This study compared the ability of clinical and ecologic simulation measures to predict performance on environment-specific criterion measures of wayfinding. Thirty-one unilateral stroke participants comprised the right and left hemisphere groups (16 patients with left sided and 15 patients with right sided strokes). Participants completed a battery of clinical tasks (e.g., traditional paper-and-pencil measures of visualization, mental rotation, visual memory and spatial orientation), ecologic simulations (e.g., slide route recall and visualization of a model town from differing perspectives) and environment specific criterion tasks (e.g., route recall and directional orientation). The groups were equivalent in age, sex, education, handedness, and weeks since stroke. Both ecologic simulation tasks were found to have fairly good internal consistency and 1 simulation task was significantly related to real world wayfinding. Of the clinical tasks, 1 visual memory test was correlated with a directional orientation criterion task, but none correlated with route navigation ability. Results are consistent with literature purporting the benefits of ecologic simulation tasks as predictors of real world functioning. (JINS, 2001, 7, 675–682.)

Visuospatial processing is accomplished in distinct neuroanatomic pathways. One such pathway, known as the where pathway, involves a dorsal route through magnocellular thalamic cells to occipital and parietal cortices and conveys location and motion information. A second pathway, known as the what pathway, involves a ventral route through parvocellular thalamic cells to occipital and temporal cortices and conveys color and form information. The where pathway is thought to be responsible for processing spatial relationships while the what pathway is responsible for object identification. Children with early-treated congenital hypothyroidism (CH) who exhibit selective visuospatial deficits may provide a good model to study the differential development of these pathways. Because children with CH lacked thyroid hormone at a time when needed by developing brain regions such as the parietal cortex, these children may be affected to a greater degree on tasks tapping where but not what pathway processing. We tested this hypothesis via retrospective analysis of their performance on 6 spatial tasks. Compared were 49 adolescents with CH and 49 matched control participants. On the basis of confirmatory factor analysis, tasks were assigned to either where or what pathway groupings. A repeated measures ANOVA showed the CH group was impaired relative to a normal comparison group only on where pathway tasks. Regression analyses indicated that severity of early hypothyroidism was the strongest predictor of where pathway processing but had no effect on what pathway tasks. It is concluded that thyroid hormone is required during late gestation and early life for the normal development of the where aspects of visuospatial processing. (JINS, 2001, 7, 556–562.)

The current study follows a recent paper reporting that individuals with autism were just as susceptible to visual illusions as those without autism (Ropar & Mitchell, 1999). The possibility that individual differences may account for the failure to replicate Happé's (1996) findings is explored by presenting a battery of visuospatial tasks thought to measure weak central coherence (embedded figures, block design, Rey complex figure test). Participants with autism were distinguished by relatively good performance on visuospatial tasks, though there was no superiority effect in those with Asperger's syndrome. Performance on the visuospatial battery did not significantly predict susceptibility to illusions in various participant groups, including those with autism and Asperger's syndrome. This suggests that perception of illusions and performance on visuospatial tasks may rely on different mechanisms. The implications for the theory of weak central coherence are discussed.