Background: Pisa syndrome (PS) is a lateral flexion of the trunk frequently associated with Parkinson's disease (PD). The pathophysiology of PS remains unclear, but the role of cognitive deficits has been postulated. Methods: We included 12 consecutive PD patients with PS (PS+) and 12 PD patients without PS (PS-) matched for gender, age, level of education, PD duration, and PD stage. As primary aim, we compared the neuropsychological scores of 16 tests evaluating 6 cognitive domains between PS+ and PS-. Additionally, we evaluated the presence of misperception of the trunk position in PS+, defined as a mismatch between the objective vs. subjective evaluation of the trunk bending angle >5°, and analyzed whether a correlation exists between the misperception of the trunk position and alterations in the visual-spatial abilities. Results: PS+ group showed significantly worse performances in the visual-spatial abilities (p: 0.008), attentional domain (p: 0.001), and language domain (p: 0.023). No differences were found in the other cognitive domains nor in the general cognitive assessment. All PS+ patients showed a misperception of the trunk position, with an average underestimation of the trunk bending angle of 11.7° ± 4.3. The degree of misperception of the trunk position showed a trend toward a correlation with the visual-spatial scores (p: 0.089). Conclusions: The study reveals an association between PS and specific cognitive alterations, suggesting a possible link between the abnormal posture of PD patients with PS and their cognitive functions.
Keywords: Parkinson's disease; Pisa syndrome; cognition; neuropsychology; self-perception.