Influence of age on results of vestibular function tests. Review of literature and presentation of caloric test results.

Following a bibliographic review of currently known, age-dependent morphological and functional changes of the vestibular and auditory system, results are presented of our investigations concerning the influence of age on the outcome of the caloric test on 102 healthy subjects from six age groups ranging between the ages of 11 and 70 years. They prove, without any doubt, that the absolute values of nystagmic parameters in the caloric test are dependent upon age; but not in such a way that the intensity of reaction decreases with advancing age. On the contrary, they indicate that in awake, healthy subjects of middle and late middle-age, the most intensive reactions occur (maximum slow phase velocity, maximum amplitude, maximum frequency, total number of beats). In addition, based on the statistical analysis, it seems probable that the extent of the side difference of excitability depends upon age. Individuals in their middle years show side differences to a considerably lesser degree than children and elderly subjects. These represent findings which, to our knowledge, are reported here for the first time. Provided our results gain further substantiation, standard values for a true quantitative evaluation of the caloric test could only be determined as in the audiometric functional tests on the basis of larger test series of healthy subjects belonging to different age groups.