Effect of rehabilitation training on an elderly population with mild to moderate hearing loss: study protocol for a randomised clinical trial

Background: Age-related hearing loss (presbycusis) is a form of hearing loss in over 60-year-olds and has a negative impact on quality of life. The pathophysiology of presbycusis is multifactorial and is predominately characterised with a loss of speech perception in noise. In the cochlea, auditory filters decompose broadband sound into a series of narrowband output signals, which contains two kinds of temporal information: slow changes in overall amplitude envelope (ENV) and faster variations in temporal fine structure (TFS). TFS is important for recognition of target speech in noise. The main aim of the study is to evaluate the effect of TFS rehabilitation training in participants over the age of 60 years with mild to moderate hearing loss. Methods: A randomised clinical trial will be conducted on 30 participants with mild (loss of 20-39dB) to moderate (40-69dB) hearing loss, aged between 60 and 75 years old. Participants with conductive hearing loss, abnormal middle ear pathology and central nerve system disease will be excluded. Participants will be randomly selected to an intervention and control group with a 1:1 ratio. Rehabilitation for the intervention group will be 30-minute sessions three times a week for a total five weeks of vowel consonant vowel words that are used to eliminate ENV and keep only TFS. Word in noise test, binaural TFS test, and Speech, Spatial and Qualities of Hearing Scale scores will be performed at the beginning and end of study to evaluate the effect of rehabilitation training. Conclusion:  Life expectancy in the elderly has improved, leading to an increased prevalence of age-related diseases including presbycusis. A literature review highlighted that TFS damage is permanent; however, in this study we will attempt to prove that TFS training may lead to speech in noise perception restored. Trial registration: Registry of Clinical Trials, IRCT2019625044006N1 (7 th August 2019).