Subjectively Estimated Pitch of Tinnitus and Results of the Pitch Match Test

Abstract

The subjectively estimated pitch of tinnitus was compared with the results of pitch match test using a pure tone audiometer. Also, the relationship between subjective expression by onomatopoeias and the results of pitch match test was analysed. The subjects were 115 tinnitus ears without hearing loss or associated with cochlear deafness.
The results obtained were as follows;
1) The pitch of tinnitus was subjectively estimated as ‘high’ in two thirds and as ‘low’ in the remaining one third.
2) When the pitch was subjectively estimated as ‘high’, the measured pitch existed in the high frequency areas beyond 4kHz in 80.0% of the ears. On the other hand, when the pitch of tinnitus was subjectively estimated as ‘low’, the measured pitch was distributed almost equally in all frequency areas and the tinnitus was not simulated by either pure tone or band noise of the pure tone audiometer in 33.3% of the ears.
3) Although the pitch was subjectively estimated as ‘low’ in only one third and as ‘high’ in the remaining two thirds, an almost equal number of onomatopoeias were used for the subjective expression in both groups.
4) The relationship between the onomatopoetic expression and the simulated tones of pure tone audiometer was analysed in 23 onomatopoeias. The tinnitus expressed by 15 onomatopoeias was simulated by pure tone and that expressed by 1 onomatopoeia by band noise. The tinnitus expressed by the remaining 7 onomatopoeias was simulated by both pure tone and band noise.
5) When the tinnitus was expressed by the onomatopoeias simulated only by pure tone, the measured pitch was confined to the frequency range of 1 octave or less, while it was distributed beyond 1 octave in tinnitus expressed by onomatopoeias simulated by both pure tone and band noise. Therefore, the onomatopoeias simulated only by pure tone could be a clinical indicator of the measured pitch, but the onomatopoeias simulated by both pure tone and band noise could not be.
6) As far as the relationship between onomatopoeias and their corresponding frequency areas of pure tone and band noise was concerned, discrepancies were found in 8 (47.1%) of 17 onomatopoeias between the results obtained in this study and the proposals by the standardized tinnitus test in 1984: the measured pitch in this study existed outside the proposed frequency areas in tinnitus expressed by 5 of the 8 onomatopoeias.