Global Coherence and Cognition in Parkinson's Disease

Area of Science:

• Neurology
• Speech and Language Pathology
• Cognitive Science

Background:

• Parkinson's disease (PD) is a neurodegenerative disorder impacting motor and non-motor functions.
• Global coherence (GC) refers to the ability to maintain a topic-related discourse.
• Assessing GC in PD is crucial for understanding communication deficits.

Purpose of the Study:

• To compare GC in individuals with PD versus healthy older adults (HOAs).
• To investigate the relationship between GC and cognitive functions in PD.
• To examine GC during single and dual-task conditions.

Main Methods:

• A cross-sectional study involving 37 individuals with PD and 19 HOAs.
• Participants produced discourse monologues during single (seated) and dual (cycling) tasks.
• GC was rated using four levels (GC1-GC4), and cognitive abilities (processing speed, working memory, inhibition, updating) were assessed.

Main Results:

• Individuals with PD showed significantly lower proportions of high-level GC (GC4) and higher proportions of low-level GC (GC1, GC2) compared to HOAs.
• No significant differences in GC were found between single and dual-task conditions.
• Faster processing speed and better inhibition were associated with higher GC, while slower processing speed correlated with lower GC.

Conclusions:

• Individuals with PD experience greater difficulties with global coherence in discourse than HOAs.
• Processing speed and inhibition are significant cognitive predictors of GC in both groups.
• Analyzing GC offers valuable insights into communicative effectiveness in PD.