Aging alone can widen frequency difference limens by two to four times

Evidence

It is widely believed that the difference limen for frequency (DLF) of pure tones depends on the use of TFS information for frequencies up to 4–5 kHz (Moore 1973 ), and perhaps even up to 8 kHz (Moore and Ernst 2012 ). If so, the DLF at low and medium frequencies provides a measure of TFS processing. Abel et al. ( 1990 ) and He et al. ( 1998 ) compared DLFs for young and older subjects with normal hearing (audiometric thresholds ≤20 dB HL from 0.25 to 4 kHz). In both studies, DLFs were larger by a factor of 2–4 for the older than for the younger subjects, suggesting that there is an effect of age. — Dijk, Pim van, Physiology, Psychoacoustics and…, 797