The association of pathological laughing and crying and cognitive impairment in multiple sclerosis

Abstract

Background: Pathological laughing and crying (PLC) is common in multiple sclerosis (MS), defined as emotional expression that is exaggerated/incongruent with underlying mood. In other neurological disorders, PLC is associated with cognitive impairment (CI). Few studies have examined this relationship in MS.

Objective: To determine the association between PLC and CI in an MS population.

Methods: Retrospective chart review study of 153 MS subjects assessed in an outpatient clinic for CI. Data was collected on the minimal assessment of cognitive function in MS (MACFIMS), the Center for neurological study-lability scale (CNS-LS), a screening measure for PLC symptoms and the hospital anxiety and depression scale (HADS). Analyses of covariance compared performance on the MACFIMS between PLC (CNS-LS score ≥ 17, HADS-D ≤ 7) and non-PLC groups.

Results: MS subjects positive for PLC on the CNS-LS but without depression had lower scores on the controlled oral word association test, a measure of verbal fluency, and the California verbal learning test - 2 immediate recall score, a verbal memory measure.

Conclusions: This study demonstrates a connection between CI, specifically verbal fluency and verbal learning, and PLC in MS subjects. Further studies are warranted to explore the causative relationship between CI and PLC.

Keywords: Cognitive impairment; Depression; Multiple sclerosis; Pathological laughing and crying; Pseudo-bulbar affect.