Thomas A. Matyas

Deficit and change in gait velocity during rehabilitation after stroke

OBJECTIVE To quantify the initial deficit, change, and outcome in gait velocity during inpatient rehabilitation following stroke. DESIGN The initial deficit on admission to rehabilitation was quantified by comparing 42 stroke patients with 42 controls matched by gender and age. The change in the stroke patients during the next 8 weeks was quantified and gait outcome was compared with functional and normal criteria. SETTING Patients were referred from four inpatient rehabilitation centers at the time of admission following a median of 16.5 days in the acute hospital. PATIENTS SELECTION CRITERIA ability to give informed consent; unilateral first stroke; ability to walk 10 meters. INTERVENTION Patients participated in a median of 17.38 hours of individual physical therapy including a median of 6.92 hours of gait training during the 8 weeks. MAIN OUTCOME MEASURE Gait velocity. RESULTS Gait velocity was initially 38.6% (26.7m/min SD = 14.9) of the performance of controls and improved to 55.1% (38.1m/min). At outcome only 24% exceeded the 5th percentile of controls (48.1m/min) or the velocity required to cross the typical signalled intersection (46.2m/min). The change was only 26% of the initial deficit. Fifty-five percent of the patients improved beyond the 95% confidence intervals surrounding the error of measuring change. Indices of responsiveness indicated that there was a high signal-to-noise ratio and a robust effect size. CONCLUSION Gait velocity discriminated the effect of stroke and the change during rehabilitation.

Can simultaneous bilateral movement involve the undamaged hemisphere in reconstruction of neural networks damaged by stroke

Normalization of upper limb movement remains a difficult problem for a significant subpopulation of hemiplegic stroke patients. Clinical observations prompted investigation of a novel approach using simultaneous identical bilateral movements performed independently. We briefly report 12 controlled single-case experiments using multiple-baseline designs across three separate grasp/reach activities. Unilateral performance tests with the hemiplegic arm using the bilaterally trained actions demonstrated clinically and statistically significant improvements in movement patterns. These improvements were specific to the trained movement and well maintained. Using recent literature we develop a theoretical model proposing that bilateral simultaneous movement promotes interhemispheric disinhibition likely to allow reorganization by sharing of normal movement commands from the undamaged hemisphere. Disinhibition may also encourage recruitment of undamaged neurones to construct new task-relevant neural networks. The potential contribution of spared ipsilateral pathways in the damaged hemisphere, indirect corticospinal pathways and ipsilateral pathways from the undamaged hemisphere is discussed.

Three‐dimensional gait biomechanics in Parkinson's disease: Evidence for a centrally mediated amplitude regulation disorder

We examined whether people with Parkinsons disease (PD) have a central amplitude regulation disorder using three‐dimensional (3‐D) gait analyses to compare the effects of medication and attentional strategies on gait in 12 PD subjects and 12 matched comparison subjects. Subjects with PD first performed several 10‐m gait trials at preferred speed while off levodopa. They then walked at preferred speed on levodopa; off levodopa with cues; and on levodopa with cues. Control subjects walked at preferred speed and then with visual cues to match their stride length to PD values. As well as spatiotemporal footstep data, pelvic and lower limb kinematic profiles and angle–angle diagrams were produced for sagittal, coronal, and transverse plane movements using a 3‐D motion analysis system. In people with PD, decreased step length was accompanied by reduced movement amplitude across all lower limb joints, in all movement planes. When control subjects were required to walk with short steps matched to the size of PD comparisons, they displayed a similar multijoint reduction in amplitude. For PD subjects, both levodopa and visual cues increased movement amplitude across all lower limb joints. Amplitude increased further when levodopa and visual cues were combined, resulting in normalization of step length. This finding suggested that reduced step length is due to a mismatch between cortically selected movement amplitude and basal ganglia maintenance mechanisms. Levodopa and cues normalized amplitude across all joints by altering motor set and bypassing defective basal ganglia mechanisms.

Sensory loss in stroke patients: Effective training of tactile and proprioceptive discrimination

Although somatosensory loss following stroke is common, with negative consequences for functional outcome, studies of existing somatosensory retraining programs are limited by theoretical weaknesses, poor methodology, and negative findings. We, therefore, developed a new program for stroke patients and investigated its effect on tactile discrimination in four AB, single-case quasi-experiments and its effect on tactile and proprioceptive discrimination in four multiple-baseline experiments. Training involved specific, graded discrimination tasks, attentive exploration of stimuli with vision occluded, deliberate anticipation, and quantitative feedback. Graphic and statistical interrupted time-series analyses indicated that treatment produced improvements in seven of eight tactile time series and all four proprioceptive time series. Baseline improvement in one tactile time series prevented unequivocal evaluation of treatment effect. Improvements were clinically significant, discrimination in the affected hand becoming comparable to the other hand and normal performance. Therapeutic effects were maintained at 3-month to 5-month follow-up tests.

Impaired limb position sense after stroke: A quantitative test for clinical use☆☆☆★

OBJECTIVE A quantitative measure of wrist position sense was developed to advance clinical measurement of proprioceptive limb sensibility after stroke. Test-retest reliability, normative standards, and ability to discriminate impaired and unimpaired performance were investigated. DESIGN Retest reliability was assessed over three sessions, and a matched-pairs study compared stroke and unimpaired subjects. Both wrists were tested, in counterbalanced order. SETTING Patients were tested in hospital-based rehabilitation units. PATIENTS AND OTHER PARTICIPANTS Reliability was investigated on a consecutive sample of 35 adult stroke patients with a range of proprioceptive discrimination abilities and no evidence of neglect. A consecutive sample of 50 stroke patients and convenience sample of 50 healthy volunteers, matched for age, sex, and hand dominance, were tested in the normative-discriminative study. Age and sex were representative of the adult stroke population. MAIN OUTCOME MEASURES The test required matching of imposed wrist positions using a pointer aligned with the axis of movement and a protractor scale. RESULTS The test was reliable (r = .88 and .92) and observed changes of 8 degrees can be interpreted, with 95% confidence, as genuine. Scores of healthy volunteers ranged from 3.1 degrees to 10.9 degrees average error. The criterion of impairment was conservatively defined as 11 degrees (+/-4.8 degrees) average error. Impaired and unimpaired performance were well differentiated. CONCLUSIONS Clinicians can confidently and quantitatively sample one aspect of proprioceptive sensibility in stroke patients using the wrist position sense test. Development of tests on other joints using the present approach is supported by our findings.

The Reliability of Selected Techniques in Clinical Arthrometrics

A number of studies which have examined reliability of spinal assessment procedures in manual therapy are reviewed. The tests examined were Passive Accessory Intervertebral Movements, Passive Physiological Intervertebral Movements, Straight Leg Raise and Forward Flexion. In general, tests of pain were found to be much more reproducible than tests of compliance. Straight Leg Raise and Forward Flexion tests were consistently more reliable than the Passive Intervertebral Movement tests. Possible explanations for these findings are advanced. The role of tests of compliance based on passive intervertebral movements in clinical decision-making may need to be re-examined. An appendix on reliability theory is included for the uninitiated reader.

Maximum voluntary weight-bearing by the affected and unaffected legs in standing following stroke

OBJECTIVE: To compare stroke patients to control subjects for ability to transfer body weight onto the affected and unaffected leg in standing; to investigate intra-session reliability. DESIGN: Comparative clinical study conducted within a single session. BACKGROUND: There is a paucity of quantitative data about maximum voluntary weight-bearing in patients during rehabilitation following stroke. METHODS: A Kistler force platform was used to quantify maximum amount of body weight transferred to a single limb in the lateral and forward directions during weight-shifting. Twelve control subjects matched by gender and age (median 64 years) were compared to 12 inpatient stroke patients after a median of 37 days post-onset. RESULTS: The median score for control subjects was approximately 95% of body weight to each leg in both directions. In contrast, stroke patients transferred less body weight (P<0.01) to the affected leg (65.5% lateral; 54.9% forward) and also to the unaffected leg (85.0% lateral; 80.1% forward). For the stroke patients, transfer of body weight was more challenging in the forward direction than the lateral direction on the affected leg (P<0.05). Relative to individual differences in the stroke group, error due to the repeated measurement process was low. CONCLUSION: The testing procedure was found to discriminate between stroke patients and control patients and had high retest reliability within a single session.

SENSe : Study of the Effectiveness of Neurorehabilitation on Sensation : A randomized controlled trial

Background. Sensory loss is common after stroke, with negative impact on exploration of the immediate environment, hand function, and return to daily activities. Objective. To compare the effectiveness of a perceptual-learning based sensory discrimination program versus non-specific exposure to sensory stimuli via passive movements and grasping of common objects. Methods. The authors conducted a randomized parallel-group controlled trial, with blinding of subjects, clinical assessors, and data analysts. Fifty subjects with impaired texture discrimination, limb position sense, and/or tactile object recognition (>6 weeks, median 48 weeks poststroke) were randomized to receive somatosensory discrimination training (n = 25) or repeated exposure to sensory stimuli (n = 25) in 60-minute sessions for a total of 10 hours. The primary outcome was change in a composite standardized somatosensory deficit (SSD) index following intervention. Follow-up was at 6 weeks and 6 months posttraining. Results. Between-group comparisons revealed a significantly greater improvement in sensory capacity following sensory discrimination training, t(47) = 2.75, P = .004, 1-tailed; mean between-group change = 11.1 SSD; confidence interval 3.0 to 19.2. Improvements were maintained at 6 weeks and 6 months. Conclusion. Sensory discrimination training can achieve significant improvements in functional sensory discrimination capacity after stroke. The clinically oriented training achieved transfer of training effects to novel stimuli. Our findings provide support for introducing SENSe discrimination training in rehabilitation of sensory deficits after stroke.

Impaired Discrimination of Surface Friction Contributes to Pinch Grip Deficit After Stroke

Background. Impaired sensation and force production could both contribute to handgrip limitation after stroke. Clinically, training is usually directed to motor impairment rather than sensory impairment despite the prevalence of sensory deficit and the importance of sensory input for grip control. Objective. The aim of this study was to investigate if sensory deficits contribute to pinch grip dysfunction beyond that attributable to motor deficits poststroke. Methods. The study enlisted 45 stroke participants and 45 healthy controls matched for age, gender, and hand dominance. Ability to differentiate surface friction (Friction Discrimination Test [FDT]), match object weight (Weight Matching Test [WMT]), produce grip force to track a visual target (Visually Guided Pinch Test [VGPT]), and perform a Pinch-Grip Lift-and-Hold Test (PGLHT) was quantified relative to normative performance, as defined by matched controls. The relationship between sensory ability (FDT, WMT) and altered PGLHT performance adjusted for motor ability (VGPT) after stroke was then examined using multivariate regression. Results. Deficits in FDT, WMT, and VGPT ability were present in at least half of the stroke sample and were largely independent across the variables. Poorer friction discrimination was significantly associated with longer latencies of grip-lift (r = .34; P = .03) and grip force dysregulation (r= .34; P= .03) after the impact of VGPT was statistically removed from PGLHT ability. However, performance on WMT did not relate to either PGLHT deficit. Conclusion. The findings indicate that impaired friction discrimination ability contributes to altered timing and force adjustment during PGLHT poststroke.

When is a change a genuine change?: A clinically meaningful interpretation of grip strength measurements in healthy and disabled women

The aim of this study was twofold: 1) to use estimates of random and systematic error to ascertain the test-retest reliability of grip strength measurements obtained with the Jamar hand dynamometer in healthy and disabled women, and 2) to determine the size of the change required to detect a genuine change in grip strength for accurate and meaningful clinical interpretation. Previous research has shown grip strength measurements obtained with a Jamar hand dynamometer from healthy and disabled subjects on different occasions to be reliable. However, the test-retest reliability has been based on correlation coefficients rather than on the actual size of the test-retest differences required to detect a genuine change in grip. The test-retest reliability of maximum grip strength measurements in 32 healthy women and painfree grip in 10 disabled women with nonspecific regional pain (NSRP) was determined. Reliability, based on estimates of systematic and random error, was high in both subject groups. There was no statistically significant systematic error between tests. Test-retest measurement error was +/-5.7 kg (12.5 lb) and +/-5.9 kg (13.0 lb) in healthy and disabled subjects, respectively, 95% of the time. In this population of healthy women and women with NSRP, any change in grip of less than 6 kg (13.2 lb) could have occurred by chance. The results of our study suggest that a change of more than 6 kg (13.2 lb) is necessary to detect a genuine change in grip strength 95% of the time.