Effects of Aging on the Subcortical Encoding of Stop Consonants

Frequency Following Responses to Tone Glides: Effects of Age and Hearing Loss

PURPOSE

Speech is characterized by dynamic acoustic cues that must be encoded by the auditory periphery, auditory nerve, and brainstem before they can be represented in the auditory cortex. The fidelity of these cues in the brainstem can be assessed with the frequency-following response (FFR). Data obtained from older adults-with normal or impaired hearing-were compared with previous results obtained from normal-hearing younger adults to evaluate the effects of age and hearing loss on the fidelity of FFRs to tone glides.

METHOD

A signal detection approach was used to model a threshold criterion to distinguish the FFR from baseline neural activity. The response strength and temporal coherence of the FFR to tone glides varying in direction (rising or falling) and extent ([Formula: see text], [Formula: see text], or 1 octave) were assessed by signal-to-noise ratio (SNR) and stimulus-response correlation coefficient (SRCC) in older adults with normal hearing and with hearing loss.

RESULTS

Significant group mean differences in both SNR and SRCC were noted-with poorer responses more frequently observed with increased age and hearing loss-but with considerable response variability among individuals within each group and substantial overlap among group distributions.

CONCLUSION

The overall distribution of FFRs across listeners and stimulus conditions suggests that observed group differences associated with age and hearing loss are influenced by a decreased likelihood of older and hearing-impaired individuals having a detectable FFR response and by lower average FFR fidelity among those older and hearing-impaired individuals who do have a detectable response.

Behavioral assessment of auditory processing in adulthood: population of interest and tests - a systematic review

PURPOSE

To identify the behavioral tests used to assess auditory processing throughout adulthood, focusing on the characteristics of the target population as an interest group.

RESEARCH STRATEGIES

PubMed, CINAHL, Web of Science, and Scielo, databases were searched with descriptors: "auditory perception" or "auditory perception disorders" or "auditory processing" or "central auditory processing" or "auditory processing disorders" or "central auditory processing disorders" with adults OR aging.

SELECTION CRITERIA

Studies with humans included, the adult population from 18 to 64 years old, who performed at least one behavioral test to assess auditory processing in the absence of hearing loss.

DATA ANALYSIS

Data extraction was performed independently, using a protocol developed by the authors that included different topics, mainly the behavioral auditory tests performed and the results found.

RESULTS

Of the 867 records identified, 24 contained the information needed to answer the survey questions.

CONCLUSION

Almost all studies were conducted verify performance in one or two auditory processing tests. The target target population was heterogeneous, with the most frequent persons with diabetes, stuttering, auditory processing disorder, and noise exposure. There is little information regarding benchmarks for testing in the respective age groups.

The effect of aging on identification of Mandarin consonants in normal and whisper registers

Consonant perception in older adults has been widely explored in recent years. However, how aging affects the identification of Mandarin consonants, especially in whispered condition, are under studied. Mandarin consonants and whispering speech have unique features, which may result in different identification difficulties for older adults. The current study investigated older adults' identification of Mandarin consonants in phonated and whispered conditions in comparison with the performance of younger adults. It was found that in phonated condition, older adults showed the lowest accuracy for affricatives and fricatives owing to their insensitivity to high-frequency information. The lower accuracy of affricatives and plosives was largely attributed to the difficulty in recognizing articulatory places. Identifying aspirated plosives was much more difficult than unaspirated counterparts for older adults. In whispered condition, the recognition of voiced consonants and aspirated-unaspirated distinction became challenging, especially for older adults. Contrary to the expectation, some consonants became easier to be recognized in the whispered condition, i.e., /p^h, tɕ^h, x/. These findings enrich our understanding of how aging affects consonant identification in different languages and less ideal conditions. It also suggests that the listener's ability, language uniqueness, and characteristics of distorted speech should be all taken into consideration when investigating speech perception in adverse conditions.