A mixed-methods study of cognitive performance in persons with multiple sclerosis: Association between neuropsychological test performance and interviews about daily cognitive functioning.

BACKGROUND: Cognitive difficulties are commonly reported in persons with multiple sclerosis (MS), however, self-reports of cognition often do not correspond well to objective neuropsychological test performance. The use of qualitative interviews can allow for persons with MS to describe in more detail how their cognitive function is impacted in daily life while also taking into consideration personal and environmental influences. No study to our knowledge has examined the association between objective neuropsychological test performance and qualitative interview reports of daily cognitive function. Such information could help explain the reported lack of correspondence between these two methods of evaluating cognitive function in MS.

OBJECTIVE: To investigate the relationship between objective neuropsychological test performance and qualitative interview reported daily cognitive function in persons with MS .

METHODS: Convergent parallel mixed-methods design whereby 12 persons with MS (mean age= 47, 9 female, 7 relapsing-remitting MS) took part in a 2-hour neuropsychological assessment [including the Brief International Cognitive Assessment for MS (BICAMS)] followed by a semi-structured qualitative interview probing daily cognitive functioning. Interview data were analysed using thematic analysis. Interview codes and themes were compared with neuropsychological performance on respective cognitive domains and between those with and without cognitive impairment on the BICAMS.

RESULTS: Based on the qualitative interview data, the most commonly reported difficulties were related to memory, word finding, and processing speed but only 43%, 0%, and 33% of the individuals reporting these deficits actually demonstrated impairment on the respective/ corresponding neuropsychological measures. Eleven of the twelve participants reported the use of strategies to manage cognitive difficulties. The most frequently reported strategies used were related to fatigue management. Personal (age, fatigue) and environmental factors (pressure of daily responsibilities, availability of support) were reported as influencers of daily cognitive function. Three of the 12 participants were classified as cognitively impaired on the BICAMS but they did not differ from those who were non-impaired with respect to use of strategies, and influence of personal and environmental factors on daily cognitive functioning.

CONCLUSIONS: Interview-reported daily cognitive difficulties did not correspond well to objective neuropsychological performance. Greater emphasis should be placed on utilizing and developing objective neuropsychological measures that have greater sensitivity, particularly to word finding difficulties in MS, and to the incorporation of personal and environmental factors into the interpretation of neuropsychological test results. As almost all participants reported the use of cognitive strategies, we feel greater emphasis needs to be placed on patient education of evidence-based strategies, particularly focused on highly reported impacted word finding and processing speed abilities.