In a sample of 50 individuals with multiple sclerosis (MS), participants able to work full-time ('W'), those who reduced their hours ('CB') and those who were unemployed ('NW') were compared on demographic and disease variables and symptoms that the participants identified as being responsible for their work status change. The NW group had significantly greater physical disability than the other two groups and significantly more fatigue than the W group. The CB group had significantly more years of education and higher occupational prestige ratings than the NW group. The W group reported significantly greater mood disturbance compared with the NW group. Employment status was unrelated to age, gender, full scale IQ estimate, disease duration, diagnosis duration or cognitive functioning. Ninety per cent of the CB group reported that fatigue was a primary symptom responsible for their work status change, whereas 86% of the NW group reported that broad physical/neurological symptoms were responsible for their change in work status.
Background
Prodromal Huntington disease (prHD) is associated with a myriad of cognitive changes, but the domains that best predict time to clinical diagnosis have not been studied. This is a notable gap because some domains may be more sensitive to cognitive decline, which would inform clinical trials.
Objectives
The present study sought to characterize cognitive domains underlying a large test battery and for the first time, evaluate their ability to predict to time to diagnosis.
Methods
Participants included gene-negative and gene-positive prHD participants who were enrolled in the PREDICT-HD study. The CAG/Age Product (CAP) score was the measure of an individual’s genetic signature. A factor analysis of 18 tests was performed to identify sets of measures or latent factors that elucidated core constructs of tests. Factor scores were then fit to a survival model to evaluate their ability to predict time to diagnosis.
Results
Six factors were identified: 1) speed/inhibition, 2) verbal working memory, 3) motor planning/speed, 4) attention-information integration, 5) sensory-perceptual processing, and 6) verbal learning/memory. Factor scores were sensitive to a worsening of cognitive functioning in prHD, typically more so than performances on individual tests comprising the factors. Only the motor planning/speed and sensory-perceptual processing factors predicted time to diagnosis, after controlling for CAP scores and motor symptoms.
Conclusions
The results suggest that motor planning/speed and sensory-perceptual processing are important markers of disease prognosis. The findings also have implications for using composite indices of cognition in preventive HD trials where they may be more sensitive than individual tests.
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