Premorbid Educational Attainment and Long-Term Motor Prognosis in Parkinson's Disease

Background: Premorbid educational attainment is a well-known proxy of reserve, not only with regard to cognition, but also to motor symptoms. Objective: In the present study, we investigated the relationship between educational attainment and long-term motor prognosis in patients with Parkinson's disease (PD). Methods: We analyzed 466 patients with de novo PD without dementia who underwent dopamine transporter (DAT) scans and were followed up more than 2 years. Patients were divided into three groups: low education (years-of-education =6, n = 125), intermediate education (6 <years-of-education < 12, n = 108), and high education (years-of-education =12, n = 233). The effects of educational attainment on the development of levodopa-induced dyskinesia (LID), wearing-off, and freezing-of-gait, and longitudinal increase in levodopa-equivalent doses (LEDs) were assessed. Results: Multiple regression analysis showed that higher education was associated with milder parkinsonian symptoms after adjusting for DAT availability in the posterior putamen. Survival analysis showed that the rate of LID was significantly lower in the high education group than in the low education group (HR = 0.565, p = 0.010). A linear mixed model showed that the high education group had lower LED than the low education group until a period of 30 months; however, this difference in LED was not observed thereafter. Conclusion: The present study demonstrated that premorbid educational attainment has protective effects on the development of LID in patients with PD and has sparing effects on LED during the early treatment period. These results suggest that high educational attainment has a beneficial effect on motor outcomes in patients with PD.