ABSTRACT
To investigate how much gain variation is required from prescription to effect tinnitus percept, and if this revised prescription affects speech recognition. Twenty participants who experienced catastrophic tinnitus even after fitted with hearing aid were included. Participants were grouped based on their tinnitus pitch and the prescriptive formula used to fit hearing aid. They were evaluated for handicap from tinnitus using Tinnitus Handicap Inventory (THI). Hearing aid was programmed using either NAL- NL2 or DSL (I/o) v5 prescriptive formula and gain at tinnitus pitch was adjusted till the tinnitus get suppressed. SNR 50 was determined soon after fitted with hearing aid and 30 days of hearing aid use. Further, THI and international outcome inventory for hearing aid (IOI-HA) were determined after 30 days of hearing aid use. A significant higher gain adjustment was needed at tinnitus pitch to reduce tinnitus precept using NAL- NL2 than DSL (I/o) v5 prescriptive formula. Further, SNR 50 was not affected by either tinnitus pitch or revised prescription formulas. However, SNR 50 improved after 30 days of hearing aid use. A 76% of the participants' experienced habituation to perception after 30 days of hearing aid use, 10% had slight, 10% had mild, and 4% had a moderate degree of tinnitus on THI. On IOA-HA, 96% (N=19) of participants have reported satisfactory, and 4% (N=1) reported moderate benefit from hearing aid. Irrespective of prescriptive formula adjusting gain at tinnitus pitch is an efficient method to reduce tinnitus symptoms and improve speech perception.
