“…With regards to the pathogenesis of the stooped posture, some experiments suggest that an abnormality of the trunk alignment perception may have a causal role. For example, in situations where the support surface is shifted from a purely horizontal position, PD patients have difficulty in re-orienting themselves to a vertical position without the aid of visual cues (Vaugoyeau et al, 2007;Proctor et al, 1964). Because of their defective axial kinaesthesia, patients might also falsely perceive their subjective vertical to be shifted backward, forcing them to adopt a stooped posture (Kitamura et al, 1993).…”