Evidências de intervenções para aumento da força muscular e melhora da marcha em indivíduos pós- acidente vascular encefálico

Abstract

Recent data indicated that more than 30 million people in the world have experienced and survived a stroke. As a consequence of stroke, more than 80% of the survivors experience muscle weakness contralateral to the brain lesion and walking limitations, which contribute to participation restrictions. Previous studies have demonstrated that strength and walking parameters in ambulatory people after stroke are approximately half of the values expected for older, able-bodied adults. Thus, there is a constant move in order to examine the most efficient interventions capable of improving weakness and walking limitations after stroke, and several clinical trials to support an evidence-based practice have been conducted. However, the main barriers to the implementation of an evidenced-based practice are the lack of time for reading all the published evidence, and the lack of skills in finding and understanding the randomised clinical trials. The increase in the number of published papers associated with the lack of time for reading and synthesizing the available evidence challenge researchers to produce summarized information, in order to enhance clinical access to the most updated evidence. Clinical Guidelines represent good alternatives for clinicians to obtain summarized information regarding a specific health condition. However, the development of a clinical guideline is a long process, and even its update process requires time and dedication of many professionals. Thus, sometimes, the information provided by Clinical Guidelines does not represent the most updated evidence, and clinicians may have to read numerous clinical trials or, preferably, systematic reviews in order to update the knowledge that will help with clinical practice. Systematic reviews of randomised clinical trials are the most robust source of information to answer questions regarding the efficacy of an intervention, with the advantage of being updated more frequently in comparison with Clinical Guidelines. Although systematic reviews are the best design to provide evidence of effect of interventions, they are dependent on the publication of clinical trials with good methodological quality. The development of clinical trials, however, is not an easy procedure, and it is constantly limited due to difficulties in funding and participants recruitment. In this case, researches should also be able to produce trials with the potential of immediately answering clinical questions that may improve clinical practice. The overall purpose of this thesis was to provide clinical evidence, based on high quality research, regarding effects of interventions delivered to people after stroke, and to provide clinical implications with the potential to enhance the effect of an intervention. Clinical interests are related to a major impairment after stroke (i.e., muscle weakness) and to walking limitations. The definition of each study which comprised the thesis and its research design began by carefully reading the Clinical Guidelines for Stroke Management a clinical guideline developed with the purpose of making clinical recommendations for prevention and treatment of patients after stroke. The rehabilitation chapter of the guideline was analyzed in order to understand the current level of evidence, to identify areas with lack of evidence, and to develop studies capable of providing evidence that could help clinical practice regarding muscle weakness and walking limitations after stroke. Four studies were planned: three systematic reviews and one experimental trial. Study 1: Cyclical electrical stimulation increases strength and improves activity after stroke: a systematic review. This study examined the effect of cyclical electrical stimulation on muscle strength and activities after stroke. The research questions were: Does electrical stimulation increase strength after stroke? Are any benefits maintained beyond the intervention period or carried over to activity? A systematic review with meta-analysis of randomised or controlled trials was conducted. Participants were adults who have had a stroke, and the intervention was cyclical electrical stimulation applied in order to increase muscle strength. The outcome measures were related to muscle strength and to activity. Strength measures had to be representative of maximum voluntary contraction and were obtained as continuous measures of force or torque, or as ordinal measures such as manual muscle tests. Activity was measured using direct measures of performance that produced continuous or ordinal data, or with scales that produced ordinal data. Sixteen trials, representing 17 relevant comparisons, were included in this systematic review. Effect sizes were calculated as standardised mean differences because various muscles were studied and different outcome measures were used. Overall, electrical stimulation increased strength by a standardised mean difference (SMD) of 0.47 (95% CI 0.26 to 0.68) and this effect was maintained beyond the intervention period (SMD 0.33, 95% CI 0.07 to 0.60). Electrical stimulation also improved activity (SMD 0.30, 95% CI 0.05 to 0.56) and this effect was also maintained beyond the intervention period (SMD 0.38, 95% CI 0.09 to 0.66). In conclusion, cyclical electrical stimulation increased strength and improved activity after stroke. These benefits were maintained beyond the intervention period with a small-to-moderate effect size. The sustained effect on activity suggests that the benefits were incorporated into daily life. Study 2: Walking training with cueing of cadence improves walking speed and stride length after stroke more than walking training alone: a systematic review. This study examined the effect of the addition of cueing of cadence to walking training for improving walking speed, stride length, cadence and symmetry after stroke. The research question was: After stroke, is walking training with cueing of cadence superior to walking training alone in improving walking speed, stride length, cadence and symmetry? A systematic review with meta-analysis of randomised or controlled trials was conducted. Participants were ambulatory adults who have had a stroke. The intervention was walking training with cueing of cadence, and four walking outcomes were of interest: walking speed, stride length, cadence and symmetry. This review included seven trials involving 211 participants. Because one trial caused substantial statistical heterogeneity, meta-analyses were conducted with and without this trial. Walking training with cueing of cadence improved walking speed by 0.23 m/s (95% CI 0.18 to 0.27, I2 = 0%), stride length by 0.21 m (95% CI 0.14 to 0.28, I2 = 18%), cadence by 19 steps/minute (95% CI 14 to 23, I2 = 40%), and symmetry by 15% (95% CI 3 to 26, random effects) more than walking training alone. In conclusion, this review provided evidence that walking training with cueing of cadence improves walking speed and stride length more than walking training alone. It may also produce benefits in terms of cadence and symmetry of walking. The evidence appears strong enough to recommend the addition of 30 minutes of cueing of cadence to walking training, four times a week for 4 weeks, in order to improve walking in moderately disabled individuals with stroke. Study 3: Walking training associated with virtual reality-based training increases walking speed of individuals with chronic stroke: systematic review with meta-analysis. This study examined the effect of the addition of virtual reality-based training to walking training for improving walking speed after stroke. The research questions were: (i) Is walking training associated with virtual reality-based training effective in increasing walking speed after stroke? (ii) Is this type of intervention more effective in increasing walking speed, than non-virtual reality-based walking interventions? A systematic review with meta-analysis of randomised clinical trials was conducted. Participants were adults with chronic stroke and the experimental intervention was walking training associated with virtual reality-based training to increase walking speed. The outcome data regarding walking speed were extracted from the eligible trials and were combined using a meta-analysis approach. Seven trials, representing eight comparisons, were included in this systematic review. Overall, the virtual reality-based training increased walking speed by 0.17 m/s (IC 95% 0.08 to 0.26), compared with placebo/nothing or non-walking interventions. In addition, the virtual reality-based training increased walking speed by 0.15 m/s (IC 95% 0.05 to 0.24), compared with non-virtual reality walking interventions. In conclusion, this review provided evidence that walking training associated with virtual reality-based training was effective in increasing walking speed after stroke, and resulted in better results than non-virtual reality interventions. Study 4: The provision of a cane provided greater benefit to the group of community-dwelling people with chronic stroke with speed between 0.4 and 0.8 m/s. This study examined the effect of the provision of a cane to ambulatory people after stroke on walking speed, step length, and cadence. The research questions were: (i) What is the effect of the provision of a cane on speed, step length, and cadence in people with chronic stroke who are independently ambulatory? (ii) Is there a differential effect according to comfortable walking speed (<0.4 versus 0.4-0.8 versus >0.8 m/s)? Twenty-four people with chronic stroke, who were not regular users of walking sticks, were evaluated under two different experimental conditions: walking with and without a cane. Walking was reported as speed (m/s), step length (m), and cadence (steps/min). Participants were categorized as slow (<0.4 m/s), intermediate (0.4-0.8 m/s), and fast walkers (>0.8 m/s). The provision of a cane to the intermediate walkers produced a 0.27 m/s (95% CI 0.18 to 0.36) increase in speed compared with the fast walkers, and a 0.12 m/s (95% CI 0.03 to 0.21) increase compared with the slow walkers. It also produced 0.05 m (95% CI 0.02 to 0.08) increase in step length and 20 steps/min (95% CI 12 to 28) increase in cadence compared with the fast walkers. The provision of a cane produced the most benefit in intermediate walkers, and was detrimental to the fast walkers. Canes can be prescribed to stroke survivors with moderate and severe walking limitations, but caution should be taken regarding their prescription for fast walkers.