Motor function and the probability of prodromal Parkinson's disease in older adults.

BACKGROUND: Identification and characterization of Parkinson's disease (PD) in its prodromal stage is crucial.

OBJECTIVE: The objective of this study was to investigate the association between motor function and the probability of prodromal PD in a community-dwelling older population.

METHODS: We used data from a population-based cohort of older adults (HELIAD study). Subjective motor function was evaluated with a 12-item motor symptoms questionnaire and objective motor function indirectly with a physical activity questionnaire and two gait speed tests. The probability of prodromal PD was calculated according to the Movement Disorder Society research criteria for n = 1731 without PD. Regression multiadjusted models were used to investigate the associations between each motor measure and prodromal PD probability.

RESULTS: For each unit increase in motor symptoms score and for each kcal/kg/day lower energy expenditure (corresponding to 20 minutes of light walking/day for a 75-kg man) there was a 27% and 3% higher probability for prodromal PD, respectively (P < 0.001). Having at least one subjective motor symptom increased the odds of having possible/probable prodromal PD (n = 49; P < 0.05). Including subjective and indirect motor variables in the same model showed that both (symptoms and physical activity) contributed significantly to the model (P < 0.01). Excluding subthreshold parkinsonism from the calculation showed that gait speed less than 0.8 m/s was also associated with a higher prodromal PD probability score (P < 0.001).

CONCLUSIONS: Subjective motor symptoms as well as simple objective motor measures of physical activity or gait speed are associated with a higher probability of prodromal PD in older adults. These data may serve to enable the early identification of prodromal PD cohorts, particularly if they are confirmed in longitudinal studies. © 2019 International Parkinson and Movement Disorder Society.