Pseudobulbar affect: clinical associations, social impact and quality of life implications - Lessons from PLS.

Background: Pseudobulbar affect (PBA) is a well-recognised and troublesome clinical phenomenon in a range of neuroinflammatory, neoplastic, neurovascular and neurodegenerative conditions. It is often under-recognised in the community, frequently mistaken for psychiatric manifestations, appropriate pharmacological treatment is often delayed, and may result in a sense of embarrassment or lead to social isolation. Despite its considerable quality of life (QoL) implications and the challenges associated with its effective management, it is notoriously understudied.

Methods: As the incidence of PBA is lower in non-motor neuron disease patient cohorts, and the social and QoL impact of PBA is not sufficiently recognised, a purpose-designed study was conducted in a Primary Lateral Sclerosis (PLS) cohort to assess the clinical correlates and social impact of PBA.

Results: PBA was very strongly associated with pseudo-bulbar motor dysfunction. Dysphagia (OR 14, P = .005) and the presence of abnormal jaw jerk (OR 19.8, P < 0.001) greatly increased odds of PBA. There was no significant difference in the cognitive or behavioural profiles between those with PBA and those without it. Poorly controlled laughing (85%) was more prevalent than crying (69%) among PLS patients with PBA. No individual experienced PBA symptoms prior to the motor manifestations of PLS. Most patients were unaware that PBA was common in their neurological condition. The mean PBA Impact score was 5 (range 1-17) and correlated with CNS-LS crying subscores (r = .693, p = .006).

Discussion: The severity of pseudobulbar affect correlates with motor manifestations of pseudobulbar palsy, a link supporting emerging imaging studies regarding bilateral corticobulbar tract degeneration as in important aetiological factor. The social and quality of life ramifications of pseudobulbar affect can be readily demonstrated by purpose-designed questionnaires.

Conclusions: Despite sporadic reports, the clinical, social, caregiver burden and quality of life implications of pseudobulbar affect remain poorly characterised. The comprehensive evaluation of the clinical correlates of PBA helps to elucidate the underlying pathophysiology. Ultimately, the comprehensive assessment of both the aetiology and social impact of PBA helps to raise awareness of this entity, reduce misdiagnoses, enhance the early recognition of this phenomenon and encourage proactive pharmacological intervention.