Pseudobulbar affect in MS

Prevalence and association with symptoms in multiple sclerosis

Background

We sought to determine the prevalence of pseudobulbar affect (PBA) in a large MS population and assess its association with disability and symptom severity.

Methods

North American Research Committee on MS (NARCOMS) registry participants completed the Center for Neurologic Study-Lability Scale (CNS-LS), a validated 7-question self-report measure of PBA. A composite PBA score was derived from the sum of responses to the 7 questions. We categorized individuals as PBA-positive (PBA[+]) if they had a composite score ≥17 without current depression. Participants also reported their demographic characteristics and their clinical characteristics using Patient-Determined Disease Steps and Performance Scales. We compared clinical and disease characteristics for PBA(+) responders with those without PBA using descriptive statistics and multivariable multinomial logistic regression.

Results

Of the 8,136 responders, 574 (7%) had scores ≥17 on the CNS-LS; however, only 200 (2.5%) individuals had scores ≥17 without comorbid depression, of whom only 22 (11%) reported a diagnosis of PBA. PBA(+) individuals tended to be younger (mean [SD] 53.4 [11.0] vs 57.2 [10.3] years), non-white (13% vs 9%), and have lower socioeconomic status (≤$30,000 annual income: 28% vs 22%). In multivariable models, PBA(+) was associated with increased odds of more severe cognitive impairment (moderate vs mild disability OR: 1.37; 95% CI: 1.01, 1.84).

Conclusions

Our findings suggest that the prevalence of PBA in MS is low, but similar symptoms may co-occur or overlap with depression, highlighting the importance of concomitant assessment of mood when evaluating potential PBA. PBA may be associated with cognitive impairment in people with MS.

Pathologic laughing or crying, or pseudobulbar affect (PBA), is a socially debilitating condition that primarily affects people with neurologic diseases including MS.^1–3 Characterized by sudden, brief, exaggerated, and uncontrollable expressions of laughing or crying, PBA is burdensome for affected persons. Emotional displays may be incongruent with mood, such as when anger is expressed as laughter. In some situations, emotional displays may be exaggerated to a contextually appropriate emotional trigger.

Detailed information regarding the prevalence of PBA in MS or its associations with disease characteristics is lacking. Prevalence estimates for PBA in MS are highly variable, ranging from 7% to 52%; several estimates are from studies conducted before 1970.^4–8 More recent studies evaluating the prevalence and characteristics of PBA in MS used relatively small samples and/or included relatively homogeneous patient populations, which limit generalizability.⁴ Furthermore, although PBA is considered pathologically distinct from psychiatric comorbidities like depression, both conditions could result in seemingly similar symptom presentations, and many previous studies did not evaluate mood concomitantly with symptoms of PBA.

Therefore, we evaluated the prevalence and characteristics of the PBA in a large population of people with MS using a validated measure of PBA and including concomitant assessment of internal emotional state. Specifically, we evaluated the association between PBA and other MS symptoms, including cognitive impairment, which we hypothesized would be more severe in individuals with PBA.

Methods

Study population

The study included participants in the North American Research Committee on MS (NARCOMS) registry, which has enrolled >38,000 individuals with self-reported MS. In a previous validation study, >98% of self-reported MS cases were physician confirmed.⁹ Upon enrollment, participants provide date of birth, race, sex, and age at MS symptom onset. Semiannually thereafter, participants update their demographic information including household income and provide information relating to MS-related disease status, symptoms and disability, and disease-modifying therapy use in the past 6 months.

Standard protocol approvals, registrations, and patient consents

At the time of the survey, the NARCOMS registry was approved by the Institutional Review Board at the University of Alabama at Birmingham. Participants agree to the use of their information for research.

MS status

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