The aim of this study was to determine whether an egocentric topographical working memory (WM) deficit is present in the early stages of Alzheimer's disease (AD) with respect to other forms of visuospatial WM. Further, we would investigate whether this deficit could be present in patients having AD without topographical disorientation (TD) signs in everyday life assessed through an informal interview to caregivers. Seven patients with AD and 20 healthy participants performed the Walking Corsi Test and the Corsi Block-Tapping Test. The former test requires memorizing a sequence of places by following a path and the latter is a well-known visuospatial memory task. Patients with AD also performed a verbal WM test to exclude the presence of general WM impairments. Preliminary results suggest that egocentric topographical WM is selectively impaired, with respect to visuospatial and verbal WM, even without TD suggesting an important role of this memory in the early stages of AD.

Body representation is a complex process involving different sources of top-down and bottom-up information. Processing the position and the relations among different body parts is necessary to build up a specific body representation, that is, the visuospatial body map (or topological map of the body). Here we aimed to investigate how the loss of peripheral or central information affects this representation by testing amputee and brain-damaged patients. Thirty-two unilateral brain-damaged patients (i.e., left-brain-damaged patients and right-brain-damaged patients who were or were not affected by personal neglect), 18 lower limb amputees and 15 healthy controls took part in the study. The topological body map was assessed by means of the "Frontal body-evocation subtest" (Daurat-Hmeljiak, Stambak, & Berges, 1978), in which participants have to put tiles (each representing a body part) on a small wooden board on which a head is depicted. Group statistical analysis showed that in amputee patients the loss of peripheral information about the right lower limb affects the ability to represent relations among different body parts as much as the loss of top-down information in brain-damaged patients with personal neglect. Single case analysis of brain-damaged patients without personal neglect showed that the topological map of the body was deficient in 1 right-brain-damaged and 2 left-brain-damaged patients. Studying amputee and brain-damaged patients together allowed us to highlight the importance of visuospatial information about one's own limbs and the role of both hemispheres (not only the left one) in creating an efficient topological body representation.

Following the triadic taxonomy, three different body representations do exist, namely the body semantics, the body structural representation and the body schema. The development of these body representations has been widely investigated in toddlers, but several issues remain to be addressed in school age. To assess age- and gender-related changes in different body representations and to investigate the presence of different patterns of interplay between these representations of the body, 90 children (age range: 7–10) and 37 young adults (age range: 18–35) were given tasks assessing the body semantics, the body structural representation and the body schema as well as control tasks. The present results suggested that the body schema, evaluated by means of hand laterality judgments, was still not completely developed in school-aged children, whereas the body structural representation reached an adult-like pattern by the age of 9–10 years. Finally, body semantics was fully developed in school-aged children. These findings were discussed in terms of their theoretical implications, for a better understanding of body representation development; also, implications for clinical assessment of body representation disorders were discussed.