Falls after stroke

Perturbation training to promote safe independent mobility post-stroke: study protocol for a randomized controlled trial

Background

Falls are one of the most common medical complications post-stroke. Physical exercise, particularly exercise that challenges balance, reduces the risk of falls among healthy and frail older adults. However, exercise has not proven effective for preventing falls post-stroke. Falls ultimately occur when an individual fails to recover from a loss of balance. Thus, training to specifically improve reactive balance control could prevent falls. Perturbation training aims to improve reactive balance control by repeatedly exposing participants to postural perturbations. There is emerging evidence that perturbation training reduces fall rates among individuals with neurological conditions, such as Parkinson disease. The primary aim of this work is to determine if perturbation-based balance training can reduce occurrence of falls in daily life among individuals with chronic stroke. Secondary objectives are to determine the effect of perturbation training on balance confidence and activity restriction, and functional balance and mobility.

Methods/design

Individuals with chronic stroke will be recruited. Participants will be randomly assigned to one of two groups: 1) perturbation training, or 2) ‘traditional’ balance training. Perturbation training will involve both manual perturbations (e.g., a push or pull from a physiotherapist), and rapid voluntary movements to cause a loss of balance. Training will occur twice per week for 6 weeks. Participants will record falls and activity for 12 months following completion of the training program. Standardized clinical tools will be used to assess functional balance and mobility, and balance confidence before and after training.

Discussion

Falls are a significant problem for those with stroke. Despite the large body of work demonstrating effective interventions, such as exercise, for preventing falls in other populations, there is little evidence for interventions that prevent falls post-stroke. The proposed study will investigate a novel and promising intervention: perturbation training. If effective, this training has the potential to not only prevent falls, but to also improve safe independent mobility and engagement in daily activities for those with stroke.

Trial registration

Current Controlled Trials: ISRCTN05434601.

Instrumented static and dynamic balance assessment after stroke using Wii Balance Boards: reliability and association with clinical tests

Background and Objectives

The Wii Balance Board (WBB) is a globally accessible device that shows promise as a clinically useful balance assessment tool. Although the WBB has been found to be comparable to a laboratory-grade force platform for obtaining centre of pressure data, it has not been comprehensively studied in clinical populations. The aim of this study was to investigate the measurement properties of tests utilising the WBB in people after stroke.

Methods

Thirty individuals who were more than three months post-stroke and able to stand unsupported were recruited from a single outpatient rehabilitation facility. Participants performed standardised assessments incorporating the WBB and customised software (static stance with eyes open and closed, static weight-bearing asymmetry, dynamic mediolateral weight shifting and dynamic sit-to-stand) in addition to commonly employed clinical tests (10 Metre Walk Test, Timed Up and Go, Step Test and Functional Reach) on two testing occasions one week apart. Test-retest reliability and construct validity of the WBB tests were investigated.

Results

All WBB-based outcomes were found to be highly reliable between testing occasions (ICC  = 0.82 to 0.98). Correlations were poor to moderate between WBB variables and clinical tests, with the strongest associations observed between task-related activities, such as WBB mediolateral weight shifting and the Step Test.

Conclusions

The WBB, used with customised software, is a reliable and potentially useful tool for the assessment of balance and weight-bearing asymmetry following stroke. Future research is recommended to further investigate validity and responsiveness.

Aktivnosti za preprečevanje padcev v rehabilitaciji pacientov po možganski kapi in njihov učinek na incidenco padcev

Uvod: Preprečevanje padcev je pomemben del rehabilitacijske obravnave. S timsko obravnavo in sistematičnim izvajanjem aktivnosti pri za padec visoko ogroženih pacientih se število padcev lahko zmanjša. Metode: V raziskavo je bilo vključenih 1.634 pacientov na rehabilitaciji po možganski kapi v Univerzitetnem rehabilitacijskem inštitutu Republike Slovenije – Soča (URI – Soča) od 1. 1. 2007 do 31. 12. 2012. Za ugotavljanje učinkovitosti aktivnosti za preprečevanje padcev pacientov je bila izvedena retrospektivna opazovalna raziskava z elementi akcijskega raziskovanja. Uspešnost izvedenih aktivnosti za preprečevanje padcev se je ugotavljala na podlagi incidence padcev. Rezultati: V primerjavi z obdobjem 2007 do 2010, ko so se izvajale splošne aktivnosti za preprečevanje padcev in je incidenca padcev npr. leta 2007 znašala 4,5/1000 bolnišničnooskrbnih dni, se je le-ta v letih 2011 in 2012 po uvedbi lestvice za oceno tveganja za padec ter sistematičnega delovanja celotnega rehabilitacijskega tima pomembno zmanjšala, tako da je leta 2012 znašala 2,8/1000 bolnišničnooskrbnih dni. Učinkovitost sistematičnega delovanja pri preprečevanju padcev se kaže v manjšem številu pacientov, ki so padli enkrat (p = 0,025). Diskusija in zaključek: S sistematičnim delovanjem multidisciplinarnega rehabilitacijskega tima lahko učinkovito zmanjšamo število padcev pacientov po možganski kapi na rehabilitacijskem oddelku. Vpliv teh aktivnosti na preprečevanje padcev pacientov v domačem okolju po zaključeni rehabilitaciji odpira tudi možnosti za nadaljnje raziskovalno delo.

Effect of dual tasking on intentional vs. reactive balance control in people with hemiparetic stroke

To examine the effect of a cognitive task on intentional vs. reactive balance control in people with hemiparetic stroke (PwHS). Community-dwelling PwHS ( n = 10) and healthy, age-similar controls performed two tests, which included the Limits of Stability Test (intentional control) and the Motor Control Test (reactive control), under single-task (ST) and dual-task (DT) conditions (addition of a cognitive task). Cognitive ability was measured on a word list generation task by recording the number of words enumerated in sitting (ST; for cognition) and during the balance tasks. The difference in response time between the ST and DT, defined as the “balance cost” was obtained [(ST − DT)/ST × 100] and compared between tests and across groups. The “cognitive cost” was similarly defined and compared. For both groups, the response time under DT condition was significantly greater for intentional than the reactive balance control task, leading to a higher balance cost for this task ( P < 0.05). However, the cognitive cost was significantly greater for the intentional than the reactive balance control task for only the PwHS. DT significantly affected intentional than reactive balance control for PwHS. The significant decrease in both balance and cognitive performance under DT compared with ST conditions during intentional balance control suggests sharing of attentional resources between semantic memory and intentional balance control. Decreased performance on the cognitive task only during the reactive balance test indicates possible central nervous system's prioritization of reactive balance control over cognition.

Varied Overground Walking Training Versus Body-Weight-Supported Treadmill Training in Adults Within 1 Year of Stroke

Background: Although task-related walking training has been recommended after stroke, the theoretical basis, content, and impact of interventions vary across the literature. There is a need for a comparison of different approaches to task-related walking training after stroke. Objective: To compare the impact of a motor-learning-science–based overground walking training program with body-weight-supported treadmill training (BWSTT) in ambulatory, community-dwelling adults within 1 year of stroke onset. Methods: In this rater-blinded, 1:1 parallel, randomized controlled trial, participants were stratified by baseline gait speed. Participants assigned to the Motor Learning Walking Program (MLWP) practiced various overground walking tasks under the supervision of 1 physiotherapist. Cognitive effort was encouraged through random practice and limited provision of feedback and guidance. The BWSTT program emphasized repetition of the normal gait cycle while supported on a treadmill and assisted by 1 to 3 therapy staff. The primary outcome was comfortable gait speed at postintervention assessment (T2). Results: In total, 71 individuals (mean age = 67.3; standard deviation = 11.6 years) with stroke (mean onset = 20.9 [14.1] weeks) were randomized (MLWP, n = 35; BWSTT, n = 36). There was no significant between-group difference in gait speed at T2 (0.002 m/s; 95% confidence interval [CI] = −0.11, 0.12; P > .05). The MLWP group improved by 0.14 m/s (95% CI = 0.09, 0.19), and the BWSTT group improved by 0.14 m/s (95% CI = 0.08, 0.20). Conclusions: In this sample of community-dwelling adults within 1 year of stroke, a 15-session program of varied overground walking-focused training was not superior to a BWSTT program of equal frequency, duration, and in-session step activity.

Falls and Use of Assistive Devices in Stroke Patients with Hemiparesis: Association with Balance Ability and Fall Efficacy

PURPOSE

This study investigates balance ability and the fall efficacy with regard to the experiences of stroke patients with hemiparesis.

METHODS

The experience of falling, the use of assistive devices, and each disease-related characteristic were assessed using face-to-face interviews and a self-reported questionnaire. The Berg Balance Scale and Fall Efficacy Scale were used to measure balance ability and confidence.

RESULTS

The fall efficacy was significantly lower in participants who had experienced falls than those who had not. The participants who used assistive devices exhibited low balance ability and fall efficacy compared to those who did not use assistive devices.

CONCLUSIONS

Stroke patients with fall experience and walking aids might be considered at increased risk of falling.

CLINICAL RELEVANCE

Preventive measures for individuals using walking aids may be beneficial in reducing the fall rate of community-dwelling stroke patients.

Dynamic instability during post-stroke hemiparetic walking

Falls and fall-related injuries cause extremely costly and potentially fatal health problems in people post-stroke. However, there is no global indicator of walking instability for detecting which individuals will have increased risk of falls. The purposes of this study were to directly quantify walking stability in stroke survivors and neurologically intact controls and to determine which stability measures would reveal the changes in walking stability following stroke. This study thus provided an initial step to establish objective measures for identifying potential fallers. Nine post-stroke individuals and nine controls walked on a treadmill at four different speeds. We computed short-term local divergence exponent (LDE) and maximum Floquet multiplier (maxFM) of the trunk motion, average and variability of dynamic margins of stability (MOS) and step spatiotemporal measures. Post-stroke individuals demonstrated larger short-term LDE (p = 0.002) and maxFM (p = 0.041) in the mediolateral (ML) direction compared to the controls but remained orbitally stable (maxFM < 1). In addition, post-stroke individuals walked with greater average step width (p = 0.003) but similar average ML MOS (p = 0.154) compared to the controls. Post-stroke individuals also exhibited greater variability in all MOS and step measures (all p < 0.005). Our findings indicate that post-stroke individuals walked with greater local and orbital instability and gait variability than neurologically intact controls. The results suggest that short-term LDE of ML trunk motion and the variability of MOS and step spatiotemporal measures detect the changes in walking stability associated with stroke. These stability measures may have the potential for identifying those post-stroke individuals at increased risk of falls.

Dynamic stability and compensatory stepping responses during anterior gait-slip perturbations in people with chronic hemiparetic stroke

To examine the control of dynamic stability and characteristics of the compensatory stepping responses to an unexpected anterior gait slip induced under the non-involved limb in people with hemi-paretic stroke (PwHS) and to examine any resulting adaptive changes in these on the second slip due to experience from prior slip exposure. Ten PwHS experienced overground slip (S1) during walking on the laboratory walkway after 5-8 regular walking (RW) trials followed by a second consecutive slip trial (S2). The slip outcome (backward loss of balance, BLOB and no loss of balance, NLOB) and COM state (i.e. its COM position and velocity) stability were examined between the RW and S1 and S1 and S2 at touchdown (TD) of non-involved limb and at liftoff (LO) of the contralateral limb. At TD there was no difference in stability between RW and S1, however at LO, subjects demonstrated a lower stability on S1 than RW resulting in a 100% backward loss of balance (BLOB) with compensatory stepping response (recovery step, RS, 4/10 or aborted step, AS, 6/10). On S2, although there was no change in stability at TD, there was a significant improvement in stability at LO with a 40% decrease in BLOB. There was also a change in step strategy with a decrease in AS response (60% to 35%, p<0.05) which was replaced by an increase in the ability to step (increased compensatory step length, p<0.05) either via a recovery step or a walkover step. PwHS have the ability to reactively control COM state stability to decrease fall-risk upon a novel slip; prior exposure to a slip did not significantly alter feedforward control but improved the ability to use such feedback control for improved slip outcomes.

Gait training with real-time augmented toe-ground clearance information decreases tripping risk in older adults and a person with chronic stroke

Falls risk increases with ageing but is substantially higher in people with stroke. Tripping-related balance loss is the primary cause of falls, and Minimum Toe Clearance (MTC) during walking is closely linked to tripping risk. The aim of this study was to determine whether real-time augmented information of toe-ground clearance at MTC can increase toe clearance, and reduce tripping risk. Nine healthy older adults (76 ± 9 years) and one 71 year old female stroke patient participated. Vertical toe displacement was displayed in real-time such that participants could adjust their toe clearance during treadmill walking. Participants undertook a session of unconstrained walking (no-feedback baseline) and, in a subsequent Feedback condition, were asked to modify their swing phase trajectory to match a “target” increased MTC. Tripping probability (PT) pre- and post-training was calculated by modeling MTC distributions. Older adults showed significantly higher mean MTC for the post-training retention session (27.7 ± 3.79 mm) compared to the normal walking trial (14.1 ± 8.3 mm). The PT on a 1 cm obstacle for the older adults reduced from 1 in 578 strides to 1 in 105,988 strides. With gait training the stroke patient increased MTC and reduced variability (baseline 16 ± 12 mm, post-training 24 ± 8 mm) which reduced obstacle contact probability from 1 in 3 strides in baseline to 1 in 161 strides post-training. The findings confirm that concurrent visual feedback of a lower limb kinematic gait parameter is effective in changing foot trajectory control and reducing tripping probability in older adults. There is potential for further investigation of augmented feedback training across a range of gait-impaired populations, such as stroke.

Feasibility and safety of acute phase rehabilitation after stroke using the hybrid assistive limb robot suit

Acute phase rehabilitation is an important treatment for improving the functional outcome of patients after stroke. The present cohort study analyzed the feasibility and safety of acute phase rehabilitation using the hybrid assistive limb robot suit in 22 patients, 7 males and 15 females (mean age 66.6 ± 17.7 years). Neurological deterioration, mortality, or other accidents were recorded as adverse events. Baseline characteristics of each patient were recorded at the first hybrid assistive limb rehabilitation. Hybrid assistive limb rehabilitation was conducted for 12.1 ± 7.0 days with the patients in stable condition. Acute phase hybrid assistive limb rehabilitation was performed a total of 84 times with no adverse events recorded except for orthostatic hypotension. Good functional outcomes were obtained in 14 patients. Orthostatic hypotension was observed during the first hybrid assistive limb rehabilitation in four patients, and was significantly associated with intracerebral hemorrhage (p = 0.007) and lower Brunnstrom stage (p = 0.033). Acute phase rehabilitation using the hybrid assistive limb suit is feasible and safe. Patients with intracerebral hemorrhage and lower Brunnstrom stage should be carefully monitored for orthostatic hypotension.

Clinical feasibility of the Nintendo Wii™ for balance training post-stroke: a phase II randomized controlled trial in an inpatient setting

OBJECTIVE

To investigate the feasibility and potential efficacy of the Nintendo Wii™ for balance rehabilitation after stroke.

DESIGN

Phase II, single-blind, randomized controlled trial.

SETTING

Inpatient rehabilitation facility.

SUBJECTS

Thirty adults (mean age 63.6 (14.7) years) undergoing inpatient rehabilitation who were less than three months post-stroke and able to stand unsupported.

INTERVENTIONS

Participants were allocated to a Balance Group, using the 'Wii Fit Plus' in standing, or Upper Limb Group, using the 'Wii Sports/Sports Resort' in sitting. Both groups undertook three 45 minute sessions per week over two to four weeks in addition to standard care.

MAIN MEASURES

The primary focus was feasibility, addressed by recruitment, retention, adherence, acceptability and safety. Efficacy was evaluated by balance, mobility and upper limb outcomes.

RESULTS

Twenty-one percent of individuals screened were recruited and 86% (n = 30) of eligible people agreed to participate. Study retention and session adherence was 90% and > 99%, respectively, at two weeks; dropping to 70% and 87% at four weeks due to early discharge. All participants reported enjoying the sessions and most felt they were beneficial. No major adverse events occurred. Wii use by the Balance Group was associated with trends for improved balance, with significantly greater improvement in outcomes including the Step Test and Wii Balance Board-derived centre of pressure scores. The Upper Limb Group had larger, non-significant changes in arm function.

CONCLUSIONS

A Wii-based approach appears feasible and promising for post-stroke balance rehabilitation. A larger randomized controlled trial is recommended to further investigate efficacy.

Falls and comorbidity: The pathway to fractures

Aims: To compare nationwide time trends and mortality in hip and proximal humeral fractures; to explore associations between incidences of falls risk related comorbidities (FRICs) and incidence of fractures. Methods: The study is a retrospective cohort study using nationwide Danish administrative registries from 2000 through 2009. Individuals aged 65 years or older who experienced a hip or a proximal humeral fracture were included. Incidence of hip and of proximal humeral fractures, incidence of FRICs (ischemic heart disease, COPD, dementia, depression, diabetes, heart failure, osteoporosis, Parkinson’s disease and stroke) and incidence rate ratios (IRR) for fractures in patients with FRICs, and all-cause mortality up to 10 years after a hip or a proximal humeral fracture were analysed. Results: A total of 89,150 patients experienced hip fractures and 48,581 proximal humeral fractures. From 2000 through 2009, the incidence of hip fractures per 100,000 individuals declined by 198 (787 to 589, OR = 0.75, CI: 0.72–0.80) among males and by 483 (1758 to 1275, OR = 0.74, CI: 0.72–0.77) among females. Incidences of FRICs decreased. The absolute reduction in fractures was most pronounced for the age group above 75 years (2393 to 1884, OR = 0.81, CI: 0.78–0.83), but the relative reduction was more pronounced in the age group of 65–75 years old (496 to 342, OR = 0.70, CI: 0.66–0.74). IRRs for hip fractures and for proximal humeral fractures were significantly elevated in patients with FRICs. Conclusions: The results suggest that the overall reduction in fractures can be explained by reduction in falls related comorbidity.

Poststroke hip fracture: prevalence, clinical characteristics, mineral-bone metabolism, outcomes, and gaps in prevention

Objective. To assess the prevalence, clinical and laboratory characteristics, and short-term outcomes of poststroke hip fracture (HF). Methods. A cross-sectional study of 761 consecutive patients aged ≥60 years (82.3 ± 8.8 years; 75% females) with osteoporotic HF. Results. The prevalence of poststroke HF was 13.1% occurring on average 2.4 years after the stroke. The poststroke group compared to the rest of the cohort had a higher proportion of women, subjects with dementia, history of TIA, hypertension, coronary artery disease, secondary hyperparathyroidism, higher serum vitamin B12 levels (>350 pmol/L), walking aid users, and living in residential care facilities. The majority of poststroke HF patients had vitamin D insufficiency (68%) and excess bone resorption (90%). This group had a 3-fold higher incidence of postoperative myocardial injury and need for institutionalisation. In multivariate analysis, independent indicators of poststroke HF were female sex (OR 3.6), history of TIA (OR 5.2), dementia (OR 4.1), hypertension (OR 3.2), use of walking aid (OR 2.5), and higher vitamin B12 level (OR 2.3). Only 15% of poststroke patients received antiosteoporotic therapy prior to HF. Conclusions. Approximately one in seven HFs occurs in older stroke survivors and are associated with poorer outcomes. Early implementation of fracture prevention strategies is needed.

Classification of falls in stroke rehabilitation – not all falls are the same

Objective:

To develop a practical taxonomy of falls and to determine whether these different fall groups have different outcomes.

Design:

Descriptive study examining patient characteristics at the time of each fall and iterative development of falls taxonomy.

Setting:

An inpatient stroke rehabilitation ward.

Methods:

All falls over 21 months were reviewed retrospectively. Case notes were reviewed and each patient’s level of functioning at the time of fall, together with admission profile and discharge outcomes, were collected. Outcomes for fallers (as opposed to falls) were compared using the predominant fall type.

Results:

There were 241 falls in 122 patients and most falls occurred around the bed (196 (81%) falls). Toileting-related falls occurred in 54 patients (22.4%). The taxonomy proposes seven main fall types. One fall type (‘I’m giving it a go’) appeared quite different and was associated with better functioning at time of fall and better outcomes. Other fall types were related to high dependency needs, visuospatial difficulties or delirium. Medication-related falls were uncommon in this cohort.

Conclusions:

The falls taxonomy developed showed four main types of falls with different, but overlapping, patient characteristics at time of fall with different outcomes. Different fall-prevention strategies may be required for each group.

Validity, reliability and minimum detectable change of the maximum step length test in people with stroke

Stroke is a significant cause of deficits in balance, mobility and disability. Although tests of stepping speed are associated with balance performance after stroke, relationships between clinical tests of stepping distance and balance performance have not been investigated in people with stroke. A validated test of stepping distance and balance in older adults (the maximum step length [MSL] test), and two clinical measures associated with balance in people with stroke (the five-times-sit-to-stand test [FTSST] and gait speed) were evaluated in nineteen independent community-dwelling people with chronic stroke. There were strong relationships between MSL and performance on the clinical balance measures (Pearson's r 0.69 to -0.88), suggesting that MSL is a valid measure of balance after stroke. Test-retest reliability coefficients were excellent for the MSL tests (ICC both limbs; 0.98). Standard error of measurement expressed as a percentage of mean MSL was computed as 5.6% (hemiparetic leg) and 5.4% (unaffected leg), indicative of low levels of measurement error and excellent absolute reliability of the MSL test in people with stroke. Minimum detectable change expressed as a percentage of mean MSL was low (14.9% to 15.4%), suggesting that MSL may be sensitive to detecting change in physical performance in people with stroke. Advantages of the MSL test are that it is easy to administer, requiring minimal training, equipment, time or space. These advantages, together with the validity of the MSL test, its excellent test-retest and absolute reliability, and its low minimum change percent value suggest that MSL may be a useful measure of balance capabilities in people with stroke.

Fall risk six weeks from onset of stroke and the ability of the Prediction of Falls in Rehabilitation Settings Tool and motor function to predict falls

Objective:

To investigate whether the Prediction of Falls in Rehabilitation Settings Tool (Predict FIRST) and motor function could be used to identify people at risk of falling during the first six weeks after stroke, and to compare the risk of falling according to Predict FIRST with real falls frequency.

Design:

A longitudinal, prospective study.

Patients:

Sixty-eight people newly diagnosed with stroke admitted to an acute stroke unit.

Methods:

The participants underwent an assessment of motor ability (Modified Motor Assessment Scale according to Uppsala University Hospital version 99 (M-MAS UAS-99)) and falls risk (Predict FIRST) on the first to fourth day at the acute stroke unit. Falls occurring in the acute stroke unit were recorded and falls occurring after discharge were reported by telephone follow-up. The prediction of falls was analysed with binary logistic regression.

Results:

Fourteen of the patients (21%) fell at least once during the first six weeks after stroke. The strongest significant predictor for falls was a high score on Predict FIRST (odds ratio 5.21, confidence interval (CI) 1.10–24.78) followed by M-MAS UAS-99 parts C–E (odds ratio 0.65, CI 0.44–0.95). Predict FIRST underestimated the risk of falling as the median fall risk was 9% according to Predict FIRST.

Conclusion:

Although Predict FIRST has the ability to predict falls in people with recent onset of stroke, there is some underestimation of fall risk.