Locomotor training remodels fMRI sensorimotor cortical activations in children after cerebral hemispherectomy

Use of water- and land-based gait training to improve walking capacity in adults with complete spinal cord injury: A pilot study

OBJECTIVE

Little is known regarding the extent to which mobility can be improved using gait-based therapies in individuals with complete spinal cord injury (cSCI). Against this backdrop, the purpose of our study was to document changes in walking capacity following an extended period of underwater treadmill training (UTT) and supplemental overground walk training (OWT) in persons with cSCI.

DESIGN

Longitudinal design.

SETTING

University research center.

PARTICIPANTS

Five adults (mean age = 41.2 ± 5.9 years) with motor-complete (AIS A), chronic (mean years post-injury = 3.2 ± 1.6 years) cSCI who had not received epidural spinal cord stimulation (eSCS).

INTERVENTION

Participants underwent one year of UTT (3 walking bouts per day; 2-3 days per week). Once independent stepping activity in the water was observed, OWT, as tolerated, was performed prior to UTT.

OUTCOME MEASURE

Walking capacity was evaluated using the Walking Index for Spinal Cord Injury (WISCI-II) prior to UTT (Time 1: T1), six months after the start of UTT (Time 2: T2), and following completion of UTT (Time 3: T3).

RESULTS

Non-parametric analyses revealed a significant time effect (P < .05) for WISCI-II. Pre-planned comparisons revealed no difference in WISCI-II levels measured at T1 (0.20 ± 0.45) and T2 (4.80 ± 4.55) and at T2 (4.80 ± 4.55) and T3 (8.40 ± 1.34). However, the WISCI-II level obtained at T3 (8.40 ± 1.34) was significantly higher compared to the T1 value.

CONCLUSION

Our preliminary findings demonstrate that in the absence of eSCS, combined UTT and supplemental OWT can improve functional walking capacity in adults with cSCI.

Results of a 2-week novel robotic rehabilitation program in 18 children with prior hemispherectomy

BACKGROUND

Partial preservation of sensory and motor functions in the contralateral extremities after hemispherectomy is likely secondary to cortical reorganization of the remaining hemisphere and can be improved by rehabilitation. This study aims to investigate behavioral changes that may occur after a 2-week novel robotic rehabilitation program in 18 children with prior anatomic hemispherectomy. Other conventional rehabilitation methods were also reviewed and compared.

METHODS

This study examined the impact of a novel robotic rehabilitation 2-week program on 18 hemispherectomy patients (average age 14.3 ± 3.9 years; age at hemispherectomy 5.6 ± 4.5 years).

RESULTS

Statistically significant improvements were seen in the six-minute walk test (29 m, p < 0.001), Canadian Occupational Performance Measure performance (1.64 points, p = 0.002) and satisfaction (2.49 points, p = 0.001), and individual perceived performance on survey (1.72 points, p = 0.042). Fifteen patients showed improvement in the upper extremity Fugl-Meyer scores with an average increase of 3 points (p = 0.006).

CONCLUSION

This study demonstrates clinically meaningful and statistically significant improvements in motor function and behavior following a novel robotic rehabilitation two-week program.

Cortical change after a 2-week novel robotic rehabilitation program in children with prior hemispherectomy: pilot imaging study

INTRODUCTION

Partial preservation of sensory and motor functions in the contralateral extremities after hemispherectomy is likely secondary to cortical reorganization of the remaining hemisphere and can be improved by rehabilitation. This study aims to investigate behavioral and structural cerebral cortical changes that may occur after a 2-week novel robotic rehabilitation program in children with prior anatomic hemispherectomy.

METHODS

Five patients with prior anatomic hemispherectomy (average age 10.8 years; all female) participated in a 2-week novel robotic rehabilitation program. Pre- and post-treatment (2 time points) high-resolution structural 3D FSPGR (fast spoiled gradient echo) magnetic resonance images were analyzed to measure cortical thickness and gray matter volume using a locally designed image processing pipeline.

RESULTS

Four of the five patients showed improvement in the Fugl-Meyer score (average increase 2.5 + 2.1 SD. Individual analyses identified small increases in gray matter volume near the hand knob area of the primary cortex in three of the five patients. Group analyses identified an increase in cortical thickness near the hand knob area of the primary motor cortex, in addition to other sensorimotor regions.

CONCLUSION

This small pilot study demonstrates that potentially rehabilitation-associated cortical changes can be identified with MRI in hemispherectomy patients.

How does the intensity of physical therapy affect the Gross Motor Function Measure (GMFM-66) total score in children with cerebral palsy? A systematic review protocol

INTRODUCTION

Intensive physical therapy (PT) interventions administered to children with cerebral palsy (CP) have received a significant amount of attention in published literature. However, there is considerable variability in therapy intensity among studies and notable lack of information on optimal intervention dosing. This makes it difficult for clinicians to use evidence to inform practice. Many studies use the Gross Motor Function Measure (GMFM-66) to assess functional progress in children with CP. The purpose of this systematic review will be to identify the GMFM-66 change score reported in published studies, with outcomes based on intervention intensity. Whether the type of PT intervention, child's age, and Gross Motor Function Classification System level influence the GMFM-66 scores will be also assessed.

METHODS AND ANALYSIS

This systematic review protocol was developed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) 2015 checklist. In March 2018, nine databases (PubMed, Ovid MEDLINE, Cochrane Library, Embase, Scopus, Web of Science, CINAHL, ClinicalTrials.gov, and REHABDATA) were searched for controlled clinical trials and single-subject design studies of PT interventions of any kind and intensity that used the GMFM-66 as an outcome measure for children with CP, age up to 18 years. Two authors independently reviewed the titles and abstracts and arrived at consensus on paper selection for a full-text review. The same process was used for a full-text article screening based on further detailed inclusion criteria, with a final selection made for those suitable for data extraction. Prior to commencement of data extraction, all searches will be updated, and new results re-screened.

ETHICS AND DISSEMINATION

This study will involve a systematic review of published articles and no primary data collection. Therefore, no ethical approval will be necessary. Results will be disseminated in a peer-reviewed publication and presented at scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42020147669.

Impacts of Sleep Loss versus Waking Experience on Brain Plasticity: Parallel or Orthogonal?

Recent studies on the effects of sleep deprivation on synaptic plasticity have yielded discrepant results. Sleep deprivation studies using novelty exposure as a means to keep animals awake suggests that sleep (compared with wake) leads to widespread reductions in net synaptic strength. By contrast, sleep deprivation studies using approaches avoiding novelty-induced arousal (i.e., gentle handling) suggest that sleep can promote synaptic growth and strengthening. How can these discrepant findings be reconciled? Here, we discuss how varying methodologies for the experimental disruption of sleep (with differential introduction of novel experiences) could fundamentally alter the experimental outcome with regard to synaptic plasticity. Thus, data from experiments aimed at assessing the relative impact of sleep versus wake on the brain may instead reflect the quality of the waking experience itself. The highlighted work suggests that brain plasticity resulting from novel experiences versus wake per se has unique and distinct features.

Asymmetry of Cerebral Peduncles for Predicting Motor Function Restoration in Young Patients Before Hemispherectomy

OBJECTIVE

Hemispherectomy has been used successfully for patients with medically intractable epilepsy. However, it is difficult to predict postoperative motor function. The aim of the present study was to analyze whether the preoperative asymmetry of cerebral peduncles could be used to predict motor function restoration before hemispherectomy for young patients with medically intractable epilepsy.

METHODS

The clinical record and magnetic resonance imaging data of 53 patients were analyzed retrospectively. The correlation between preoperative cerebral peduncle asymmetry ratio (pCPAR) and pre- and postoperative changes in motor function was evaluated, as well as the influencing factors for pCPAR, such as duration and etiology factors. The restoration of motor function was defined as changes in pre- and postoperative hemiparesis.

RESULTS

The pCPARs of patients with improved and unchanged hemiparesis were significantly greater than that of worsened patients. Patients with a pCPAR of more than 1.5 had an obvious restorative capacity of motor function of the intact hemisphere, and these patients had a lower risk of worsening hemiparesis. The duration in the improved/unchanged and worsened groups was 5.84 ± 3.85 years and 2.67 ± 2.03 years, respectively. Furthermore, there were more patients with no-progressive pathology in the group in whom pCPAR was more than 1.5.

CONCLUSIONS

pCPAR is a useful and objective indicator for predicting the restoration of motor function in pediatric patients with medically intractable epilepsy before hemispherectomy. Most patients with nonprogressive pathology and a duration of more than 5 years presented with greater pCPARs, exhibited better restoration of motor function, and had less risk of worsening hemiparesis.

Optimization of fMRI methods to determine laterality of cortical activation during ankle movements of children with unilateral cerebral palsy

Measurement of laterality of motor cortical activations may provide valuable information about lower limb control in children with unilateral cerebral palsy (UCP). Evidence from upper limb research suggests that increased contralateral activity may accompany functional gains. However, lower limb areas of activation and associated changes have been underexplored due to challenges with imaging motor cortical leg representations. In this study, methods for a task-based functional magnetic resonance imaging (fMRI) ankle dorsiflexion paradigm were refined with three pilot groups of participants: (i) adults (n = 5); (ii) typically developing (TD) children (n = 5) and; (iii) children with UCP (n = 4). Parameters of experimental design, task resistance, reproducibility, and pre-scan procedures were tested/refined using a staged development approach with additions or changes introduced if image quality did not meet pre-defined standards. When image quality was acceptable for two consecutive participants, the next participant group was recruited to test/refine the next parameter. The final paradigm involved an event-related design of a single dorsiflexion movement against individualized resistance, with two runs per leg. It included a pre-scan session to increase child comfort and determine task resistance. This paradigm produced valid data for laterality index (LI) calculations to determine the ratio of activity in each hemisphere. Ventricle and lesion masks were used in non-linear image registration, and individual thresholds were used for extent-based LI calculations. LI of dominant ankle movements were contralateral (LI ≥ +0.2) for TD children (mean LI = +0.89, std = 0.27) and children with UCP (mean LI = +0.86, std = 0.26). For the affected ankle of children with UCP, LI values indicated ipsilateral and/or contralateral activation (mean LI = +0.02, std = 0.71, range -0.92 to +1.00). This fMRI paradigm will support investigations of cortical activation and mechanisms of skill improvement following lower limb interventions.

Corticospinal tract atrophy and motor fMRI predict motor preservation after functional cerebral hemispherectomy

OBJECTIVE The potential loss of motor function after cerebral hemispherectomy is a common cause of anguish for patients, their families, and their physicians. The deficits these patients face are individually unique, but as a whole they provide a framework to understand the mechanisms underlying cortical reorganization of motor function. This study investigated whether preoperative functional MRI (fMRI) and diffusion tensor imaging (DTI) could predict the postoperative preservation of hand motor function. METHODS Thirteen independent reviewers analyzed sensorimotor fMRI and colored fractional anisotropy (CoFA)-DTI maps in 25 patients undergoing functional hemispherectomy for treatment of intractable seizures. Pre- and postoperative gross hand motor function were categorized and correlated with fMRI and DTI findings, specifically, abnormally located motor activation on fMRI and corticospinal tract atrophy on DTI. RESULTS Normal sensorimotor cortical activation on preoperative fMRI was significantly associated with severe decline in postoperative motor function, demonstrating 92.9% sensitivity (95% CI 0.661-0.998) and 100% specificity (95% CI 0.715-1.00). Bilaterally robust, symmetric corticospinal tracts on CoFA-DTI maps were significantly associated with severe postoperative motor decline, demonstrating 85.7% sensitivity (95% CI 0.572-0.982) and 100% specificity (95% CI 0.715-1.00). Interpreting the fMR images, the reviewers achieved a Fleiss' kappa coefficient (κ) for interrater agreement of κ = 0.69, indicating good agreement (p < 0.01). When interpreting the CoFA-DTI maps, the reviewers achieved κ = 0.64, again indicating good agreement (p < 0.01). CONCLUSIONS Functional hemispherectomy offers a high potential for seizure freedom without debilitating functional deficits in certain instances. Patients likely to retain preoperative motor function can be identified prior to hemispherectomy, where fMRI or DTI suggests that cortical reorganization of motor function has occurred prior to the operation.

Treadmill interventions in children under six years of age at risk of neuromotor delay

BACKGROUND

Delayed motor development may occur in children with Down syndrome, cerebral palsy, general developmental delay or children born preterm. It limits the child's exploration of the environment and can hinder cognitive and social-emotional development. Literature suggests that task-specific training, such as locomotor treadmill training, facilitates motor development.

OBJECTIVES

To assess the effectiveness of treadmill interventions on locomotor development in children with delayed ambulation or in pre-ambulatory children (or both), who are under six years of age and who are at risk for neuromotor delay.

SEARCH METHODS

In May 2017, we searched CENTRAL, MEDLINE, Embase, six other databases and a number of trials registers. We also searched the reference lists of relevant studies and systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that evaluated the effect of treadmill intervention in the target population.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted the data. Outcome parameters were structured according to the International Classification of Functioning, Disability and Health model.

MAIN RESULTS

This is an update of a Cochrane review from 2011, which included five trials. This update includes seven studies on treadmill intervention in 175 children: 104 were allocated to treadmill groups, and 71 were controls. The studies varied in population (children with Down syndrome, cerebral palsy, developmental delay or at moderate risk for neuromotor delay); comparison type (treadmill versus no treadmill; treadmill with versus without orthoses; high- versus low-intensity training); study duration, and assessed outcomes. Due to the diversity of the studies, only data from five studies were used in meta-analyses for five outcomes: age of independent walking onset, overall gross motor function, gross motor function related to standing and walking, and gait velocity. GRADE assessments of quality of the evidence ranged from high to very low.The effects of treadmill intervention on independent walking onset compared to no treadmill intervention was population dependent, but showed no overall effect (mean difference (MD) -2.08, 95% confidence intervals (CI) -5.38 to 1.22, 2 studies, 58 children; moderate-quality evidence): 30 children with Down syndrome benefited from treadmill training (MD -4.00, 95% CI -6.96 to -1.04), but 28 children at moderate risk of developmental delay did not (MD -0.60, 95% CI -2.34 to 1.14). We found no evidence regarding walking onset in two studies that compared treadmill intervention with and without orthotics in 17 children (MD 0.10, 95% CI -5.96 to 6.16), and high- versus low-intensity treadmill interventions in 30 children with Down syndrome (MD -2.13, 95% -4.96 to 0.70).Treadmill intervention did not improve overall gross motor function (MD 0.88, 95% CI -4.54 to 6.30, 2 studies, 36 children; moderate-quality evidence) or gross motor skills related to standing (MD 5.41, 95% CI -1.64 to 12.43, 2 studies, 32 children; low-quality evidence), and had a negligible improvement in gross motor skills related to walking (MD 4.51, 95% CI 0.29 to 8.73, 2 studies, 32 children; low-quality evidence). It led to improved walking skills in 20 ambulatory children with developmental delay (MD 7.60, 95% CI 0.88 to 14.32, 1 study) and favourable gross motor skills in 12 children with cerebral palsy (MD 8.00, 95% CI 3.18 to 12.82). A study which compared treadmill intervention with and without orthotics in 17 children with Down syndrome suggested that adding orthotics might hinder overall gross motor progress (MD -8.40, 95% CI -14.55 to -2.25).Overall, treadmill intervention showed a very small increase in walking speed compared to no treadmill intervention (MD 0.23, 95% CI 0.08 to 0.37, 2 studies, 32 children; high-quality evidence). Treadmill intervention increased walking speed in 20 ambulatory children with developmental delay (MD 0.25, 95% CI 0.08 to 0.42), but not in 12 children with cerebral palsy (MD 0.18, 95% CI -0.09 to 0.45).

AUTHORS' CONCLUSIONS

This update of the review from 2011 provides additional evidence of the efficacy of treadmill intervention for certain groups of children up to six years of age, but power to find significant results still remains limited. The current findings indicate that treadmill intervention may accelerate the development of independent walking in children with Down syndrome and may accelerate motor skill attainment in children with cerebral palsy and general developmental delay. Future research should first confirm these findings with larger and better designed studies, especially for infants with cerebral palsy and developmental delay. Once efficacy is established, research should examine the optimal dosage of treadmill intervention in these populations.

Functional reorganization after hemispherectomy in humans and animal models: What can we learn about the brain's resilience to extensive unilateral lesions?

Hemispherectomy (HS) is an effective surgical procedure aimed at managing otherwise intractable epilepsy in cases of diffuse unihemispheric pathologies. Neurological recovery in subjects treated with HS is not limited to seizure reduction, rather, sensory-motor and behavioral improvement is often observed. This outcome highlights the considerable capability of the brain to react to such an extensive lesion, by functionally reorganizing and rewiring the cerebral cortex, especially early in life. In this narrative review, we summarize the animal studies as well as the human neurophysiological and neuroimaging studies dealing with the reorganizational processes that occur after HS. These topics are of particular interest in understanding mechanisms of functional recovery after brain injury. HS offers the chance to investigate contralesional hemisphere activity in controlling ipsilateral limb movements, and the role of transcallosal interactions, before and after the surgical procedure. These post-injury neuroplastic phenomena actually differ from those observed after less extensive brain damage. Therefore, they illustrate how different lesions could lead the contralesional hemisphere to play the "good" or "bad" role in functional recovery. These issues may have clinical implications and could inform rehabilitation strategies aiming to improve functional recovery following unilateral hemispheric lesions. Future studies, involving large cohorts of hemispherectomized patients, will be necessary in order to obtain a greater understanding of how cerebral reorganization can contribute to residual sensorimotor, visual and auditory functions.

[Hemispherectomy in the treatment of pediatric symptomatic epilepsy of children]

INTRODUCTION AND PURPOSE

Hemispherectomy is a recognized option in the treatment of symptomatic forms of intractable focal epilepsy in patients with developmental brain malformations and some acquired lesions of one the hemispheres. The prognosis for an outcome of the technique is important in terms of the indications for surgical treatment.

MATERIAL AND METHODS

We described the hemispherectomy technique and its variants and analyzed our own experience of surgery in 40 children. The most common (27 cases) brain pathology was extended unilateral cortical dysplasia with polymicro- or pachygyria and consequences of perinatal stroke. Six children had Rasmussen encephalitis; 6 patients had hemimegalencephaly; 1 child with Sturge-Weber syndrome had angiomatosis of the soft meninges. The patients' mean age was 3 years. Functional hemispherectomy (hemispherotomy) was used in most cases (37); 3 patients underwent anatomical hemispherectomy.

RESULTS

At the time of discharge, seizures resolved in all patients; later, no seizure recurrence was observed in 25 out of 29 cases with known follow-up (the follow-up median was 2.5 years), which corresponded to class 1 outcomes on the ILAE scale (86%). Serious complications developed in 2 cases; 1 patient died; hydrocephalus and the need for bypass surgery occurred in other 2 children. These results are discussed along with the literature data, and the indications for hemispherectomy are provided.

CONCLUSION

Hemispherectomy is a reliable and effective technique for treatment of symptomatic hemispheric forms of epilepsy in children. More than in 80% of patients with congenital or acquired pathology of one of the cerebral hemispheres, its deafferentation or resection leads to persistent elimination of seizures. Children with severe forms of intractable epilepsy should be promptly referred to dedicated centers to address the issue of advisability of surgical treatment.

Interpreting Intervention Induced Neuroplasticity with fMRI: The Case for Multimodal Imaging Strategies

Direct measurement of recovery from brain injury is an important goal in neurorehabilitation, and requires reliable, objective, and interpretable measures of changes in brain function, referred to generally as “neuroplasticity.” One popular imaging modality for measuring neuroplasticity is task-based functional magnetic resonance imaging (t-fMRI). In the field of neurorehabilitation, however, assessing neuroplasticity using t-fMRI presents a significant challenge. This commentary reviews t-fMRI changes commonly reported in patients with cerebral palsy or acquired brain injuries, with a focus on studies of motor rehabilitation, and discusses complexities surrounding their interpretations. Specifically, we discuss the difficulties in interpreting t-fMRI changes in terms of their underlying causes, that is, differentiating whether they reflect genuine reorganisation, neurological restoration, compensation, use of preexisting redundancies, changes in strategy, or maladaptive processes. Furthermore, we discuss the impact of heterogeneous disease states and essential t-fMRI processing steps on the interpretability of activation patterns. To better understand therapy-induced neuroplastic changes, we suggest that researchers utilising t-fMRI consider concurrently acquiring information from an additional modality, to quantify, for example, haemodynamic differences or microstructural changes. We outline a variety of such supplementary measures for investigating brain reorganisation and discuss situations in which they may prove beneficial to the interpretation of t-fMRI data.

Predictors and biomarkers of treatment gains in a clinical stroke trial targeting the lower extremity

BACKGROUND AND PURPOSE

Behavioral measures are often used to distinguish subgroups of patients with stroke (eg, to predict treatment gains, stratify clinical trial enrollees, or select rehabilitation therapy). In studies of the upper extremity, measures of brain function using functional magnetic resonance imaging (fMRI) have also been found useful, but this approach has not been examined for the lower extremity. The current study hypothesized that an fMRI-based measure of cortical function would significantly improve prediction of treatment-induced lower extremity behavioral gains. Biomarkers of treatment gains were also explored.

METHODS

Patients with hemiparesis 1 to 12 months after stroke were enrolled in a double-blind, placebo-controlled, randomized clinical trial of ropinirole+physical therapy versus placebo+physical therapy, results of which have previously been reported (NCT00221390).(15) Primary end point was change in gait velocity. Enrollees underwent baseline multimodal assessment that included 19 measures spanning 5 assessment categories (medical history, impairment, disability, brain injury, and brain function), and also underwent reassessment 3 weeks after end of therapy.

RESULTS

In bivariate analysis, 8 baseline measures belonging to 4 categories (medical history, impairment, disability, and brain function) significantly predicted change in gait velocity. Prediction was strongest, however, using a multivariate model containing 2 measures (leg Fugl-Meyer score and fMRI activation volume within ipsilesional foot sensorimotor cortex). Increased activation volume within bilateral foot primary sensorimotor cortex correlated positively with treatment-induced leg motor gains.

CONCLUSIONS

A multimodal model incorporating behavioral and fMRI measures best predicted treatment-induced changes in gait velocity in a clinical trial setting. Results also suggest potential use of fMRI measures as biomarkers of treatment gains.

Betamethasone therapy in ataxia telangiectasia: unraveling the rationale of this serendipitous observation on the basis of the pathogenesis

Ataxia telangiectasia (A-T) is a rare autosomal recessive disorder characterized by progressive neurological dysfunction. To date, only supportive care aimed to halt the progressive neurodegeneration is available for the treatment. Recently, an improvement of neurological signs during short-term treatment with betamethasone has been reported. To date, the molecular and biochemical mechanisms by which the steroid produces such effects have not yet been elucidated. Therefore, a review of the literature was carried out to define the potential molecular and functional targets of the steroid effects in A-T. Glucocorticoids (GCs) are capable of diffusing into the CNS by crossing the blood-brain barrier (BBB) where they exert effects on the suppression of inflammation or as antioxidant. GCs have been shown to protect post-mitotic neurons from apoptosis. Eventually, GCs may also modulate synaptic plasticity. A better understanding of the mechanisms of action of GCs in the brain is needed, because in A-T during the initial phase of cell loss the neurological impairment may be rescued by interfering in the biochemical pathways. This would open a new window of intervention in this so far incurable disease.

Cerebral hemispherectomy: sensory scores before and after intensive mobility training

PURPOSE

It is unclear whether sensory modalities can be modified by rehabilitation and if sensory functions vary on the affected side many years after cerebral hemispherectomy. This pilot, proof-of-concept study assessed light touch and proprioception before and after 10 days of intensive mobility training in individuals after hemispherectomy.

METHODS

Light touch and proprioception of the upper and lower extremity was measured using the Fugl-Meyer sensory subtest on the paretic side in 18 individuals with hemispherectomy before and after mobility training. Sensory scores and differences related to mobility training were compared with clinical variables.

RESULTS

Patients were 7.1±5.7 years from time of surgery to sensory assessment and mobility training. Light touch scores were 81±22% and proprioception values were 64±23% of normal (p=0.0022). Light touch did not correlate with proprioception scores, and differences comparing after with before mobility training did not correlate. In multivariate analysis, younger age at seizure onset correlated with better light touch scores, and older age at onset correlated with improvements in light touch scores with mobility training. By comparison, proprioception scores were better in individuals with perinatal infarcts compared with Rasmussen encephalitis and Sturge-Weber. Post-training, proprioception scores were better in Sturge-Weber cases.

CONCLUSION

Light touch was less affected than proprioception on the paretic side after cerebral hemispherectomy. Improvements with mobility training correlated with older age at seizure onset and etiology. These findings suggest that many years after epilepsy surgery sensory functions are not static supporting the notion of existing developmental neuroplasticity of the remaining cerebral cortex along with brain stem and spinal cord pathways.

Adaptive neuroplastic responses in early and late hemispherectomized monkeys

Behavioural recovery in children who undergo medically required hemispherectomy showcase the remarkable ability of the cerebral cortex to adapt and reorganize following insult early in life. Case study data suggest that lesions sustained early in childhood lead to better recovery compared to those that occur later in life. In these children, it is possible that neural reorganization had begun prior to surgery but was masked by the dysfunctional hemisphere. The degree of neural reorganization has been difficult to study systematically in human infants. Here we present a 20-year culmination of data on our nonhuman primate model (Chlorocebus sabeus) of early-life hemispherectomy in which behavioral recovery is interpreted in light of plastic processes that lead to the anatomical reorganization of the early-damaged brain. The model presented here suggests that significant functional recovery occurs after the removal of one hemisphere in monkeys with no preexisting neurological dysfunctions. Human and primate studies suggest a critical role for subcortical and brainstem structures as well as corticospinal tracts in the neuroanatomical reorganization which result in the remarkable behavioral recovery following hemispherectomy. The non-human primate model presented here offers a unique opportunity for studying the behavioral and functional neuroanatomical reorganization that underlies developmental plasticity.

Functional MRI applications in epilepsy surgery

Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique that has grown rapidly in popularity over the past decade. It is already prevalent in psychology, cognitive and basic neuroscience research and is being used increasingly as a tool for clinical decision-making in epilepsy. It has been used to determine language location and laterality in patients, sometimes eliminating the need for invasive tests. fMRI can been used pre-surgically to guide resection margins, preserving eloquent cortex. Other fMRI paradigms assessing memory, visual and somatosensory systems have limited clinical applications currently, but show great promise. Simultaneous recording of electroencephalogram (EEG) and fMRI has also provided insights into the networks underlying seizure generation and is increasingly being used in epilepsy centres. In this review, we present some of the current clinical applications for fMRI in the pre-surgical assessment of epilepsy patients, and examine a number of new techniques that may soon become clinically relevant.

Should body weight-supported treadmill training and robotic-assistive steppers for locomotor training trot back to the starting gate?

Body weight-supported treadmill training (BWSTT) and robotic-assisted step training (RAST) have not, so far, led to better outcomes than a comparable dose of progressive over-ground training (OGT) for disabled persons with stroke, spinal cord injury, multiple sclerosis, Parkinson's disease, or cerebral palsy. The conceptual bases for these promising rehabilitation interventions had once seemed quite plausible, but the results of well-designed, randomized clinical trials have been disappointing. The authors reassess the underpinning concepts for BWSTT and RAST, which were derived from mammalian studies of treadmill-induced hind-limb stepping associated with central pattern generation after low thoracic spinal cord transection, as well as human studies of the triple crown icons of task-oriented locomotor training, massed practice, and activity-induced neuroplasticity. The authors retrospectively consider where theory and practice may have fallen short in the pilot studies that aimed to produce thoroughbred interventions. Based on these shortcomings, the authors move forward with recommendations for the future development of workhorse interventions for walking. In the absence of evidence for physical therapists to employ these strategies, however, BWSTT and RAST should not be provided routinely to disabled, vulnerable persons in place of OGT outside of a scientifically conducted efficacy trial.

Treadmill interventions with partial body weight support in children under six years of age at risk of neuromotor delay

BACKGROUND

Delayed motor development may occur in children with Down syndrome, cerebral palsy or children born preterm, which in turn may limit the child's opportunities to explore the environment. Neurophysiologic and early intervention literature suggests that task-specific training facilitates motor development. Treadmill intervention is a good example of locomotor task-specific training.

OBJECTIVES

To assess the effectiveness of treadmill intervention on locomotor motor development in pre-ambulatory infants and children under six years of age who are at risk for neuromotor delay.

SEARCH METHODS

In March 2011 we searched CENTRAL (The Cochrane Library 2011, Issue 1), MEDLINE (1948 to March Week 2, 2011), EMBASE (1980 to Week 11, 2011), PsycINFO (1887 to current), CINAHL (1937 to current), Science Citation Index (1970 to 19 March 2011), PEDro (until 7 March 2011), CPCI-S (1990 to 19 March 2011) and LILACS (until March 2011). We also searched ICTRP, ClinicalTrials.gov, mRCT and CenterWatch.

SELECTION CRITERIA

We included randomised controlled trials, quasi-randomised controlled trials and controlled clinical trials that evaluated the effect of treadmill intervention in children up to six years of age with delays in gait development or the attainment of independent walking or who were at risk of neuromotor delay.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted the data using standardised forms. Outcome parameters were structured according to the "Body functions" and "Activity and Participation" components of the International Classification of Functioning, Disability and Health, Children & Youth version (ICFCY), which was developed by the World Health Organization.

MAIN RESULTS

We included five studies, which reported on treadmill intervention in 139 children. Of the 139 children, 73 were allocated to treadmill intervention groups, with the other children serving as controls. The studies varied in the type of population studied (children with Down syndrome, cerebral palsy or who were at risk for neuromotor delay); the type of comparison (for example, treadmill versus no intervention, high intensity treadmill versus low intensity); the time of evaluation (during the intervention or at various intervals after intervention), and the parameters assessed. Due to the diversity of the studies, we were only able to use data from three studies in meta-analyses and these were limited to two outcomes: age of onset of independent walking and gross motor function.Evidence suggested that treadmill intervention could lead to earlier onset of independent walking when compared to no treadmill intervention (two studies; effect estimate -1.47; 95% confidence interval (CI): -2.97, 0.03), though these trials studied two different populations and children with Down syndrome seemed to benefit while it was not clear if this was the case for children at high risk of neuromotor disabilities. Another two studies, both in children with Down syndrome, compared different types of treadmill intervention: one compared treadmill intervention with and without orthotics, while the other compared high versus low intensity treadmill intervention. Both were inconclusive regarding the impact of these different protocols on the age at which children started to walk.There is insufficient evidence to determine whether treadmill intervention improves gross motor function (two studies; effect estimate 0.88; 95% CI: -4.54, 6.30). In the one study evaluating treadmill with and without orthotics, results suggested that adding orthotics might hinder gross motor progress (effect estimate -8.40; 95% CI: -14.55, -2.25).One study of children with Down syndrome measured the age of onset of assisted walking and reported those receiving the treadmill intervention were able to walk with assistance earlier than those who did not receive the intervention (effect estimate -74.00; 95% CI: -135.40, -12.60). Another study comparing high and low intensity treadmill was unable to conclude whether one was more effective than the other in helping children achieve supported walking at an earlier age (effect estimate -1.86; 95% CI: -4.09, 0.37).One study of children at high risk of neuromotor disabilities evaluated step quality and found a statistically significant benefit from treadmill intervention compared to no treadmill intervention (effect estimate at 16 months of age: -15.61; 95% CI: -23.96, -7.27), but was not able to conclude whether there was a beneficial effect from treadmill training on step frequency at the same age (effect estimate at 16 months of age: 4.36; 95% CI: -2.63, 11.35). Step frequency was also evaluated in children with Down syndrome in another study and those who received high intensity rather than low intensity treadmill training showed an increased number of alternating steps (effect estimate 11.00; 95% CI: 6.03, 15.97).Our other primary outcome, falls and injuries due to falls, was not measured in any of the included studies.

AUTHORS' CONCLUSIONS

The current review provided only limited evidence of the efficacy of treadmill intervention in children up to six years of age. Few studies have assessed treadmill interventions in young children using an appropriate control group (which would be usual treatment or no treatment). The available evidence indicates that treadmill intervention may accelerate the development of independent walking in children with Down syndrome. Further research is needed to confirm this and should also address whether intensive treadmill intervention can accelerate walking onset in young children with cerebral palsy and high risk infants, and whether treadmill intervention has a general effect on gross motor development in the various subgroups of young children at risk for developmental delay.

A combined robotic and cognitive training for locomotor rehabilitation: evidences of cerebral functional reorganization in two chronic traumatic brain injured patients

It has been demonstrated that automated locomotor training can improve walking capabilities in spinal cord-injured subjects but its effectiveness on brain damaged patients has not been well established. A possible explanation of the discordant results on the efficacy of robotic training in patients with cerebral lesions could be that these patients, besides stimulation of physiological motor patterns through passive leg movements, also need to train the cognitive aspects of motor control. Indeed, another way to stimulate cerebral motor areas in paretic patients is to use the cognitive function of motor imagery. A promising possibility is thus to combine sensorimotor training with the use of motor imagery. The aim of this paper is to assess changes in brain activations after a combined sensorimotor and cognitive training for gait rehabilitation. The protocol consisted of the integrated use of a robotic gait orthosis prototype with locomotor imagery tasks. Assessment was conducted on two patients with chronic traumatic brain injury and major gait impairments, using functional magnetic resonance imaging. Physiatric functional scales were used to assess clinical outcomes. Results showed greater activation post-training in the sensorimotor and supplementary motor cortices, as well as enhanced functional connectivity within the motor network. Improvements in balance and, to a lesser extent, in gait outcomes were also found.

Lateralization of motor innervation in children with intractable focal epilepsy--a TMS and fMRI study

PURPOSE

To correlate hand function with lateralization of motor innervation, as studied with transcranial magnetic stimulation (TMS) and functional magnetic imaging (fMRI), in children with intractable epilepsy and lesions in the vicinity of the motor cortex.

METHODS

In 34 children hand motor function was examined and motor evoked potentials (MEPs) were recorded after TMS of both hemispheres, establishing lateralization of corticospinal innervation. When feasible, patients underwent fMRI using a manual motor task.

RESULTS

Good function of the contralesional hand was associated with early lesions (p=0.02). Lateralization of motor innervation to the contralesional hand correlated with quality of motor function (p=0.001); 83% of children with poor hand function had ipsi- or bilateral innervation, whereas all children with good hand function had pure contralateral control. Mirror movements during movement of the unaffected hand predicted ipsilateral contribution to motor innervation (p=0.006). Fourteen children who had no TMS responses were younger than those with elicitable MEPs (p<0.001). TMS led to a temporary increase of seizure frequency in four children. fMRI results were concordant with TMS.

CONCLUSIONS

Poor function of the contralesional hand is strongly associated with ipsilateral motor innervation. Reorganization in the lesioned hemisphere mainly occurs in early developmental lesions and seems efficient in maintaining good hand function. Clinical examination of hand function has predictive value for the pattern of motor innervation prior to epilepsy surgery, which in older children can further be established by TMS and fMRI.

Effectiveness of treadmill training in children with motor impairments: an overview of systematic reviews

PURPOSE

The purpose of this review was to synthesize current evidence from systematic reviews on the effectiveness of treadmill training (TT), including partial body-weight support (PBWS) TT (PBWSTT), TT only, robotic-assist PBWSTT, and mixed TT, in children with motor impairments.

METHODS

Systematic literature searches were conducted in 10 databases through May 2010. Two reviewers independently selected titles, abstracts (k = 0.78), and full-text articles (k = 1.0). Of the 1166 titles retrieved, 5 studies met the inclusion criteria. Quality of included studies was assessed using AMSTAR criteria.

RESULTS

Results of each systematic review were tabulated on the basis of levels of evidence, with outcomes categorized according to the International Classification of Functioning, Disability, and Health framework. Conflicting interpretations of outcomes were found between reviews, yet conclusions were similar.

CONCLUSIONS

TT demonstrates encouraging results, but more rigorous research is needed before clinicians can be confident of its effectiveness and clinical guidelines can be developed.

Rehabilitation of gait speed after stroke: a critical review of intervention approaches

PURPOSE

Walking speed is a cardinal indicator of poststroke gait performance; however, no consensus exists regarding the optimal treatment method(s) for its enhancement. The most widely accepted criterion for establishing the contribution of treatment to walking speed is the gain in speed. The actual speed, however, at the end of the intervention (final speed) may be more important for functional community ambulation. This review examines the contribution of the prevailing methods for gait rehabilitation to final walking speed.

METHOD

Walking speed information was derived from studies included in meta-analyses, systematic reviews, and clinical practice guidelines. Recent references, not included in the mentioned sources, were incorporated in cases when gait speed was an outcome variable. Final speed was assessed by the reported speed values and by inferring the capacity for functional community walking at the end of the intervention period.

RESULTS

Similar outcomes for final walking speed were found for the different prevailing treatment methods. Treatment gains were likewise comparable and generally insufficient for upgrading patients' functional community walking capacity.

CONCLUSIONS

Different treatment methods exist for poststroke gait rehabilitation. Their availability, mode of application, and costs vary, yet outcomes are largely similar. Therefore, choosing an appropriate method may be guided by a pragmatic approach. Simple "low technology" and conventional exercise to date is at least as efficacious as more complex strategies such as treadmill and robotic-based interventions.

Partial recovery of hemiparesis following hemispherectomy in infant monkeys

Hemiparesis, unilateral weakness or partial paralysis, is a common outcome following hemispherectomy in humans. We use the non-human primate as an invaluable translational model for our understanding of developmental plasticity in response to hemispherectomy. Three infant vervet monkeys (Chlorocebus sabeus) underwent hemispherectomy at a median age of 9 weeks and two additional monkeys at 48 months. Gross motor assessment was conducted in a large open field that contained a horizontal bar spanning the width of the cage. Subjects were assessed yearly following surgery in infantile lesions for a period of 3 years. Adult-lesioned subjects were assessed 40 months following surgery. Shortly after surgery both infant and adult-lesioned subjects were unable to move the contralateral side of their body, but all subjects were able to walk within 6 months following surgery. At each time point the lower limb gait was normal in infant-lesioned subjects with no apparent limp or dragging, however the upper limb demonstrated significant impairment. Horizontal bar crossing was significantly impaired during the first 24 months following surgery. Adult-lesioned subjects also displayed upper limb movement impairments similar to infant-lesioned subjects. In addition the adult-lesioned subjects displayed a noticeable lower limb limp, which was not observed in the infant-lesioned group. Both groups at each time point showed a propensity for ipsiversive turning. The upper limb gait impairment and horizontal bar crossing of lesioned subjects are reminiscent of hemiparesis seen in hemisperectomized humans with the young-lesioned subjects showing a greater propensity for recovery.

Plasticity in the developing brain: implications for rehabilitation

Neuronal plasticity allows the central nervous system to learn skills and remember information, to reorganize neuronal networks in response to environmental stimulation, and to recover from brain and spinal cord injuries. Neuronal plasticity is enhanced in the developing brain and it is usually adaptive and beneficial but can also be maladaptive and responsible for neurological disorders in some situations. Basic mechanisms that are involved in plasticity include neurogenesis, programmed cell death, and activity-dependent synaptic plasticity. Repetitive stimulation of synapses can cause long-term potentiation or long-term depression of neurotransmission. These changes are associated with physical changes in dendritic spines and neuronal circuits. Overproduction of synapses during postnatal development in children contributes to enhanced plasticity by providing an excess of synapses that are pruned during early adolescence. Clinical examples of adaptive neuronal plasticity include reorganization of cortical maps of the fingers in response to practice playing a stringed instrument and constraint-induced movement therapy to improve hemiparesis caused by stroke or cerebral palsy. These forms of plasticity are associated with structural and functional changes in the brain that can be detected with magnetic resonance imaging, positron emission tomography, or transcranial magnetic stimulation (TMS). TMS and other forms of brain stimulation are also being used experimentally to enhance brain plasticity and recovery of function. Plasticity is also influenced by genetic factors such as mutations in brain-derived neuronal growth factor. Understanding brain plasticity provides a basis for developing better therapies to improve outcome from acquired brain injuries.

Rhythmic exercises in rehabilitation of TBI patients: a case report

SUMMARY

Patients who have sustained traumatic brain injury (TBI) often present with a multiplicity of dysfunctions making rehabilitation challenging. Patients who have taken part in studies of rehabilitation exercises that incorporated monotonous timed auditory cues (using a metronome) following cerebrovascular events demonstrated improvement in gait and motor functions. The purpose of this case report is to describe the efficacy of Rhythmic Exercises with Auditory Cues (REAC) to improve functions in a patient, years after their traumatic brain injury.

METHODS

A single case report of a 24-year-old female patient, nine years post hemispherectomy following TBI that resulted in right hemiparesis. The patient was taught to perform REAC exercises at home. These exercises were designed to activate the body while Alternating hands and feet Bilaterally with Cross-midline movements for a short Duration while synchronizing the movements with a metronome as a Rhythm regulator. Outcome measurements included gait and functional assessment and cognitive and psychological instrument scores that were compared pre and post treatment. Clinical improvement was observed in the patient's gait pattern with reduced hip hiking motion and increased cadence. There was a decrease in spasticity in the right arm and leg with some isolated volitional movements of the hand and fingers returning. She also regained sensation in her right arm and leg. Cognitive improvement was demonstrated by increased IQ scores from 78 to 94.

Brain activity changes associated with treadmill training after stroke

BACKGROUND AND PURPOSE

The mechanisms underlying motor recovery after stroke are not fully understood. Several studies used functional MRI longitudinally to relate brain activity changes with performance gains of the upper limb after therapy, but research into training-induced recovery of lower limb function has been relatively neglected thus far.

METHODS

We investigated functional reorganization after 4 weeks of treadmill training with partial body weight support in 18 chronic patients (mean age, 59.9+/-13.5 years) with mild to moderate paresis (Motricity Index affected leg: 77.7+/-10.5; range, 9 to 99) and gait impairment (Functional Ambulation Category: 4.4+/-0.6; range, 3 to 5) due to a single subcortical ischemic stroke using repeated 3.0-T functional MRI and an ankle-dorsiflexion paradigm.

RESULTS

Walking endurance improved after training (2-minute timed walking distance: 121.5+/-39.0 versus pre: 105.1+/-38.1 m; P=0.0001). For active movement of the paretic foot versus rest, greater walking endurance correlated with increased brain activity in the bilateral primary sensorimotor cortices, the cingulate motor areas, and the caudate nuclei bilaterally and in the thalamus of the affected hemisphere.

CONCLUSIONS

Despite the strong subcortical contributions to gait control, rehabilitation-associated walking improvements are associated with cortical activation changes. This is similar to findings in upper limb rehabilitation with some differences in the involved cortical areas. We observed bihemispheric activation increases with greater recovery both in cortical and subcortical regions with movement of the paretic foot. However, although the dorsal premotor cortex appears to play an important role in recovery of hand movements, evidence for the involvement of this region in lower extremity recovery was not found.

Progressive Staging of Pilot Studies to Improve Phase III Trials for Motor Interventions

Based on the suboptimal research pathways that finally led to multicenter randomized clinical trials (MRCTs) of treadmill training with partial body weight support and of robotic assistive devices, strategically planned successive stages are proposed for pilot studies of novel rehabilitation interventions. Stage 1, consideration-of-concept studies, drawn from animal experiments, theories, and observations, delineate the experimental intervention in a small convenience sample of participants, so the results must be interpreted with caution. Stage 2, development-of-concept pilots, should optimize the components of the intervention, settle on most appropriate outcome measures, and examine dose-response effects. A well-designed study that reveals no efficacy should be published to counterweight the confirmation bias of positive trials. Stage 3, demonstration-of-concept pilots, can build out from what has been learned to test at least 15 participants in each arm, using random assignment and blinded outcome measures. A control group should receive an active practice intervention aimed at the same primary outcome. A third arm could receive a substantially larger dose of the experimental therapy or a combinational intervention. If only 1 site performed this trial, a different investigative group should aim to reproduce positive outcomes based on the optimal dose of motor training. Stage 3 studies ought to suggest an effect size of 0.4 or higher, so that approximately 50 participants in each arm will be the number required to test for efficacy in a stage 4, proof-of-concept MRCT. By developing a consensus around acceptable and necessary practices for each stage, similar to CONSORT recommendations for the publication of phase III clinical trials, better quality pilot studies may move quickly into better designed and more successful MRCTs of experimental interventions.

A New System for Monitoring Gait Training in Infants With Down Syndrome

Infants with Down syndrome show an altered pattern of motor development at early childhood. Treadmill-walking training can be used to promote the earlier attainment of motor milestones in infants with locomotion deficiencies but quantitative data on their motor development are limited to gait laboratory studies. Our purpose was to develop, validate, and test a low-cost portable system for detecting infant steps on a treadmill while training. The system includes five infrared distance sensors, which were placed on a motorized treadmill to record the location of the feet of the infant during walking and thus measure his/her step length and cadence. The system was validated using synthetic objects, with a healthy 13-month-old infant. Pilot studies were then conducted in additional five infants with Down syndrome (aged 11–28 months) to determine step length (17.5–22.3 cm) and cadence (0.33–2.16 steps/s) at baseline, as well as at follow-ups 1 month and 3 months after the first trial. Measurements were repeatable per session and agreed with values reported in the literature. These pilot studies indicate the potential utility of the present system in quantitative monitoring of the process of acquisition of initial gait in infants with Down syndrome at the care facility where routine therapy is given.

Constraint-induced movement therapy for individuals after cerebral hemispherectomy: a case series

BACKGROUND AND PURPOSE

This case report describes the feasibility and efficacy of the use of constraint-induced movement therapy (CIMT) in 4 individuals (aged 12-22 years) who underwent cerebral hemispherectomy (age at time of surgery=4-10 years). The aims of this case series were: (1) to evaluate the feasibility of this therapeutic approach involving a shortened version of CIMT, (2) to examine improvements that occurred within the upper extremity of the hemiparetic side, (3) to investigate the feasibility of conducting brain imaging in individuals with depressed mental ages, and (4) to examine changes in the sensorimotor cortex following intervention.

CASE DESCRIPTION

The patients received a shortened version of CIMT for 3 hours each day for a period of 10 days. In addition, a standard resting splint was used for the unimpaired hand for an 11-day period. Each patient was encouraged to wear the splint for 90% of his or her waking hours. The following outcome measures were used: the Actual Amount of Use Test (AAUT), the Box and Block Test (BBT), and the upper-extremity grasping and motor portions of the Fugl-Meyer Assessment of Motor Recovery (FM).

OUTCOMES

Immediately after therapy, improvements were found in AAUT and BBT scores, but no improvements were found in FM scores. Three patients underwent brain imaging before and after therapy and showed qualitative changes consistent with reorganization of sensorimotor cortical representations of both paretic and nonparetic hands in one isolated hemisphere.

DISCUSSION

The findings suggest that CIMT may be a feasible method of rehabilitation in individuals with chronic hemiparesis, possibly leading to neuroplastic therapy-related changes in the brain.

A systematic review of the effectiveness of treadmill training and body weight support in pediatric rehabilitation

BACKGROUND AND PURPOSE

Given the extensive literature on body weight-supported treadmill training (BWSTT) in adult rehabilitation, a systematic review was undertaken to explore the strength, quality, and conclusiveness of evidence supporting use of treadmill training and body weight support in those with pediatric motor disabilities. A secondary goal was to ascertain whether protocol guidelines for BWSTT are available to guide pediatric physical therapy practice.

METHODS

The database search included MEDLINE, EMBASE, CINAHL Plus, PEDro, Cochrane Library databases, and ERIC from January 1, 1980 to May 31, 2008 for articles that included treadmill training and body weight support for individuals under 21 years of age, with or at risk for a motor disability. We identified 277 unique articles from which 29 met all inclusion criteria.

RESULTS

Efficacy of treadmill training in accelerating walking development in Down syndrome has been well demonstrated. Evidence supporting efficacy or effectiveness of BWSTT in pediatric practice for improving gait impairments and level of activity and participation in those with cerebral palsy, spinal cord injury, and other central nervous system disorders remains insufficient, although many studies noted positive effects.

DISCUSSION AND CONCLUSION

The original evidence demonstrates efficacy of BWSTT in children with Down syndrome, but large-scale controlled trials are needed to support the use of BWSTT in other pediatric subgroups. Increased use of randomized designs, studies with treadmill training-only groups, and dosage studies are needed before practice guidelines can be formulated. Neural changes in response to training warrant exploration, especially given the capacity for change in developing nervous systems.

Motor and cognitive outcomes in children after functional hemispherectomy

PURPOSE

Medically intractable epilepsy is a chronic recurrence of seizures that often requires surgery to reduce or eliminate them. Although a reduction of seizures is the primary goal of hemispherectomy, the effect of surgery on motor and cognitive skills is also of importance. This review will provide a discussion of (1) evidence regarding motor and cognitive outcomes, (2) predictors of these outcomes, and (3) neural mechanisms responsible for preservation of function after hemispherectomy.

SUMMARY OF KEY POINTS

Motor and cognitive outcomes after hemispherectomy are variable and depend on many predictors including etiology and duration of seizure disorder, age at the time of surgery, premorbid status, and postsurgical seizure control. A refined ipsilateral pathway may explain the preservation of motor function in some children.

CONCLUSIONS

A clear understanding of outcome predictors is important for planning effective rehabilitative programs after surgery.

Electrodermal recording and fMRI to inform sensorimotor recovery in stroke patients

BACKGROUND

Functional magnetic resonance imaging (fMRI) appears to be useful for investigating motor recovery after stroke. Some of the potential confounders of brain activation studies, however, could be mitigated through complementary physiological monitoring.

OBJECTIVE

To investigate a sensorimotor fMRI battery that included simultaneous measurement of electrodermal activity in subjects with hemiparetic stroke to provide a measure related to the sense of effort during motor performance.

METHODS

Bilateral hand and ankle tasks were performed by 6 patients with stroke (2 subacute, 4 chronic) during imaging with blood oxygen level-dependent (BOLD) fMRI using an event-related design. BOLD percent changes, peak activation, and laterality index values were calculated in the sensorimotor cortex. Electrodermal recordings were made concurrently and used as a regressor.

RESULTS

Sensorimotor BOLD time series and percent change values provided evidence of an intact motor network in each of these well-recovered patients. During tasks involving the hemiparetic limb, electrodermal activity changes were variable in amplitude, and electrodermal activity time-series data showed significant correlations with fMRI in 3 of 6 patients. No such correlations were observed for control tasks involving the unaffected lower limb.

CONCLUSIONS

Electrodermal activity activation maps implicated the contralesional over the ipsilesional hemisphere, supporting the notion that stroke patients may require higher order motor processing to perform simple tasks. Electrodermal activity recordings may be useful as a physiological marker of differences in effort required during movements of a subject's hemiparetic compared with the unaffected limb during fMRI studies.

Fatigue versus activity-dependent fatigability in patients with central or peripheral motor impairments

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.

Training and exercise to drive poststroke recovery

To make practical recommendations regarding therapeutic strategies for the rehabilitation of patients with hemiparetic stroke, it is important to have a general understanding of the fundamental mechanisms underlying the neuroplasticity that is induced by skills training and by exercise programs designed to increase muscle strength and cardiovascular fitness. Recent clinical trials have provided insights into methods that promote adaptations within the nervous system that correlate with improved walking and upper extremity function, and that can be instigated at any time after stroke onset. Data obtained to date indicate that patients who have mild to moderate levels of impairment and disability can benefit from interventions that depend on repetitive task-oriented practice at the intensity and duration necessary to reach a plateau in a reacquired skill. Studies are underway to lessen the consequences of more-severe motor deficits by drawing on medications that augment plasticity, biological interventions that promote neural repair, and strategies that employ electrical stimulation and robotics.