Influence of combined action observation and motor imagery of walking on lower limb reflex modulation in patients after stroke-preliminary results

Abstract

Objective: The combined use of action observation and motor imagery (AOMI) is a promising technique in neurorehabilitation that can be usefully applied in addition to conventional forms of therapy. Previous studies with healthy participants showed that the mere passive observation of walking results in a phase-dependent reflex modulation in the tibialis anterior muscle that resembles the pattern occurring when walking. In patients after stroke, a similar reflex modulation was found in several lower limb muscles during the real execution of walking, but responses were blunted. To clarify whether and how lower limb reflex responses are also modulated in such patients during the combined synchronous observation and imagery of walking, medium-latency cutaneous reflexes from the tibialis anterior muscle were measured. We compared the reflex responses of seven patients after stroke during the AOMI of walking from two different conditions: (a) elicited during the end stance phase and (b) during the end swing phase, both normalized to a baseline condition.

Results: So far, using the identical methodological set-up as in our study with healthy individuals, we could not find any noteworthy reflex response modulation. The study was registered with the German Clinical Trials Register (DRKS00028255).

Trial registration: The study was registered with the German Clinical Trials Register: DRKS00028255.

Keywords: Action observation; Motor imagery; Reflex responses; Stroke; Walking.

Fig. 1

Mean (RMS after rectification) normalized responses of seven stroke patients with standard errors and individual, normalized values. Horizontal grey line: baseline/control condition