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Mechanisms of Impairment and Compensation Underlying Speech Comprehension in Multitalker Environments Across the Adult Life Span
Poster Session A, Wednesday, September 30, 11:00 am - 1:00 pm, Wangari Maathai
Vivien Barchet1,2, Andrea Bruera1, Johanna M. Rimmele3, Jonas Obleser4, Gesa Hartwigsen1,2; 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Leipzig University, Leipzig, Germany, 3International Max Planck Research School on Cognitive NeuroImaging, Leipzig, Germany, 4Max Planck Institute for Empirical Aesthetics, Frankfurt, Germany, 5University of Luebeck, Luebeck, Germany
In everyday life, spoken speech streams are often masked by noise or competing speech streams in the surrounding, creating challenging listening situations, particularly for older adults. However, it remains unclear why older adults' speech comprehension is impaired in multitalker contexts. Disentangling the causes for impaired speech comprehension is particularly important as speech comprehension is crucial for the maintenance of social integration and psychosocial functioning in late adulthood. In an EEG study, we investigated how acoustic and higher-level linguistic processing contribute to competing speech comprehension across the adult life span providing fine-grained resolution on the behavioral and neural levels. Our hypotheses included that older adults compensate for declines in lower-level sensory processing by relying more on higher-level information on the behavioral and the neural levels to maintain speech comprehension. 63 normally hearing participants (age range = 18 – 70 years) heard 240 trials of two sentences presented simultaneously and were instructed to follow one speaker while ignoring the other one. They subsequently repeated the target sentence. The individual task difficulty was adjusted using an adaptive staircase procedure to account for peripheral hearing differences. The hypothesis was assessed using a generalized linear mixed effects model predicting word comprehension performance from the interactions of age with acoustic and linguistic word-level variables. Additionally, we assessed the strength of neural tracking of acoustic and linguistic features of the target and distractor sentences using the trial-wise, cross-validated fits of multivariate temporal response functions. Behavioral results revealed a stronger reliance on higher-level features with increasing age. Neural results revealed that enhanced target tracking was associated with increased comprehension performance (Estimate = 0.03, SE = 0.01, z = 2.7, p = .011*). Additionally, enhanced acoustic distractor tracking was correlated with improved comprehension performance (Estimate = 0.03, SE = 0.01, z = 2.45, p = .022*). An interaction between age and the trial-wise neural tracking of distractor word and phoneme onsets revealed that there was a stronger negative effect of distractor tracking on comprehension in older adults (Estimate = -0.03, SE = 0.01, z = -2.85, p = .008**). This suggests that impaired attentional filtering underlies speech comprehension deficits in older adults. Additionally, there was a positive correlation between age and the neural tracking of word-level linguistic features (Estimate = 0.48, SE = 0.18, t = 2.69, p = .009**). An explorative analysis revealed that increased higher-level linguistic tracking can compensate for an increased individual distractibility (Estimate = 0.29, SE = 0.09, t = 3.09, p = .008**), suggesting a compensational function of higher-level linguistic tracking across the adult life span. In sum, the results provide novel insights into age-related speech comprehension difficulties by uncovering age-related difficulties in attentional filtering, as well as potential compensational mechanisms on the behavioral and the neural levels.
Topic Areas: Speech Perception,