title: White matter correlates of neuropsychological dysfunction in systemic lupus erythematosus.
abstract: Patients diagnosed with Systemic Lupus Erythematosus have similar levels of neuropsychological dysfunction (i.e., 20-50%) as those with Neuropsychiatric Systemic Lupus Erythematosus (NPSLE). We hypothesized a gradient between cognition and white matter integrity, such that strongest brain-behavior relationships would emerge in NPSLE, intermediate in non-NPSLE, and minimal in controls. We studied thirty-one patients (16 non-NPSLE; 15 NPSLE), ranging in age from 18 to 59 years old (100% female), and eighteen age and gender matched healthy controls. DTI examinations were performed on a 1.5T scanner. A broad neuropsychological battery was administered, tapping attention, memory, processing speed, and executive functioning. The Total z-score consisted of the combined sum of all neuropsychological measures. In control subjects, we found no significant FA-Total z-score correlations. NPSLE, non-NPSLE, and control subjects differed significantly in terms of Total z-score (NPSLE = -2.25+/-1.77, non-NPSLE = -1.22+/-1.03, Controls = -0.10+/-.57; F = 13.2, p<.001). In non-NPSLE subjects, FA within the right external capsule was significantly correlated with Total z-score. In NPSLE subjects, the largest FA-Total z-score clusters were observed within the left anterior thalamic radiation and right superior longitudinal fasciculus. In subsequent analyses the largest number of significant voxels linked FA with the Processing Speed z-score in NPSLE. The current results reflect objective white matter correlates of neuropsychological dysfunction in both NPSLE and (to a lesser degree) in non-NPSLE. non-NPSLE and NPSLE subjects did not differ significantly in terms of depression, as measured by the GDI; thus, previous hypotheses suggesting moderating effects of depression upon neuropsychological performance do not impact the current FA results.
authors.affiliation: Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico, United States of America. rex.jung@gmail.com
authors.forename: Rex E
authors.initials: RE
authors.lastname: Jung
authors.forename: Robert S
authors.initials: RS
authors.lastname: Chavez
authors.forename: Ranee A
authors.initials: RA
authors.lastname: Flores
authors.forename: Clifford
authors.initials: C
authors.lastname: Qualls
authors.forename: Wilmer L
authors.initials: WL
authors.lastname: Sibbitt
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Roldan
mesh_terms: D000293:Adolescent; D000328:Adult; D001519:Behavior / Q000502:physiology; D001921:Brain / Q000502:physiology* / Q000503:physiopathology; D002493:Central Nervous System Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000503:physiopathology*; D008297:Male; D016555:Matched-Pair Analysis; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D055815:Young Adult