Neuropsychological Dysfunction in Chronic Fatigue Syndrome and the Relation Between Objective and Subjective Findings

Objective: This study aimed to explore the relationship between self-reported cognitive difficulties, objective neuropsychological test performances, and subjective health complaints in chronic fatigue syndrome (CFS) and to examine the degree of impaired cognitive functions. Method: A total of 236 consecutively recruited outpatients. 18-62 years of age, completed the tests. Self-administered questionnaires were used for assessing fatigue, pain. depression. anxiety and subjective cognitive complaints (Everyday Memory Questionnaire [EMQ]). Also, neuropsychological tests, that is. Stroop I-IV, California Verbal Learning Test-Second Edition (CVLT-II) learning and delay, Wechsler Adult Intelligence Scale-Third Edition (WAIS -III) Letter Number (L-N) Sequencing, and the Paced Auditory Serial Addition Task were performed to examine whether these objective measures correlated with subjective complaints and were compared with normative data. Results: There was a trend of association (p < .05) between the unadjusted EMQ with Stroop IV (inhibition and shifting attention), the CVLT learning and delay (verbal learning and memory), and the WAIS -III L-N Sequencing (working memory), but none were statistically significant at the .001 level. The EMQ was positively associated with fatigue. pain. and depression (p < .001). The PASAT (working memory) was negatively associated with pain (p < .001). Between 21% and 38% of the patients performed below the 1.5-SD cutoff for clinically significant impairment on the Stroop tests. Conclusion: The self-reported cognitive performance was not strongly associated with the objective cognitive performances on any domains in patients with CFS. Patients with higher fatigue. pain, and depression levels reported greater subjective cognitive difficulties, as well as higher pain related to lower objective working memory function. The CFS patients had problems mainly in the domains of psychomotor speed and attention measured by the objective neuropsychological tests.