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 (ß = 2.12, p < .05), social ability (ß = 1.73, p < .05), analytic skills, (ß = 3.12, p < .01) and humanities knowledge (ß = 1.83, p<.01) were associated with better performance on the ECAS, while jobs involving more exposure to environmental hazards (ß=-2.57, p < .01) and technical skills (ß=-2.16, p<.01) were associated with lower ECAS scores. Jobs requiring more precision skills (ß = 1.91, p < .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.

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

Background: Amyotrophic Lateral Sclerosis (ALS) is a heterogeneous neurodegenerative condition featuring variable degrees of motor decline and cognitive impairment. We test the hypothesis that cognitive reserve (CR), defined by occupational histories involving more complex cognitive demands, may protect against cognitive decline, while motor reserve (MR), defined by working jobs requiring complex motor skills, may protect against motor dysfunction. Methods: Individuals with ALS (n=150) were recruited from the University of Pennsylvania's Comprehensive ALS Clinic. Cognitive performance was evaluated using the Edinburgh Cognitive and Behavioral ALS Screen (ECAS), and motor functioning was measured using Penn Upper Motor Neuron (PUMNS) scale and ALS Functional Rating Scales (ALSFRS-R). The Occupational Information Network (O*NET) Database was used to derive 17 factors representing distinct worker characteristics, occupational requirements, and worker requirements, which were related to ECAS, PUMNS, and ALSFRS-R scores using multiple linear regression. Results: A history of working jobs involving greater reasoning ability (ß=2.12, p<.05), social ability (ß=1.73, p<.05), analytic skills, (ß=3.12, p<.01) and humanities knowledge (ß=1.83, p<.01) was associated with better performance on the ECAS, while jobs involving more exposure to environmental hazards (ß=-2.57, p<.01) and technical skills (ß=-2.16, p<.01) were associated with lower ECAS Total Scores. Jobs involving greater precision skills (ß=1.91, p<.05) were associated with greater disease severity on the PUMNS. Findings for the ALSFRS-R did not survive correction for multiple comparisons. Discussion: Jobs requiring greater reasoning abilities, social skills, and humanities knowledge were related to preserved cognitive functioning consistent with CR, while jobs with greater exposure to environmental hazards and technical demands were linked to poorer cognitive functioning. We did not find evidence of MR as no protective effects of occupational skills and requirements were found for motor symptoms, and jobs involving greater precision skills and reasoning abilities were associated with worse motor functioning. Occupational history provides insight into protective and risk factors for variable degrees of cognitive and motor dysfunction in ALS.