Seah Sue Ann, Griffin Michael J
Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, Southampton, UK.
Somatosens Mot Res. 2010;27(3):82-92. doi: 10.3109/08990220.2010.510867.
Thresholds for the detection of changes in temperature are used to indicate neuropathy, but a variety of different contact areas and contact locations are used. This study was designed to determine the effects of variations in contact area and contact location on both warm and cool thresholds at the fingertip. With 20 healthy subjects (10 females and 10 males aged 20-30 years), warm thresholds and cool thresholds were determined in two separate sessions using the method of limits. In the first part of each session, thresholds were determined around the centre of the whorl using circular contactors with five different diameters (3, 6, 9, 12, and 55 mm). In the second part of each session, thresholds were determined using two contactors (6- and 12-mm diameter) at three locations along the fingertip: (i) distal (5 mm from the nail), (ii) middle (centre of whorl), and (iii) proximal (3 mm from the distal interphalangeal joint). With increasing contact area, the warm thresholds decreased, the cool thresholds increased, and the inter-subject variability in both warm and cool thresholds decreased. Using the 6-mm diameter contactor, warm thresholds were independent of location but cool thresholds increased from distal to proximal locations. It is concluded that temperature sensitivity at the fingertip increases with increasing area of contact, with the variability in thresholds consistent with the existence of warm and cool "insensitive fields". The findings show that the influence of contact area and contact location should be considered when assessing thermotactile thresholds at the fingertip.
检测温度变化的阈值被用于指示神经病变，但使用了各种不同的接触面积和接触位置。本研究旨在确定接触面积和接触位置的变化对指尖温热和冷觉阈值的影响。对20名健康受试者（10名女性和10名年龄在20至30岁之间的男性），采用极限法在两个独立的时段分别测定温热阈值和冷觉阈值。在每个时段的第一部分，使用五种不同直径（3、6、9、12和55毫米）的圆形接触体在指纹中心周围测定阈值。在每个时段的第二部分，使用两个接触体（直径6毫米和12毫米）在指尖的三个位置测定阈值：（i）远端（距指甲5毫米处）、（ii）中间（指纹中心）和（iii）近端（距远侧指间关节3毫米处）。随着接触面积的增加，温热阈值降低，冷觉阈值升高，并且温热和冷觉阈值的受试者间变异性均降低。使用直径6毫米的接触体时，温热阈值与位置无关，但冷觉阈值从远端到近端位置升高。得出的结论是，指尖的温度敏感性随着接触面积的增加而增加，阈值的变异性与温热和冷觉“不敏感区”的存在一致。研究结果表明，在评估指尖热触觉阈值时应考虑接触面积和接触位置的影响。
