Effects of Age and Hearing Loss on the Processing of Auditory Temporal Fine Structure

Abstract

Within the cochlea, broadband sounds like speech and music are filtered into a series of narrowband signals, each of which can be considered as a relatively slowly varying envelope (ENV) imposed on a rapidly oscillating carrier (the temporal fine structure, TFS). Information about ENV and TFS is conveyed in the timing and short-term rate of nerve spikes in the auditory nerve. There is evidence that both hearing loss and increasing age adversely affect the ability to use TFS information, but in many studies the effects of hearing loss and age have been confounded. This paper summarises evidence from studies that allow some separation of the effects of hearing loss and age. The results suggest that the monaural processing of TFS information, which is important for the perception of pitch and for segregating speech from background sounds, is adversely affected by both hearing loss and increasing age, the former being more important. The monaural processing of ENV information is hardly affected by hearing loss or by increasing age. The binaural processing of TFS information, which is important for sound localisation and the binaural masking level difference, is also adversely affected by both hearing loss and increasing age, but here the latter seems more important. The deterioration of binaural TFS processing with increasing age appears to start relatively early in life. The binaural processing of ENV information also deteriorates somewhat with increasing age. The reduced binaural processing abilities found for older/hearing-impaired listeners may partially account for the difficulties that such listeners experience in situations where the target speech and interfering sounds come from different directions in space, as is common in everyday life.

Retracted Article: Temporal fine structure: relations to cognition and aided speech recognition

“…In addition to investigating the effects of severity of hearing loss, we also investigated the influence of ageing on sensitivity to TFS. Based on previous literature (see , F€ ullgrabe 2013; F€ ullgrabe et al 2015), we would expect to find a significant effect of aging on performance in the TFS task, particularly since we used the TFS-LF test which is a measure of binaural TFS sensitivity thought to be more affected by ageing that performance in monaural TFS tests (Moore 2016). Our results were consistent with these studies, and ageing was significantly associated with performance on not only the TFS task, but on each of the tasks we assessed.…”

“…However, if the effects of TFS on speech recognition are partly related to a more general age-related decline e.g. in temporal or cognitive processing, or processing efficiency (see Kortlang et al 2016;Moore 2016), it seems reasonable to think that the effects of TFS may be more evident in tasks where cognitive skills can be used to aid performance, that is to say when contextual information, rather than simply auditory information, can be used to aid performance. If this were the case, we would expect TFS to correlate most with high context sentence recognition, than lower context sentence recognition, and least with single word or nonsense syllable recognition.…”

“…Ageing has also been shown to affect sensitivity to TFS, even when audiometric thresholds are within the normal range (F€ ullgrabe 2013;F€ ullgrabe, Moore, and Stone 2015), or when the effects of hearing threshold are partialled out (L eger, Moore, and Lorenzi 2012;King, Hopkins, and Plack 2014). However, the relative contribution of age and hearing loss to deficits to TFS processing seems to vary according to whether TFS is processed monaurally or binaurally, with monaural TFS being affected more by hearing loss than age, and binaural TFS being affected more by age than hearing loss (Hopkins and Moore 2011;Moore, Vickers, and Mehta 2012;Moore 2016). Furthermore, there is some evidence to suggest that monaural and binaural tests of TFS may index somewhat different skills, with sensitivity to binaural TFS thought to also reflect binaural processing, resulting in lower thresholds in tests of binaural than tests of monaural TFS (Ewert, Paraouty, and Lorenzi 2018).…”

Age-related changes in envelope-following responses at equalized peripheral or central activation

“…Cochlear neuropathy results in a decrease in auditory nerve fiber (ANF) population size, but does not significantly affect pure tone thresholds [Sergeyenko et al, 2013]. Instead, precise coding of temporal fine-structure and envelope cues of supra-threshold sounds are compromised in these older listeners with clinically normal hearing thresholds (NHTs; ≤20 dB hearing level) [Ruggles et al, 2012, Moore, 2016]. As this type of auditory disorder is found in listeners with clinically normal audiogram, it has been described as "hidden hearing loss" [Schaette and McAlpine, 2011].…”

Evaluation of a method for enhancing interaural level differences at low frequencies

“…(2) Sensitivity to ITDs may be reduced (H€ ausler et al, 1983;Gabriel et al, 1992;Moore, 2007b;Moore, 2014), a) Electronic mail: bcjm@cam.ac.uk especially for narrowband signals. Also, sensitivity to ITDs tends to become poorer with increasing age, even when audiometric thresholds are normal or near-normal (Hopkins and Moore, 2011;Moore et al, 2012a;Moore et al, 2012b).…”