Aging Degrades the Neural Encoding of Simple and Complex Sounds in the Human Brainstem

Abstract

FFR components representing the tone and consonant-vowel /da/ stimulus were negatively affected by age, showing age-related reductions in response synchrony and amplitude, as well as prolonged latencies. These aging effects were evident in middle age, even in the absence of significant hearing loss.

Neural representation of dynamic frequency is degraded in older adults

“…These stimuli contain dynamic frequency information in the form of formant transitions and have revealed age effects even in the absence of significant hearing loss Clinard et al, 2013;Vander Werff et al, 2011). Plyler and Krishnan (2001) found that FFRs from adults with sensorineural hearing loss had poorer representation of second formant transitions than normal-hearing adults; age may have influenced those findings, considering that their subjects included older individuals.…”

“…In addition, synthetic speech stimuli with Mandarin fundamental frequency tone contours have also been used to elicit FFRs in young adults (Krishnan et al, 2004(Krishnan et al, , 2005. In older adults, FFRs elicited by synthetic consonant-vowel stimuli have been reported to have poorer onset and offset responses with decreased amplitude Clinard et al, 2013); however, these studies have focused primarily on fundamental frequency representation and have not included time-frequency analysis in examining the frequency representation of formant transitions.…”

Partial maintenance of auditory-based cognitive training benefits in older adults

“…We evaluated neural speech-in-noise processing with the frequency following response (FFR) to a CV syllable presented in quiet and noise and found that training decreased FFR peak latencies and peak variability, two putative measures of subcortical neural synchrony, and improved untrained measures of sentence recognition in noise, short-term memory, and speed of processing. We used the FFR because it reflects temporal processing deficits in older adults (Anderson, Parbery-Clark, White-Schwoch, & Kraus, 2012; Clinard & Tremblay, 2013; Vander Werff & Burns, 2011) and because it can be modulated by training in young adults (Carcagno & Plack, 2011; Song, Skoe, Banai, & Kraus, 2012; Song, Skoe, Wong, & Kraus, 2008). The FFR reflects neural transcription of stimulus properties and is highly modulated by cognitive influences (Kraus & Chandrasekaran, 2010; Krishnan, Gandour, & Bidelman, 2010).…”

Complementary metrics of human auditory nerve function derived from compound action potentials

“…However, these responses are generated at the level of the brainstem and individual 410 differences in both central and AN function could contribute to the response. This limitation is of 411 particular importance when examining different experimental or patient populations, as both age 412 and experience are known to affect central neural function (Clinard and Tremblay 2013;Clinard 413 et al 2010;Krishnan et al 2016;Wong et al 2007). Therefore, changes observed in these 414 responses could be a consequence of a combination of AN and central factors.…”