Imaging executive functions in Parkinson's disease: An activation likelihood estimation meta-analysis

Area of Science:

• Neuroscience
• Cognitive Neurology
• Medical Imaging

Background:

• Executive dysfunction is a common early symptom in Parkinson's disease (PD), significantly impacting patient and caregiver quality of life.
• Neuroimaging studies have explored the neural basis of this impairment, but findings regarding brain changes are inconsistent.
• Identifying reliable neural correlates is crucial for understanding and potentially treating cognitive deficits in PD.

Purpose of the Study:

• To systematically assess the convergence of abnormal brain activation in Parkinson's disease patients during executive function (EF) tasks.
• To synthesize findings from existing functional neuroimaging studies on EF in PD.
• To determine if a consistent neural signature of executive dysfunction in PD can be identified.

Main Methods:

• A comprehensive literature search was conducted on PubMed for functional imaging studies on EF in PD.
• Stereotactic data from eligible studies were extracted and analyzed using a coordinate-based activation likelihood estimation (ALE) approach.
• Convergence of deviant neural activation in PD patients compared to healthy controls (HC) was statistically tested.

Main Results:

• Twenty-two studies were included, primarily focusing on working memory, involving 354 PD patients and 306 HC.
• Despite the number of studies, no significant converging aberrant brain activation was found between PD patients and HC after controlling for multiple comparisons.
• This lack of convergence was observed across different medication states (ON, OFF, or ON+OFF).

Conclusions:

• Current evidence is insufficient to pinpoint a specific neural correlate for executive dysfunction in Parkinson's disease.
• Methodological inconsistencies and small sample sizes across studies may contribute to the lack of convergent findings.
• Future research should employ larger sample sizes and more consistent methodologies to better understand functional brain changes associated with EF in PD.