Investigating and stimulating walking after stroke

Abstract

Many people who survive a stroke, experience physical consequences such as reduced walking ability. Task-oriented Circuit Class Training (CCT) is an effective physical therapy intervention aimed at improving walking in the chronic stages after stroke. This thesis showed its effectiveness and feasibility moderately impaired people in the subacute stages (i.e. up to three months) after a stroke, for example during inpatient rehabilitation. Information about the effectiveness of interventions during this stage of rehabilitation may be of particular importance, as the period up to three months after stroke is regarded as a critical time window of enhanced neuroplasticity. Interventions during this period may enhance biological recovery and improve functional outcome. As a consequence of the finding that the integration of aerobic exercise into task-oriented CCT appeared to increase its effectiveness in improving walking capacity compared to task-oriented CCT alone in mildly impaired people in the subacute stage after stroke, the association between aerobic capacity and walking capacity was further investigated. The systematic review and meta-analyses in this thesis showed a low combined correlation coefficient for aerobic capacity and walking speed, and a moderate for aerobic capacity and walking distance. These results supported the notion that the association between aerobic capacity and walking capacity justifies the integration of aerobic exercise into task-oriented CCT. The wide range of correlation coefficients, that were reported in the included studies also suggested that other factors, besides aerobic capacity, determine walking capacity after stroke. Multivariate analysis in the following cross-sectional study in mildly to moderately impaired people after a stroke, showed that postural control confounded the strong association between aerobic capacity and walking capacity after stroke. The findings confirmed that aerobic capacity is an important factor associated with walking capacity after stroke. Postural control, however, needs to be taken into account to understand this relationship. Both aerobic capacity and postural control may need to be addressed during interventions aiming to improve walking capacity after stroke. Task-oriented CCT effectively improves walking capacity, and its effectiveness may even be enhanced by incorporating aerobic exercise. However, the resulting gains in walking capacity do not seem to translate into walking performance, e.g. outdoor walking. This may be attributed to the fact that most studies and programs address merely one aspect of the comprehensive problem. For instance, task-oriented CCT aims at the physical problem, whereas behavioral, environmental or social problems may also need to be addressed. The results of the qualitative study in this thesis showed that outdoor walking was determined by intention, ability and opportunity. The intention to walk outdoors was determined by personal factors such as social influence, for instance from restrictive attitudes of caregivers in the social environment, as well as by self-efficacy, influenced by the physical environment, and by the attitude towards physical activity. Walking ability was influenced by loss of balance and reduced walking distance, and by impairments of motor control, cognition and aerobic capacity, as well as fatigue. Outdoor walking was facilitated by opportunities demanding walking performance arising from household tasks and lively social contacts.