In clinical practice the taste perception threshold for electric current is almost always a fixed stimulus time of 500 msec. In this work a specific personal computer controlled electrogustometer is used, allowing measurement of the electrical taste threshold of 0.1 to 2000 msec at stimulus strengths during 14 stimulus times in the range -20 to 50 decibels (0.3 to 1000 microamperes). The representation of the measurement results on a double logarithmic scale yields what we consider a typically characteristic electrogustometric curve. Intensity and time parameters are extracted from these characteristic curves using a mathematical model. For the present work 156 healthy probands, uniformly distributed between 6 and 87 years of age, were examined to obtain age-typical characteristic curves, and 53 patients with one-sided facial palsy and 65 patients with malignant tumors in the head and neck area. Measurement of the taste threshold was carried out in the innervation field of the chorda tympani on the lateral margin of the tongue at the level of the dens caninus. As a result of these examinations, the spreads of the measured values and of the model parameters are shown to be age-dependend. In addition to the known increase of the sensory threshold significant changes occur in the transition region between gustatory and trigeminal parts of the characteristic curve. To evaluate the within-subject test-retest reliability, examination of 12 probands aged 19 to 56 years were repeated after two days. With patients suffering from an advanced tumor affection in the head and neck area, the method can only be applied under certain conditions. PC-electrogustometry can be used to determine disorders of gustatory function and is especially suitable for the determination of pathological side differences in the innervation field of the chorda tympani. |