Frequency discrimination worsens with age even when audiometric thresholds stay normal

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. However, performance on other tasks (duration discrimination for Abel et al. and intensity discrimination for He et al.) was also poorer for the older group, suggesting that there may be a general effect of age that leads to reduced “processing efficiency”. The effect of age cannot be attributed to reduced frequency selectivity, since auditory filters do not broaden with increasing age when absolute thresholds remain normal (Lutman et al. — Dijk, Pim van, Physiology, Psychoacoustics and…, 798

Categorization

• QUESTION: If processing efficiency explains the DLF deficit, what specific mechanism — attention, neural synchrony, cognitive slowing — drives it, and does it generalize across all auditory tasks?
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 798