Detection of pseudohypacusis: A prospective, randomized study of the use of otoacoustic emissions

Objectives: This study was designed to evaluate the effectiveness of transient otoacoustic emissions in an audiological protocol used in the evaluation of patients suspicious of pseudohypacusis. Design: This was a prospective study of 72 adult patients suspicious of pseudohypacusis on the grounds of case history and inconsistent audiometric results. The subjects were randomly assigned to a treatment group or control group. The treatment group consisted of 42 patients who underwent a four-stage protocol that included (1) standard speech and pure-tone audiometry, (2) transiently evoked otoacoustic emissions (TEOAEs) and tympanometry, (3) repeat modified pure-tone audiometry, and (4) auditory brain stem response (ABR) audiometry. The control group consisted of 30 patients, who underwent an identical protocol except that Stage 2 (TEOAEs and tympanometry) was omitted. The main outcome measure was the mean exaggeration level defined as the difference in mean pure tone average (PTA) between the initial and the repeat session (mean PTA(initial) minus mean PTA(repeat)). Results: The mean PTA (average threshold at 1, 2, 3, and 4 kHz) on repeat audiometry was significantly better than the mean PTA obtained on the initial evaluation for each group. However, the mean exaggeration level was significantly greater for the treatment group (35.2 dB HL) than for the control group (11.0 dB HL). In addition, there was no significant difference between the mean PTA(repeat) (32.7 dB HL) and the mean click-evoked ABR threshold (31.6 dB nHL) for the treatment group whereas the mean PTA(repeat) (52.9 dB HL) was significantly poorer than the click evoked ABR threshold (29.2 dB nHL) for the control group. Conclusions: The inclusion of TEOAEs and tympanometry in an audiological protocol used in the evaluation of patients suspicious of pseudohypacusis resulted in a significantly greater threshold improvement on repeat modified pure-tone audiometry when compared to the improvement observed for a control group in which these tests were not performed.