This study aims to evaluate the representation of action peripersonal space (PPS) in subjects suffering from unilateral segmental exclusion syndrome of the upper limb compared to healthy control subjects. Segmental exclusion is defined by non-use or under-use of a limb segment without central nervous system damage. The study hypothesizes that this syndrome leads to a modification (shrinkage) of the PPS representation. Participants will perform reachability judgments in a Virtual Reality (VR) environment.
Segmental exclusion syndrome often occurs after limb trauma and manifests as a neglect-like behavior of peripheral origin, sometimes associated with Complex Regional Pain Syndrome (CRPS). The study explores whether the lack of limb use affects the representation of peripersonal space (PPS)-the space immediately surrounding the body where interactions with objects occur. The study is monocentric, observational, with a matched control group. Participants will undergo: Clinical assessment (questionnaires on pain, anxiety, body perception, and kinesiophobia). A Virtual Reality (VR) test (approx. 40 minutes). In VR, participants will judge whether a cylinder presented at different distances and angles is reachable without moving (Perceived Reachable Distance - DMA-p). This will be compared to their Real Reachable Distance (DMA-r). The goal is to measure the error of judgment to assess PPS representation and check for correlations with body schema disturbances or functional impairment
Study Type
OBSERVATIONAL
Enrollment
60
Participants wear an Oculus Quest 2 VR headset. They first perform a motor task to measure Real Reachable Distance (DMA-r). Then, they perform a perceptual task where they must judge, without moving, if a virtual object is reachable (DMA-p). The test evaluates different spatial planes (front, 45° right, 45° left) and heights (shoulder, navel).
Institut Régional de Médecine Physique et de Réadaptation (IRR), Centre Louis Pierquin.
Nancy, France
Judgment Error of Reachability
Difference between Perceived and Real Reachable Distance. Calculated as the normalized difference between the Perceived Maximum Reachable Distance (DMA-p) and the Real Maximum Reachable Distance (DMA-r). Formula: ((DMA-p - DMA-r) / DMA-r) \* 100. This assesses the overestimation or underestimation of the peripersonal space.
Time frame: Day 1 (During the 40-minute VR assessment)
Body Perception Disturbance Score
Assessed using the Bath CRPS Body Perception Disturbance Scale (French version). Scores range from 0 to 57, with higher scores indicating greater disturbance.
Time frame: Day 1 (Before VR task)
Functional Impairment Score (400-Point Hand Assessment)
Evaluation of functional hand use (score and number of perturbed items).
Time frame: Day 1
Anxiety and Depression Score (HAD)
Hospital Anxiety and Depression Scale. Scores range from 0 to 21 for each dimension (Anxiety and Depression).
Time frame: Day 1
Kinesiophobia Score (Tampa Scale)
Tampa Scale for Kinesiophobia (TSK). Assesses fear of movement. Scores range to 68; \>40 indicates significant kinesiophobia.
Time frame: Day 1
Pain Catastrophizing Score (PCS)
Pain Catastrophizing Scale. Scores range from 0 to 52.
Time frame: Day 1
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