Whole-body coordination when turning on the spot in people with stroke and healthy controls

Ahmad, R., Verheyden, G., Burnett, M., Samuel, D. and Ashburn, A. (2012) Whole-body coordination when turning on the spot in people with stroke and healthy controls. International Society for Posture and Gait Research/ Gait and Mental Function 1st joint World Congress, Trondheim, Norway. 23 - 27 Jun 2012.

Abstract

Background and Aim:
Turning around to interact with the environment is a common activity of daily living. The location of a target for interaction may be known or unknown prior to turning and the angle of a turn may vary depending on the task to be carried out. A stroke can compromise coordination of body movement during turning] which may pose a risk for instability and subsequent falls. The aim of this study was to investigate the kinematic sequence of rotation of body segments in people with stroke and healthy controls when turning on the spot to predictable and unpredictable targets placed at three different angles (45°, 90° and 135°).

Methods:
Nine people with stroke [age: 64±9 (mean±SD) years] and nine healthy controls [age: 64±9 (mean±SD) years] were asked to stand in front of a light and either turn to a specific light (predictable condition) or locate and turn to a random light (unpredictable condition) placed at 45°, 90° or 135° to the right or left when the light in front extinguished. There were five trials for each task and the tasks were randomized. The onset latency of the horizontal eye movement was measured by an eye camera (VNG Ulmer) and that of the horizontal head, shoulder, pelvis and feet movement were measured by CODA motion.

Results:
There was a top to bottom initiation of rotation of the segments when turning to unpredictable targets and a more simultaneous initiation of the segments when turning to predictable targets in both groups (interaction of segment
and predictability: F=27.004, p=0.001). However, this was not different between the stroke and control groups (Interaction of segment, predictability and group: F=2.887, p=0.082). In the unpredictable condition, there was more simultaneous onset of eye, head and shoulder movement when turning to 45 and 90 degrees as compared to more increasing latencies for the 135 degrees condition (interaction of segment, predictability and angle: F=19.443, p=0.001). There was no difference in the sequence of the segments when turning to both sides in the stroke participants (paretic/non?paretic sides) and controls (right/left sides) (Interaction of segment, direction and group: F=0.300, p=0.876.

Conclusions:
Predictability of a target affects the sequence of rotation of segments during turning on the spot. The turn angle also affects the sequence when turning to unpredictable targets. The balance of an individual during a task is determined by the movement of the centre of mass within the base of support. This could be affected by the relative movement of the segments involved in the task. The clinical significance of the results of this study may be investigated by relating the sequence of the movement of the body segments to stability during turning. The similarity in the sequence between the groups may be due to motor and sensory deteriorations in the elderly.

This record has no associated files available for download.

Contributors

Author: M. Burnett

Author: D. Samuel

Download statistics