Evaluation of center of mass acceleration during quiet standing in patients with stroke

The postural instability was observed in patients following-stroke during standing, showing an altered center of mass acceleration (COMacc). This study aimed to investigate the effects of stroke on fluctuation and complexity of COMacc during quiet standing. Eleven stroke survivals and eleven gender- and age-matched healthy subjects participated in this experiment. The COMacc series in anteroposterior (AP) and mediolateral (ML) directions during quiet standing with vision condition (VC) and non-vision condition (NVC) were recorded by a three-dimensional motion analysis system (BTS Bioengineering Corp, Italy). The standard deviation (SD) and the detrended fluctuation analysis (DFA) of COM
_acc
were calculated under two vision conditions. Stroke patients showed increased SD of AP-COM
_acc
(VC: p <; 0.01; NVC: p <; 0.001), increased αdfa of COM
_acc
in AP under NVC (p <; 0.05) and in ML under VC (p <; 0.05) and NVC (p <; 0.001) compared to healthy subjects. Significant differences were found between VC and NVC in the SD of ML-COM
_acc
of healthy subjects (p <; 0.05), and in œdfa of ML-COM
_acc
of post-stroke patients (p <; 0.01), respectively. The increased fluctuation and decreased complexity of COM
_acc
implied postural balance control mechanism during standing in hemiplegic patients, which may be conducive to improve the rehabilitation strategy of standing balance for poststroke patients.