Posterior Fossa Lesion Load and Pathological Laughing and Crying in Multiple Sclerosis

Pathological laughing and crying (PLC) encompasses episodes of involuntary laughing, crying, or both that are contextually incongruous with the individual's subjective mood. Despite a 10% to 46% prevalence in people with multiple sclerosis (MS) and reduced quality of life, localization of neuroanatomical lesions associated with PLC remains poorly delineated.

The relationship between posterior fossa lesions and PLC in people with MS was examined using a retrospective medical record review of people with MS (2012-2016) who had completed the Center for Neurologic Study-Liability Scale (CNS-LS) and had undergone 1.5-T magnetic resonance imaging within 6 months of each other.

Medical record review identified 80 potential cases, with 77 included. Brainstem and cerebellar lesions were counted, measured, and compared between people with MS who had positive results on the CNS-LS (scores ≥17, n = 22) with those who had negative results on the CNS-LS (scores ≤16, n = 55). Initial χ² analysis showed no significant difference in lesion numbers in people with MS without (CNS-LS score ≤16) versus with (CNS-LS score ≥17) PLC. When analyzing only people with MS without evidence of depression, a significant inverse relationship was identified such that fewer posterior fossa lesions on automated magnetic resonance imaging was associated with the presence of PLC.

Posterior fossa lesion load is not indicative of which individuals could develop PLC. Further investigations to delineate the primary source of PLC symptoms would aid in diagnosis and treatment of this condition.