Jannette M. Blennerhassett

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.

The Four Square Step Test is a feasible and valid clinical test of dynamic standing balance for use in ambulant people poststroke.

OBJECTIVE To examine if the Four Square Step Test (FSST), a previously reported clinical test of dynamic standing balance, which involves stepping over obstacles and turning, was a feasible and valid test, and sensitive to change during stroke rehabilitation. DESIGN Prospective observational cohort study over a 4-week duration. SETTING Rehabilitation hospital. PARTICIPANTS People with stroke (N=37) who could walk at least 50m with minimal assistance were recruited consecutively when attending physical therapy during rehabilitation. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Dynamic standing balance was examined at 2 weekly intervals using 2 clinical tests: the FSST and the Step Test. Falls events were monitored using a falls diary and by an audit of medical histories. RESULTS Strong agreement was observed between performance scores for the FSST and Step Test obtained within the same testing session (intraclass correlation coefficient(3,k), .94-.99). A moderate to strong inverse relationship (Spearman rho=-.73 to -.86) was observed between the FSST and Step Test scores at each assessment. Scores from both tests revealed significant improvements in dynamic balance across the 4-week period (P<.001-.010). Five of the participants reported falls during the study. These 5 people had low scores for both clinical tests and difficulty clearing their foot when stepping over objects in the FSST. CONCLUSIONS The FSST is a feasible and valid test of dynamic standing balance that is sensitive to change during stroke rehabilitation.

Changes in Balance and Walking From Stroke Rehabilitation to the Community: A Follow-Up Observational Study

OBJECTIVES To investigate (1) whether clinical test scores at discharge predict falls or limited community mobility after discharge from inpatient stroke rehabilitation; and (2) how walking and dynamic standing balance change after discharge. DESIGN Follow-up observational study between 6 and 36 months after discharge. SETTING Rehabilitation setting. PARTICIPANTS Community-dwelling stroke survivors (N=30) who could walk unassisted when discharged from inpatient rehabilitation. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Six-minute walk test (6MWT), Four Square Step Test (FSST), Step Test (ST), Environmental Analysis of Mobility Questionnaire (EAMQ), Falls Efficacy Scale-International (FES-I), and self-reported falls. RESULTS Follow-up occurred at a median of 14.5 months postdischarge. Significant improvements occurred between discharge and follow-up for the 6MWT (mean difference [MD]=110.1m; 95% confidence interval [CI], 70.8-149.4; P<.001), ST (MD=1.8 steps; 95% CI, 0.3-3.4; P=.03), and FSST (MD=4.3s; 95% CI, -10.3 to 1.6; P=.05). Despite this, 40% of participants reported falling. The group who fell had lower clinical test scores at discharge and follow-up than nonfallers. Specific cutoff scores for the clinical tests accurately classified falls history in 70% to 78% of participants. The cutoff scores were <250m for the 6MWT, <10 steps on the ST, and a failure or ≥15 seconds to complete the FSST. Participants performing under the cutoff scores reported lower levels of community mobility (EAMQ, P<.04). Concern about falling was only higher for those classified at risk by the FSST (FES-I, P=.008). CONCLUSIONS The FSST, ST, and 6MWT scores at discharge had good falls prediction. People classified at risk of falls avoided more tasks in their home and community than those not classified at risk.

Clinical measures of handgrip limitation relate to impaired pinch grip force control after stroke.

This study examined whether clinical measures of handgrip limitation relate to laboratory measures of grip force impairment during a pinch grip, lift, and hold task post-stroke. Handgrip ability in 45 people with stroke who had residual grip ability was examined relative to 45 age-matched healthy adults. The clinical tests included items from a) the Jebsen Taylor Hand Function Test; b) the Motor Assessment Scale; c) the Functional Independence Measure (FIM); and d) a custom-designed survey about hand-use in daily life. The laboratory test was summarized by principal components: 1) Pre-Lift Delay and 2) Grip Force Dyscontrol. For the stroke group, a moderate to strong correlation was found between Pre-Lift Delay and each clinical measure of handgrip limitation (rs=0.70-0.85) except the FIM (rs=0.38-0.49). In contrast, Grip Force Dyscontrol was not associated with handgrip limitation on any of the clinical tests (rs=-0.08 to 0.18).

Over-ground walking on level and sloped surfaces in people with stroke compared to healthy matched adults.

Purpose: To investigate the basic spatio-temporal gait characteristics of people with stroke whilst walking on sloped and level terrain, and to compare this performance to healthy matched adults. Method: Fifteen community dwelling people with stroke who walked with a hemiplegic gait and a reference group of 15 adults without impairments matched for sex, age and height participated in this descriptive, observational study. Basic gait spatio-temporal measures were recorded at self-selected speed across a GAITRite mat placed on level, uphill and downhill (ramp gradient 1:14 or 4.1°) surfaces. Measures recorded were gait speed, cadence, step length, support base, single and double limb support duration and step length symmetry. Group and walking condition effects were assessed by two separate 2-way (group × slope) repeated measures multivariate analysis of variance. Results: The stroke group walked slower (p < 0.001) than the reference group for all conditions. Within-group analyses found the stroke group decreased their speed and step length when walking downhill compared to level and uphill walking (p < 0.001). In contrast, the reference group maintained speed across all walking conditions. Conclusions: The findings suggest that walking on slopes affects gait speed in people with stroke and this may have implications when walking in the community. Implications for Rehabilitation Although a high percentage of people achieve walking independence following a stroke, few achieve independent community mobility. Walking on slopes is an important aspect of community mobility. When walking down a standard gradient ramp, people with stroke reduced their speed and step length, relative to level over-ground and uphill walking. It is recommended that attention be directed to assessment and treatment of walking on slopes as part of stroke rehabilitation, as this may have implications when walking in the community.

The test-retest reliability and responsiveness to change for the Hand Function Survey during stroke rehabilitation.

BACKGROUND/AIM The Hand Function Survey (HFS) is a questionnaire designed to measure self-reported ability to use the affected hand during 13 everyday tasks in people with stroke. The HFS appears practical for clinical use and has established psychometric properties. This study aimed to investigate test-retest reliability and responsiveness to change for the HFS during stroke rehabilitation. METHODS Twenty-two people with a first episode stroke, and without severe cognitive and language difficulties, participated. Participants were assessed on three occasions: baseline, 48 hours later and at follow-up (four to six weeks later) using two tests of upper extremity function, the HFS and the Action Research Arm Test (ARAT). Test-retest reliability of the HFS between baseline and 48 hours was examined using tests of agreement (Lins Concordance and Cohens Kappa). Responsive to change for the HFS was investigated by comparing the difference between baseline and follow-up scores. The level of agreement between the change observed for the ARAT and HFS was analysed. RESULTS Strong agreement (Rho_c = 0.99; Κ(w) =0.97) was observed between the test-retest HFS scores. Significant improvement between baseline and follow-up occurred for both the HFS and ARAT. A moderate agreement was found between change observed for the HFS and ARAT (Rho_c=0.62; Κ(w) =0.65). CONCLUSION The HFS was found to be a reliable and responsive self-report test of hand function during stroke rehabilitation. The HFS could be used in conjunction with other clinical tests of hand function during the rehabilitation of people with stroke without severe cognitive and language difficulties.

Change in Functional Arm Use Is Associated With Somatosensory Skills After Sensory Retraining Poststroke

OBJECTIVE. We investigated changes in functional arm use after retraining for stroke-related somatosensory loss and identified whether such changes are associated with somatosensory discrimination skills. METHOD. Data were pooled (N = 80) from two randomized controlled trials of somatosensory retraining. We used the Motor Activity Log to measure perceived amount of arm use in daily activities and the Action Research Arm Test to measure performance capacity. Somatosensory discrimination skills were measured using standardized modality-specific measures. RESULTS. Participants’ arm use improved after somatosensory retraining (z = −6.80, p < .01). Change in arm use was weakly associated with somatosensation (tactile, &bgr; = 0.31, p < .01; proprioception, &bgr; = −0.17, p > .05; object recognition, &bgr; = 0.13, p < .05). CONCLUSION. Change in daily arm use was related to a small amount of variance in somatosensory outcomes. Stroke survivors’ functional arm use can increase after somatosensory retraining, with change varying among survivors.

One-Quarter of People Leave Inpatient Stroke Rehabilitation with Physical Capacity for Community Ambulation

BACKGROUND AND PURPOSE Ability to walk in the community is important for independence and participation in life roles, but is difficult for many people following stroke. The purpose of this study was to determine the proportion of people with stroke with the physical capacity to be independent community ambulators at discharge from a publicly funded inpatient rehabilitation setting. METHOD Consecutive medical records were audited to collate walking outcome at discharge, and to clarify if people with stroke had potential to walk independently in the community as defined by 4 criteria: independence with stairs; ability to traverse slopes and inclines; walking speed of .8m/s or more; and walking distance 367 m or higher on 6-Minute Walk Test. RESULTS While 80% of the 124 persons with stroke could walk indoors, only 27% could perform 4 essential skills needed to walk independently in the community at discharge from hospital. The proportion that met each criterion was 52% for stairs, 39% for slopes and inclines, 58% for speed, and 40% for distance. For the overall sample, mean (standard deviation) walking speed was .90 (.33) m/s, and distance for 6-Minute Walk Test was 349.6 (146.5) m. DISCUSSION AND CONCLUSION A retrospective review found that three quarters of stroke survivors lacked physical capacity for 4 skills required to walk independently in the community at the time of discharge from a public inpatient rehabilitation. Our findings recommend that people with stroke have access to outpatient physical rehabilitation to optimize walking outcome.