A case series of PLS patients with frontotemporal dementia and overview of the literature

Abstract

Objective: Primary lateral sclerosis (PLS) is a rare form of motor neuron disease characterised by UMN degeneration leading to slowly progressive spasticity. Whether it is a separate disease or a subtype of ALS has been debated. In ALS comorbid frontotemporal dementia (FTD) is frequently seen (±15%). However, cognitive and behavioural changes are generally not considered to be a part of PLS. Methods: To report the clinical findings and frequency of PLS patients that developed FTD in a referral-based cohort and provide an overview of the literature. Results: In our cohort six out of 181 (3.3%) PLS patients developed FTD. In the literature a few cases of PLS with FTD have been reported and only a limited number of small studies have investigated cognition in PLS. However, when these studies are summarised a pattern emerges with FTD diagnoses in ±2% and frontotemporal impairment in 22% of patients. Conclusions: These findings suggest that PLS is part of the FTD-MND continuum and would favour viewing it as a subtype of ALS. It is, however, not a restricted (isolated UMN involvement) phenotype.

Keywords:

• Primary lateral sclerosis
• cognition
• frontotemporal dementia
• dementia

Disclosure statement

MAvE serves on the UK Motor Neurone Disease Association biomedical research advisory panel, has consulted for Biogen and has received travel grants from Shire (formerly Baxalta).

Funding

MAvE receives funding from the Netherlands Organisation for Health Research and Development (Veni scheme), The Thierry Latran Foundation and the ALS Foundation Netherlands.

Supplementary material available online