Cortical Thinning Associated with Mild Cognitive Impairment in Parkinson's Disease (P4.103)

Objective: To investigate patterns of cortical thinning associated with mild cognitive impairment (MCI) in a large sample of Parkinson’s disease (PD) patients and to explore relationships with cognitive deficits. Background: Parkinson's disease (PD) is often associated to cognitive deficits. Cortical thickness analysis might be a valid instrument to investigate the structural correlates of such deficits in PD. Methods: We studied 108 PD patients (54 without cognitive impairment [PD-ncog], and 54 with MCI [PD-MCI]), and 41 healthy controls. All subjects underwent structural magnetic resonance imaging (MRI) and clinical and neuropsychological evaluation. The cortical thickness analysis was performed using Freesurfer. Results: Compared to PD-ncog and healthy controls, PD-MCI showed cortical thinning of superior temporal sulcus, inferior parietal, middle and superior temporal gyri bilaterally, as well as left frontal pole and supramarginal gyrus. Bilateral precentral gyri and left enthorinal cortex and superior frontal gyrus as well as right inferior frontal gyrus revealed reduced thickness only when PD-MCI were compared to controls. When compared to PD-ncog, PD-MCI showed additional cortical thinning of the postcentral gyri bilaterally. PD-ncog did not show differences relative to controls. Lower scores on global cognition tasks were associated with widespread cortical thinning. Cortical thinning of fronto-temporo-parietal regions was correlated to lower executive and visual spatial scores. Conclusions: Our results demonstrate that MCI in PD has a neuroanatomical substrate of cortical thinning. We showed that cortical atrophy correlates with the performance in neuropsychological test involving executive functions and visual spatial abilities that typically are deficient in PD patients with cognitive impairment. The fronto-temporo-parietal atrophy pattern that was identified in this study might be used as a surrogate marker of cognitive impairment in nondemented PD. Supported by: Italian Ministry of Health (Grant #GR091577482).