Executive functions in primary progressive aphasia: A meta-analysis

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurology

Background:

• Primary Progressive Aphasia (PPA) is a neurodegenerative disease affecting language.
• Executive functions (EFs) are crucial for cognitive control, but their status in PPA is debated.
• Previous studies on EFs in PPA yielded conflicting results.

Approach:

• A multi-level meta-analysis was conducted to synthesize existing research on EFs in PPA.
• 141 studies comprising 294 EFs tasks were analyzed.
• The analysis focused on a composite EFs score and individual components: shifting, inhibition, and updating.

Key Points:

• A large overall effect size (d = -1.28) indicates significantly poorer EFs in PPA compared to healthy controls.
• All EFs components (shifting, inhibition, updating) were similarly affected.
• PPA variant and disease duration significantly moderated EFs performance, with semantic variant showing less impairment.

Conclusions:

• This meta-analysis confirms widespread executive function deficits in PPA.
• Impairments affect all core EFs components similarly across PPA variants, with nuances for semantic PPA.
• Findings have implications for clinical assessment and future research directions in PPA.