Aging Trumps Normal Hearing in Speech Identification
Fullgrabe, Moore, and Stone (2015) investigated whether aging reduces the ability of people with normal audiograms to understand speech, and to determine the impact of cognition and auditory temporal processing.
They report on aging in adults is associated with deterioration of speech processing and increased effort in speech processing. Fullgrabe, Moore, and Stone report that hearing-impaired people have a lower quality of life and they experience greater social isolation, greater depression, and older people with hearing loss demonstrate poorer cognitive function and increased cognitive decline. The authors note that top-down cognitive processing is involved with speech processing and cognitive processing, and cognitive ability tend to decrease as age increases.
The authors evaluated 21 older people (aged 60-79) with normal hearing and 9 young (aged 18-27 years) people with normal hearing. Tests administered included the Abbreviated Profile of Hearing Aid Benefit (APHAB), the Speech, Spatial and Qualities (SSQ) of Hearing Scale, self-report inventories, tests of monaural and binaural temporal fine structure (TFS), digit span tests, reading span tests, the Test of Everyday Attention, and more.
The authors state that “in the absence of gross cognitive dysfunction, elevated audiometric thresholds in older listeners have been identified as the major contributor to the reduction in speech intelligibility. However, audibility generally did not explain all of the variance in identification performance.” Among their 13 findings, they report that identification scores for consonants in quiet and in speech-shaped noise were lower for older than for younger participants. Identification scores for sentences in quiet were identical for the two age groups, but identification of sentences in the presence of spatially co-located or separate interfering two-talker babble was worse for the older group. The lower speech-perception performance of the older participants was not associated with higher subjective ratings of hearing disabilities. Sensitivity to monaural and binaural TFS information was reduced for older participants.
Fullgrabe, Moore, and Stone state that on the whole, even in the absence of hearing loss as measured by the audiogram, speech-in-noise (SiN) identification declines with age. They note that “these findings indicate a need for clinical tests in addition to the audiogram when assessing the hearing of older people, and confirm the need to take age into account in studies examining the effects of hearing loss.”
For More Information, References, and Recommendations
Fullgrabe C, Moore BCJ, Stone MA. (2015) Age-group Differences in Speech Identification Despite Matched Audiometrically Normal Hearing: Contributions from Auditory Temporal Processing and Cognition. Frontiers.