Abstract| Volume 22, ISSUE 3, SUPPLEMENT , S115-S116, March 2014

PRISM: A Novel Research Tool to Assess the Prevalence of Pseudobulbar Affect Symptoms Across Neurological Conditions


      Pseudobulbar affect (PBA) is a neurological condition characterized by involuntary, uncontrollable, sudden, and frequent episodes of laughing and/or crying that can be socially disabling. PBA occurs secondary to a variety of neurological diseases or brain injury, and is estimated to affect 1.5 to 2 million people in the United States. The PBA Registry Series (PRISM) was conducted from May 2011 to September 2012 to estimate the prevalence of PBA symptoms in a large, representative clinic sample of US patients with neurological conditions associated with PBA. The final data for PRISM patients aged ≥65 years are presented here.


      After obtaining Institutional Review Board approval, PRISM Investigators were asked to enroll ≥20 consenting patients with any of 6 conditions: Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson's disease (PD), stroke, or traumatic brain injury (TBI). Patients (or their caregivers) completed the Center for Neurologic Study-Lability Scale (CNS-LS), a measure of PBA symptom frequency and severity validated in patients with ALS and MS. Presence of PBA symptoms was defined as a CNS-LS score ≥13. Patients (or their caregivers) were also asked a quality of life (QOL) question, “How has your (your patient's) neurological condition affected your (their) QOL?” to be rated on an 11-point scale from 0 (not at all) to 10 (strongly affected). In addition, demographic data and use of antidepressant/antipsychotic medications were recorded. No further screening was conducted for other neurological/psychiatric disorders.


      A final total of 5290 patients were enrolled in PRISM, of whom over half (n=3048; 57.6%) were aged 65 to 102 years. Patients aged ≥65 years had the following neurological diagnoses: AD, 1660 (54.5%); ALS, 54 (1.8%); MS, 112 (3.7%); PD, 639 (21.0%); stroke, 476 (15.6%); and TBI, 107 (3.5%). The overall prevalence of PBA symptoms (CNS-LS ≥13) in the ≥65 cohort was 27.4% (n=835), and was highest in patients with underlying ALS and lowest in patients with PD (AD 27.3%, ALS 38.9%, MS 25.0%, PD 23.6%, stroke 31.1%, TBI 31.8%). The overall prevalence in older patients was significantly lower than that seen in younger patients (<65 years) where 49.5% had CNS-LS ≥13 (P<0.0001). The reasons for the prevalence difference by age are unclear, but do not appear to be explained by a difference in the relative percentage of underlying neurological conditions between younger and older patients. Similar to the overall patient sample, patients aged ≥65 years with PBA symptoms had significantly higher mean scores for impact of neurological condition on QOL (6.3 for CNS-LS ≥13 vs 4.6 for CNS-LS <13; P<0.0001, two-sample t-test). Older patients with CNS-LS ≥13 vs older patients with CNS-LS <13 were also more likely to be taking antidepressants (selective serotonin reuptake inhibitors, 34.9% vs 27.1%; P<0.0001; tricyclics, 25.5% vs 11.0%; P<0.0001) or antipsychotics (5.9% vs 2.7%; P<0.0001, chi-square test).


      These data from PRISM, the largest clinic-based study to assess PBA symptom prevalence, suggest PBA symptoms are common in patients with diverse neurological diseases aged ≥65 years, albeit less prevalent than in a comparable cohort of patients aged <65 years. However, PBA symptoms were associated with greater impact of the neurological condition on QOL and greater incidence of antidepressant/antipsychotic use. These data suggest a need for greater identification of PBA symptoms and diagnosis of PBA in elderly individuals with neurological conditions affecting the brain. Use of targeted questions or screening tools can help clinicians with PBA screening. Further research is needed to understand the extent to which diagnosis and appropriate treatment of PBA may improve patient outcomes.