Verbal as well as spatial working memory predicts visuospatial processing in male schizophrenia patients.
BACKGROUND
Visuospatial processing (VSP) is impaired in schizophrenia. Recent studies showed significant associations between the Judgment of Line Orientation (JLO) test, a common test of VSP and Verbal (VWM) as well as Spatial (SWM) working memory. VWM and SWM show different associations with various genes so subgroups of patients with similar VSP but different WM impairment profiles may vary in genetic associations. In this study we investigated the relationship among VSP, VWM and SWM.


METHODS
Sixty seven men with schizophrenia and 51 healthy men completed computerized JLO and tests of VWM (digit span), and SWM (Dot test). Tests of attention (CPT) and psychomotor processing speed (Finger Tap) were also included.


RESULTS
Patients' performance was impaired on all tests. Multivariate regression with JLO as the outcome variable and VWM, SWM, attention, psychomotor processing speed and interactions between group and these variables, as predictors showed significant contribution of VWM and SWM. The model explained 34.4% of the variance (R(2)=0.344).


CONCLUSIONS
VSP, as measured by JLO, receives independent contributions from VWM and SWM. Patient subgroups matched for VSP may differ in the relative contributions and impairments of VWM and SWM. Such heterogeneity may limit the usefulness of VSP in genetic studies. The possibility that WM may be more useful than VSP in this regard deserves further study.
Silver
Henry
H
Brain Behavior Laboratory, Sha'ar Menashe Mental Health Center, Mobile Post Hefer 38814, Israel. mdsilver@tx.technion.ac.il
Goodman
Craig
C
D000328:Adult; D001288:Attention / Q000502:physiology; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013028:Space Perception / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology*