Inclusion Criteria - Inclusion criteria are as follows. Healthy participants: absence of detectable neurological or physical malfunction which might affect postural control, no use of drugs affecting body balance and preserved mental capacity. Stroke patients: capacity to sustain independently orthostatic posture for at least 5 min. and preserved mental capacity.
Exclusion Criteria - Exclusion Criteria are: no orthopedic malfunction, no clinical instability associated with systemic disease, no use of drugs affecting body balance and presence of "pusher syndrome".