Age-related hearing loss (ARHL), or presbycusis, refers to the gradual deterioration of auditory sensitivity and related cognitive processing of speech, a condition that affects over 250 million individuals worldwide. ARHL is estimated to account for nearly 5 percent of total global years lost to disability (YLD), making it the second-leading cause of YLD, behind unipolar depression. Hearing loss of all types is categorized by the World Health Organization into five hearing loss ranges with values representing the softest sounds a person can detect: no impairment, 25 decibels hearing level (dB HL) or less; slight impairment, 26 to 40dB HL; moderate impairment, 41 to 60 dB HL; severe impairment, 61 to 80 dB HL; and profound impairment (including deafness), 80 dB HL and higher.

As one ages, ...