Cognitive Reserve in Parkinson's Disease without Dementia: ß-Amyloid and Metabolic Assessment.

BACKGROUND: Cognitive reserve (CR) is the mismatch between preserved cognition and neuropathological damage. Amyloidopathy in Parkinson's disease (PD) could be associated with faster progression to dementia, but the putative protective effect of CR is unknown. OBJECTIVES: To evaluate the effect of CR on ß-amyloid burden and brain metabolism in non-demented PD subjects. METHODS: Participants with PD (n = 53) underwent a clinical evaluation, [18 F]-fluorodeoxyglucose and [18 F]-flutemetamol positron emission tomography magnetic resonances, and were classified according to CR. The metabolic pattern of 16 controls was compared to PD subjects. RESULTS: The PD subjects showed hypometabolism mainly in the bilateral posterior cortex. Superior-CR subjects (n = 22) exhibited better cognitive performance, increased amyloid burden, and higher metabolism in several right hemisphere areas compared to low-medium-CR subjects (n = 31). CONCLUSIONS: Higher CR in non-demented PD is associated with better cognitive performance, which might reduce vulnerability to the effect of ß-amyloid. Whether superior CR leads to protection against metabolic deterioration, and predominantly right hemisphere involvement, deserves further exploration.

Levodopa-Induced Dyskinesias are Frequent and Impact Quality of Life in Parkinson's Disease: A 5-Year Follow-Up Study.

BACKGROUND: Levodopa-induced dyskinesias (LID) are frequent in Parkinson's disease (PD). OBJECTIVE: To analyze the change in the frequency of LID over time, identify LID related factors, and characterize how LID impact on patients' quality of life (QoL). PATIENTS AND METHODS: PD patients from the 5-year follow-up COPPADIS cohort were included. LID were defined as a non-zero score in the item "Time spent with dyskinesia" of the Unified Parkinson's Disease Rating Scale-part IV (UPDRS-IV). The UPDRS-IV was applied at baseline (V0) and annually for 5 years. The 39-item Parkinson's disease Questionnaire Summary Index (PQ-39SI) was used to asses QoL. RESULTS: The frequency of LID at V0 in 672 PD patients (62.4 ± 8.9 years old; 60.1% males) with a mean disease duration of 5.5 ± 4.3 years was 18.9% (127/672) and increased progressively to 42.6% (185/434) at 5-year follow-up (V5). The frequency of disabling LID, painful LID, and morning dystonia increased from 6.9%, 3.3%, and 10.6% at V0 to 17.3%, 5.5%, and 24% at V5, respectively. Significant independent factors associated with LID (P < 0.05) were a longer disease duration and time under levodopa treatment, a higher dose of levodopa, a lower weight and dose of dopamine agonist, pain severity and the presence of motor fluctuations. LID at V0 (ß = 0.073; P = 0.027; R2 = 0.62) and to develop disabling LID at V5 (ß = 0.088; P = 0.009; R2 = 0.73) were independently associated with a higher score on the PDQ-39SI. CONCLUSION: LID are frequent in PD patients. A higher dose of levodopa and lower weight were factors associated to LID. LID significantly impact QoL.