Assessing Mental Imagery to Evaluate Topographical Disorientation: Group Study and Preliminary Normative Data.

There is currently no specific neuropsychological test assessing spatial orientation abilities, despite the fact that navigational deficits are heavily incapacitating in daily life. This lack of a specific test is probably due to theoretical vagueness of concepts in this field and important interindividual differences in spatial cognition. Here we propose a new standardized test assessing a fundamental component of spatial orientation-namely, mental imagery: Adequate mental visualization of the environment is indeed a necessary step in finding one's way. Two conditions of mental imagery were proposed to a group of 58 patients with a right cerebral lesion and to a control group (N = 117). The 1st condition assessed global, categorical imagery; the 2nd evaluated precise, metric imagery. We evaluated performance of the 2 groups in the 2 conditions and the impact of sociodemographic variables (age, gender, education). Results show that the right-lesioned patients presented difficulties in mental imagery, especially in the metric condition. Moreover, the data indicate a global impact of age and a milder effect of education on mental imagery abilities. Although sample sizes are sometimes small, preliminary normative data are given; already in the present form, they are usable and informative in assessing mental imagery, and more generally, spatial orientation, in a clinical practice.