Pure tone audiograms from 68 dentists with a minimum of 10 yr in dental practice were taken in 1973 and a follow-up was carried out in 1988. The aim was to study whether the dental occupation carried a risk for hearing handicap or not. Allowance for age and sex was made by using the presbyacusis values of SPOOR as the reference. At the speech range of frequencies dentists did not differ from the reference. At higher frequencies of 4, 6, and 8 kHz dentists tended to have higher hearing thresholds than expected. At 6 kHz, both male and female dentists had highly significantly greater hearing thresholds than expected by the corresponding references in both the studies. This difference remained essentially similar over the follow-up period, indicating that dental drill noise was insufficient to cause continuous loss of hearing. While mild NIHL was very common and tended to appear earlier in male than in female dentists, there was in the long run no continuous loss of hearing in either sex other than that attributable to the natural development of presbyacusis.

Forty-one patients with unilateral acoustic neuroma (AN) were diagnosed by magnetic resonance imaging (MRI) between 1992 and 1997. All cases were analyzed with respect to tumor location and the results of audiometric examinations, auditory brainstem response (ABR) testing, and electronystagmography (ENG). Tumor location was determined by MRI and cases were divided into intracanalicular and extracanalicular sites. Intracanalicular tumors were significantly smaller than the extracanalicular ones The pure-tone hearing thresholds were better in ears with intracanalicular lesions than in those with extracanalicular ones. Respectively, speech reception thresholds were 33 dB and 45 dB, and speech discrimination scores 79% and 65%. ABR was abnormal in 98% of ANs, but was insufficient for determining tumor location. The ENG pursuit test was more frequently normal and the caloric side difference was smaller in ears with intracanalicular than extracanalicular AN. These findings show that the results of pure-tone and speech audiometry and ENG are better in ears with intracanalicular AN, while ABR results are similar regardless of tumor location.