BARESTHESIA

BARESTHESIA (from Greek baros-weight and aisthesis-sensation), sensation of pressure, one of the types of deep sensitivity. These irritations are transmitted to the brain via the posterior root fibers of the posterior columns. The investigation of B. is performed by means of weights (with areas of application to the body of equal size, covered with cloth to eliminate temperature irritations) or special instruments (baresthesiometer). In clinical practice, B. is rarely investigated due to the inaccuracy of the instrument readings, which depends on the almost complete impossibility of exerting pressure on the skin without shifting it to one side or another with varying degrees of tension. A baresthesiometer is an instrument for measuring the sensation of pressure, constructed on the principle of evaluating the smallest difference between two successive irritations ("difference threshold"); the relative magnitude of weight necessary to recognize barely noticeable differences in pressure equals ¹/₃₀ of the original weight. The most commonly used instrument in clinical practice is the Eilenburg or Bekhterev B.; the pressure exerted by these instruments is regulated by a spring and is indicated in grams on the dial (see figure). A barelectroresthesiometer is an instrument for simultaneously measuring the sensation of pressure and electrocutaneous sensitivity. The instrument represents a combination of a baresthesiometer with two electrodes applied to the site of investigation and irritating the skin with faradic current. By varying the strength of the electrical irritation, changes in the ability to distinguish differences in pressure are observed. BAS, see Voice.