Feuerstein Johanna, Austin Daniel, Sack Robert, Hayes Tamara L
Department of Biomedical Engineering, Oregon Health & Science University, 3303 SW Bond Avenue, Portland, OR 97239, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:3652-5. doi: 10.1109/IEMBS.2011.6090615.
Scratching is a symptom of many dermatological disorders, especially atopic dermatitis. For the development of anti-itch medications, there is a need for objective measures of scratching. Wrist actigraphy (monitoring wrist and hand movements with micro-accelerometers) is a promising method for assessing scratching; however, currently available technology has a limited capacity to discriminate scratching from other similar movements. In this study, we investigated methods to improve the specificity of actigraphy for scratch detection on movement data collected from subjects using the PAM-RL actigraph. A k-means cluster analysis was used to differentiate scratching from walking and restless sleep, which are potential confounds for nighttime scratching. Features used in the analysis include variance, peak frequency, autocorrelation value at one lag, and number of counts above 0.01 g's. The k-means cluster analysis exhibited a high sensitivity (0.90 ± 0.10) and specificity for walking (0.98 ± 0.05) and restless sleep (0.88 ± 0.06), respectively, demonstrating the separability of these activities. This work indicates that the features described here can be used to develop a classifier that discriminates scratch from other activities. The described method of scratch detection shows promise as an objective method for assessing scratching movements in clinical trials and longitudinal studies of scratch.
搔抓是许多皮肤病的症状，尤其是特应性皮炎。对于抗瘙痒药物的研发，需要对搔抓进行客观测量。手腕活动记录仪（用微型加速度计监测手腕和手部运动）是评估搔抓的一种有前景的方法；然而，目前可用的技术区分搔抓和其他类似运动的能力有限。在本研究中，我们研究了一些方法，以提高使用PAM-RL活动记录仪从受试者收集的运动数据中检测搔抓的活动记录仪的特异性。采用k均值聚类分析来区分搔抓与行走和不安稳睡眠，这两者是夜间搔抓的潜在干扰因素。分析中使用的特征包括方差、峰值频率、滞后1处的自相关值以及高于0.01g的计数数量。k均值聚类分析对行走（0.98±0.05）和不安稳睡眠（0.88±0.06）分别表现出高灵敏度（0.90±0.10）和特异性，证明了这些活动的可分离性。这项工作表明，这里描述的特征可用于开发一种区分搔抓与其他活动的分类器。所描述的搔抓检测方法有望成为临床试验和搔抓纵向研究中评估搔抓运动的一种客观方法。
