PREVALENCE AND NEUROBEHAVIORAL CORRELATES OF PATHOLOGICAL LAUGHING AND CRYING IN MULTIPLE-SCLEROSIS

Objectives: To establish the point prevalence of pathological laughing and crying (PLC) in multiple sclerosis (MS). To define associated neu rological, emotional, and cognitive correlates of PLC. Design: A conse cutive sample of 152 patients with clinically or laboratory definite M S were screened for PLC, defined as sudden, involuntary displays of la ughing or crying or both, without associated subjective feelings of de pression or euphoria. Thereafter, a case-control design was followed w ith patients with PLC matched to patients with MS without PLC on age, gender, physical disability (Expanded Disability Status Scale), durati on of MS, and premorbid IQ. Setting: An MS outpatient clinic, the popu lation representative of a large urban catchment area. Patients: Fifte en of 152 patients had PLC, 11 of whom (mean [SD] age, 43.7 [8.3] year s, 7 women) agreed to further testing. Thirteen patients with MS witho ut PLC acted as controls. Main Outcome Measures: Neurological examinat ion, Pathological Laughter and Crying Scale, Hospital Anxiety and Depr ession Scale, 28-item General Health Questionnaire, and the Wechsler A dult Intelligence Scale-Revised. Results: The point prevalence of PLC in MS was 10%. Patients had a mean Expanded Disability Status Scale sc ore of 6.5, had had MS for a mean (SD) of 10 (5.8) years, and had ente red a chronic-progressive phase of their illness. Pathological laughin g and crying was not associated with disease exacerbations. Compared w ith controls, patients were not more depressed or anxious, but had a g reater decline in IQ. Conclusions: Pathological laughing and crying as distinct from emotional lability affects 1 in 10 patients with MS. It occurs in severely physically disabled patients, generally with long- standing disease. The presence of cognitive deficits relative to contr ols implies more extensive brain involvement.