Cognitive reserve in ALS: the role of occupational skills and requirements.

Objective: Amyotrophic Lateral Sclerosis (ALS) is a heterogeneous neurodegenerative condition featuring variable degrees of motor and cognitive impairment. We assessed the impact of specific, empirically derived occupational skills and requirements on cognitive and motor functioning in ALS.

Methods: Individuals with ALS (n = 150) were recruited from the University of Pennsylvania's Comprehensive ALS Clinic. The Edinburgh Cognitive and Behavioral ALS Screen (ECAS) measured cognition, and the Penn Upper Motor Neuron (PUMNS) and ALS Functional Rating Scales (ALSFRS-R) measured motor symptoms. We derived 17 factors representing distinct occupational skills and requirements from the Occupational Information Network (O*NET), which were related to cognitive and motor scores using multiple linear regression.

Results: Occupational roles involving greater reasoning ability (β = 2.12,  < .05), social ability (β = 1.73,  < .05), analytic skills, (β = 3.12,  < .01) and humanities knowledge (β = 1.83, <.01) were associated with better performance on the ECAS, while jobs involving more exposure to environmental hazards (β=-2.57,  < .01) and technical skills (β=-2.16, <.01) were associated with lower ECAS scores. Jobs requiring more precision skills (β = 1.91,  < .05) were associated with greater motor dysfunction on the PUMNS.

Conclusions: Occupational histories involving more cognitively complex skills and activities were related to preserved cognitive functioning in ALS consistent with the cognitive reserve hypothesis, while jobs with greater exposure to environmental hazards and technical demands were linked to poorer cognitive functioning. Jobs involving more repetitive movements were associated with worse motor functioning, possibly due to overuse. Occupational history provides insight into protective and risk factors for variable degrees of cognitive and motor dysfunction in ALS.