Habituation of sleep to road traffic noise by Actiwatch

研究对象为4名21岁的学生，他们在睡眠实验室独立睡了17个晚上，通过腕部加速度计的身体运动和睡眠多导图来评估睡眠对道路交通噪声的习惯性。5日至14日夜间，道路交通噪声整夜暴露。从5日到17日晚上，连续进行了实验。日常生活不受限制。他们通常在22点上床睡觉，第二天早上7点左右起床。Actiwatch被安装在他们隐性手臂的手腕上。采样频率为32 Hz，灵敏度为0.05g，以1min为单位。体动次数通过有效电数的总和来计算。如果伯爵年龄在40岁或以上，我们就认为这是觉醒。虽然不到40岁，但n(e-2)×0.04+n(e-1)×0.2+n(e)+n(e+1)×0.2+n(e+2)×0.04超过40，那么我们就判断它是觉醒的。在该算法下，通过计算18个夜晚，Actiwatch与睡眠测谎仪的符合率平均为87%，脑肌活动没有变化趋势。受试者A在最近三天的睡眠潜伏期迅速增加。受试者B的整夜体动百分率显著降低，睡眠多聚体与脑肌活动显著相关，受试者B、C、D的MT体动显著增加，受试者A、B、D的REM体动显著增加，后一事实不符合逻辑，因为肌肉张力下降。受试者在慢波睡眠中，体动明显减少。从简单性角度看，加速度计的体动是监测噪声对睡眠影响的一个很好的指标。由于存在一定的个体差异，需要更多的病例来检验睡眠多导图的有效性。

The habituation of sleep to road traffic noise was evaluated by body movement using wrist accerelometer and also sleep polygraphy.Subjects were four 21-year old students and they slept for 17 nights independently in a sleep laboratory. From fifth to 14th nights, road traffic noise was exposed all-night long. From fifth to 17th night, consecutive experiments were conducted. The daily life is not limited. They usually go to bed at 22 o'clock and gets up around seven o'clock in the next morning. ACTIWATCH【encircledR】 was installed in the wrist of their recessive arms. The sampling frequency was 32Hz and sensitivity was 0.05G, counting for one minute as a unit. The number of body movement was calculated by the summation in the number of active electricity. If the count is 40 or over, we judged it as awakening. Though under 40, n(e-2)×0.04+n(e-1)×0.2+n(e)+n(e+1)×0.2+n(e+2)×0.04 exceeds 40, then we judged it as awakening. By this algorithm, the agreement between ACTIWATCH【encircledR】 and sleep polygraph was 87% on average by calculating 18 nights.There was no trend in activity of mental muscle. Sleep latency in subject A in the last three days increased rapidly. Body movement % for all-night long decreased significantly in subject B. There was a significant relationship between body movement % and activity of mental muscle by sleep polygraphy.A significant increase of body movement in MT was recognized in subjects B, C, D. A significant increase of body movement in REM was recognized in subjects A, B, D. The latter fact is not logical because of drop in muscle tonus. There was a significant decrease of body movement in slow wave sleep in subject D.Body movement by accerelometer seems to be a good indicator for monitoring the effect of noise on sleep from the point of simplicity. As some individual differences are existed, much more cases are needed to check the validity using sleep polygraphy.