Suspected Pseudobulbar Affect in Neurodegenerative Disease

Objective

To investigate the association between suspected pseudobulbar affect (PBA), clinical diagnosis, cognitive testing, and self-reported mood in older adults presenting for evaluation of dementia.

Participants

Patients presenting to an outpatient memory disorders clinic (N = 311).

Methods

We used traditional and novel network modeling approaches to examine associations between neuropsychological (NP) tests, patient and clinician rating scales, and the Center for Neurological Study-Lability Scale (CNS-LS) among patients with suspected AD (n = 133) and other neurocognitive diagnosis (n = 178). We then examined differences in test performance between patients with and without suspected PBA (CNS-LS cut-off of ≥ 13), while accounting for demographic and psychiatric covariates with propensity score matching. Group differences were assessed with Bayesian models.

Results

Prevalence of suspected PBA in AD was slightly less than half (44.4%) and at a similar rate in other dementias (e.g., 46.9% in CVD and 45.5% in LBD). In network models, the CNS-LS was associated with higher anxiety and better word list recall. After accounting for covariates, AD patients with suspected PBA performed better on word list recall β_M = 0.40, 95% CI [0.15, 0.66], and committed fewer false positive errors on recognition β_M = −1.51, 95% CI [−2.34, −0.59] than AD patients without suspected PBA. There were no differences in patients with any other diagnostic impression, nor group differences on other NP measures.

Conclusions

Patients with suspected PBA and AD diagnosis had better memory recall and recognition than those without suspected PBA, suggesting that impaired emotional regulation may be an early sign of AD in patients with less prominent memory decline. Better understanding PBA in neurodegenerative diseases, including prevalence and comorbidity with psychiatric conditions, could help with early identification, education, and initiation of treatment.