Cognition and motor phenotypes in ALS: a retrospective study

Area of Science:

• Neuroscience
• Neurology
• Clinical Research

Background:

• Amyotrophic lateral sclerosis (ALS) presents with heterogeneous motor symptoms, often described by upper versus lower motor neuron involvement.
• Understanding cognitive variations across these motor phenotypes is crucial for comprehensive patient care.

Purpose of the Study:

• To investigate and compare cognitive function across distinct motor phenotypes of amyotrophic lateral sclerosis (ALS).
• To determine the prevalence of frontotemporal cognitive deficits in different ALS patient groups.

Main Methods:

• 124 ALS patients were categorized into classical, bulbar, predominant-upper motor neuron (PUMN), and predominant-lower motor neuron (PLMN) phenotypes.
• Cognitive function was assessed using the Edinburgh Cognitive and Behavioural ALS Screen (ECAS).
• Functional status was measured by the ALS Functional Rating Scale-Revised (ALSFRS-R), with cognitive/behavioral phenotyping using revised ALS-FTD criteria.

Main Results:

• Cognitive impairments (defective ECAS-total scores) were observed in all ALS phenotypes, ranging from 15.4% in bulbar to 36.8% in PUMN.
• Classical and PUMN ALS patients exhibited poorer performance on ECAS-total, ALS-specific, Fluency, and Executive measures compared to PLMN patients.
• A correlation was found between worse ALSFRS-R scores and poorer ECAS-total scores in the classical ALS group.

Conclusions:

• Frontotemporal cognitive deficits are more prevalent in PUMN and classical ALS phenotypes.
• Cognitive deficits in classical ALS are associated with disease severity.
• These deficits, however, are also present in PLMN ALS phenotypes, highlighting the widespread cognitive impact of ALS.