Allocentric visuospatial processing in patients with cerebral gliomas: a neurocognitive assessment

Visuospatial function is a central neuropsychological domain which has been neglected in brain tumor studies. This study examined visuospatial functio n in 4 groups of brain tumor patients. The investigation involved 27 adult tumor subjects, 25 of whom had undergone resection and radiotherapy. Ten no rmal adults acted as controls. The 4 tumor groups were based on neuroanatom ic locus - focal lesions were localized to clearly defined visuospatial are as in the left or right posterior parietal cortex or prefrontal cortex. Neuroanatomic and visuospatial assessment parameters were specified: only a llocentric ('mental' or 'conceptual') operations were examined. A theoretic al framework outlined the role of the posterior parietal and prefrontal cor tices in allocentric spatial processing. Six visuospatial tests involving a llocentric operations were applied to patients in whom tumors involved thes e cortical areas. In numerous analyses, the 4 tumor groups showed no significant differences with the control group on the allocentric tests. Between-group comparisons were also not significant. Analyses by gender revealed significant differen ces on shape rotation and line orientation tests, especially in the right h emisphere and parietal groups. Comparisons between focal radiation subgroup s and 'nonradiation' subgroups produced unclear results. The main conclusio ns are that despite the presence of frontal or parietal tumors, (1) allocen tric processing is hardly compromised, and (2) females show lower spatial p erformance than males due to tumor-related effects on a pre-existing patter n of cerebral lateralization. The study emphasizes the need to address visu ospatial function in the neuropsychological study of brain tumor patients, particularly the role of intact spatial processing in this patient group.