Understanding motor control in the lower extremity in severely impaired stroke patients

Rationale: Stroke is one of the leading causes of disability of adults in the European Union. Around 80% of stroke survivors experience deficits in motor control, resulting in problems with keeping balance and walking, for instance. The extent and amount of deficits differ per individual. Interventions to train the lower extremity almost always consist of walking exercises. However, patients in the acute phase or with severely affected lower extremity function are often unable to walk or to walk independently. In addition, there is a limited amount of knowledge about the muscle activity in these patients. Therefore, the current study proposes to investigate the motor control in this group. This in order to provide information for follow-up research into robot assisted rehabilitation (ROBERT) combined with functional electrical stimulation (FES) targeted at severely impaired stroke patients.
Objective: Determine the differences in timing, frequency and magnitude of the muscle activity signals during static conditions in stroke patients with severely affected lower extremity function, between the affected and non-affected leg.
Study design: The current study is a cross-sectional observational study.
Study population: Ten participants with a chronic stroke and severely affected lower extremity function will be included in the current study. All participants should have a unilateral stroke, score ≥ 18 and ≤ 75 on the motricity index and an age above 18 years.
Main study parameters/endpoints: The main outcome parameter in the current study is muscle activity of the different muscles during performance of specified static tasks. Different parameters in terms of frequency, amplitude and timing will be subtracted from the muscle activity data.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The current study consist of one visit to the lab of Roessingh Research and Development. The muscle activity will be measured with surface electrodes and maximal force with a prefixed framework. All measuring instruments are CE-certified and are used following the user guides and the intended use. There is no direct advantage for the participants and there are no negative effects of the planned measurements because the study load is relatively low, with room for rest in between trial sets as required by the participant and all forces exerted by the participants will be within their individual capability.

It is expected that the affected lower extremity has lower motor control than the unaffected side and in severely affected stroke patient, the motor control is lower compared to less affected stroke patients.

One time point. At this time point the muscle acitivity will be measured with (HD-)sEMG, the force with force sensors and some general characteristics will be noted, like age, gender and clinical tests. The clinical tests entail the motricity index, fugl-meyer and functional ambulation catagories. The muscle activity and force will be measured in single joint and multi-joint setting. Both the primary and secondary outcomes will be gatherd during this one time point, which will take about 2.5 hours in total.