Topographical orientation in Parkinson’s disease: the role of embodiment in performing the VR Road Map Test

Recent findings in neuroscience allow increasing insights in the interplay of perception and action determining knowledge acquisition. One of the findings for spatial cognition consists on the adoption of the embodied perspective, that considers knowledge as unfolded through action: stored in the form of motor responses and acquired by the act of "doing". In order to understand the impairment of spatial orientation in Parkinson’s disease, we tested 49 Parkinson’s subjects (23 female, 26 male; age 50–80 years) in a virtual version of the Money’s Road Map test (Morganti et al. 2009). Thirty-two patients are classified as Parkinson’s without dementia (PD) (MMSE: M = 28.94; sd = 1.7); 17 patients as Parkinson’s with dementia (PDD) (MMSE: M = 25.59; sd = 1.8). They were compared with a control group of healthy subjects (n = 68). We found significant differences in performing the VR Road Map Test between Parkinson’s patients (PD: M = 5.5; sd = 4.1; PDD: M = 2.18; sd = 1.8) and controls subjects (M = 15.53 SD 11.35). Moreover a 3(group) 9 4(age cohort) ANOVA revealed a significant difference between groups in the different age cohorts (Group*Age Cohort F (12.00) p \ 0.005). PD-patients showed reduced ability to navigate in comparison to healthy controls of same age (p \ 0.001), PDD- patients showed reduced topographical orientation compared to PD- patients (p \ 0.001). Results will be discussed in the light of the assumption that the allocentric/egocentric (embodied) perspective, requested by the virtual reality version of the Road Map Test, appears to be relevant for topographical orientation.