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Prosodic Boundary Processing during Sentence Comprehension in Parkinson’s Disease: Evidence from CPS, N400, and P600 Responses
Poster Session B, Wednesday, September 30, 4:30 - 6:30 pm, Wangari Maathai
Tena Grahovac1, Pia Knoeferle2,3,4, Fabian Klostermann1,2; 1Charité – Universitätsmedizin Berlin, 2Berlin School of Mind and Brain, 3Humboldt-Universität zu Berlin, 4Einstein Center for Neurosciences Berlin
Background: Prosodic boundaries provide important cues for syntactic and semantic sentence interpretation. Parkinson’s disease (PD) has been associated with impairments in temporal processing and sequencing, suggesting that the use of prosodic information during online sentence comprehension may be altered. We investigated whether prosodic breaks influence the processing of locally ambiguous sentences differently in individuals with PD and healthy controls (HC), and whether break length modulates these effects. Methods: Twenty-two individuals with PD (mean age = 69.05 years) and 25 HC participants (mean age = 66.28 years) listened to auditorily presented German sentences containing prosodic breaks that were either syntactically appropriate or inappropriate. Breaks were manipulated in length (short (330ms) vs. long (660ms)). Participants judged whether each sentence sounded grammatically acceptable. EEG was recorded throughout the task. Event-related potentials associated with prosodic boundary processing (Closure Positive Shift (CPS): 0–400 ms after onset of break), semantic integration (N400: 150–450 ms after onset of disambiguating verb), and late syntactic reanalysis (P600: 700–1300 ms after onset of disambiguating verb) were analyzed using linear mixed-effects models. Results: Contrary to our prediction, CPS amplitudes did not differ significantly between groups. In contrast, group differences emerged during the N400 time window. Individuals with PD showed ERP amplitudes that differed from those of HC during the N400 time window at the sentence-final disambiguating verb, particularly over anterior and midline regions. During the P600 time window, no overall group difference was observed. However, significant interactions involving group, scalp region, and break length emerged during the P600 time window. Specifically, the influence of prosodic break length on P600 amplitudes differed between groups and varied across scalp regions. Conclusions: The findings suggest that prosodic boundary detection itself remains relatively intact in Parkinson’s disease, whereas later stages of sentence processing are altered. Preserved CPS responses alongside group differences during the N400 time window and differential P600 modulation by break length suggest that distinct stages of sentence processing may be differentially affected in PD. These findings are consistent with proposals linking Parkinson’s disease to alterations in later stages of language processing.
Topic Areas: Disorders: Acquired, Speech Perception