Cognitive dysfunction associated with chronic or recurrent infection with Epstein-Barr virus.

Abstract

Twenty-two subjects with chronic/recurrent Epstein-Barr Virus (EBV) infection were compared with 22 controls to assess cognitive dysfunction. Subjects were compared on 15 measures of cognitive functioning from the Boston Diagnostic Aphasia Examination, Perceptual Speed, Wechsler Adult Intelligence Scale-Revised, Finger Tapping Test, Stroop Test, Trail-Making Test, Wisconsin Card Sorting Test and Revised Wechsler Memory Scale. They also were compared on measures of depression including the Beck Depression Inventory, Minnesota Multiphasic Personality Inventory (MMPI) depression subscale and SCL-90-Revised depression subscale. Group differences were assessed using discriminant analysis. Only some measures were included in this analysis, i.e. percent retention on Visual Reproduction and Logical Memory subtests of the Revised Wechsler Memory Scale, differential between time scores and between error scores on conditions three and two of the Stroop Test and total number of errors and perseverative errors on the Wisconsin Card Sorting Test. The Beck Depression Inventory was included to statistically remove depression effects from cognitive performances. Remaining measures were administered for exploratory and/or comparative purposes only. Results from discriminant analysis revealed significant group differences on the Beck, but not on any cognitive measure either before or after removal of depression effects. However, direction of group differences on cognitive measures occurred as expected. Also, a post-hoc multivariate analysis of variance revealed significant group differences on MMPI scales 1, 2 and 3 with EBV subjects showing higher elevations. Significant group differences also occurred on MMPI scale 7. Two categories of explanation for results are offered. The first suggests that cognitive deficits were missed due to shortcomings in study design. Remaining hypotheses address the possibility that no cognitive deficits occur with chronic/recurrent EBV infection. Suggestion for why EBV patients complain of cognitive deficits include discussion of hysteroid tendencies and intensification of sensations by a focus on somatic processes. The usefulness of assuming a multifactorial basis for symptoms associated with chronic/recurrent EBV infection, and the importance of abandoning the either/or approach of earlier investigators to hypothesizing about etiology, are discussed.