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

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.

研究目的：原发性侧索硬化症（PLS）是一种罕见的运动神经元疾病，其特征为上运动神经元（UMN）的退行性变，导致缓慢进展的痉挛。关于其是否为一种独立的疾病或肌萎缩侧索硬化症（ALS）的一个亚型，一直存在争议。在ALS中，常常并发前额叶痴呆症（FTD），其发生率约为±15%。然而，认知和行为变化通常不被视为PLS的一部分。研究方法：旨在报告基于转诊队列的PLS患者的临床发现和FTD的发生频率，并概述相关文献。研究结果：在我们的队列中，181名PLS患者中有6名（3.3%）发展为FTD。在文献中，已有少数PLS伴FTD的案例报道，且仅有少数小型研究调查了PLS的认知功能。然而，当这些研究被汇总时，出现了一个模式，即±2%的患者被诊断为FTD，22%的患者存在前额叶功能障碍。研究结论：这些发现表明PLS是FTD-MND连续体的一部分，并倾向于将其视为ALS的一个亚型。然而，它并非局限于（孤立的上运动神经元）表型。