Ageing impacts basic auditory and timing processing

Deterioration in the peripheral and central auditory systems is common in older adults and often leads to hearing and speech comprehension difficulties. Even when hearing remains intact, electrophysiological data of older adults frequently exhibit altered neural responses across the auditory pathway, reflected in variability in the phase alignment of neural activity to speech sound onsets. However, it remains unclear whether speech processing challenges in older adults stem from more fundamental deficits in auditory and timing processing. Here, we investigated the efficiency of aging individuals in encoding temporal regularities in acoustic sequences and their ability to predict future events. We recorded EEG in older and young individuals listening to simple isochronous tone sequences. A comprehensive analysis pipeline evaluated the amplitude, latency, and variability of event-related responses (ERPs) to each tone onset along the auditory sequences. Spectral parametrization and Inter-Trial Phase Coherence (ITPC) analyses assessed how participants encoded the temporal regularity in the acoustic environment. Our findings indicate that aging individuals exhibit altered temporal processing and reduced capacity to generate and utilize temporal predictions to time-lock and adaptively suppress neural responses to predictable and repeated tones in auditory sequences. Given that deteriorations in these basic timing capacities may affect other higher-order cognitive processes (e.g., attention, perception, and action), our results underscore the need for future research examining the link between timing abilities and general cognition across the lifespan.