AI Insight
This study examined how subjective cognitive decline (SCD) affects brain activity during speech processing in 60 cognitively normal older adults using EEG recordings. Researchers found that individuals with greater self-reported cognitive decline showed weaker neural tracking of linguistic features, particularly when listening to speech with flat prosody (monotone delivery), while acoustic processing remained intact. The findings suggest that reduced cortical tracking of subsyllabic linguistic features during prosodically flat speech could serve as an early neural marker for cognitive decline risk.
Why it matters
This research identifies a potential biomarker for detecting early-stage cognitive decline before clinical symptoms appear, which could enable earlier intervention in at-risk individuals. The use of naturalistic speech perception tasks offers a non-invasive approach to monitoring cognitive health in older adults who report subjective memory concerns.
Understand the Science
arXiv:2509.21277v3 Announce Type: replace
Abstract: Subjective cognitive decline (SCD) doubles dementia risk. This study investigates how self-perceived cognitive worsening shapes neural dynamics during naturalistic speech perception. EEG was collected from 60 cognitively normal older adults as they listened to speech varied in prosodic contexts, categorized by expressive style (scrambled, descriptive, dialogue, exciting). Encoding models mapping three speech representations — acoustic, subsyllabic segmentation and phonotactic features — to ongoing EEG signals were built. Cortical tracking strength (CTS) showed that models fitted with subsyllabic linguistic features outperformed acoustic ones. Crucially, greater SCD severity was associated with weaker CTS of (1) subsyllabic linguistic but not acoustic features, and (2) prosodically flat speech (scrambled and descriptive). Thus, the CTS of higher-level linguistic features while listening to prosodically flat speech may serve as a potential neural marker for early-stage cognitive decline.