Colleen G. Canning

Strengthening interventions increase strength and improve activity after stroke: a systematic review

QUESTION Is strength training after stroke effective (ie, does it increase strength), is it harmful (ie, does it increase spasticity), and is it worthwhile (ie, does it improve activity)? DESIGN Systematic review with meta-analysis of randomised trials. PARTICIPANTS Stroke participants were categorised as (i) acute, very weak, (ii) acute, weak, (iii) chronic, very weak, or (iv) chronic, weak. INTERVENTION Strengthening interventions were defined as interventions that involved attempts at repetitive, effortful muscle contractions and included biofeedback, electrical stimulation, muscle re-education, progressive resistance exercise, and mental practice. OUTCOME MEASURES Strength was measured as continuous measures of force or torque or ordinal measures such as manual muscle tests. Spasticity was measured using the modified Ashworth Scale, a custom made scale, or the Pendulum Test. Activity was measured directly, eg, 10-m Walk Test, or the Box and Block Test, or with scales that measured dependence such as the Barthel Index. RESULTS 21 trials were identified and 15 had data that could be included in a meta-analysis. Effect sizes were calculated as standardised mean differences since various muscles were studied and different outcome measures were used. Across all stroke participants, strengthening interventions had a small positive effect on both strength (SMD 0.33, 95% CI 0.13 to 0.54) and activity (SMD 0.32, 95% CI 0.11 to 0.53). There was very little effect on spasticity (SMD -0.13, 95% CI -0.75 to 0.50). CONCLUSION Strengthening interventions increase strength, improve activity, and do not increase spasticity. These findings suggest that strengthening programs should be part of rehabilitation after stroke.

Recurrent Falls in Parkinson’s Disease: A Systematic Review

Most people with Parkinsons disease (PD) fall and many experience recurrent falls. The aim of this review was to examine the scope of recurrent falls and to identify factors associated with recurrent fallers. A database search for journal articles which reported prospectively collected information concerning recurrent falls in people with PD identified 22 studies. In these studies, 60.5% (range 35 to 90%) of participants reported at least one fall, with 39% (range 18 to 65%) reporting recurrent falls. Recurrent fallers reported an average of 4.7 to 67.6 falls per person per year (overall average 20.8 falls). Factors associated with recurrent falls include: a positive fall history, increased disease severity and duration, increased motor impairment, treatment with dopamine agonists, increased levodopa dosage, cognitive impairment, fear of falling, freezing of gait, impaired mobility and reduced physical activity. The wide range in the frequency of recurrent falls experienced by people with PD suggests that it would be beneficial to classify recurrent fallers into sub-groups based on fall frequency. Given that there are several factors particularly associated with recurrent falls, fall management and prevention strategies specifically targeting recurrent fallers require urgent evaluation in order to inform clinical practice.

The effects of an exercise program on fall risk factors in people with Parkinson's disease: a randomized controlled trial

This randomized controlled trial with blinded assessment aimed to determine the effect of a 6‐month minimally supervised exercise program on fall risk factors in people with Parkinsons disease (PD). Forty‐eight participants with PD who had fallen or were at risk of falling were randomized into exercise or control groups. The exercise group attended a monthly exercise class and exercised at home three times weekly. The intervention targeted leg muscle strength, balance, and freezing. The primary outcome measure was a PD falls risk score. The exercise group had no major adverse events and showed a greater improvement than the control group in the falls risk score, which was not statistically significant (between group mean difference = −7%, 95% CI −20 to 5, P = 0.26). There were statistically significant improvements in the exercise group compared with the control group for two secondary outcomes: Freezing of Gait Questionnaire (P = 0.03) and timed sit‐to‐stand (P = 0.03). There were statistically nonsignificant trends toward greater improvements in the exercise group for measures of muscle strength, walking, and fear of falling, but not for the measures of standing balance. Further investigation of theimpact of exercise on falls in people with PD is warranted.

Loss of strength contributes more to physical disability after stroke than loss of dexterity

Objective: The major contributors to physical disability after stroke are considered to be the negative impairments of loss of dexterity (defined here as loss of the ability to co-ordinate muscle activity in the performance of any motor task) and loss of strength. The aims of this study were: (1) to determine the relative contributions of strength and dexterity to function during recovery after stroke; and (2) to determine the predictive value of initial strength, dexterity and function on long-term function after stroke. Design: A longitudinal descriptive study. Setting: The inpatient and outpatient rehabilitation departments of two metropolitan hospitals. Subjects: Twenty-two patients undergoing rehabilitation after acute stroke participated. Main outcome measures: Strength and dexterity of the elbow flexors and extensors were measured, along with arm function, at 3, 5, 7, 9, 11, 15, 19, 23 and 27 weeks after stroke. Results: Standard multiple linear regression analysis demonstrated that strength and dexterity in total contributed significantly to function at all times (r2 = 0.66-0.82, p < 0.0001). Furthermore, strength always made an additional separate contribution to function (r2 0.05-0.26, p<0.05). Function at week 3 was the best clinical predictor of function at week 27 (r2 0.55, p < 0.001). Conclusions: Loss of strength is a more significant contributor than loss of dexterity to physical disability after stroke. This suggests that, where significant weakness is present, exercise designed to increase strength will be required to decrease disability.

Abnormal muscle activation characteristics associated with loss of dexterity after stroke

The aim of this study was to characterise the abnormalities of muscle activation which underlie low dexterity after stroke. A broad definition of dexterity was adopted, where loss of dexterity refers to an inability to coordinate muscle activity in the performance of a motor task (i.e. dexterity was not confined to manual dexterity). EMG of biceps brachii and triceps brachii were monitored from 16 people after stroke and 10 neurologically normal controls as they performed a tracking task requiring coordinated elbow flexion and extension. Weakness could not interfere with performance since the task was designed to require minimal strength. Stroke subjects were assigned to a low (n=10) or high (n=6) dexterity group based on their performance. Spatiotemporal aspects of biceps and triceps EMG were analysed. Low dexterity performance after stroke was characterised by excessive biceps muscle activation (P=0.002) and decreased coupling of muscle activation to target motion (P=0.002). In this study, we could rule out weakness, slowness of muscle activation, excessive co-contraction and spasticity as causes of these abnormalities. Therefore, the loss of dexterity after stroke can be seen as a specific negative impairment which can exist independently of other motor impairments and reflects a loss of skill in generating spatial and temporal muscle activation patterns which conform with environmental demands.

Parkinson's disease: An investigation of exercise capacity, respiratory function, and gait

OBJECTIVE To evaluate the exercise capacity of subjects with mild to moderate Parkinsons disease and determine whether abnormalities in respiratory function and gait affect exercise capacity. DESIGN Descriptive. Subjects were categorized according to exercise history, disease severity, and presence/absence of upper airway obstruction. SUBJECTS AND SETTING Sixteen volunteers with mild to moderate idiopathic Parkinsons disease attended a university research laboratory. MAIN OUTCOME MEASURES Subjects performed a maximum exercise test on a cycle ergometer, together with respiratory function tests and a walking test. Peak values for oxygen consumption and work rate were recorded for the maximum exercise test. Measures of respiratory function included spirometry, flow-volume loops, lung volumes, and mouth pressures. Velocity, stride length, and cadence were measured for preferred and fast speeds of walking. The values obtained on each of these tests were compared with published predicted age- and gender-matched normal values. RESULTS Peak oxygen consumptions and peak work loads achieved by subjects with Parkinsons disease were not significantly different from normal values, despite evidence of respiratory and gait abnormalities typical of Parkinsons disease. Exercise category was significantly correlated with percent predicted VO2peak (r = .64, p < .01), with sedentary subjects producing lower scores than exercising subjects. There was no significant correlation between disease severity and percent predicted VO2peak. CONCLUSION Despite their neurological deficit, individuals with mild to moderate Parkinsons disease have the potential to maintain normal exercise capacity with regular aerobic exercise.

Slowness to Develop Force Contributes to Weakness After Stroke

OBJECTIVE To examine weakness after stroke, in terms of both level and rate of torque generation. DESIGN Descriptive. T tests for dependent and independent samples and Pearsons product moment correlation coefficients were performed. SETTING A rehabilitation unit. PARTICIPANTS Ten stroke subjects, aged 56 to 81 years, undergoing rehabilitation. Ten neurologically normal subjects aged 55 to 78 years were the controls. OUTCOME MEASURES Peak isometric elbow flexor and extensor torque and time to 90% peak elbow flexor and extensor torque at 6 weeks and at 25 weeks after stroke. RESULTS At 6 weeks after stroke, subjects were only half as strong and took two to three times longer to produce torque compared to controls (p < or = .05). By 25 weeks after stroke, significant improvements in peak torque (p < or = .02) and time to 90% peak flexor torque (p < or = .05) were seen so that values were within normal limits. CONCLUSION Decreased rate of torque development compounds the problem of reduced peak torque, which may have significant implications for stroke patients, especially in situations where muscles are very weak or where force needs to be generated quickly.

Exercise for falls prevention in Parkinson disease: A randomized controlled trial

Objective: To determine whether falls can be prevented with minimally supervised exercise targeting potentially remediable fall risk factors, i.e., poor balance, reduced leg muscle strength, and freezing of gait, in people with Parkinson disease. Methods: Two hundred thirty-one people with Parkinson disease were randomized into exercise or usual-care control groups. Exercises were practiced for 40 to 60 minutes, 3 times weekly for 6 months. Primary outcomes were fall rates and proportion of fallers during the intervention period. Secondary outcomes were physical (balance, mobility, freezing of gait, habitual physical activity), psychological (fear of falling, affect), and quality-of-life measures. Results: There was no significant difference between groups in the rate of falls (incidence rate ratio [IRR] = 0.73, 95% confidence interval [CI] 0.45–1.17, p = 0.18) or proportion of fallers (p = 0.45). Preplanned subgroup analysis revealed a significant interaction for disease severity (p < 0.001). In the lower disease severity subgroup, there were fewer falls in the exercise group compared with controls (IRR = 0.31, 95% CI 0.15–0.62, p < 0.001), while in the higher disease severity subgroup, there was a trend toward more falls in the exercise group (IRR = 1.61, 95% CI 0.86–3.03, p = 0.13). Postintervention, the exercise group scored significantly (p < 0.05) better than controls on the Short Physical Performance Battery, sit-to-stand, fear of falling, affect, and quality of life, after adjusting for baseline performance. Conclusions: An exercise program targeting balance, leg strength, and freezing of gait did not reduce falls but improved physical and psychological health. Falls were reduced in people with milder disease but not in those with more severe Parkinson disease. Classification of evidence: This study provides Class III evidence that for patients with Parkinson disease, a minimally supervised exercise program does not reduce fall risk. This study lacked the precision to exclude a moderate reduction or modest increase in fall risk from exercise. Trial registration: Australian New Zealand Clinical Trials Registry (ACTRN12608000303347).

Three Simple Clinical Tests to Accurately Predict Falls in People With Parkinson's Disease

Falls are a major cause of morbidity in Parkinsons disease (PD). The objective of this study was to identify predictors of falls in PD and develop a simple prediction tool that would be useful in routine patient care. Potential predictor variables (falls history, disease severity, cognition, leg muscle strength, balance, mobility, freezing of gait [FOG], and fear of falling) were collected for 205 community‐dwelling people with PD. Falls were monitored prospectively for 6 months using monthly falls diaries. In total, 125 participants (59%) fell during follow‐up. A model that included a history of falls, FOG, impaired postural sway, gait speed, sit‐to‐stand, standing balance with narrow base of support, and coordinated stability had high discrimination in identifying fallers (area under the receiver‐operating characteristic curve [AUC], 0.83; 95% confidence interval [CI], 0.77–0.88). A clinical tool that incorporated 3 predictors easily determined in a clinical setting (falling in the previous year: odds ratio [OR], 5.80; 95% CI, 3.00–11.22; FOG in the past month: OR, 2.39; 95% CI, 1.19–4.80; and self‐selected gait speed < 1.1 meters per second: OR, 1.86; 95% CI, 0.96–3.58) had similar discrimination (AUC, 0.80; 95% CI, 0.73–0.86) to the more complex model (P = 0.14 for comparison of AUCs). The absolute probability of falling in the next 6 months for people with low, medium, and high risk using the simple, 3‐test tool was 17%, 51%, and 85%, respectively. In people who have PD without significant cognitive impairment, falls can be predicted with a high degree of accuracy using a simple, 3‐test clinical tool. This tool enables individualized quantification of the risk of falling.

Exercise therapy for prevention of falls in people with Parkinson's disease: a protocol for a randomised controlled trial and economic evaluation.

BackgroundPeople with Parkinsons disease are twice as likely to be recurrent fallers compared to other older people. As these falls have devastating consequences, there is an urgent need to identify and test innovative interventions with the potential to reduce falls in people with Parkinsons disease. The main objective of this randomised controlled trial is to determine whether fall rates can be reduced in people with Parkinsons disease using exercise targeting three potentially remediable risk factors for falls (reduced balance, reduced leg muscle strength and freezing of gait). In addition we will establish the cost effectiveness of the exercise program from the health providers perspective.Methods/Design230 community-dwelling participants with idiopathic Parkinsons disease will be recruited. Eligible participants will also have a history of falls or be identified as being at risk of falls on assessment. Participants will be randomly allocated to a usual-care control group or an intervention group which will undertake weight-bearing balance and strengthening exercises and use cueing strategies to address freezing of gait. The intervention group will choose between the home-based or support group-based mode of the program. Participants in both groups will receive standardized falls prevention advice. The primary outcome measure will be fall rates. Participants will record falls and medical interventions in a diary for the duration of the 6-month intervention period. Secondary measures include the Parkinsons Disease Falls Risk Score, maximal leg muscle strength, standing balance, the Short Physical Performance Battery, freezing of gait, health and well being, habitual physical activity and positive and negative affect schedule.DiscussionNo adequately powered studies have investigated exercise interventions aimed at reducing falls in people with Parkinsons disease. This trial will determine the effectiveness of the exercise intervention in reducing falls and its cost effectiveness. This pragmatic program, if found to be effective, has the potential to be implemented within existing community services.Trial registrationThe protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12608000303347).