Epidemiology of age related hearing loss: A review

Presbycusis or age related hearing loss (ARHL) is the most common sensory deficit in the elderly. It is a multifactorial condition that involves a multitude of intrinsic and extrinsic factors acting on the inner ear over a lifetime, which cumulatively lead to impairments in cochlear transduction of acoustic signals. ARHL is characterized by a loss of hearing sensitivity and a decreased ability to understand speech in the presence of background noise. Epidemiological studies have shown that in the USA hearing loss prevalence approximately doubles every decade of life from the second through to the seventh decade. In Europe, approximately 30% of males and 20% of females have a hearing loss of 30dB HL or more at age 70 years, and 55% of males and 45% of females at age 80 years. Central auditory processing disorders (CAPD) refer to an impairment in the central auditory pathways that leads to impaired speech understanding. The prevalence of CAPD in subjects older than 65 years has been reported to be between 9% and 14%. Recent studies have highlighted the strict correlation between ARHL and cognition in older adults; in particular, hearing impairment could precede the onset of mild cognitive impairment and dementia. The use of hearing tests, and the early diagnosis and treatment of ARHL, may potentially represent a way to prevent cognitive impairment and deserves further research.