Distinctive Pathophysiology Underlying Constipation in Parkinson's Disease: Implications for Cognitive Inefficiency

Area of Science:

• Neurology
• Gastroenterology
• Psychiatry

Background:

• Constipation is a common non-motor symptom in Parkinson's disease (PD).
• Inefficient cognitive processing, or bradyphrenia, is a hallmark of PD.
• The relationship between constipation, bradyphrenia, and mood in PD requires further definition.

Purpose of the Study:

• To characterize the typical bowel function in Parkinson's disease (PD).
• To investigate the association between bowel dysfunction, cognitive processing, mood, and motor symptoms in PD and controls.

Main Methods:

• Colonic transit time was assessed using radio-opaque markers over 6 days in 58 PD patients and 71 controls.
• Bowel function, psychometric questionnaires, and Parkinson's disease (PD) facets including bradyphrenia were measured.
• Abdominal X-rays and functional constipation status were analyzed for predictive value.

Main Results:

• Total retained marker count and transverse colon delay predicted PD status, with functional constipation status improving classification accuracy.
• In PD patients, constipation was associated with higher depression scores and slower cognitive processing.
• In controls, misclassification by bowel dysfunction correlated with increased depression and anxiety, but not cognitive slowing.

Conclusions:

• Constipation in Parkinson's disease (PD) exhibits distinct localized pathophysiology.
• Bowel dysfunction in PD is significantly associated with bradyphrenia (inefficient cognitive processing).
• Motor features were independent of bowel function sub-classification in both PD patients and controls.