Kunita Kenji, Fujiwara Katsuo
Research Center for Urban Health and Sports, Osaka City University, Osaka.
J Physiol Anthropol. 2006 May;25(3):257-61. doi: 10.2114/jpa2.25.257.
We investigated changes in saccadic reaction time during maintenance of neck flexion in elderly individuals. Subjects comprised 49 volunteers, including 19 young adults and 30 elderly adults. Elderly subjects were separated into 2 groups (trained group: n=18; untrained group: n=12) based on responses to a questionnaire concerning activities of daily living. Saccadic reaction time was measured at angles of neck flexion of 0 degrees (resting position), 10 degrees and 20 degrees , with the chin either resting on a stand (chin-on) or not (chin-off). Reaction time was determined as the latency to the beginning of eye movement toward the lateral target, which was moved at random intervals in jumps of 20 degrees amplitude. In the chin-on posture, the angle of neck flexion had no significant effect on reaction time in any group. In the chin-off posture, the flexion angle significantly affected reaction time in both young and elderly trained groups. Significant shortenings of the reaction time were obtained at 10 degrees and 20 degrees neck flexion in the young group, and at 20 degrees neck flexion in the elderly trained group. No significant shortening of reaction time was noted in the elderly untrained group. These findings suggest that neural function associated with shortening of saccadic reaction time due to neck extensor activity decreases with age, and the decrements become more marked with inactivity in daily life.
我们研究了老年人在保持颈部屈曲时扫视反应时间的变化。受试者包括49名志愿者，其中19名年轻人和30名老年人。根据关于日常生活活动的问卷回答，老年受试者被分为两组（训练组：n = 18；未训练组：n = 12）。在颈部屈曲角度为0度（休息位置）、10度和20度时测量扫视反应时间，下巴要么靠在支架上（下巴靠上），要么不靠在支架上（下巴不靠上）。反应时间被确定为眼睛开始向侧向目标移动的潜伏期，侧向目标以20度幅度的跳跃随机间隔移动。在下巴靠上的姿势下，颈部屈曲角度对任何组的反应时间均无显著影响。在下巴不靠上的姿势下，屈曲角度对年轻和老年训练组的反应时间均有显著影响。年轻组在颈部屈曲10度和20度时反应时间显著缩短，老年训练组在颈部屈曲20度时反应时间显著缩短。老年未训练组未观察到反应时间的显著缩短。这些发现表明，与颈部伸肌活动导致扫视反应时间缩短相关的神经功能随年龄增长而下降，并且在日常生活中缺乏活动时这种下降变得更加明显。
