Working memory predicts semantic comprehension in dichotic listening in older adults

Age-Related Listening Performance Changes Across Adulthood

OBJECTIVES

This study compares auditory processing performance across different decades of adulthood, including young adults and middle-aged individuals with normal hearing and no spontaneous auditory complaints.

DESIGN

We assessed 80 participants with normal hearing, at least 10 years of education, and normal global cognition. The participants completed various auditory tests, including speech-in-noise, dichotic digits, duration, pitch pattern sequence, gap in noise, and masking level difference. In addition, we conducted working memory assessments and administered a questionnaire on self-perceived hearing difficulties.

RESULTS

Our findings revealed significant differences in auditory test performance across different age groups, except for the masking level difference. The youngest group outperformed all other age groups in the speech-in-noise test, while differences in dichotic listening and temporal resolution emerged from the age of 40 and in temporal ordering from the age of 50. Moreover, higher education levels and better working memory test scores were associated with better auditory performance as individuals aged. However, the influence of these factors varied across different auditory tests. It is interesting that we observed increased self-reported hearing difficulties with age, even in participants without spontaneous auditory complaints.

CONCLUSIONS

Our study highlights significant variations in auditory test performance, with noticeable changes occurring from age 30 and becoming more pronounced from age 40 onward. As individuals grow older, they tend to perceive more hearing difficulties. Furthermore, the impact of age on auditory processing performance is influenced by factors such as education and working memory.

Attentional Inhibition Ability Predicts Neural Representation During Challenging Auditory Streaming

Focusing on a single source within a complex auditory scene is challenging. M/EEG-based auditory attention detection (AAD) allows to detect which stream an individual is attending to within a set of multiple concurrent streams. The high interindividual variability in the auditory attention detection performance often is attributed to physiological factors and signal-to-noise ratio of neural data. We hypothesize that executive functions-in particular sustained attention, working memory, and attentional inhibition-may partly explain the variability in auditory attention detection performance, because they support the cognitive processes required when listening to complex auditory scenes. We chose a particularly challenging auditory scene by presenting dichotically polyphonic classical piano excerpts that lasted 1 min each. Two different excerpts were presented simultaneously, one in each ear. Forty-one participants, with different degrees of musical expertise, listened to these complex auditory scenes focusing on one ear while we recorded the EEG. Participants also completed several tasks assessing executive functions. As expected, EEG-based auditory attention detection was greater for attended than unattended stimuli. Importantly, attentional inhibition ability did explain 6% of the reconstruction accuracy and 8% of the classification accuracy. No other executive function was a significant predictor of reconstruction or classification accuracies. No clear effect of musical expertise was found on reconstruction and classification performance. In conclusion, cognitive factors seem to impact the robustness of the neural auditory representation and hence the performance of EEG-based decoding approaches. Taking advantage of this relation could be useful to improve next-generation hearing aids.

Onset Age of Language Acquisition Effects in a Foreign Language Context: Evidence from Chinese-English Bilingual Children

The present study examined the relationship between age of acquisition (AoA) and bilingual development for native Chinese children who learned English as a foreign language. A composite test measuring different aspects of language and cognitive skills in Chinese and English was administered on 85 Chinese native primary schoolers, who received bilingual instruction at different points of development (for Chinese, 0 ≤ AoA ≤ 7 years; for English, 2 ≤ AoA ≤ 10 years). Results found AoA constraints on the outcomes of L1 Chinese acquisition are significantly different from those for L2 English. Not all domains of bilingual skills follow the pattern of "the earlier, the better" in language development. Additionally, L1 AoA made unique contributions to L2 English learning. These findings contribute to our understanding on the nature of the AoA effect on bilingual learning.

Age-Related Atrophy and Compensatory Neural Networks in Reading Comprehension

OBJECTIVES

Despite changes to brain integrity with aging, some functions like basic language processes remain remarkably preserved. One theory for the maintenance of function in light of age-related brain atrophy is the engagement of compensatory brain networks. This study examined age-related changes in the neural networks recruited for simple language comprehension.

METHODS

Sixty-five adults (native English-speaking, right-handed, and cognitively normal) aged 17-85 years underwent a functional magnetic resonance imaging (fMRI) reading paradigm and structural scanning. The fMRI data were analyzed using independent component analysis to derive brain networks associated with reading comprehension.

RESULTS

Two typical frontotemporal language networks were identified, and these networks remained relatively stable across the wide age range. In contrast, three attention-related networks showed increased activation with increasing age. Furthermore, the increased recruitment of a dorsal attention network was negatively correlated to gray matter thickness in temporal regions, whereas an anterior frontoparietal network was positively correlated to gray matter thickness in insular regions.

CONCLUSIONS

We found evidence that older adults can exert increased effort and recruit additional attentional resources to maintain their reading abilities in light of increased cortical atrophy.