تأثیر بینائی بر تعادل ایستگاهی افراد مبتلا به قطع عضو زیر زانو

 Background & Aims: Human stability is controlled by various parts of neuromuscular, visual and vestibular systems. It depends upon integration of afferent information from the visual, vestibular and proprioception systems. Below knee amputees miss the ankle strategy and do not have the mechanoreceptors and sensory inputs from ankle and sole of the foot and should use other mechanisms to improve their standing balance. There is not enough evidence in literature regarding stability of below knee amputees. Moreover, it is not cleared weather the dependency of these subjects on vision to compensate lack of sensory input is more than normal subjects or not. Therefore, the aim of this study was to evaluate the stability of below knee amputees and also to determine the influence of vision on stability.Materials & Method: Two groups of normal and amputees (20 amputee subject and 20 normal subjects) participated in this research study. The stability of subjects was evaluated using a Kistler force plate. The difference between the stability of subjects was determined by two sample t-test.Results: The mean values of COP excursion of the amputees were 23.71±7.8 and 13.49±5.3 mm in the anteroposterior and mediolateral directions, respectively compared to 24.21±9.76 and 14.55±8.06 mm for normal subjects under open eyes condition (P>0.05). The results showed that there was no difference between stability of amputees and normal subjects. Moreover, there was no difference between stability parameters between two test conditions.Conclusion: There was no difference between stability of amputees and normal subjects. It can be concluded that although the amputees missed the ankle strategy and foot and ankle sensory inputs, they could enhance their standing stability by other mechanisms such as internal mechanism and the information obtained from the skin in contact with socket and also external mechanism such as alignment of prosthesis. The stability of the amputees during quiet standing with open eyes is the same as that of closed eyes. It means that the amputees do not depend upon vision to restore their standing stability. SOURCE: URMIA MED J 2014: 25(9): 852 ISSN: 1027-3727