Executive function improvement in response to meta-cognitive training in chronic mTBI / PTSD

Objective

We tested Goal Management Training (GMT), which has been recommended as an executive training protocol that may improve the deficits in the complex tasks inherent in life role participation experienced by those with chronic mild traumatic brain injury and post-traumatic stress disease (mTBI/PTSD). We assessed, not only cognitive function, but also life role participation (quality of life).

Methods

We enrolled and treated 14 individuals and administered 10 GMT sessions in-person and provided the use of the Veterans Task Manager (VTM), a Smartphone App, which was designed to serve as a "practice-buddy" device to ensure translation of in-person learning to independent home and community practice of complex tasks. Pre-/post-treatment primary measure was the NIH Examiner, Unstructured Task. Secondary measures were as follows: Tower of London time to complete (cTOL), Community Reintegration of Service Members (CRIS) three subdomains [Extent of Participation; Limitations; Satisfaction of Life Role Participation (Satisfaction)]. We analyzed pre-post-treatment, t-test models to explore change, and generated descriptive statistics to inspect given individual patterns of change across measures.

Results

There was statistically significant improvement for the NIH EXAMINER Unstructured Task (p < .02; effect size = .67) and cTOL (p < .01; effect size = .52. There was a statistically significant improvement for two CRIS subdomains: Extent of Participation (p < .01; effect size = .75; Limitations (p < .05; effect size = .59). Individuals varied in their treatment response, across measures.

Conclusions and Clinical Significance

In Veterans with mTBI/PTSD in response to GMT and the VTM learning support buddy, there was significant improvement in executive cognition processes, sufficiently robust to produce significant improvement in community life role participation. The individual variations support need for precision neurorehabilitation. The positive results occurred in response to treatment advantages afforded by the content of the combined GMT and the employment of the VTM learning support buddy, with advantages including the following: manualized content of the GMT; incremental complex task difficulty; GMT structure and flexibility to incorporate individualized functional goals; and the VTM capability of ensuring translation of in-person instruction to home and community practice, solidifying newly learned executive cognitive processes. Study results support future study, including a potential randomized controlled trial, the manualized GMT and availability of the VTM to ensure future clinical deployment of treatment, as warranted.

Targeting CNS Neural Mechanisms of Gait in Stroke Neurorehabilitation

The central nervous system (CNS) control of human gait is complex, including descending cortical control, affective ascending neural pathways, interhemispheric communication, whole brain networks of functional connectivity, and neural interactions between the brain and spinal cord. Many important studies were conducted in the past, which administered gait training using externally targeted methods such as treadmill, weight support, over-ground gait coordination training, functional electrical stimulation, bracing, and walking aids. Though the phenomenon of CNS activity-dependent plasticity has served as a basis for more recently developed gait training methods, neurorehabilitation gait training has yet to be precisely focused and quantified according to the CNS source of gait control. Therefore, we offer the following hypotheses to the field: Hypothesis 1. Gait neurorehabilitation after stroke will move forward in important ways if research studies include brain structural and functional characteristics as measures of response to treatment. Hypothesis 2. Individuals with persistent gait dyscoordination after stroke will achieve greater recovery in response to interventions that incorporate the current and emerging knowledge of CNS function by directly engaging CNS plasticity and pairing it with peripherally directed, plasticity-based motor learning interventions. These hypotheses are justified by the increase in the study of neural control of motor function, with emerging research beginning to elucidate neural factors that drive recovery. Some are developing new measures of brain function. A number of groups have developed and are sharing sophisticated, curated databases containing brain images and brain signal data, as well as other types of measures and signal processing methods for data analysis. It will be to the great advantage of stroke survivors if the results of the current state-of-the-art and emerging neural function research can be applied to the development of new gait training interventions.

Trajectories of stroke recovery of impairment, function, and quality of life in response to 12-month mobility and fitness intervention

BACKGROUND

Gait deficits and functional disability are persistent problems for many stroke survivors, even after standard neurorehabilitation. There is little quantified information regarding the trajectories of response to a long-dose, 12-month intervention.

OBJECTIVE

We quantified treatment response to an intensive neurorehabilitation mobility and fitness program.

METHODS

The 12-month neurorehabilitation program targeted impairments in balance, limb coordination, gait coordination, and functional mobility, for five chronic stroke survivors. We obtained measures of those variables every two months.

RESULTS

We found statistically and clinically significant group improvement in measures of impairment and function. There was high variation across individuals in terms of the timing and the gains exhibited.

CONCLUSIONS

Long-duration neurorehabilitation (12 months) for mobility/fitness produced clinically and/or statistically significant gains in impairment and function. There was unique pattern of change for each individual. Gains exhibited late in the treatment support a 12-month intervention. Some measures for some subjects did not reach a plateau at 12 months, justifying further investigation of a longer program (>12 months) of rehabilitation and/or maintenance care for stroke survivors.

Four methods of brain pattern analyses of fMRI signals associated with wrist extension versus wrist flexion studied for potential use in future motor learning BCI

OBJECTIVE

In stroke survivors, a treatment-resistant problem is inability to volitionally differentiate upper limb wrist extension versus flexion. When one intends to extend the wrist, the opposite occurs, wrist flexion, rendering the limb non-functional. Conventional therapeutic approaches have had limited success in achieving functional recovery of patients with chronic and severe upper extremity impairments. Functional magnetic resonance imaging (fMRI) neurofeedback is an emerging strategy that has shown potential for stroke rehabilitation. There is a lack of information regarding unique blood-oxygenation-level dependent (BOLD) cortical activations uniquely controlling execution of wrist extension versus uniquely controlling wrist flexion. Therefore, a first step in providing accurate neural feedback and training to the stroke survivor is to determine the feasibility of classifying (or differentiating) brain activity uniquely associated with wrist extension from that of wrist flexion, first in healthy adults.

APPROACH

We studied brain signal of 10 healthy adults, who performed wrist extension and wrist flexion during fMRI data acquisition. We selected four types of analyses to study the feasibility of differentiating brain signal driving wrist extension versus wrist flexion, as follows: 1) general linear model (GLM) analysis; 2) support vector machine (SVM) classification; 3) 'Winner Take All'; and 4) Relative Dominance.

RESULTS

With these four methods and our data, we found that few voxels were uniquely active during either wrist extension or wrist flexion. SVM resulted in only minimal classification accuracies. There was no significant difference in activation magnitude between wrist extension versus flexion; however, clusters of voxels showed extension signal > flexion signal and other clusters vice versa. Spatial patterns of activation differed among subjects.

SIGNIFICANCE

We encountered a number of obstacles to obtaining clear group results in healthy adults. These obstacles included the following: high variability across healthy adults in all measures studied; close proximity of uniquely active voxels to voxels that were common to both the extension and flexion movements; in general, higher magnitude of signal for the voxels common to both movements versus the magnitude of any given uniquely active voxel for one type of movement. Our results indicate that greater precision in imaging will be required to develop a truly effective method for differentiating wrist extension versus wrist flexion from fMRI data.

Construct Validity of the Gait Assessment and Intervention Tool (GAIT) in People With Multiple Sclerosis

INTRODUCTION

In clinical practice, observational scales are the most common approach used to assess gait pattern in people with neurological disorders. The Gait Assessment and Intervention Tool (GAIT) is an observational gait scale, and it has proved to be the most comprehensive, homogeneous, and objective of all the observational gait scales studied in people with neurological conditions.

OBJECTIVE

To study the construct validity of the GAIT in people with multiple sclerosis (MS).

DESIGN

An observational study was conducted.

SETTING

Multiple Sclerosis Foundation in Madrid (Spain).

PATIENTS

Thirty-five patients with MS were assessed.

MAIN OUTCOME MEASURE(S)

GAIT construct validity was assessed using the following scales: Rivermead Visual Gait Assessment (RVGA), Tinetti Gait Scale (TGS), 10-Meter Walking Test (10MWT), Timed Up&Go (TUG), Hauser Ambulatory Index (HAI), Multiple Sclerosis Walking Scale-12 (MSWS-12), Functional Gait Assessment (FGA), Modified Ashworth Scale (MAS), and Rivermead Mobility Index (RMI).

RESULTS

A total of 35 subjects with MS were assessed. The correlations between the GAIT and the RVGA were excellent (r > .90) and moderate with TGS (values between -.62 and -.59). Correlations with HAI, FGA, MSWS-12, and RMI were moderate (with values between .57 and .67). Correlations were lower for the velocity scales TUG and MAS.

CONCLUSIONS

The construct validity of the GAIT is high, as a measure of gait coordination in people with MS. Specifically, there was excellent correlation with the RVGA. There was a moderate correlation for the GAIT with measures of functional mobility, but a lesser correlation of the GAIT with measures restricted to temporal gait characteristics (speed measures) or measurements of impairments underlying gait patterns such as balance or muscle tone.

Development of a combined, sequential real-time fMRI and fNIRS neurofeedback system to enhance motor learning after stroke

BACKGROUND

After stroke, wrist extension dyscoordination precludes functional arm/hand. We developed a more spatially precise brain signal for use in brain computer interface (BCI's) for stroke survivors.

NEW METHOD

Combination BCI protocol of real-time functional magnetic resonance imaging (rt-fMRI) sequentially followed by functional near infrared spectroscopy (rt-fNIRS) neurofeedback, interleaved with motor learning sessions without neural feedback. Custom Matlab and Python code was developed to provide rt-fNIRS-based feedback to the chronic stroke survivor, system user.

RESULTS

The user achieved a maximum of 71 % brain signal accuracy during rt-fNIRS neural training; progressive focus of brain activation across rt-fMRI neural training; increasing trend of brain signal amplitude during wrist extension across rt-fNIRS training; and clinically significant recovery of arm coordination and active wrist extension.

COMPARISON WITH EXISTING METHODS

Neurorehabilitation, peripherally directed, shows limited efficacy, as do EEG-based BCIs, for motor recovery of moderate/severely impaired stroke survivors. EEG-based BCIs are based on electrophysiological signal; whereas, rt-fMRI and rt-fNIRS are based on neurovascular signal.

CONCLUSION

The system functioned well during user testing. Methods are detailed for others' use. The system user successfully engaged rt-fMRI and rt-fNIRS neurofeedback systems, modulated brain signal during rt-fMRI and rt-fNIRS training, according to volume of brain activation and intensity of signal, respectively, and clinically significantly improved limb coordination and active wrist extension. fNIRS use in this case demonstrates a feasible/practical BCI system for further study with regard to use in chronic stroke rehab, and fMRI worked in concept, but cost and some patient-use issues make it less feasible for clinical practice.

Reliability and Minimal Detectable Change in the Gait Assessment and Intervention Tool in Patients With Multiple Sclerosis

BACKGROUND

Gait impairment is one of the main causes of disability in people with multiple sclerosis. The Gait Assessment and Intervention Tool is an observational gait scale that assesses kinematic parameters using video recordings.

OBJECTIVE

To study intra- and interrater reliability and the minimal detectable change of the Gait Assessment and Intervention Tool in individuals with multiple sclerosis.

DESIGN

Observational study.

SETTING

Multiple Sclerosis Foundation.

PARTICIPANTS

Thirty-five participants with multiple sclerosis were assessed (12 men, 23 women; 47.7 ± 11 y; Expanded Disability Status Scale = 4.32 ± 1.4).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASUREMENTS

Intra- and interrater reliability of the Gait Assessment and Intervention Tool was assessed for each limb using the Intraclass Correlation Coefficient. In addition, the minimal detectable change was calculated.

RESULTS

The Intraclass Correlation Coefficient for the intrarater reliability was found to be excellent for the total score both for the right side (.91; 95% confidence interval 95% CI .85-.95) and the left side (.93; 95% CI .88-.96). The intraclass correlation coefficient for the interrater reliability was .91 (95% CI .85-.95) for the right side, and .93 (95% CI .88-.96) for the left side. The minimal detectable change for the intrarater reliability was 1.19 points for the right side and .77 for the left side.

CONCLUSIONS

The Gait Assessment and Intervention Tool exhibits excellent intra- and interrater reliability and a small minimal detectable change for people with multiple sclerosis.

Long-Dose Intensive Therapy Is Necessary for Strong, Clinically Significant, Upper Limb Functional Gains and Retained Gains in Severe/Moderate Chronic Stroke

Background. Effective treatment methods are needed for moderate/severely impairment chronic stroke. Objective. The questions were the following: (1) Is there need for long-dose therapy or is there a mid-treatment plateau? (2) Are the observed gains from the prior-studied protocol retained after treatment? Methods. Single-blind, stratified/randomized design, with 3 applied technology treatment groups, combined with motor learning, for long-duration treatment (300 hours of treatment). Measures were Arm Motor Ability Test time and coordination-function (AMAT-T, AMAT-F, respectively), acquired pre-/posttreatment and 3-month follow-up (3moF/U); Fugl-Meyer (FM), acquired similarly with addition of mid-treatment. Findings. There was no group difference in treatment response (P ≥ .16), therefore data were combined for remaining analyses (n = 31; except for FM pre/mid/post, n = 36). Pre-to-Mid-treatment and Mid-to-Posttreatment gains of FM were statistically and clinically significant (P < .0001; 4.7 points and P < .001; 5.1 points, respectively), indicating no plateau at 150 hours and benefit of second half of treatment. From baseline to 3moF/U: (1) FM gains were twice the clinically significant benchmark, (2) AMAT-F gains were greater than clinically significant benchmark, and (3) there was statistically significant improvement in FM (P < .0001); AMAT-F (P < .0001); AMAT-T (P < .0001). These gains indicate retained clinically and statistically significant gains at 3moFU. From posttreatment to 3moF/U, gains on FM were maintained. There were statistically significant gains in AMAT-F (P = .0379) and AMAT-T P = .003.

Interpreting Prefrontal Recruitment During Walking After Stroke: Influence of Individual Differences in Mobility and Cognitive Function

Background: Functional near-infrared spectroscopy (fNIRS) is a valuable neuroimaging approach for studying cortical contributions to walking function. Recruitment of prefrontal cortex during walking has been a particular area of focus in the literature. The present study investigated whether task-related change in prefrontal recruitment measured by fNIRS is affected by individual differences in people post-stroke. The primary hypotheses were that poor mobility function would contribute to prefrontal over-recruitment during typical walking, and that poor cognitive function would contribute to a ceiling in prefrontal recruitment during dual-task walking (i.e., walking with a cognitive task). Methods: Thirty-three adults with chronic post-stroke hemiparesis performed three tasks: typical walking at preferred speed (Walk), serial-7 subtraction (Serial7), and walking combined with serial-7 subtraction (Dual-Task). Prefrontal recruitment was measured with fNIRS and quantified as the change in oxygenated hemoglobin concentration (ΔO2Hb) between resting and active periods for each task. Spatiotemporal gait parameters were measured on an electronic walkway. Stepwise regression was used to assess how prefrontal recruitment was affected by individual differences including age, sex, stroke region, injured hemisphere, stroke chronicity, 10-meter walking speed, balance confidence measured by Activities-specific Balance Confidence (ABC) Scale, sensorimotor impairment measured by Fugl-Meyer Assessment, and cognitive function measured by Mini-Mental State Examination (MMSE). Results: For Walk, poor balance confidence (ABC Scale score) significantly predicted greater prefrontal recruitment (ΔO2Hb; R 2 = 0.25, p = 0.003). For Dual-Task, poor cognitive function (MMSE score) significantly predicted lower prefrontal recruitment (ΔO2Hb; R 2 = 0.25, p = 0.002). Conclusions: Poor mobility function predicted higher prefrontal recruitment during typical walking, consistent with compensatory over-recruitment. Poor cognitive function predicted lower prefrontal recruitment during dual-task walking, consistent with a recruitment ceiling effect. These findings indicate that interpretation of prefrontal recruitment should carefully consider the characteristics of the person and demands of the task.

Spanish Cross-cultural Adaptation of the Gait Assessment and Intervention Tool

BACKGROUND

The Gait Assessment and Intervention Tool (G.A.I.T.) has been shown to be a comprehensive and objectively scored tool to assess gait in people with neurologic disease. However, there is only an English version of the scale, the language in which it was developed.

OBJECTIVE

To carry out a cross-cultural adaptation of the Gait Assessment and Intervention Tool (G.A.I.T.) scale for its use in the Spanish-speaking population, and to study the content validity of the Spanish version.

DESIGN

A cross-cultural adaptation and validation study of the G.A.I.T.

SETTING

University Laboratory (Alcorcón, Madrid, Spain).

PARTICIPANTS

Not applicable.

METHODS OR INTERVENTIONS

Cross-cultural adaptation of a scale.

MAIN OUTCOME MEASUREMENTS

The Spanish version of the G.A.I.T. was obtained using the double-translation and back-translation method, and a subsequent Expert Committee revision. The Expert Committee studied the content validity of the Spanish G.A.I.T. using the content validity index (CVI).

RESULTS

The final version of the G.A.I.T. in Spanish was obtained after the cross-cultural process. The CVI was found to be excellent for the overall G.A.I.T. (0.94), and excellent for 87% of its 31 items (≥0.78). CVI was good for 10% of the items (arm swing and toes, CVI ≥0.72). Although 3% of items (shoulder and elbow position) showed CVI = 0.28, these items were retained for completeness.

CONCLUSIONS

The Spanish version of the G.A.I.T. was developed through a cross-cultural adaptation process from its original version in English, and according to an Expert Committee it has an excellent overall content validity.

Greater Cortical Thickness Is Associated With Enhanced Sensory Function After Arm Rehabilitation in Chronic Stroke

Objective. Somatosensory function is critical to normal motor control. After stroke, dysfunction of the sensory systems prevents normal motor function and degrades quality of life. Structural neuroplasticity underpinnings of sensory recovery after stroke are not fully understood. The objective of this study was to identify changes in bilateral cortical thickness (CT) that may drive recovery of sensory acuity. Methods. Chronic stroke survivors (n = 20) were treated with 12 weeks of rehabilitation. Measures were sensory acuity (monofilament), Fugl-Meyer upper limb and CT change. Permutation-based general linear regression modeling identified cortical regions in which change in CT was associated with change in sensory acuity. Results. For the ipsilesional hemisphere in response to treatment, CT increase was significantly associated with sensory improvement in the area encompassing the occipital pole, lateral occipital cortex (inferior and superior divisions), intracalcarine cortex, cuneal cortex, precuneus cortex, inferior temporal gyrus, occipital fusiform gyrus, supracalcarine cortex, and temporal occipital fusiform cortex. For the contralesional hemisphere, increased CT was associated with improved sensory acuity within the posterior parietal cortex that included supramarginal and angular gyri. Following upper limb therapy, monofilament test score changed from 45.0 ± 13.3 to 42.6 ± 12.9 mm ( P = .063) and Fugl-Meyer score changed from 22.1 ± 7.8 to 32.3 ± 10.1 ( P < .001). Conclusions. Rehabilitation in the chronic stage after stroke produced structural brain changes that were strongly associated with enhanced sensory acuity. Improved sensory perception was associated with increased CT in bilateral high-order association sensory cortices reflecting the complex nature of sensory function and recovery in response to rehabilitation.

Prefrontal over-activation during walking in people with mobility deficits: Interpretation and functional implications

BACKGROUND

Control of walking by the central nervous system includes contributions from executive control mechanisms, such as attention and motor planning resources. Executive control of walking can be estimated objectively by recording prefrontal cortical activity using functional near infrared spectroscopy (fNIRS).

OBJECTIVE

The primary objective of this study was to investigate group differences in prefrontal/executive control of walking among young adults, older adults, and adults post-stroke. Also assessed was the extent to which walking-related prefrontal activity fits existing cognitive frameworks of prefrontal over-activation.

METHODS

Participants included 24 adults post-stroke with moderate to severe walking deficits, 15 older adults with mild gait deficits, and 9 young healthy adults. Executive control of walking was quantified as oxygenated hemoglobin concentration in the prefrontal cortex measured by fNIRS. Three walking tasks were assessed: typical walking, walking over obstacles, and walking while performing a verbal fluency task. Walking performance was assessed by walking speed.

RESULTS

There was a significant effect of group for prefrontal activity (p < 0.001) during typical and obstacles walking tasks, with young adults exhibiting the lowest level of prefrontal activity, followed by older adults, and then adults post-stroke. In young adults the prefrontal activity during typical walking was much lower than for the verbal fluency dual-task, suggesting substantial remaining prefrontal resources during typical walking. However, in older and post-stroke adults these remaining resources were significantly less (p < 0.01). Cumulatively, these results are consistent with prefrontal over-activation in the older and stroke groups, which was accompanied by a steeper drop in walking speed as task complexity increased to include obstacles (p < 0.05).

CONCLUSIONS

There is a heightened use of prefrontal/executive control resources in older adults and post-stroke adults during walking. The level of prefrontal resource utilization, particularly during complex walking tasks like obstacle crossing, may approach the ceiling of available resources for people who have walking deficits. Prior cognitive research has revealed that prefrontal over-activation combined with limited prefrontal resources can lead to poor cognitive performance. The present study suggests a similar situation influences walking performance. Future research should further investigate the extent to which prefrontal over-activation during walking is linked to adverse mobility outcomes.

Topographical measures of functional connectivity as biomarkers for post-stroke motor recovery

BACKGROUND

Biomarkers derived from neural activity of the brain present a vital tool for the prediction and evaluation of post-stroke motor recovery, as well as for real-time biofeedback opportunities.

METHODS

In order to encapsulate recovery-related reorganization of brain networks into such biomarkers, we have utilized the generalized measure of association (GMA) and graph analyses, which include global and local efficiency, as well as hemispheric interdensity and intradensity. These methods were applied to electroencephalogram (EEG) data recorded during a study of 30 stroke survivors (21 male, mean age 57.9 years, mean stroke duration 22.4 months) undergoing 12 weeks of intensive therapeutic intervention.

RESULTS

We observed that decreases of the intradensity of the unaffected hemisphere are correlated (r s =-0.46;p<0.05) with functional recovery, as measured by the upper-extremity portion of the Fugl-Meyer Assessment (FMUE). In addition, high initial values of local efficiency predict greater improvement in FMUE (R 2=0.16;p<0.05). In a subset of 17 subjects possessing lesions of the cerebral cortex, reductions of global and local efficiency, as well as the intradensity of the unaffected hemisphere are found to be associated with functional improvement (r s =-0.60,-0.66,-0.75;p<0.05). Within the same subgroup, high initial values of global and local efficiency, are predictive of improved recovery (R 2=0.24,0.25;p<0.05). All significant findings were specific to the 12.5-25 Hz band.

CONCLUSIONS

These topological measures show promise for prognosis and evaluation of therapeutic outcomes, as well as potential application to BCI-enabled biofeedback.

Effects of expiratory muscle strength training on maximal respiratory pressure and swallow-related quality of life in individuals with multiple sclerosis

BACKGROUND

Weakening and dyscoordination of expiratory muscles in multiple sclerosis (MS) can impair respiratory and swallow function.

OBJECTIVE

The objective of this paper is to test a novel expiratory muscle strength training (EMST) device on expiratory pressure, swallow function, and swallow-related quality-of-life (SWAL-QOL) in individuals with MS.

METHODS

Participants with MS were randomized to a five-week breathing practice of either positive pressure load (EMST) or near-zero pressure (sham). We compared baseline to post-treatment data according to maximum expiratory pressure (MEP), abnormal airway penetration and aspiration (PAS), and SWAL-QOL.

RESULTS

Both groups improved in MEP (p < 0.001). Forty percent of the EMST group improved on PAS, and 15% worsened; conversely, 21.4% of the sham group worsened and 14.3% improved. There was no group difference in overall SWAL-QOL; but the EMST group had significantly greater gain versus sham on the Burden (p = 0.014) and Pharyngeal Swallow (p = 0.022) domains. Both groups improved in SWAL-QOL domains of Fear, Burden Mental Health, but only the EMST group improved in the SWAL-QOL and domains of Pharyngeal Swallow function, and Saliva management.

CONCLUSION

Results suggest that strengthening of expiratory muscles can occur with repetition of focused breathing practice in the absence of high resistance. Conversely, results from the PAS and SWAL-QOL domains suggest that the high resistance of the EMST was required in order to improve the functional safety (reduced penetration/aspiration) and coordination of swallowing, specifically pharyngeal function and saliva management.

Abstract 73: Improvement of Arm Function Following Intensive Rehabilitation in Chronic Stroke Correlates With Increase in Fractional Anisotropy in Major White Matter Tracts

Introduction: White matter changes in response to rehabilitation of chronic motor deficits after stroke has not been well understood. Our hypothesis is that there is a relationship between gains in motor function and changes in structure of white matter tracts.

Methods: Fugl-Meyer upper limb (FM) score and Diffusion Tensor Imaging (DTI) were collected before and after a 12-week upper limb motor learning therapy. DTI data was processed using the longitudinal Freesurfer Tracula stream where white matter tracts are reconstructed using global probabilistic tractography. The average fractional anisotropy (FA), as well as axial diffusivity (Da) and radial diffusivity (Dr) were computed for 14 major white matter tracts. General linear models were fit where pre-to-post change in FA for a given tract were dependent variables and pre-to-post change in FM was a predictor. The relationship was adjusted for baseline FM score. Spearman correlations were determined between FA, Da and Dr. Wilcoxon test was used for pre-to-post comparisons.

Results: We evaluated and treated 21 stroke survivors; they were 1.9±1.2 (mean±std.dev) years post stroke, 55.1±12.9 yrs old and 42% female. FM improved from 23±8.75 to 34.1±10.5 (p<0.001). There was a significant association between gain in motor function and the decrease in FA for the following tracts: ipsilesional inferior longitudinal fasciculus (iplsi-ILF), contralesional ILF (contra-ILF) and transcallosal forceps major tract, controlling for baseline FM scores, (for ipsi-ILF: R2=0.4, p=0.006; for contra-ILF: R2=0.38, p=0.004; for forceps major: R2=0.31,p=0.02). According to the correlation analysis, decrease in FA could be explained by increase in Dr, but not by change in Da. Correlation between FA and Dr for ipsi-ILF was r=.75,p<0.001, for contra-ILF - r=.72,p<0.001 and for forceps major - r=.88, p<0.001.

Conclusion: Improvement in function of chronic motor deficits in the upper extremity is related to structural changes in temporal-occipital and transcallosal occipital tracts that connect visual-spatial processing regions. Furthermore, our results suggest that changes in neuronal activity of the identified tracts may be associated with microstructural changes that increase radial diffusivity.

Classification of hand movement direction based on EEG high-gamma activity

The Electroencephalogram (EEG) is a non-invasive technique used in the medical field to record and analyze brain activity. In particular, Brain Machine Interfaces (BMI) create this bridge between brain signals and the external world through prosthesis, visual interfaces and other physical devices. This paper investigates the relation between particular hand movement directions while using a BMI and the EEG recordings during such movement. The Common Spatial Pattern method (CSP) over the high-γ frequency band is utilized in order to discriminate opposite hand movement directions. The experiment is performed with three subjects and the average classification accuracy is obtained for two different cases.

Static and dynamic postural stability in veterans with combat-related mild traumatic brain injury

Persistent post-concussive symptoms are reported by 10-15% of individuals who suffer mild traumatic brain injury (mTBI), but their basis is often uncertain. One such symptom is disequilibrium, a sensation of impaired balance during standing and walking. The hypothesis for this study was that this subjective symptom is associated with objective and measurable deficits in static and dynamic postural stability. An infrared motion tracking system was used to record body motion during quiet standing and in response to waist perturbations in fourteen veterans (age 22-40 years, 13 male) of the Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF), who had a history of mTBI that occurred 7 months to 7 years prior to testing. We compared body sway between veterans with mTBI reporting persistent disequilibrium (TD, n=8) and those with no vestibular symptoms (n=6), as well as to a group of non-veterans with no balance symptoms (n=10). Static postural stability was reduced in TD veterans in comparison to each of the other two groups (p<0.0002), most notably on a compliant surface with eyes closed. The TD group also had decreased dynamic stability of the upper trunk (p<0.05) and enhanced postural oscillations (p<0.02) following waist perturbations. Our findings support a physiological basis for persistent disequilibrium after mTBI and are consistent with impaired vestibular processing. Disruption of semicircular canal inputs is unlikely to be the cause, as head impulse responses were normal in all groups. The unexpected finding of dynamic postural oscillations requires further study but may indicate enhanced instability in sensorimotor networks responsible for postural control.

Recovery of post stroke proximal arm function, driven by complex neuroplastic bilateral brain activation patterns and predicted by baseline motor dysfunction severity

Objectives: Neuroplastic changes that drive recovery of shoulder/elbow function after stroke have been poorly understood. The purpose of this study was to determine the relationship between neuroplastic brain changes related to shoulder/elbow movement control in response to treatment and recovery of arm motor function in chronic stroke survivors.Methods: Twenty-three chronic stroke survivors were treated with 12 weeks of arm rehabilitation. Outcome measures included functional Magnetic Resonance Imaging (fMRI) for the shoulder/elbow components of reach and a skilled motor function test (Arm Motor Abilities Test, AMAT), collected before and after treatment.Results: We observed two patterns of neuroplastic changes that were associated with gains in motor function: decreased or increased task-related brain activation. Those with significantly better motor function at baseline exhibited a decrease in brain activation in response to treatment, evident in the ipsilesional primary motor and contralesional supplementary motor regions; in contrast, those with greater baseline motor impairment, exhibited increased brain activation in response to treatment. There was a linear relationship between greater functional gain (AMAT) and increased activation in bilateral primary motor, contralesional primary and secondary sensory regions, and contralesional lateral premotor area, after adjusting for baseline AMAT, age, and time since stroke.Conclusions: Recovery of functional reach involves recruitment of several contralesional and bilateral primary motor regions. In response to intensive therapy, the direction of functional brain change (i.e., increase or decrease in task-related brain recruitment) for shoulder/elbow reach components depends on baseline level of motor function and may represent either different phases of recovery or different patterns of neuroplasticity that drive functional recovery.

Brain-computer interface: current and emerging rehabilitation applications

A formal definition of brain-computer interface (BCI) is as follows: a system that acquires brain signal activity and translates it into an output that can replace, restore, enhance, supplement, or improve the existing brain signal, which can, in turn, modify or change ongoing interactions between the brain and its internal or external environment. More simply, a BCI can be defined as a system that translates "brain signals into new kinds of outputs." After brain signal acquisition, the BCI evaluates the brain signal and extracts signal features that have proven useful for task performance. There are 2 broad categories of BCIs: implantable and noninvasive, distinguished by invasively and noninvasively acquired brain signals, respectively. For this supplement, we will focus on BCIs that use noninvasively acquired brain signals.

Abstract 1: Improvement of Sensory Function Following Rehabilitation in Chronic Stroke Is Associated With Increased Cortical Thickness

Introduction: Loss of somatosensory function after stroke weakens the ability to adequately relate to our environment, thus significantly reduces quality of life. Neuroplastic processes of sensory recovery are poorly understood. The objective of this study was to identify cortical regions that undergo structural changes (measured by change in cortical thickness (CT)) during sensory recovery. The hypothesis was that for subjects who improve sensory acuity, CT change in regions of the bilateral sensory network correlates with change in sensory acuity.

Methods: Chronic stroke survivors were treated with 12-weeks rehabilitation. Outcome measures were sensory acuity (monofilament), Fugl-Meyer upper limb coordination and CT (T1 Magnetic Resonance Imaging). CT change was calculated based on T1 images using Freesurfer longitudinal processing stream. General linear regression modeling identified cortical regions where change in CT was associated with change in sensory acuity after controlling for baseline sensory impairment and change in motor function. Cluster-wise correction for multiple comparisons was conducted using Monte-Carlo simulation at p<0.05.

Results: Subjects, who improved in sensory acuity (n=18), were 55.8±13.7 year old; 10% female; 1.8±0.9 years after first ever stroke. Acuity improved from 43.9±14mm to 40.53±13mm (p=0.004). FM improved from 22.4±8 to 34.5±10 (p<0.0001). For the ipsilesional hemisphere, CT increase correlated with sensory improvement in lateral occipital gyrus (size=1543mm2; peak vertex coordinates in MNI space x=-10.9, y=-97, z=10.9, cluster wise p=0.0002) and in middle temporal gyrus (795mm2, x=-57.2, y=-56.5,z=0.9, p=0.002). For the contralesional hemisphere, increased CT was associated with improved monofilament acuity within supramarginal gyrus (930mm2 ; x=47.2, y=-43.0, z=43.2, p=0.0002) and middle temporal gyrus (974mm2; x=53.5, y=-59.6, z=-1.7; p= 0.0001).

Conclusion: Rehabilitation produces modality-specific structural brain changes that can be measured by changes in cortical thickness. Improved sensation correlates with increased thickness in bilateral high-order association sensory cortices reflecting a complex nature of sensory rehabilitation.

Addressing low frequency movement artifacts in EEG signal recorded during center-out reaching tasks

The successful application of noninvasive brain-computer interfaces (BCI) to neurological rehabilitation requires examination of low frequency movement artifacts and development of accurate new methods for their correction. To this end, this study applies an adaptive trend extraction method to electroencephalogram (EEG) signals recorded during active and passive center-out reaching tasks. Distinct patterns are discovered, which correlate to arm kinematics, but are shown to be largely artifactual in nature. Notably, these patterns are found to be similar to features currently used for discrimination of movement direction, indicating a necessity for caution and precise signal processing methods when utilizing low frequency content of EEG signals in such applications.

Hemispheric activation during planning and execution phases in reaching post stroke: a consort study

Enhanced activation in the non-lesion hemisphere in stroke patients was widely observed during movement of the affected upper limb, but its functional role related to motor planning and execution is still unknown.This study was to characterize the activation in the non-lesion hemisphere during movement planning and execution by localizing sources of high-density electroencephalography (EEG) signal and estimating the source strength (current density [A/m]).Ten individuals with chronic stroke and shoulder/elbow coordination deficits and 5 healthy controls participated in the study.EEG (64 channels) was recorded from scalp electrodes while the subjects performed a reach task involving shoulder flexion and elbow extension of the affected (patients) or dominant (controls) upper extremity. Sources of the EEG were obtained and analyzed at 17 time points across movement preparation and execution phases. A 3-layer boundary element model was overlaid and used to identify the brain activation sources. A distributed current density model, low-resolution electromagnetic tomography (LORETA) L1 norm method, was applied to the data pre-processed by independent component analysis.Subjects with stroke had stronger source strength in the sensorimotor cortices during the movement compared with the controls. Their contralesional/lesional activation ratio (CTLR) for the primary motor cortices was significantly higher than that of the controls during the movement-planning phase, but not during the execution phase. The CTLR was higher in planning than in the execution phase in the stroke group.Excessive contralesional motor cortical activation appears to be more related to movement preparation rather than execution in chronic stroke.

Response of gait deficits to neuromuscular electrical stimulation for stroke survivors

Persistent gait deficits after stroke can cause falls, elevated energy cost and poor endurance. Coordination impairment is an underlying cause of gait deficits. Few efficacious interventions have been described that have targeted and measured restoration of coordinated gait components. Neuromuscular electrical stimulation can provide the critical gait practice characteristic of close-to-normal movements, by electrically inducing muscle contractions and coordinated movements that are not possible under volitional effort. Two-channel, surface neuromuscular electrical stimulation can be synchronized with phases of gait and can provide faster, more symmetrical neuromuscular electrical stimulation-assisted gait than gait with no neuromuscular electrical stimulation. Difficulties encountered during the use of surface neuromuscular electrical stimulation for gait training led to the development of neuromuscular electrical stimulation with implanted technologies. Implanted electrodes and/or stimulators proved to be feasible for gait training in stroke survivors. Gait training with a multichannel neuromuscular electrical stimulation system with implanted electrodes proved more advantageous than gait training without neuromuscular electrical stimulation, according to measures of volitional coordinated gait components (neuromuscular electrical stimulation deactivated).

Capability of 2 gait measures for detecting response to gait training in stroke survivors: Gait Assessment and Intervention Tool and the Tinetti Gait Scale

OBJECTIVE

To characterize the performance of 2 observational gait measures, the Tinetti Gait Scale (TGS) and the Gait Assessment and Intervention Tool (G.A.I.T.), in identifying improvement in gait in response to gait training.

DESIGN

In secondary analysis from a larger study of multimodal gait training for stroke survivors, we measured gait at pre-, mid-, and posttreatment according to G.A.I.T. and TGS, assessing their capability to capture recovery of coordinated gait components.

SETTING

Large medical center.

PARTICIPANTS

Cohort of stroke survivors (N=44) greater than 6 months after stroke.

INTERVENTIONS

All subjects received 48 sessions of a multimodal gait-training protocol. Treatment consisted of 1.5 hours per session, 4 sessions per week for 12 weeks, receiving these 3 treatment aspects: (1) coordination exercise, (2) body weight-supported treadmill training, and (3) overground gait training, with 46% of subjects receiving functional electrical stimulation.

MAIN OUTCOME MEASURES

All subjects were evaluated with the G.A.I.T. and TGS before and after completing the 48-session intervention. An additional evaluation was performed at midtreatment (after session 24).

RESULTS

For the total subject sample, there were significant pre-/post-, pre-/mid-, and mid-/posttreatment gains for both the G.A.I.T. and the TGS. According to the G.A.I.T., 40 subjects (91%) showed improved scores, 2 (4%) no change, and 2 (4%) a worsening score. According to the TGS, only 26 subjects (59%) showed improved scores, 16 (36%) no change, and 1 (2%) a worsening score. For 1 treatment group of chronic stroke survivors, the TGS failed to identify a significant treatment response to gait training, whereas the G.A.I.T. measure was successful.

CONCLUSIONS

The G.A.I.T. is more sensitive than the TGS for individual patients and group treatment response in identifying recovery of volitional control of gait components in response to gait training.

Abstract 3137: Significant Impairment in Gait Coordination Consistency at Two Self-Selected Walking Speeds in Chronic Stroke

Background/Objectives: Gait coordination is not well-studied nor well-described in chronic stroke. Gait coordination can be defined as the simultaneous consideration of spatial and temporal movement characteristics. One aspect of gait coordination is the consistency of relative movements of hip/knee, hip/ankle, and knee/ankle across the gait cycle. Without consistency of relative joint movement from step to step, safety of gait is compromised and function is reduced. Therefore, the hypothesis of this study was that in chronic stroke survivors with persistent gait deficits, consistency of gait coordination is impaired, according to a measure of inter-joint coordination consistency (hip/knee; hip/ankle; and knee/ankle) of movement excursion and timing across the gait cycle from step to step.

Methods: Ten healthy adults and thirty-eight subjects with persistnet gait deficits were enrolled (>6mos after stroke). In terms of gait speed, stroke subjects were either household ambulators (HA; <.4m/s; n=28) or limited community ambulators (CA; .41-.9m/s; n=10). Control subjects’ gait variables were measured at each of these two speeds imposed during testing. Gait kinematics were measure using Vicon MX (Oxford Metrics, UK) and modified Helen Hayes model of marker placement. The average consistency coefficient (ACC, range 0 - 1) was calculated for hip/knee (H/K ACC), hip/ankle (H/A ACC), and knee/ankle (K/A AC) for both controls and stroke. ACC=1, indicated perfect consistency from step-to-step in terms of relative inter-limb joint movement. T-test was employed to compare stroke versus controls for each coordination consistency measure. Findings: Within the HA-speed group, there was a significant difference between stroke and HA-speed controls in terms of H/K ACC, H/A ACC, and K/A ACC (p = .0001). Also within the CA-speed group, there was a significant difference between stroke and CA-speed controls for all three measures of coordination consistency (p=.0001). Control subject ACC’s ranged from .85 - .95; whereas, stroke ACC’s ranged from .7063 - .8638 (1=perfect consistency).

Conclusions: Inconsistent relative joint movement between hip, knee, and ankle across the gait cycle, could be a source of falls, poor walking endurance, and dysfunction. The presence of this impairment should be noted in assessment and targeted during treatment.

Abstract 16: Pattern Of Brain Function Change In Multiple Regions Predicts Mitigation Of Spasticity Following Intensive Arm Neurorehabilitation In Chronic Stroke

Background: Spasticity can prevent productive practice of skilled movement that should occur during neurorehabilitation of coordinated arm movements after stroke. Studies showed that spasticity could be reduced following an intervention that inhibited activation of the contralesional primary motor region (M1) using non-invasive transcranial magnetic or electric stimulation. However, there is little understanding of how the mitigation of spasticity might be controlled by the multiple sensorimotor control brain regions. Therefore, the aim of this study was to evaluate the change in activation patterns of multiple sensorimotor regions that predict the mitigation of spasticity, in response to intensive upper limb neurrehabiltiation.

Methods: Twenty three stroke subjects (>6 months after stroke) with persistent arm motor deficits were treated with intensive upper extremity rehabilitation (5 hours/day, 5 days/week for 12 weeks). Baseline and post-rehab evaluation consisted of three measures: 1) functional magnetic resonance imaging (fMRI) during a shoulder/elbow reach task for the paretic arm, 2) a skilled motor function (Arm Motor Assessment test (AMAT)), and 3) spasticity (Modified Ashworth Scale(MAS)). Volume of brain activation (voxel count) during the reach task was calculated for sensory and motor control regions using SPM05 (London, UK) and in-house software in MATLAB (Natick, MA). Paired t-test analysis was conducted for pre- vs post-treatment comparisons. Multiple linear regression analysis was conducted, where post-rehab AMAT was the dependent variable, the co-variate was pre-rehab score, and the predictors were change from pre- to post-rehab in voxel count in bilateral M1, somatosensory (SS), posterior parietal (PP), lateral premotor (LPM) and supplementary motor (SMA) areas.

Results: Subject characteristics were as follows: mean age, 56.3 ±12.8years; 41%, female; and 1.8±1.1 years after first ever stroke. Change in the activation pattern in a number of regions significantly predicted mitigated spasticity (R2=.86). Specifically, in response to treatment, increased activation, in ipsilesional SMA (p=.002) and contralesional M1 (p=.002), predicted mitigated spasticity. Reduction in activation volume, in ipsilesional PP region (p=.0009), contralesional SS (p=.008) and SMA (p=.006), predicted mitigated spasticity. AMAT score improved from 1636.63±668.41 to 1213.67±6643.79 seconds (p<.0001) and MAS scores improved from 6.81±2.75 to 1.86±1.49 (p<.0001).

Conclusions: A specific pattern of functional brain change across multiple regions predicted mitigation of spasticity following neurorehabilitation; skill functional recovery occurred, as well. This information could be used in constructing study design for future research that would investigate brain training to mitigate spasticity and improve skilled functional task performance.

Recovery of coordinated gait: randomized controlled stroke trial of functional electrical stimulation (FES) versus no FES, with weight-supported treadmill and over-ground training

BACKGROUND

No single intervention restores the coordinated components of gait after stroke.

OBJECTIVE

The authors tested the multimodal Gait Training Protocol, with or without functional electrical stimulation (FES), to improve volitional walking (without FES) in patients with persistent (>6 months) dyscoordinated gait.

METHODS

A total of 53 subjects were stratified and randomly allocated to either FES with intramuscular (IM) electrodes (FES-IM) or No-FES. Both groups received 1.5-hour training sessions 4 times a week for 12 weeks of coordination exercises, body weight-supported treadmill training (BWSTT), and over-ground walking, provided with FES-IM or No-FES. The primary outcome was the Gait Assessment and Intervention Tool (G.A.I.T.) of coordinated movement components, with secondary measures, including manual muscle testing, isolated leg movements (Fugl-Meyer scale), 6-Minute Walk Test, and Locomotion/Mobility subscale of the Functional Independence Measure (FIM).

RESULTS

No baseline differences in subject characteristics and measures were found. The G.A.I.T. showed an additive advantage with FES-IM versus No-FES (parameter statistic 1.10; P = .045, 95% CI = 0.023-2.179) at the end of training. For both FES-IM and No-FES, a within-group, pre/posttreatment gain was present for all measures (P < .05), and a continued benefit from mid- to posttreatment (P < .05) was present. For FES-IM, recovered coordinated gait persisted at 6-month follow-up but not for No-FES.

CONCLUSION

Improved gait coordination and function were produced by the multimodal Gait Training Protocol. FES-IM added significant gains that were maintained for 6 months after the completion of training.

Weakening of synergist muscle coupling during reaching movement in stroke patients

BACKGROUND

After hemiparetic stroke, coordination of the shoulder flexor and elbow extensor muscles during a reaching movement is impaired and contributes to poor performance.

OBJECTIVE

The aim was to determine whether functional coupling between electromyographic signals of synergist muscles during reaching was weakened in stroke patients who had poor motor coordination.

METHODS

Surface electromyography (EMG) from the anterior deltoid, triceps brachii, biceps brachii, pectoralis major, supraspinatus, and latissimus dorsi of the affected upper limb in 11 stroke patients (mean Fugl-Meyer upper extremity score 27 ± 8) and in the dominant arm of 8 healthy controls were measured.

RESULTS

Coherence between the EMG of the anterior deltoid and triceps brachii, 2 synergists for reaching, was lower in patients compared with controls, in the 0- to 11-Hz range. Detailed segmented frequency-range analysis indicated significant differences in the coherence between groups in 0- to 3.9-Hz and 4- to 7.9-Hz ranges.

CONCLUSIONS

This weakened functional coupling may contribute to poor reaching performance and could be a consequence of a loss of common drive at the frequency bands as a result of interruption of information flow in the corticospinal pathway.

Feasibility of combining gait robot and multichannel functional electrical stimulation with intramuscular electrodes

After stroke rehabilitation, many survivors of stroke exhibit persistent gait deficits. In previous work, we demonstrated significant gains in gait kinematics for survivors of chronic stroke using multichannel functional electrical stimulation with intramuscular electrodes (FES-IM). For this study, we tested the feasibility of combining FES-IM and gait robot technologies for treating persistent gait deficits after stroke. Six subjects, >or= 6 months after stroke, received 30-minute intervention sessions of combined FES-IM and gait robotics 4 days a week for 12 weeks. Feasibility was assessed according to three factors: (1) performance of the interface of the two technologies during intervention sessions, (2) clinicians' success in using two technologies simultaneously, and (3) subject satisfaction. FES-IM system hardware and software design features combined with the gait robot technology proved feasible to use. Each technology alone provided unique advantages and disadvantages of gait practice characteristics. Because of the unique advantages and disadvantages of each technology, gait deficits need to be accurately identified and a judicious treatment plan properly targeted before FES-IM, a gait robot, or both combined are selected.

Functional corticomuscular connection during reaching is weakened following stroke

OBJECTIVE

To investigate the functional connection between motor cortex and muscles, we measured electroencephalogram-electromyogram (EEG-EMG) coherence of stroke patients and controls.

METHODS

Eight healthy controls and 21 patients with shoulder and elbow coordination deficits were enrolled. All subjects performed a reaching task involving shoulder flexion and elbow extension. EMG of the anterior deltoid (AD) and brachii muscles (BB, TB) and 64-channel scalp EEG were recorded during the task. Time-frequency coherence was calculated using the bivariate autoregressive model.

RESULTS

Stroke patients had significantly lower corticomuscular coherence compared with healthy controls for the AD and BB muscles at both the beta (20-30 Hz) and lower gamma (30-40 Hz) bands during the movement. BH procedure (FDR) identified a reduced corticomuscular coherence for stroke patients in 11 of 15 scalp area-muscle combinations. There was no statistically significant difference between stroke patients and control subjects according to coherence in other frequency bands.

CONCLUSION

Poorly recovered stroke survivors with persistent upper-limb motor deficits exhibited significantly lower gamma-band corticomuscular coherence in performing a reaching task.

SIGNIFICANCE

The study suggests poor brain-muscle communication or poor integration of the EEG and EMG signals in higher frequency band during reaching task may reflect an underlying mechanism producing movement deficits post-stroke.

Comparison of filtering and classification techniques of electroencephalography for brain-computer interface

In this paper several methods are investigated for feature extraction and classification of mu features from electroencephalographic (EEG) readings of subjects engaged in motor tasks. EEG features are extracted by autoregressive (AR) filtering, mu-matched filtering, and wavelet decomposition (WD) methods, and the resulting features are classified by a linear classifier whose weights are set by an expert using a-priori knowledge, as well as support vector machines (SVM) using various kernels. The classification accuracies are compared to each other. SVMs are shown to offer a potential improvement over the simple linear classifier, and wavelets and mu-matched filtering are shown to offer potential improvement over AR filtering.

Development and testing of the Gait Assessment and Intervention Tool (G.A.I.T.): a measure of coordinated gait components

Recent neuroscience methods have provided the basis upon which to develop effective gait training methods for recovery of the coordinated components of gait after neural injury. We determined that there was not an existing observational measure that was, at once, adequately comprehensive, scored in an objectively-based manner, and capable of assessing incremental improvements in the coordinated components of gait. Therefore, the purpose of this work was to use content valid procedures in order to develop a relatively inexpensive, more comprehensive measure, scored with an objectively-based system, capable of incrementally scoring improvements in given items, and that was both reliable and capable of discriminating treatment response for those who had a stroke. Eight neurorehabilitation specialists developed criteria for the gait measure, item content, and scoring method. In subjects following stroke (>12 months), the new measure was tested for intra- and inter-rater reliability using the Intraclass Correlation Coefficient; capability to detect treatment response using Wilcoxon Signed Ranks Test; and discrimination between treatment groups, using the Plum Ordinal Regression. The Gait Assessment and Intervention Tool (G.A.I.T.) is a 31-item measure of the coordinated movement components of gait and associated gait deficits. It exhibited the following advantages: comprehensive, objective-based scoring method, incremental measurement of improvement within given items. The G.A.I.T. had good intra- and inter-rater reliability (ICC=.98, p=.0001, 95% CI=.95, .99; ICC=.83, p=.007, 95% CI=.32, .96, respectively. The inexperienced clinician who had training, had an inter-rater reliability with an experienced rater of ICC=.99 (p=.0001, CI=.97, .999). The G.A.I.T. detected improvement in response to gait training for two types of interventions: comprehensive gait training (z=-2.93, p=.003); and comprehensive gait training plus functional electrical stimulation (FES; z=-3.3, p=.001). The G.A.I.T. was capable of discriminating between two gait training interventions, showing an additive advantage of FES to otherwise comparable comprehensive gait training (parameter estimate=1.72, p=.021; CI, .25, 3.1).

Brain-computer interfaces in neurological rehabilitation

Recent advances in analysis of brain signals, training patients to control these signals, and improved computing capabilities have enabled people with severe motor disabilities to use their brain signals for communication and control of objects in their environment, thereby bypassing their impaired neuromuscular system. Non-invasive, electroencephalogram (EEG)-based brain-computer interface (BCI) technologies can be used to control a computer cursor or a limb orthosis, for word processing and accessing the internet, and for other functions such as environmental control or entertainment. By re-establishing some independence, BCI technologies can substantially improve the lives of people with devastating neurological disorders such as advanced amyotrophic lateral sclerosis. BCI technology might also restore more effective motor control to people after stroke or other traumatic brain disorders by helping to guide activity-dependent brain plasticity by use of EEG brain signals to indicate to the patient the current state of brain activity and to enable the user to subsequently lower abnormal activity. Alternatively, by use of brain signals to supplement impaired muscle control, BCIs might increase the efficacy of a rehabilitation protocol and thus improve muscle control for the patient.

Automatic synchronization of functional electrical stimulation and robotic assisted treadmill training

This work presents a means to automatically synchronize two promising gait training technologies to address gait deficits in stroke survivors: functional electrical stimulation using intramuscular electrodes (FES-IM) and the Lokomat robotic gait orthosis. A system of hardware and software was developed to achieve the automatic synchronization. A series of bench tests were performed to verify the feasibility and reliability of automatic synchronization. The bench tests showed that automatic synchronization of FES-IM to the Lokomat gait cycle was feasible and reliable. Automatic synchronization was more consistent than manually triggered stimulation (10-fold smaller standard deviation of latency), and produced no early or missed stimulations across 634 strides. Automatic synchronization had greater accuracy than manually triggered stimulation, producing stimulation timed to an accuracy of 2.5% of one gait cycle duration (heel strike to heel strike = 100).

A detection scheme for frontalis and temporalis muscle EMG contamination of EEG data

Electroencephalogram (EEG) recordings are highly susceptible to noise from electromyogram (EMG) signals of the frontalis and temporalis muscles. In this paper, we propose and evaluate a new method for detecting frontalis and temporalis muscle EMG contamination in EEG signals based on recent findings on topographic and spectral characteristics of cranial EMG.

Response of sagittal plane gait kinematics to weight-supported treadmill training and functional neuromuscular stimulation following stroke

After stroke, persistent gait deficits cause debilitating falls and poor functional mobility. Gait restoration can preclude these outcomes. Sixteen subjects (>12 months poststroke) were randomized to two gait training groups. Group 1 received 12 weeks of treatment, 4 times a week, 90 min per session, including 30 min strengthening and coordination, 30 min over-ground gait training, and 30 min weight-supported treadmill training. Group 2 received the same treatment, but also used functional neuromuscular stimulation (FNS) with intramuscular (IM) electrodes (FNS-IM) for each aspect of treatment. Outcome measures were kinematics of gait swing phase. Both groups showed no significant pre-/posttreatment gains in peak swing hip flexion. Group 1 (no FNS) had no significant gains in other gait components at posttreatment or at follow-up. Group 2 (FNS-IM) had significant gains in peak swing knee flexion and mid-swing ankle dorsiflexion (p < 0.05) that were maintained for 6 months.

Answering the call: the influence of neuroimaging and electrophysiological evidence on rehabilitation

Functional recovery after brain damage or disease is dependent on the neuroplastic capability of the cortex and the nonaffected brain. Following cortical injury in the motor and sensory regions, the adjacent spared neural tissues and related areas undergo modifications that are required in order to drive more normal motor control. Current rehabilitation models seek to stimulate functional recovery by capitalizing on the inherent potential of the brain for positive reorganization after neurological injury or disease. This article discusses how neuroimaging and electrophysiological data can inform clinical practice; representative data from the modalities of functional magnetic resonance imaging, diffusion tensor imaging, magnetoencephalography, electroencephalography, and positron emission tomography are cited. Data from a variety of central nervous system disease and damage models are presented to illustrate how rehabilitation practices are beginning to be shaped and informed by neuroimaging and electrophysiological data.

Physiological Cost Index as a proxy measure for the oxygen cost of gait in stroke patients

BACKGROUND

Stroke survivors can exhibit abnormally elevated oxygen consumption during walking. Therapeutic interventions can improve gait deficits and oxygen consumption. A practical measure of oxygen cost is not available. This study tested the usefulness of an indirect index of oxygen cost, the Physiological Cost Index, and the ability of this index to discriminate between healthy adults and stroke survivors.

METHODS

The authors studied 17 subjects with stroke and 10 healthy control participants. Participants walked 10 minutes at their chosen comfortable speed on a treadmill. Oxygen consumption and heart rate data were collected. Primary measures were oxygen cost and the Physiological Cost Index. Secondary measures were age and gait speed.

RESULTS

The Physiological Cost Index and oxygen cost had a good to excellent correlation (r = .83, P < .001) for subjects with stroke. Both oxygen cost and the Physiological Cost Index were comparable in detecting a significantly abnormal elevation for stroke survivors versus healthy adults (P = .003 and .002, respectively). Age was not correlated with oxygen cost, the Physiological Cost Index, or chosen gait speed. A moderate correlation of gait speed to both the Physiological Cost Index and oxygen cost was found.

CONCLUSIONS

The Physiological Cost Index can be used as a proxy index for the oxygen cost of walking in subjects after stroke because it is correlated with oxygen cost and is comparable to oxygen cost in its capability to discriminate between healthy controls and subjects with stroke. The Physiological Cost Index can be performed inexpensively on a routine basis in a clinical environment.

Abnormal cognitive planning and movement smoothness control for a complex shoulder/elbow motor task in stroke survivors

PURPOSE

Cortical function is not well understood in stroke survivors with persistent dyscoordination. The study purpose was two-fold: 1) characterize cognitive planning time and cognitive effort level for a circle-drawing motor task in stroke survivors using shoulder/elbow muscles and 2) identify the relationship between cognitive effort level and movement smoothness.

METHODS

Twelve stroke survivors with shoulder/elbow coordination deficits (>12 mo) and eight controls were enrolled. The motor task was to draw a circle on a horizontal surface using only shoulder/elbow muscles. Outcome measures were: EEG-derived cognitive planning time, cognitive effort level, and movement smoothness. Comparisons between stroke and controls were made using t-tests. The Pearson's correlation model was analyzed to determine the relationship between movement smoothness and cognitive effort level.

RESULTS

Stroke subjects showed a statistically significant prolonged motor planning time versus controls for both lesion and non-lesion sides (p=0.013 and 0.049, respectively). They also showed a statistically significant elevated effort level versus controls for both sides (p=0.016 and 0.013). The patients exhibited statistically significant poor movement smoothness in the medial/lateral and forward/backward movement directions versus controls (p=0.035 and 0.037, respectively). For stroke, there was a significant correlation between cognitive effort level on the non-lesion side and smoothness of movement in the medial/lateral and forward/backward directions (r=0.54, p=0.036 and r=0.76, p=0.002, respectively). On the lesion side, results were mixed (r=0.268, p=0.2 r=0.59, p=0.023, respectively).

CONCLUSIONS

Stroke survivors with upper limb motor deficits exhibit a longer cognitive planning time and elevated cognitive effort for performance of a complex shoulder/elbow motor coordination task. The elevated cognitive effort level was associated with poor (jerky) motor performance, suggesting a potential role of the CNS in controlling movement smoothness of the arm.

Intra-limb coordination deficit in stroke survivors and response to treatment

PURPOSE

Purpose one was to characterize the consistency of intra-limb hip/knee (H/K) coordination according to a measure of average coefficient of correspondence (ACC) across strides. Purpose two was to investigate H/K ACC validity and ability to discriminate pre-/post-treatment change in stroke survivors.

METHODS

Five healthy controls and 32 chronic (>12 mos) stroke survivors were enrolled, and H/K ACC was calculated for both groups. Comparison between controls and stroke was made using the Mann-Whitney Test. Convergent validity of H/K ACC was tested using the Pearson Correlation model with gait speed and the 6 min Walk Test (6MWT). Stroke survivors were randomized to either: (1) gait training with functional neuromuscular stimulation (FNS) using intramuscular (IM) electrodes or (2) gait training without FNS. Both groups had treatment 1.5 h/day, 5 days/week, for 12 weeks, including .5 h coordination exercise, .5 h body weight supported treadmill training (BWSTT), and .5 h over ground gait training. The FNS-IM group used FNS-IM for all treatment components; the No-FNS group did not. Pre-/post-treatment comparisons were made using ANOVA.

RESULTS

H/K ACC detected a significant difference between controls versus stroke involved limb (p=.0001) and controls versus stroke uninvolved limb (p=.042). The H/K ACC measure was well-correlated with gait speed (r=.70) and 6MWT (r=.69). H/K ACC showed a significant treatment response to FNS-IM (p=.003), but not No-FNS (p=.747).

CONCLUSIONS

H/K ACC sensitively discriminated between controls versus stroke involved or uninvolved limbs. H/K ACC was valid, with significant correlations with both walking speed and 6MWT. FNS-IM produced a significant gain in H/K ACC, and No-FNS did not.

Prolonged cognitive planning time, elevated cognitive effort, and relationship to coordination and motor control following stroke

Understanding cortical function can provide accurately targeted interventions after stroke. Initially, stroke survivors had prolonged cognitive planning time and elevated cognitive effort, highly correlated with motor control impairments. Exploratory results suggest that neurorehabilitation, accurately targeted to dyscoordination, weakness, and dysfunctional task component execution, can improve cognitive processes controlling motor function.