视觉因素对青年平衡功能的影响

Effects of visual factors on balance function in young adults

背景:视觉是维持平衡的主要感觉系统,大约50%的青年视力障碍人士存在跌倒风险。国内的报道更多关注视力障碍人群数量的流行病学调查,忽视了视力障碍者的平衡能力表现及控制策略,尤其是对影响因素的研究。目的:分析不同视觉因素(视力损伤程度:全盲、部分视力损伤、正常视力;视觉状态:睁、闭眼)对青年平衡能力的影响。方法:招募43名青年,根据视力情况将其分为3组:全盲组(n=12)、部分视力损伤组(n=9)和正常视力组(n=22),进行单脚站立测试(睁、闭眼)及功能性前伸测试(视力正常组:睁眼及闭眼;部分视力损伤及全盲组:日常状态)。组间各测量参数采用单因素方差分析,组内采用配对样本t检验比较不同视觉状态间的差异。结果与结论:①单脚站立测试中,正常视力组睁眼时压力中心移动总轨迹长度显著少于全盲与部分视力损伤组(P<0.05),闭眼时组间差异无显著性意义(P>0.05);损伤程度及视觉状态对视力障碍青年的静态平衡没有显著影响(P>0.05);②功能性前伸测试中,正常视力组睁眼前伸距离显著大于闭眼(P<0.05),闭眼显著小于全盲(P<0.05);③提示视力损伤显著降低了青年的静态平衡,视力状态显著影响视力正常青年的姿势稳定性,视力损伤程度对视力障碍青年静态和动态平衡的影响均不显著;视障青年视觉反馈的不足可以通过非视觉因素代偿。

BACKGROUND:Vision is the primary sensory system to maintain balance.Approximately 50%of visually impaired youth have an increased risk of falling.Chinese reports focus more on the epidemiological survey of the number of people with visual impairment,but ignore balance performance and control strategies in such people,especially the study of influencing factors.OBJECTIVE:To explore the effects of visual factors(degree of visual impairment:blind,partially sighted and normal vision group;vision condition:eyes open and eyes closed conditions)on balance function of young adults.METHODS:Forty-three young adults were recruited and divided into three groups:blind(n=12),partially sighted(n=9)and normal vision group(n=22),and then underwent the following tests:one-leg stance test(eyes open and eyes closed conditions)and functional reach test(normal vision group:eyes open and closed conditions;partially sighted or blind groups:daily state).Measurement parameters between groups were analyzed using one-way analysis of variance.Paired sample t-tests were used to compare differences between different vision conditions within groups.RESULTS AND CONCLUSION:In the one-leg stance test,the center of pressure trajectory length in the normal vision group with eyes open was significantly shorter than that in the blind and partially sighted groups(P<0.05),and there was no significant difference between the groups when the eyes were closed(P>0.05).Degree of injury and visual status had no significant effect on the static balance of visually impaired youth(P>0.05).In the functional reach test,the reaching distance with eyes open was significantly greater than that with eyes closed in the normal vision group(P<0.05)and the distance with eyes closed was significantly less than that of the blind group(P<0.05).To conclude,visual impairment dramatically reduces the static balance of young adults,and vision conditions remarkably affect postural stability of the sighted youth,while the degree of visual impairment has no significant effect on static and dynamic balance of visually impaired youth.The lack of visual feedback can be compensated by non-visual factors in visually impaired youth.