Background Pseudobulbar affect (PBA) is prevalent in amyotrophic lateral sclerosis (ALS), but there is limited information on its associations and course.
Objectives Explore prevalence, associations, course and manifestations of PBA in outpatient cohort of patients with ALS and examine its relationship to depression.
Methods Self-reported measures of PBA and depression (Center for Neurologic Study-Lability Scale (CNS-LS) and Patient Health Questionnaire (PHQ-9), respectively) were obtained from consecutive patients with ALS using tablet devices in waiting rooms (Knowledge Program).
Results PBA (CNS-LS ≥13) was seen in 209/735 patients (28.4%). PBA was associated with bulbar onset and dysfunction, upper motor neuron dysfunction, cognitive impairment, depression and lower quality of life. A multivariable model that included lower bulbar and gross motor subscores, female gender, younger age and shorter duration of disease predicted PBA with 74% accuracy. CNS-LS scores increased only slowly with time. Women with PBA reported more crying than men. Crying (but not laughter) correlated with depression, and crying was associated with poorer quality of life. Exploratory factor analysis of pooled questions of CNS-LS and PHQ-9 identified three underlying factors (laughter, crying and depression) loaded on appropriate questions of the respective instruments.
Conclusion This study identifies associations of PBA and additionally finds PBA (especially crying-predominant PBA) more prevalent in women with ALS. Although the two self-report instruments (CNS-LS and PHQ-9) discriminate well between PBA and depression, there is significant overlap between depression and crying in PBA. Studies of PBA should stratify for gender, examine crying and laughter as separate outcomes and adjust for depression.
- amyotrophic lateral sclerosis
- pseudobulbar affect
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Contributors NJT conceptualised the study, conducted the statistical analysis, interpreted the data and prepared the initial manuscript. EPP conducted clinical examination of the patients described in the study, conceptualised the study, interpreted the data and critically revised the manuscript for important intellectual content. All authors contributed equally to the study design and approval of the final manuscript.
Funding This study was not supported by any external or internal grant. NJT reports no disclosures. EPP is holder of the Barry Winovich (Bright Side of the Road Foundation) Chair in ALS Research, receives support from Samuel J. and Connie M. Frankino Charitable Foundation, and serves as consultant to Avanir Pharmaceuticals, Inc. and Otsuka America Pharmaceuticals, Inc.
Competing interests None declared.
Patient consent Patient consent was not obtained for this retrospective study because patient-reported outcome data used for this study are collected as part of routine clinical care at our institution to inform clinical care.
Ethics approval The Institutional Review Board at Cleveland Clinic approves retrospective studies of datasets extracted from the KP Data Registry (IRB #07-591). Examination of existing records to study predictors of progression ALS has also received approval (IRB #14-871). The practice of collecting patient-reported outcomes is standard of care in neurology at Cleveland Clinic, and no additional consent is sought.
Provenance and peer review Not commissioned; externally peer reviewed.
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