The Efficacy of Digital Hearing Aids in the Management of Tinnitus in Individuals with Sensorineural Hearing Loss.

Abstract

Tinnitus is a condition which is often seen coexisting with hearing loss. In many persons with tinnitus, the use of amplification devices has been reported to show improvement in difficulties due to tinnitus. Though the underlying physiological mechanism is not clearly understood, hearing aids have proven beneficial. The aim of the study is to evaluate the benefit of the hearing aid in management of tinnitus. This study was conducted to assess whether such claims are true and, if so, what is the quantum of such benefit. In order to ascertain this, we studied the effects of three commonly used newer designs of digital programmable hearing aids namely, (i) Hearing aids with Basic programming, D-Basic (ii) those with tinnitus specific programming, DTS and (iii) those with in-built masking facility, DIM. In this study 108 subjects (65 males and 43 females), in the age range of 18 to 81 years were included. Each subject was fitted with one of the above mentioned three types of hearing aids, by qualified audiologists, purely on clinical grounds. All the subjects showed improvement in their hearing. The efficacy of the hearing aids, in mitigating the tinnitus, was assessed by employing the Tinnitus Handicap Inventory - THI. The THI has been developed by Newman et al in 1996 to study the effects of tinnitus, comprehensively under three domains viz. functional, emotional and catastrophic domains. A reduction in the THI scores indicates improvement. This tool is very popular and is acclaimed worldwide. It had been translated into several languages. In this study, the translated Telugu language version (THIT) of THI was used. The use of the local language (Telugu) afforded easy comprehension and better reliability. In each subject, we documented the THIT scores, before fitting of hearing aid and after two months of proper usage of the hearing aids. In the entire sample population of 108 subjects, across all the three different designtypes of hearing aids, we found a mean reduction of 42.6 points in the THIT scores. When the design of hearing aid was taken into reckoning, the mean post-fitting reduction of THIT scores in the subjects fitted with D-Basic, DTS, DIM hearing aids were 32.2, 43.5 and 51.9 respectively. In all the three designs, several subjects, those who were in a worse grade of tinnitus severity category of tinnitus severity before fitting, improved to a better grade after fitting. Further, we studied relief in the domain sub scales of the THIT viz. functional, emotional and the catastrophic domains. While all the three designs gave over-all relief of tinnitus, we found differences in the domain sub scales. However, designs with the In built maskers and tinnitus specific programming fared better. The conclusion drawn from our study is that, apart from the amplification benefit, all the three types of digital programmable hearing aids provided appreciable mitigation of tinnitus. Among the three design-types, hearing aids with inbuilt masker (DIM) were found to give the best benefit. Hearing aids with tinnitus specific programming (DTS) were the second best.