Thesis defense Hanneke van Duijnhoven (Donders series 424)
10 February 2020
Promotor: prof. dr. A. Geurts
Co-promotor: dr. V. Weerdesteyn
The challenges of dynamic balance and gait for people after stroke
People after stroke often experience balance and gait deficits, specifically under dynamic circumstances. This puts them at an increased fall risk. The aims of this thesis were to study the mechanisms underlying the problems that people after stroke experience during dynamic balance and gait tasks; and to provide insight into the effects of dynamic balance and gait training in the chronic phase after stroke. In particular, it focuses on three important but relatively understudied topics: trunk control, gait adaptability, and stepping reactions after balance perturbations. People early after stroke were studied during a lateral reach task, a seated dynamic balance task that requires good trunk control. The participants showed an altered movement pattern of the head, trunk and pelvis while reaching, and they reached less far and moved at a slower speed compared to healthy subjects. An obstacle avoidance task showed that, even in persons who were mildly affected by stroke, gait adaptability was impaired. Delayed and decreased muscle responses were identified as a possible mechanism, leading to a diminished capacity to adapt step length when avoiding an unexpected obstacle. To obtain insight into the effects of exercise training on balance capacity in people in the chronic phase after stroke, a systematic review and meta-analysis were performed. These showed that balance capacities can be improved by well-targeted exercise therapy, with balance and gait training as the most successful training regimens. Furthermore, the development and process evaluation of a stroke-specific fall prevention program in people in the chronic phase after stroke (the FALL prevention after Stroke (FALLS) program) was addressed. Both people after stroke and health care professionals deemed this program suitable and feasible. Subsequently, a phase 1 modeling study assessed the effects of the FALLS program on a set of commonly used clinical tests. This resulted in preliminary evidence for the possible effectiveness of this program with regard to balance capacity and trunk control. Finally, this thesis showed that a 5-week perturbation-based balance training on a moveable platform appears to improve reactive step quality in people with chronic stroke.