Thermoesthesiometers

THERMOESTHESIOMETERS, instruments for the precise examination of the temperature sense. In Russian clinics, the thermoesthesiometer of prof. Roth is the most commonly used (Fig. 1). The instrument consists of a hollow metal cylinder into which a thermometer and two metal tubes are inserted. A pump is placed on one, and a rubber tube on the other. The latter is immersed in a vessel with water of the desired temperature. The water pumped into the instrument has its temperature indicated by the thermometer. The instrument is applied by its base to the skin, thus determining the sensitivity of the skin surface to the temperature of the instrument. Then the water is pumped out and replaced with water of a different temperature, the sensitivity to which is again determined by applying the instrument.- For a more accurate examination, it is better to use

Figure 1.

two Roth thermoesthesiometers filled with water having a difference of 6-7°. Having ascertained that the person under examination can distinguish these temperatures, cold water is added to the thermoesthesiometer in which the temperature was higher, and thus the temperature difference between the two is reduced. Through successive procedures, the smallest temperature difference perceived by the person under examination is established and compared with the normal numbers for temperature sensitivity from Nothnagel's table. A healthy person everywhere distinguishes a temperature of 1°. Goldscheider's thermoesthesiometer consists of a solid metal cylinder with a base of 1 cm², equipped with an ebonite handle. To obtain an extreme temperature, the cylinder is immersed in cold water or heated on a fire. The instrument is applied to various parts of the body having both the same temperature sensitivity and different ones. For cold sensitivity, the areas, according to Goldscheider, are distributed according to a 12-point system, for heat-according to an 8-point system. The subject compares the sensations received from the instrument in various areas and determines whether they are identical in the area under examination with the sensitivity of places of the same points, whether they are weaker compared to places of highest sensitivity, and stronger towards points of lowest.- Eulenburg's thermoesthesiometer consists of two thermometers mounted on a rubber plate (Fig. 2). The thermometer attached to the edge is immovable, while the second

moves freely.

The immovable thermometer is wound with platinum wire through which a current from an electric power source is passed. The movable thermometer is set on the skin and shows its temperature. Then the immovable

Figure 2

one is heated to a temperature one degree lower than the skin temperature. It is applied to the skin and it is ascertained whether it is felt as colder. Or, conversely, the immovable one is overheated by ¹/₂-1-1¹/₂° higher than the skin temperature, and it is determined whether it is felt as warmer. Thus, the ability to distinguish the difference between the skin's own temperature and the temperature of an object is recognized. Bekhterev pointed out the need to invent an instrument that would not touch the skin in order to avoid the feeling of touch, however, such an instrument has not yet been proposed.

M. Neidish¹.