limb paralysis in patients with chronic stroke (6 months or more after stroke) improve motor outcome. This randomized controlled study determined in patients with upper limb motor impairment after chronic stroke whether movement therapy delivered by a robot or by a therapist using an intensive training protocol was superior. Robotic training (n = 11) and an intensive movement protocol (n = 10) improved the impairment measures of motor outcome significantly and comparably; there were no significant changes in disability measures. Motor gains were maintained at the 3-month evaluation after training. These data contribute to the growing awareness that persistent impairments in those with chronic stroke may not reflect exhausted capacity for improvement. These new protocols, rendered by either therapist or robot, can be standardized, tested, and replicated, and potentially will contribute to rational activity-based programs.

Citalopram Improves Dexterity in Chronic Stroke Patients

Zittel, S., Weiller, C., Liepert, J. — 2008-05-06

Background. A majority of stroke patients have persisting motor deficits despite ongoing physiotherapy. Therefore, additional treatment options are desirable. Objective. We investigated if the serotonin reuptake inhibitor, citalopram, would improve motor functions in chronic stroke patients. Methods. In all, 8 patients >6 months after their stroke participated in a double-blind, placebo-controlled, single-dose crossover experiment. The order (first drug then placebo or vice versa) was randomized. Sessions were separated by at least 2 weeks. Motor function was assessed by nine-hole peg test, and measurements of hand grip-strength before drug intake, 2 hours after drug intake, and after 1 hour of training aimed at improving the function of the paretic hand. Results. Compared with placebo, citalopram intake significantly improved performance of the nine-hole peg test for the paretic hand but not for the unaffected hand. Hand grip-strength remained unchanged. Conclusions. A single dose of citalopram can enhance dexterity in chronic stroke patients. This pilot study justifies a test of efficacy of citalopram in a larger group of stroke patients.

ASNR/WFNR News: Member News

2008-02-19

Fatigue Versus Activity-Dependent Fatigability in Patients With Central or Peripheral Motor Impairments

Dobkin, B. H. — 2008-02-19

In the rehabilitation literature, fatigue is a common symptom of patients with any neurological impairment when defined as a subjective lack of physical and mental energy that interferes with usual activities. Some complaints may, however, arise from fatigability , an objective decline in strength as routine use of muscle groups proceeds. By this refined definition of fatigue, exercise or sustained use reduces the ability of muscles to produce force or power, regardless of whether the task can be sustained. Fatigability may be masked clinically because (1) the degree of weakening is not profound, (2) activity-induced weakness rapidly lessens with cessation of exertion, and (3) clinicians rarely test for changes in strength after repetitive movements to objectively entertain the diagnosis. The repetitive movements that induce fatigability during daily activities are an iterative physiological process that depends on changing states induced by activation of spared central and peripheral neurons and axons and compromised muscle. Fatigability may be especially difficult to localize in patients undergoing neurorehabilitation, in part because no finite boundary exists between the central and peripheral components of motor reserve and endurance. At the bedside, however, manual muscle testing before and after repetitive movements could at least put some focus on the presence of fatigability in any patient with motor impairments and related disabilities. Reliable measures of fatigability beyond a careful clinical examination, such as physiological changes monitored by cerebral functional neuroimaging techniques and more standardized central and peripheral electrical and magnetic stimulation paradigms, may help determine the mechanisms of activity-dependent weakening and lead to specific therapies. Testable interventions to increase motor reserve include muscle strengthening and endurance exercises, varying the biomechanical requirements of repetitive muscle contractions, and training-induced neural plasticity or pharmacologic manipulations to enhance synaptic efficacy.

Effects of Robot-Assisted Therapy on Upper Limb Recovery After Stroke: A Systematic Review

Kwakkel, G., Kollen, B. J., Krebs, H. I. — 2008-02-19

Objective. The aim of the study was to present a systematic review of studies that investigate the effects of robot-assisted therapy on motor and functional recovery in patients with stroke. Methods. A database of articles published up to October 2006 was compiled using the following Medline key words: cerebral vascular accident, cerebral vascular disorders, stroke, paresis, hemiplegia, upper extremity, arm, and robot. References listed in relevant publications were also screened. Studies that satisfied the following selection criteria were included: (1) patients were diagnosed with cerebral vascular accident; (2) effects of robot-assisted therapy for the upper limb were investigated; (3) the outcome was measured in terms of motor and/or functional recovery of the upper paretic limb; and (4) the study was a randomized clinical trial (RCT). For each outcome measure, the estimated effect size (ES) and the summary effect size (SES) expressed in standard deviation units (SDU) were calculated for motor recovery and functional ability (activities of daily living [ADLs]) using fixed and random effect models. Ten studies, involving 218 patients, were included in the synthesis. Their methodological quality ranged from 4 to 8 on a (maximum) 10-point scale. Results. Meta-analysis showed a nonsignificant heterogeneous SES in terms of upper limb motor recovery. Sensitivity analysis of studies involving only shoulder-elbow robotics subsequently demonstrated a significant homogeneous SES for motor recovery of the upper paretic limb. No significant SES was observed for functional ability (ADL). Conclusion. As a result of marked heterogeneity in studies between distal and proximal arm robotics, no overall significant effect in favor of robot-assisted therapy was found in the present meta-analysis. However, subsequent sensitivity analysis showed a significant improvement in upper limb motor function after stroke for upper arm robotics. No significant improvement was found in ADL function. However, the administered ADL scales in the reviewed studies fail to adequately reflect recovery of the paretic upper limb, whereas valid instruments that measure outcome of dexterity of the paretic arm and hand are mostly absent in selected studies. Future research into the effects of robot-assisted therapy should therefore distinguish between upper and lower robotics arm training and concentrate on kinematical analysis to differentiate between genuine upper limb motor recovery and functional recovery due to compensation strategies by proximal control of the trunk and upper limb.

Conceptualizing Functional Cognition in Stroke

2008-02-19

Background. Up to 65% of individuals demonstrate poststroke cognitive impairments, which may increase hospital stay and caregiver burden. Randomized stroke clinical trials have emphasized physical recovery over cognition. Neuropsychological assessments have had limited utility in randomized clinical trials. These issues accentuate the need for a measure of functional cognition (the ability to accomplish everyday activities that rely on cognitive abilities, such as locating keys, conveying information, or planning activities). Objective. The aim of the study was to present the process used to establish domains of functional cognition for development of computer adaptive measure of functional cognition for stroke. Methods. Functional cognitive domains involved in identifying relevant neuropsychological constructs from the literature were conceptualized and finalized after advisory panel feedback from experts in neurology, neuropsychology, aphasiology, clinical trials, and epidemiology. Results. The following 17 domains were proposed: receptive aphasia, expressive aphasia, agraphia, alexia, calculation, visuospatial, visuoperceptual, visuoconstruction, attention, language usage, executive functions, orientation, processing speed, memory, working memory, mood, awareness and abstract reasoning. The advisory panel recommended retaining the first 12 domains. Recommended changes included: to address only encoding and retrieval of recent information in the memory domain; to add domains for limb apraxia and poststroke depression; and to keep orientation as a separate domain or reclassify it under memory or attention. The final 10 domains included: language, reading and writing, numeric/calculation, limb praxis, visuospatial function, social use of language, emotional function, attention, executive function, and memory. Conclusion. Conceptualizing domains of functional cognition is the first step in developing a computer adaptive measure of functional cognition for stroke. Additional steps include developing, refining, and field-testing items, psychometric analysis, and computer adaptive test programming.

Brain Activity Associated With Stimulation Therapy of the Visual Borderzone in Hemianopic Stroke Patients

2008-02-19

Background and objective. Visual restoration therapy is a home-based treatment program intended to expand visual fields of hemianopic patients through repetitive stimulation of the borderzone adjacent to the blind field. We hypothesized that the training itself would induce visual field location-specific changes in the brain's response to stimuli, a phenomenon demonstrated in animal experiments but never in humans with brain injury. Methods. Six chronic right hemianopic patients underwent functional magnetic resonance imaging (fMRI)—responding to stimuli in the trained visual borderzone versus the nontrained seeing field before and after 1 month of visual restoration therapy. Spatially normalized fMRI time-series data were analyzed in a fixed-effects group analysis comparing blood oxygen level dependent (BOLD) activity in the borderzone versus seeing location at baseline and at 1 month. Percent BOLD change was measured to determine each condition's contribution to the time-by-condition interaction. Results. There was a significant time by condition interaction manifested as increased BOLD activity for borderzone detection relative to seeing detection after the first month of therapy, which correlated with a relative improvement in response times in the borderzone location out-of-scanner. The right inferior and lateral temporal, right dorsolateral frontal, bilateral anterior cingulate, and bilateral basal ganglia showed the greatest response. Conclusion. Visual restoration therapy appears to induce an alteration in brain activity associated with a shift of attention from the nontrained seeing field to the trained borderzone. The effect appears to be mediated by the anterior cingulate and dorsolateral frontal cortex in conjunction with other higher order visual areas in the occipitotemporal and middle temporal regions. Demonstration of a visual field—specific training effect on brain activity provides an important starting point for understanding the potential for visual therapy in hemianopia.

Changes in Activity After a Complete Spinal Cord Injury as Measured by the Spinal Cord Independence Measure II (SCIM II)

Wirth, B., van Hedel, H. J.A., Kometer, B., Dietz, V., Curt, A. — 2008-02-19

Background. The assessment of rehabilitation efficacy in spinal cord injury (SCI) should be based on a combination of neurological and functional outcome measures. The Spinal Cord Independence Measure II (SCIM II) is an independence scale that was specifically developed for subjects with SCI. However, little is known about the changes in SCIM II scores during and after rehabilitation. Objective. The aims of this study were to evaluate changes in functional recovery during the first year after a complete SCI as measured by the SCIM II compared with neurological recovery (motor scores according to the American Spinal Injury Association [ASIA]). Methods. SCIM II data and ASIA motor scores at 1, 3, 6, and 12 months after injury (derived from the database of the European Multicenter Study of Human Spinal Cord Injury) of 64 patients with complete paraplegia and 36 patients with complete quadriplegia were analyzed. Results. In patients with complete paraplegia, the SCIM II total score improved significantly during the 1-year follow-up, even after discharge from rehabilitation. In contrast, the ASIA motor scores showed little recovery. In patients with quadriplegia, functional and motor recovery developed in parallel during rehabilitation and after discharge. Conclusions. The SCIM II is responsive to functional changes in patients with a persistent motor complete SCI. It is clinically useful for monitoring functional improvement during rehabilitation and after discharge. The SCIM II and the clinical examination based on the ASIA protocol are of complementary value and separately describe changes in independence and sensorimotor deficits in SCI patients.

Neural Correlates of Proprioceptive Integration in the Contralesional Hemisphere of Very Impaired Patients Shortly After a Subcortical Stroke: An fMRI Study

2008-02-19

Background. The effects of physiotherapy are difficult to assess in very impaired early stroke patients. Objective. The aim of the study was to characterize the impact of 4 weeks of passive proprioceptive training of the wrist on brain sensorimotor activation after stroke. Methods. Patients with a subcortical ischemic lesion of the pyramidal tract were randomly assigned to a control or a wrist-training group. All patients had a single pure motor hemiplegia with severe motor deficit. The control group (6 patients) underwent standard Bobath rehabilitation. The second, "trained," group (7 patients) received Bobath rehabilitation plus 4 weeks of proprioceptive training with daily passive calibrated wrist extension. Before and after the training period, patients were examined with validated clinical scales and functional MRI (fMRI) while executing a passive movement versus rest. The effect of standard rehabilitation on sensorimotor activation was assessed in the control group on the wrist, and the effect of standard rehabilitation plus proprioceptive training was assessed in the trained group. The effect of 4-week proprioceptive training alone was statistically evaluated by difference between groups. Results. Standard rehabilitation along with natural recovery mainly led to increases in ipsilesional activation and decreases in contralesional activation. On the contrary, standard rehabilitation and paretic wrist proprioceptive training increased contralesional activation. Proprioceptive training produced change in the supplementary motor area (SMA), prefrontal cortex, and a contralesional network including inferior parietal cortex (lower part of BA 40), secondary sensory cortex, and ventral premotor cortex (PMv). Conclusion. We have demonstrated that purely passive proprioceptive training applied for 4 weeks is able to modify brain sensorimotor activity after a stroke. This training revealed fMRI change in the ventral premotor and parietal cortices of the contralesional hemisphere, which are secondary sensorimotor areas. Recent studies have demonstrated the crucial role of these areas in severely impaired patients. We propose that increased contralesional activity in secondary sensorimotor areas likely facilitates control of recovered motor function by simple proprioceptive integration in those patients with poor recovery.

Sensory Loss in Hospital-Admitted People With Stroke: Characteristics, Associated Factors, and Relationship With Function

Tyson, S. F., Hanley, M., Chillala, J., Selley, A. B., Tallis, R. C. — 2008-02-19

Objective: To characterize the nature of sensory impairments after stroke, identify associated factors, and assess the relationships between sensory impairment, disability, and recovery. Methods: Prospective cross-sectional survey of 102 people with hemiparesis following their first stroke. Tactile and proprioceptive sensation in the affected arm and leg were measured using the Rivermead Assessment of Somatosensory Perception 2-4 weeks post-stroke. Demographics, stroke pathology, weakness, neglect, disability, and recovery were documented. Results: Tactile impairment was more common than proprioceptive (P < .000), impairment of discrimination was more common than detection (P < .000), and tactile sensation was more severely impaired in the leg than the arm ( P < .000). No difference in proprioception between the arm and leg (P = .703) or between proximal and distal joints (P = .589, P = .705) was found. The degree of weakness and the degree of stroke severity were significantly associated with sensory impairment; demographics, stroke side and type, and neglect were not associated. All the sensory modalities were significantly related to independence, mobility, and recovery (r = 0.287 [P < .011] to r = 0.533 [P < .000]). Conclusion: Sensory impairments of all modalities are common after stroke, although tactile impairment is more frequent than proprioceptive loss, especially in the leg. They are associated with the degree of weakness and the degree of stroke severity but not demographics, stroke pathology, or neglect, and they are related to mobility, independence in activities of daily living, and recovery.

Time Course of Trunk, Arm, Leg, and Functional Recovery After Ischemic Stroke

2008-02-19

Background. Patterns of recovery provide useful information concerning the potential of physical recovery over time and therefore the setting of realistic goals for rehabilitation programs. Objective. To compare the time course of trunk recovery with the patterns of recovery of arm, leg, and functional ability. Methods . Consecutive stroke patients were recruited in 2 acute neurology wards. Participants were evaluated at 1 week, 1 month, and 3 and 6 months after stroke. Patients were assessed with the Trunk Impairment Scale, Fugl-Meyer arm and leg test, and Barthel Index. Results. Thirty-two patients were included in the study. There were no dropouts. Repeated measures analysis of the recovery patterns of motor and functional performance revealed the most striking improvement for all measures from 1 week to 1 month (P value between .0021 and <.0001) and a significant improvement from 1 month to 3 months after stroke (P value ranges from .0008 to <.0001). No significant improvement was found between 3 and 6 months after stroke for any of the measures. Statistical analysis revealed no significant difference between time course of trunk, arm, leg, and functional recovery (P = .2565). No significant differences in level of motor and functional recovery were found at the different time points. Conclusions. Separate analyses of motor and functional recovery patterns after stroke confirm the importance of the first month for recovery. Contrary to common belief, the time course of recovery of the trunk is similar to the recovery of arm, leg, and functional ability.

Bilateral Arm Training With Rhythmic Auditory Cueing in Chronic Stroke: Not Always Efficacious

Richards, L. G., Senesac, C. R., Davis, S. B., Woodbury, M. L., Nadeau, S. E. — 2008-02-19

Objective. Bilateral arm training with rhythmic auditory cueing (BATRAC) has been reported to be efficacious in promoting upper-extremity (UE) recovery in chronic stroke. We tested a modified form of BATRAC (modBATRAC) in a new group of participants with a condensed treatment regime to determine whether we could replicate these reported results. Methods. Fourteen subjects with chronic stroke completed 2 weeks of 2.25 hours per session, 4 sessions per week of modBATRAC. Results. No significant changes were observed in UE Fugl-Meyer or Wolf Motor Function Test scores. Subjects did report increased paretic UE use on the Motor Activity Log (mean change, 0.50; SD = 0.70). Conclusions. The results of this study offer only partial support for the efficacy of modBATRAC. As in previous trials, modBATRAC facilitated increased use of the paretic arm, but unlike previous trials, it did not increase motor performance. These differences may reflect a more temporally condensed training schedule and less impaired patients.

Safety of 6-Hz Primed Low-Frequency rTMS in Stroke

2008-02-19

Background. Suppression of activity in the contralesional motor cortex may promote recovery of function after stroke. Furthermore, the known depressant effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) can be increased and prolonged by preceding it with 6-Hz priming stimulation. Objective. The authors explored the safety of 6-Hz primed low-frequency rTMS in 10 patients with ischemic stroke. Methods. Priming consisted of 10 minutes of 6-Hz rTMS applied to the contralesional hemisphere at 90% of resting motor threshold delivered in 2 trains/min with 5 s/train and 25-second intervals between trains. Low-frequency rTMS consisted of an additional 10 minutes of 1-Hz rTMS at 90% of resting motor threshold without interruption. Possible adverse effects were assessed with the National Institutes of Health Stroke Scale (NIHSS), the Wechsler Adult Intelligence Scale—Third Edition (WAIS-III), the Hopkins Verbal Learning Test—Revised (HVLT-R), the Beck Depression Inventory—Second Edition (BDI-II), a finger movement tracking test, and individual self-assessments. Pretest, treatment, and posttest occurred on the first day with follow-up tests on the next 5 weekdays. Results. There were no seizures and no impairment of NIHSS, WAIS-III, or BDI-II scores. Transient impairment occurred on the HVLT-R. Transient tiredness was common. Occasional reports of headache, neck pain, increased sleep, reduced sleep, nausea, and anxiety occurred. Conclusion. Because there were no major adverse effects, the authors concluded that the treatment was safe for the individuals in this study and that further investigation is now warranted to examine efficacy and safety of serial treatments of 6-Hz primed low-frequency rTMS.

Abstracts

2008-02-19

ASNR/WFNR News

2007-12-11

Relationship Between Interhemispheric Inhibition and Motor Cortex Excitability in Subacute Stroke Patients

Butefisch, C. M., We ling, M., Netz, J., Seitz, R. J., Homberg, V. — 2007-12-11

Background. Studies of stroke patients using functional imaging and transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) demonstrated increased recruitment and abnormally decreased short interval cortical inhibition (SICI) of the M1 contralateral to the lesioned hemisphere (contralesional M1) within the first month after infarction of the M1 or its corticospinal projections. Objective. The authors sought to identify mechanisms underlying decreased SICI of the contralesional M1. Methods. In patients within 6 weeks of their first ever infarction of the M1 or its corticospinal projections, SICI in the M1 of the lesioned and nonlesioned hemisphere was studied using paired-pulse TMS. Interhemispheric inhibition (IHI) was measured by applying TMS to the M1 of the lesioned hemisphere and a second pulse to the homotopic M1 of the nonlesioned hemisphere and vice versa with the patient at rest. The results were compared to M1 stimulation of age-matched healthy controls. Results. SICI was decreased in the M1 of lesioned and nonlesioned hemispheres regardless of cortical or subcortical infarct location. IHI was abnormally decreased from the M1 of the lesioned on nonlesioned hemisphere. In contrast, IHI was normal from the M1 of the nonlesioned on the lesioned hemisphere. Abnormal IHI and SICI were correlated in patients with cortical but not with subcortical lesions. Conclusions. In subacute stroke patients, abnormally decreased SICI of a contralesional M1 can only partially be explained by loss of IHI from the lesioned on nonlesioned hemisphere. As decreased SICI of the contralesional M1 did not result in excessive IHI from the nonlesioned on lesioned hemisphere with subsequent suppression of ipsilesional M1 excitability and all patients showed excellent recovery of motor function, decreased SICI of the contralesional M1 may represent an adaptive process supporting recovery.

Gait Training Induced Change in Corticomotor Excitability in Patients With Chronic Stroke

Yen, C.-L., Wang, R.-Y., Liao, K.-K., Huang, C.-C., Yang, Y.-R. — 2007-12-11

Background. Numerous studies have reported the effects of gait training on motor performance after stroke. However, there is limited information on treatment-induced changes in corticomotor excitability. Objectives. The purpose of the study was to investigate the effects of additional gait training on motor performance and corticomotor excitability and to demonstrate the relationship between motor improvement and corticomotor excitability change in patients with chronic stroke. Methods. Fourteen patients were randomly assigned to the experimental or control group. Participants in both groups participated in general physical therapy. Those in the experimental group received additional body weight– supported treadmill training for 4 weeks. All participants received baseline and posttreatment assessments. The outcome measures included assessment of the Berg Balance Scale (BBS) and gait parameters. Focal transcranial magnetic stimulation was used to measure the motor threshold, map size, and location of the amplitude-weighted center of gravity of the motor map for the tibialis anterior (TA) and abductor hallucis (AH) muscles. Results . After general physical therapy, we noted that the patients showed an improvement only in walking speed and cadence, and there were no significant changes in corticomotor excitability. After additional gait training, participants improved significantly on BBS score, walking speed, and step length. Moreover, the motor threshold for TA decreased significantly in the unaffected hemisphere. The map size for TA was increased in both hemispheres, whereas that for AH was increased only in the affected hemisphere. There were significant differences between the change scores of the groups in terms of walking speed, step length, and motor threshold for TA in the unaffected hemisphere and map size for AH in the affected hemisphere. Additionally, the changes in corticomotor excitability correlated with functional improvement. Conclusions . Additional gait training may improve balance and gait performance and may induce changes in corticomotor excitability.

Using Kinematic Analysis to Evaluate Constraint-Induced Movement Therapy in Chronic Stroke Patients

2007-12-11

Objective. This preliminary study aims to verify if the method of kinematic analysis proposed here may be suitable for evaluating the effects of constraint-induced movement therapy (CIMT) in chronic stroke patients and may be of help in the study of the mechanisms underlying functional improvement following CIMT. Methods. Clinical and kinematic data were collected from a group of chronic stroke patients and from an age-matched healthy control group. Affected and less affected upper-limb kinematics related to hand-to-mouth and reaching movements were acquired before and immediately after 2 weeks of CIMT. Healthy subjects were submitted to kinematic analysis of the nondominant side and reevaluated after 2 weeks. Results. The clinical results were consistent with those reported in the literature and showed motor function improvement of the hemiparetic limb after CIMT. Kinematic data of the healthy control group showed high test-retest reliability. Statistically significant differences between the affected limb and both the less affected limb and the healthy subjects' nondominant limb were observed. After CIMT, kinematic data showed improvement in the speed of movement and in measures related to the capacity for coordination. Conclusions. The method of kinematic analysis was sensitive for an assessment of motor recovery induced by CIMT. The kinematic results suggest that the increase in the use of the paretic limb in activities of daily living after the intervention is not only attributable to the patient's increased attention to it and better hand dexterity, but it is also a consequence of the improved speed of movement and better coordination between shoulder and elbow joints.

Effects of Passive Leg Movement on the Oxygenation Level of Lower Limb Muscle in Chronic Stroke Patients

Jigjid, E., Kawashima, N., Ogata, H., Nakazawa, K., Akai, M., Eto, F., Haga, N. — 2007-12-11

Objective. To evaluate the effects of passive leg movements on the muscle oxygenation level and electromyographic (EMG) activity in the lower limbs in chronic stroke patients. Methods. With a gait training apparatus, passive movements were imposed on the lower limbs of 15 chronic stroke patients at a frequency of 0.8 Hz for 10 minutes. During the passive leg movements, muscle oxygenation level and muscular EMG activity of the paretic and nonparetic calf muscles were assessed. Results. The passive leg movements caused increases in the EMG activity and muscle oxygenation level in both paretic and nonparetic lower limbs. Although a significant difference was found in the concentration changes of the oxygenated hemoglobin (Oxy-Hb), both paretic and nonparetic sides of the muscle showed enhancement of the tissue oxygenation level (TOI). The degree of the changes of the Oxy-Hb depended on the level of motor recovery after stroke; subjects with good motor recovery showed less difference in the Oxy-Hb level between the paretic and nonparetic sides of the muscle. Conclusion. Passive leg movements have the capacity to induce muscular activity and enhance oxygen metabolism, even in the paretic lower limb muscle of chronic stroke patients. This type of exercise might be a useful and efficient method for the prevention of metabolic deterioration in the lower limb paretic muscles of chronic stroke patients.

Assessing Mechanisms of Recovery During Robot-Aided Neurorehabilitation of the Upper Limb

2007-12-11

Objective. The present study aimed to qualify and quantify the different components of motor recovery in a group of stroke patients treated by robot-aided techniques. In addition, the learning model of each motor recovery component was analyzed. Methods . Two groups of poststroke patients were treated with the use of an elbow-shoulder manipulator, respectively, within (recent) and after (chronic) the first 6 months of their cerebrovascular accident. Both groups were evaluated by means of standard clinical assessment scales and a robot-measured evaluation method. Results. These findings confirm that motor training consisting of voluntary movements assisted by the robot device led to significant improvements in motor performance in terms of the kinematic and dynamic components of the arm movements. This corresponded to improvement of impairment as confirmed by the clinical scale results. Conclusions. Knowledge of the recovery components and of the associated performance acquisition model may be useful in assessing and training stroke patients and should make it possible to precisely plan and, if necessary, modify the rehabilitation strategies.

Inter-individual Variability in the Capacity for Motor Recovery After Ischemic Stroke

2007-12-11

Background. Motor recovery after stroke is predicted only moderately by clinical variables, implying that there is still a substantial amount of unexplained, biologically meaningful variability in recovery. Regression diagnostics can indicate whether this is associated simply with Gaussian error or instead with multiple subpopulations that vary in their relationships to the clinical variables. Objective. To perform regression diagnostics on a linear model for recovery versus clinical predictors. Methods. Forty-one patients with ischemic stroke were studied. Impairment was assessed using the upper extremity Fugl-Meyer Motor Score. Motor recovery was defined as the change in the upper extremity Fugl-Meyer Motor Score from 24 to 72 hours after stroke to 3 or 6 months later. The clinical predictors in the model were age, gender, infarct location (subcortical vs cortical), diffusion weighted imaging infarct volume, time to reassessment, and acute upper extremity Fugl-Meyer Motor Score. Regression diagnostics included a Kolmogorov-Smirnov test for Gaussian errors and a test for outliers using Studentized deleted residuals. Results. In the random sample, clinical variables explained only 47% of the variance in recovery. Among the patients with the most severe initial impairment, there was a set of regression outliers who recovered very poorly. With the outliers removed, explained variance in recovery increased to 89%, and recovery was well approximated by a proportional relationship with initial impairment (recovery 0.70 x initial impairment). Conclusions. Clinical variables only moderately predict motor recovery. Regression diagnostics demonstrated the existence of a subpopulation of outliers with severe initial impairment who show little recovery. When these outliers were removed, clinical variables were good predictors of recovery among the remaining patients, showing a tight proportional relationship to initial impairment.

Rehabilitation of Executive Functioning After Focal Damage to the Cerebellum

2007-12-11

Executive dysfunction accounts for significant disability in patients with many types of brain injury in many locations. Clinical reports have described impaired executive functioning after damage to the cerebellum, and anatomical and neuroimaging studies have identified the likely basis for this effect: a cortico—ponto—cerebellar network through which the cerebellum is densely connected to areas of frontal cortex. The patterns of executive impairment attributable to cerebellar damage have been extensively described in the past 15 years, but there has been no assessment of the efficacy of rehabilitation in this patient population. Here, the use of a cognitive rehabilitation technique, Goal Management Training, in a patient with persisting executive dysfunction after a right cerebellar hemorrhage is described. The patient made and maintained modest gains on measures of sustained attention, planning, and organization that translated into significant improvement in real-life functioning. This is the first report on the rehabilitation of impaired executive functioning following focal damage to the cerebellum and in the presence of intact frontal cortex.

A Standardized Approach to Performing the Action Research Arm Test

Yozbatiran, N., Der-Yeghiaian, L., Cramer, S. C. — 2007-12-11

The study of stroke and its treatment in human subjects requires accurate measurement of behavioral status. Arm motor deficits are among the most common sequelae after stroke. The Action Research Arm Test (ARAT) is a reliable, valid measure of arm motor status after stroke. This test has established value for characterizing clinical state and for measuring spontaneous and therapy-induced recovery; however, sufficient details have not been previously published to allow for performance of this scale in a standardized manner over time and across sites. Such an approach to ARAT scoring would likely reduce variance between investigators and sites. This report therefore includes a manual that provides a highly detailed and standardized approach for assigning ARAT scores. Intrarater reliability and interrater reliability, as well as validity, with this approach were measured and are excellent. The ARAT, when performed in a standardized manner, is a useful tool for assessment of arm motor deficits after stroke.

Origin of Fatigue in Multiple Sclerosis: Review of the Literature

Kos, D., Kerckhofs, E., Nagels, G., D'hooghe, M.B., Ilsbroukx, S. — 2007-12-11

Fatigue is one of the most common and most disabling symptoms of multiple sclerosis (MS). Although numerous studies have tried to reveal it, no definite pathogenesis factor behind this fatigue has been identified. Fatigue may be directly related to the disease mechanisms (primary fatigue) or may be secondary to non—disease-specific factors. Primary fatigue may be the result of inflammation, demyelination, or axonal loss. A suggested functional cortical reorganization may result in a higher energy demand in certain brain areas, culminating in an increase of fatigue perception. Higher levels of some immune markers were found in patients with MS-related fatigue, whereas other studies rejected this hypothesis. There may be a disturbance in the neuroendocrine system related to fatigue, but it is not clear whether this is either the result of the interaction with immune activation or the trigger of this process. Fatigue may be secondary to sleep problems, which are frequently present in MS and in their turn result from urinary problems, spasms, pain, or anxiety. Pharmacologic treatment of MS (symptoms) may also provoke fatigue. The evidence for reduced activity as a cause of secondary fatigue in MS is inconsistent. Psychological functioning may at least play a role in the persistence of fatigue. Research did not reach consensus about the association of fatigue with clinical or demographic variables, such as age, gender, disability, type of MS, education level, and disease duration. In conclusion, it is more likely to explain fatigue from a multifactor perspective than to ascribe it to one mechanism. The current evidence on the pathogenesis of primary and secondary fatigue in MS is limited by inconsistency in defining specific aspects of the concept fatigue, by the lack of appropriate assessment tools, and by the use of heterogeneous samples. Future research should overcome these limitations and also include longitudinal designs.