Beyond the consensus criteria: multiple cognitive profiles in amyotrophic lateral sclerosis?

Area of Science:

• Neurology
• Neuropsychology
• Cognitive Science

Background:

• Current consensus identifies two primary non-motor cognitive profiles in amyotrophic lateral sclerosis (ALS): behavioral (ALSbi) and dysexecutive (ALSci).
• These classifications may not encompass the full spectrum of cognitive impairment in non-demented ALS patients.

Purpose of the Study:

• To investigate if neuropsychological performance patterns in ALS patients reveal additional clinical syndromes beyond established phenotypes.
• To identify distinct clusters of cognitive deficits using a data-driven approach.

Main Methods:

• Principal component analysis (PCA) was applied to comprehensive neuropsychological data from 71 non-demented ALS patients.
• PCA aimed to identify clusters of highly correlated neuropsychological tests, indicating distinct performance patterns.

Main Results:

• PCA revealed three main clusters of test performance.
• Two clusters aligned with the recognized ALSbi and ALSci profiles.
• A third cluster emerged, characterized by deficits in social cognition, language, and memory, affecting 24% of patients. Notably, 15% of these patients had unclassifiable profiles based on current criteria.

Conclusions:

• A distinct third dimension of cognitive impairment in ALS patients exists, encompassing language, social cognition, and episodic memory.
• This finding suggests that current classifications of non-motor manifestations in ALS may be incomplete.