Noise exposure of care providers during otosurgical procedures.

OBJECTIVE: To monitor the noise exposure of care providers during otological surgery due to drilling and suction in the operating room. METHODS: A clinical study monitoring different standard otosurgical procedures was conducted; cochlear implantation (CI), mastotympanoplasty, and mastoidectomy alone. Noise exposure to the surgeon and assistant were monitored with wireless personal noise dosimetry and stationary sound monitoring. Both maximum peak level in dBC (Lpeak) and time-average sound pressure level in dBA (equivalent level or Leq) were measured during drilling episodes. Frequency analysis in one third octaves covering the frequency bands 6.3 Hz to 20 k Hz was performed using a sound analyzing program. RESULTS: When averaged over the entire procedure, the sound pressure level was highest for the surgeon and the assistant with values of 76.0 dBA and 72.5 dBA, respectively, during CI. Lpeak was 135.9 dBC. Leq for the stationary sound measurement was 74.2 dBA. During cortical bone work using a cutting burr, 84.6 dBA was measured. Mean values of L95% (estimation of the background noise) were between 55.8 dBA and 61.2 dBA. Frequency analysis showed the highest sound pressure level for all procedures was between 2.5 kHz and 3.15 kHz. CONCLUSION: This is the first study to use personal sound dosimetry to monitor noise exposure during otosurgical drilling. In accordance with other studies, the results presented show sound levels below international occupational noise level regulations. However, the measured noise exposure during drilling could have negative effects on care providers based on unfavorable acoustical comfort.

Digital hearing aids and future directions for hearing aids.

In recent years many technical evolutions have been applied in hearing aids. In this paper differences between analog, programmable and fully digital hearing aids, the basic and supplementary functions of a hearing aid, and some important issues and future directions for digital hearing aids will be mentioned.