[The relation between the auditory threshold and the threshold of middle ear reflexes induced by ipsilateral stimulation in occupational deafness].

The author examined and evaluated middle ear reflexes obtained by ipsilateral stimulation in a group of 115 men, mean age 52.5 years (s = 9 years) who worked exposed to noise in uranium mines on average for 16.5 years (s = 4.6 years). Their total percentage auditory loss calculated according to Fowler is 49.7% (s = 15.1%). The arithmetic mean of differences of the auditory threshold and the threshold of middle ear reflexes in 214 ears examined at a frequency of 1000 Hz is 45.5 dB (s = 16.3 dB, min. 0 dB, max. 80 dB), in 208 ears at a frequency of 2000 Hz 30.4 dB (s = 13.5 dB, min. 0 dB, max. 75 dB), in 196 ears at frequency 3000 Hz 23.2 dB (s = 12.6 dB, min. 0 dB, max. 85 dB). The relation--ship between the auditory threshold and middle ear reflexes obtained by ipsilateral stimulation corresponds to the following equations Y1000Hz = 105.86--9.73 square root chi i Y2000Hz = 119.21--11.61 square root chi i Y3000Hz = 108.62--10.59 square root chi i Individual forecasts of the auditory threshold for pure tones only from values of the threshold of middle ear reflexes in occupational deafness are of restricted value due to the great scatter of values.