STUDY OF OTOACOUSTIC EMISSIONS IN SUBJECTS OF NORMAL HEARING WITH AND WITHOUT TINNITUS

Aim- To determine relation between change in otoacoustic emissions in subjects of normal hearing with and without tinnitus. Material And Methods- The study was conducted as observational study to compare Transient Evoked Otoacoustic Emission and Distortion Product Otoacoustic Emission in subjects of normal hearing with tinnitus and without tinnitus in the Department of Otorhinolaryngology, Gandhi Medical College, (madhya Pradesh) for a duration of 18 months. The study included 114 adult patients visiting the department with and without tinnitus but with normal hearing. Subjects with a perception of tinnitus for less than a month and a history of use of ototoxic drugs, head trauma, and middle ear surgery were excluded from the study. The sampling technique employed was the Convenience sampling technique. Result - The majority of the subjects had normal TEOAE (83.3%). The percentage of subjects with normal TEOAE was signicantly higher in Group B compared to Group A (p-value <.05). Overall, majority of the subjects had normal DPOAE (84%). The percentage of subjects with normal DPOAE was signicantly higher in Group B compared to Group A (p-value <.05). Conclusion- Transitory Evoked Otoacoustic Emissions and Distortion product otoacoustic emissions are signicantly affected among normal hearing subjects with tinnitus. This indicated that patients with tinnitus might have neural dysfunction at either the level of the cochlea, of the auditory nerve, or of the brainstem. In the present work, we indirectly assessed the integrity of the afferent auditory pathway by using DPOAEs in tinnitus cases with normal hearing. The results showed that those affected by tinnitus show reduced OHC activity, as detected by reduced DPOAE levels which may manifest as tinnitus even before there is a shift in the hearing threshold.