Relation of Distortion Product Otoacoustic Emission With Tinnitus

Abstract

Our results suggest that reduced outer hair cell activity, as detected by reduced DPOAE levels, may manifest as tinnitus even before there is a shift on hearing threshold. We also postulate that further reduction of cochlear outer hair cell activity, as shown by further reduced DPOAE levels, may actually terminate the source of tinnitus.

Comparison of otoacoustic emissions in patients with tinnitus having normal hearing versus mild hearing loss

“…In their study, the average DPOAE amplitudes for frequencies of 3003, 4004, and 5005 Hz in patients with tinnitus and proper hearing were higher than in the control group. These results were consistent with Gouviers et al 33 but not in accordance with the present study and studies referred above 3,9,[23][24][25]27,29,31 which reported lower DPOAE amplitudes in cases with tinnitus than in cases without tinnitus. Sztuka et al 34 similarly to Gouveris et al 33 recognized the increase in amplitude of the DPOAE to an increased movement of the OHCs induced by reduced neural activity in the auditory nerve.…”

“…Some studies reported that a tinnitus patient seems to have lower DPOAE than nontinnitus patients 9,22,23,25,29,31,32 . However, many of these studies included patients with poor hearing thresholds and with tinnitus, and this could possibly influence the results.…”

“…Other studies reported increased DPOAE amplitude 33,34 but again, the involved subjects in these studies presented differences in the hearing thresholds, what does not clarify if the irregularities in DPOAE are due to the expansion of tinnitus or due to the hearing losses 32 . Until now, a few studies have investigated DPOAE by including tinnitus patients with normal audiometric thresholds 9,22,29,[30][31][32] . Quite different results were found by Gouveris et al 33 who compared the cochlear OHC function by DPOAE-grams of 32 ears with acute tonal tinnitus and normal hearing or minimal hearing loss with 17 healthy nontinnitus ears.…”

Investigation of temporal bone asymmetry in cases with unilateral tinnitus: morphometric and multicentric clinical study

“…They suggested that even if the audiogram of patients is normal, there is hidden hearing loss in tinnitus patients. The authors were also found to be reduced in tinnitus patients with normal hearing [2]. Kim et al [16] investigated extended high frequency (above 8 kHz) hearing loss in patients with normal audiograms, and 74% of the patients had hearing loss above 8 kHz.…”

Temporal Bone Posterior Wall Defect, a New Clinic Entity?

“…In our study, the pattern of DPOAE decrease was similar to the pattern of patients who had tinnitus after exposure to noise [18,19] . We thought that this phenomenon may be due to the lack of a barrier at the posterior temporal bone, which may cause an increased effect of the inner voice on the external hairy cells in the cochlea.…”