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.

We wanted to ascertain whether a physiological horizontal vestibular spontaneous nystagmus is existent, or whether the spontaneous and positional nystagmus seen in clinically healthy persons in the electronystagmogram -- when fixation had been excluded completely -- was always the result of earlier damages to the vestibular system (Jatho). For this purpose we tried to detect a spontaneous and positional nystagmus in 102 healthy persons from 6 age groups (17 each) between 11 and 70 years of age. When the ENG was registered with open eyes in darkness, 63 out of the 102 test persons had a horizontal spontaneous or positional nystagmus, however, under the Frenzel glasses there was a nystagmus in only 2 out of these test persons. With open eyes in darkness, the frequency and intensity was the same in all age groups. With this, we believe to have proved that a physiological horizontal vestibular nystagmus does exist. We share Kornhuber's opinion that the examination with the Frenzel glasses in a dark room, together with the head shaking test and positional test, at the present time represents the best method for differentiating between physiological and pathological spontaneous nystagmus.

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The problem of a replacement material for the reconstruction of the posterior wall of the auditory canal, as well as for the obliteration of the radical cavity has not been solved satisfactor;ly so far. In order to examine the possible applicability of porous plastics, the posterior wall of the auditory canal of guinea pigs was first removed and then reconstructed using porous polyethylene and filling the bulla tympanica with fine polyethylene chips. One third of the animals had an infected middle ear at the time of implantation. Histologic assessments were made until 24 weeks after implantation. In 80% of the animals the implant settled well, even in cases where the middle ears had been originally infected. By proliferation of vessels and connective tissue, the polyethylene had almost been completely integrated into the surrounding tissue after one week. Extent and frequency of metaplastic osseous growth was greater inthe chip-filled bulla than in the reconstructedposterior wall(Fig. 9). After four weeks, the new osteoid substance was firmly connected with the regional bone (Fig. 4). According to these results, it would seem possible to use porous polyethylene even for the nonaseptic implant bed as it is found in the chronically infected middle ear.

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