Neuroanatomy of pseudobulbar affect : a quantitative MRI study in multiple sclerosis

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Pseudobulbar affect (PBA) involves involuntary emotional expression incongruent with mood.
• PBA is a neuropsychiatric syndrome associated with various neurological conditions, including multiple sclerosis (MS).

Purpose of the Study:

• To identify neuroanatomical correlates of PBA in MS using MRI.
• To compare brain lesion distribution in MS patients with and without PBA.

Main Methods:

• A case-control 1.5T MRI study matched 14 MS patients with PBA to 14 MS patients without PBA.
• Demographic, disease course, and disability variables were matched; comorbid psychiatric disorders were excluded.
• Hypo- and hyperintense lesion volumes and atrophy were measured and localized anatomically.

Main Results:

• MS patients with PBA showed significantly higher lesion volumes in the brainstem (hypointense), bilateral inferior parietal (hyperintense), medial inferior frontal (hyperintense), and right medial superior frontal (hyperintense) regions.
• A logistic regression model identified brainstem hypointense, left inferior parietal hyperintense, and bilateral medial inferior frontal hyperintense lesions as key predictors, explaining 70% of PBA variance.
• These findings indicate a distinct pattern of brain lesions associated with PBA in MS.

Conclusions:

• MS patients with PBA exhibit a unique distribution of brain lesions compared to MS patients without PBA.
• The lesion data suggest a widespread neural network, including frontal, parietal, and brainstem regions, is implicated in the pathophysiology of PBA.
• This study provides neuroanatomical insights into PBA in MS, supporting a distributed network model.