Cognitive-Nigrostriatal Relationships in De Novo, Drug-Naive Parkinson's Disease Patients: A [I-123]FP-CIT SPECT Study

To unveil cognitive-nigrostriatal correlations in Parkinson's disease (PD), 30 de novo, drug-naive PD patients and 15 patients with essential tremor (Controls, CTR) underwent a neuropsychological (NPS) battery and brain SPECT with [I-123]Ioflupane, as a biomarker of nigrostriatal function. Automatic extraction of uptake at caudate and putamen level was counted through the BasGan software, also allowing partial volume effect correction Because of the multicollinearity among neuropsychological tests and among SPECT variables, factor analysis was applied to 16 neuropsychological scores, moreover. the four SPECT variables were merged into a mean SPECT value (mSPECT) Factor analysis identified four NPS factors a dys-executive (NPS-EX), a visuospatial (NPS-VS), a verbal memory (NPS-VM), and a mixed (NPD-MIX) factor In PD group. there were inverse correlations between UPDRS-III score and both NPS-VS (P < 001) and mSPECT (P < 0.05). and a direct correlation between mSPECT and NPS-EX (P < 0.05) Post hoc analysis showed a direct correlation between NPS-EX and caudate Uptake in both hemispheres (P < 005) Moreover. inverse correlations were found between UPDRS-III and, respectively, putamen uptake in the less affected hemisphere (P < 001), and putamen and caudate uptake in the more affected hemisphere (P < 0.05) In CTR, no correlation was found between mSPECT and either NPS or GDS values Nigro-caudate function affects executive capabilities in PD but not in CTR. which appears to be unrelated to the disease molol severity at its onset Inslead. PD motor severity is related to nigro-putaminal impairment and visuospatial dysfunction The role of these data as predictive features of cognitive decline and eventually dementia remains to be emablished in logitudinal studies. (C) 2010 Movement Disorder Society