Do measures of reactive balance control predict falls in people with stroke returning to the community?

OBJECTIVE: To determine if reactive balance control measures predict falls after discharge from stroke rehabilitation. DESIGN: Prospective cohort study. SETTING: Rehabilitation hospital and community. PARTICIPANTS: Independently ambulatory individuals with stroke who were discharged home after inpatient rehabilitation (n=95). MAIN OUTCOME MEASURES: Balance and gait measures were obtained from a clinical assessment at discharge from inpatient stroke rehabilitation. Measures of reactive balance control were obtained: (1) during quiet standing; (2) when walking; and (3) in response to large postural perturbations. Participants reported falls and activity levels up to 6 months post-discharge. Logistic and Poisson regressions were used to identify measures of reactive balance control that were related to falls post-discharge. RESULTS: Decreased paretic limb contribution to standing balance control [rate ratio 0.8, 95% confidence interval (CI) 0.7 to 1.0; P=0.011], reduced between-limb synchronisation of quiet standing balance control (rate ratio 0.9, 95% CI 0.8 to 0.9; P<0.0001), increased step length variability (rate ratio 1.4, 95% CI 1.2 to 1.7; P=0.0011) and inability to step with the blocked limb (rate ratio 1.2, 95% CI 1.0 to 1.3; P=0.013) were significantly associated with increased fall rates when controlling for age, stroke severity, functional balance and daily walking activity. CONCLUSIONS: Impaired reactive balance control in standing and walking predicted increased risk of falls post-discharge from stroke rehabilitation. Specifically, measures that revealed the capacity of both limbs to respond to instability were related to increased risk of falls. These results suggest that post-stroke rehabilitation strategies for falls prevention should train responses to instability, and focus on remediating dyscontrol in the more-affected limb.

Clinical assessment of reactive postural control among physiotherapists in Ontario, Canada.

Reactive postural control, the ability to recover from an external perturbation to stability, ultimately determines whether an individual will fall following a loss of balance and should be routinely incorporated in balance assessment. The purpose of this study was to identify (1) methods used to assess reactive postural control in clinical practice and (2) factors associated with regular assessment of reactive postural control. A cross-sectional survey was conducted. Three hundred and fifty-seven physiotherapists in Ontario, Canada who treated adults with balance impairments answered questions about the components of balance they assess and how they assess reactive control in their practice. Of the 273 respondents who assessed reactive postural control at least some of the time, 15.4% used a standardized measure, 79.1% used a non-standardized approach, and 5.5% used both. Forty-five methods of assessing reactive control were reported. The most common methods used were non-standardized perturbations (43.5%; 104/239 respondents) and movement observation (18.8%; 45/239). The remaining 43 methods were each used by less than 8% of respondents. Practice area had the strongest association with regular assessment of reactive postural control (>60% of the time), and respondents working with neurological disorders were more likely to regularly evaluate reactive control than those working with people with orthopedic conditions. Despite the availability of valid standardized measures to evaluate reactive postural control, respondents relied primarily on non-standardized approaches and observational assessment. Future work should examine the factors influencing choice of reactive control assessment tools and awareness of standardized measures for reactive postural control.

Changes in gait variability during different challenges to mobility in patients with traumatic brain injury.

Postural stability may be compromised in patients who have sustained a traumatic brain injury (TBI). The purpose of the present study was to examine dynamic stability during gait by measuring spatial and temporal variability of foot placement, and to determine the effect of increased difficulty of the walking task on gait variability in patients with TBI. It was hypothesized that patients with TBI will show increased variability in step time, step length, and step width in comparison to healthy controls and that such differences would be accentuated by increased task difficulty. Participants (patients: n=20, controls: n=20) were asked to walk across a pressure sensitive mat at their preferred pace (PW), as fast as possible (FW), and with their eyes closed (EC). In accordance with the hypotheses, patients had significantly greater variability in step time and step length in comparison to healthy controls, and when the complexity of the gait task increased (FW and EC tasks). Although step width variability showed no significant difference between the groups, both control and patient groups had increased step width variability in the EC task. It is proposed that such increases in variability reflect greater challenges to maintaining dynamic stability during gait among individuals with TBI and when performing more difficult tasks.

The Community Balance and Mobility Scale--a balance measure for individuals with traumatic brain injury.

OBJECTIVE: To provide evidence for the validity and reliability of a new outcome measure of balance, the Community Balance and Mobility Scale, developed for the ambulatory individual with traumatic brain injury. DESIGN: A validity and reliability study. SETTING: Acute care, in- and outpatient rehabilitation and day hospital settings. SUBJECTS: Two convenience samples (n=36, 32) of ambulatory patients with traumatic brain injury. MAIN MEASURES: The content and construct validity, test-retest, inter- and intra-rater reliability and internal consistency of the Community Balance and Mobility Scale. RESULTS: Content validity was demonstrated by the involvement of patients with traumatic brain injury (n=7) and clinicians (n=17) in the process of item generation and by physical therapists' ratings of item relevance. Further support is the correlation of the Community Balance and Mobility Scale scores with physical therapists' global balance ratings of the patient (r=0.62). Construct validity was supported by the ability of the measure to differentiate between patients along the continuum of care and also by comparisons with maximal walking velocity (r=0.64). Patients who scored greater than or less than 50 on the balance measure demonstrated significantly different Community Integration Questionnaire scores (P=0.004). The Community Balance and Mobility Scale demonstrated intraclass correlation coefficients (ICCs) of 0.977, 0.977, 0.975 and Cronbach's alpha of 0.96 for intra-, inter-, test-retest reliability and internal consistency, respectively. CONCLUSION: The Community Balance and Mobility Scale is a valid and reliable outcome measure for the ambulatory individual with traumatic brain injury.

Is there a trade-off between cognitive and motor recovery after traumatic brain injury due to competition for limited neural resources?

The status of neurorehabilitation for traumatic brain injury (TBI) is under active debate because of a dearth of research findings demonstrating effectiveness. This may be due, in part, to limitations in our understanding of basic mechanisms of cognitive and motor recovery,including those that might impede recovery. In this regard, we examined whether overall recovery following TBI might be undermined by competition between cognitive and motor functions for finite neural resources during recovery. In this preliminary study, 21 moderately and severely impaired patients were administered cognitive and motor assessments at 1, 4, and 12 months post-TBI, and recovery of cognitive and motor functions was measured using regression residuals. Negative correlations between recovery of cognitive versus motor functions were used as the index of competition. We found suggestive evidence that there may indeed be a trade-off between the recovery of cognitive and motor functions after TBI. Implications for rehabilitation are discussed.