Relation between neuropsychological impairment and functionaldisability in patients with chronic fatigue syndrome

OBJECTIVES—To examine the relation betweenneuropsychological impairment and functional disability in patientswith chronic fatigue syndrome, and determine whether the relation isindependent of psychiatric factors.
METHODS—The subjects were 53 patients with chronicfatigue syndrome and 32 healthy controls who did not exerciseregularly. Subjects were administered a structured psychiatricinterview and completed questionnaires focusing on depression andfunctional disability. They also completed a battery of standardisedneuropsychological tasks focusing on the cognitive domains thatpatients with chronic fatigue syndrome experience as particularlydifficult: memory (verbal and visual), and attention/concentration. Atest score was defined as failing when it was 2 SD below the meanof the healthy controls after controlling for demographic factors.
RESULTS—Those patients with chronic fatiguesyndrome with higher numbers of failing neuropsychological test scoresreported significantly more days of general inactivity in the pastmonth than those with fewer failing scores. This result remainedsignificant even after partialling out the contribution of the presenceof a comorbid axis I psychiatric episode and the overall level ofdepressive symptomology. Patients with failing verbal memory scoreswere particularly functionally disabled compared with those withpassing scores.
CONCLUSION—A relation was found between cognitiveimpairment and functional disability which could not be explainedentirely on the basis of psychiatric factors.