Measuring impulsivity in Parkinson's disease: a correlational and structural neuroimaging study using different...

Area of Science:

• Neuroscience
• Psychiatry
• Neurology

Background:

• Impulsivity is a key personality trait and a significant factor in neuropsychiatric disorders.
• In Parkinson's disease (PD), impulsivity is linked to impulse control disorders, a common non-motor symptom.
• The choice of impulsivity assessment tool's impact in PD has not been thoroughly investigated.

Purpose of the Study:

• To determine if different impulsivity measures in Parkinson's disease patients correlate with each other.
• To investigate if these measures share common brain structural correlates.
• To explore whether distinct impulsivity assessments reflect different underlying neurological phenomena.

Main Methods:

• The study included 89 Parkinson's disease patients without impulse control disorders.
• Four common impulsivity tests were administered: impulsiveness trait, decisions under implicit risk (with/without losses), and delay discounting.
• Voxel-based morphometry (VBM) analyzed grey matter volume (GMV) correlations with each impulsivity test score.

Main Results:

• No significant correlations were found between the scores of the different impulsivity tests.
• Brain structural correlates for each impulsivity measure were distinct and divergent.
• Specific associations included impulsiveness trait with prefrontal cortex GMV, risk-taking with nucleus accumbens and insula GMV, and delay discounting with nucleus accumbens GMV.

Conclusions:

• Different measures of impulsivity in Parkinson's disease represent distinct behavioral and neuroanatomical phenomena.
• Impulsivity in Parkinson's disease is not a monolithic entity but a heterogeneous condition.
• These findings highlight the importance of considering specific impulsivity facets and their unique neural underpinnings in Parkinson's disease research and clinical practice.