Multiple sclerosis patients of working age who are unemployed or on a reduced work schedule are likely to show considerable cognitive impairment on tests, especially those measuring mental processing speeds, than patients who are more gainfully employed, a review study reports.
This link held true even in patients with little evident physical disability, its researchers said.
The study, “How does cognition relate to employment in multiple Sclerosis? A systematic Review,” was published in the journal Multiple Sclerosis and Related Disorders.
About half of all MS patients are unemployed, a status that affects their social engagement and support. Lack of employment is also linked to depression, anxiety and feelings of loneliness, and unemployed patients report poorer health status and greater difficulties with daily life activities.
Progressive disease, longer disease duration and greater disability — as measured through the Expanded Disability Status Scale (EDSS) — plus older age, and lower levels of education associate with higher unemployment rates in MS patients.
But an exceptionally high rate — 54 percent — of MS patients in Europe are unemployed despite only mild to moderate disability evident on EDSS, with scores up to 3. (A score of 3 or less marks moderate disability in one, or mild disability in three to four, measures of bodily function like movement, swallowing, mental capacities, and bowel/bladder control. Walking is possible without any assistance, including a cane.)
Studies suggest that reasons for this might be independent of physical disability, with some showing that cognitive scores differ among healthy people who are employed, working MS patients (part- and full-time), and those who are unemployed.
Researchers at the University of London conducted a systematic literature review (via PubMed, PSYCH Info, and Web of Science) to assess a possible link between cognition and employment status in patients of working age. Studies included in their review were all peer-reviewed, involved people ages 18 to 65, and had data on standardized neuropsychological testing, and self-reported employment information.
They believe this is the first such review of its kind.
A total of 13 studies met the inclusion criteria — nine in North America, three in Europe, and one in South America — and covered 1,278 MS patients, 972 of whom (76.1%) were women. Most patients (921, 72.1%) had relapsing-remitting MS, 177 (13.8%) had secondary progressive MS, 45 (3.5%) had primary progressive MS, seven (0.5%) had clinically isolated syndrome, and four (0.3%) had progressive relapsing MS. Another 21 people (1.6%) did not know their MS type, and 103 (8.1%) were unspecified.
Four studies also included a total of 263 healthy controls.
The most frequently used measure of cognitive function was the Paced Auditory Serial Addition Test (PASAT), with puts emphasis on processing speed — the time it takes a person to understand and react to information — and immediate recall.
Results showed that unemployed patients or those with reduced working hours did worse on cognitive tests — including assessments of processing speed — than fully employed patients and healthy controls.
Unemployed MS patients also had worse scores in a test of immediate visual memory recall — the Brief Visuospatial Memory Test-Revised — in some studies. Links were likewise reported between unemployment and lesser verbal memory, verbal immediate recall, delayed recall, and learning skills.
Fully employed MS patients, in contrast, performed better on tests of multitasking, verbal fluency, and semantic and phonemic fluency (category and letter recall; measures of executive function in the brain). One study reported that RRMS patients earning a salary performed better in the Wisconsin Card Sorting Test of executive function, particularly in tasks requiring idea generation and set shifting, than did others.
Among the review’s limitations, its authors said, were a lack of distinction made among types of jobs held and a lack of analysis of potential gender differences.
MS patients “who were unemployed or had reduced working hours had a greater level of cognitive impairment than PwMS [people with MS] who remained employed or maintained their working hours,” the researchers concluded, adding “processing speed, immediate and delayed recall, and executive functions were the domains that frequently differentiated employed from unemployed” patients.
They called for further research into “meaningful benchmarks” of impairment that affect employment, and a better sense of a “consistent, objective definition” of employment in MS patients.