Hayes Tamara L, Abendroth Francena, Adami Andre, Pavel Misha, Zitzelberger Tracy A, Kaye Jeffrey A
Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, USA.
Alzheimers Dement. 2008 Nov;4(6):395-405. doi: 10.1016/j.jalz.2008.07.004.
Timely detection of early cognitive impairment is difficult. Measures taken in the clinic reflect a single snapshot of performance that might be confounded by the increased variability typical in aging and disease. We evaluated the use of continuous, long-term, and unobtrusive in-home monitoring to assess neurologic function in healthy and cognitively impaired elders.
Fourteen older adults 65 years and older living independently in the community were monitored in their homes by using an unobtrusive sensor system. Measures of walking speed and amount of activity in the home were obtained. Wavelet analysis was used to examine variance in activity at multiple time scales.
More than 108,000 person-hours of continuous activity data were collected during periods as long as 418 days (mean, 315 +/- 82 days). The coefficient of variation in the median walking speed was twice as high in the mild cognitive impairment (MCI) group (0.147 +/- 0.074) as compared with the healthy group (0.079 +/- 0.027; t(11) = 2.266, P < .03). Furthermore, the 24-hour wavelet variance was greater in the MCI group (MCI, 4.07 +/- 0.14; healthy elderly, 3.79 +/- 0.23; F = 7.58, P </= .008), indicating that the day-to-day pattern of activity of subjects in the MCI group was more variable than that of the cognitively healthy controls.
The results not only demonstrate the feasibility of these methods but also suggest clear potential advantages to this new methodology. This approach might provide an improved means of detecting the earliest transition to MCI compared with conventional episodic testing in a clinic environment.
早期认知障碍的及时检测颇具难度。临床所采取的措施反映的是表现的单一快照，可能会因衰老和疾病中典型的变异性增加而混淆。我们评估了使用持续、长期且不引人注意的居家监测来评估健康及认知受损老年人的神经功能。
使用不引人注意的传感器系统对14名65岁及以上独立生活在社区的老年人进行居家监测。获取步行速度和居家活动量的测量值。使用小波分析来检查多个时间尺度上活动的方差。
在长达418天（平均315±82天）的时间段内收集了超过108,000人时的连续活动数据。轻度认知障碍（MCI）组的中位步行速度变异系数（0.147±0.074）是健康组（0.079±0.027；t(11)=2.266，P<.03）的两倍。此外，MCI组的24小时小波方差更大（MCI为4.07±0.14；健康老年人为3.79±0.23；F=7.58，P≤.008），表明MCI组受试者的日常活动模式比认知健康对照组更具变异性。
结果不仅证明了这些方法的可行性，还表明了这种新方法具有明显的潜在优势。与临床环境中的传统间歇性测试相比，这种方法可能提供一种更好的手段来检测向MCI的最早转变。
