Striatal dopaminergic denervation and gait in healthy adults.

Parkinsonian-like motor impairments are common in the elderly. The etiology of these symptoms in the absence of clinically diagnosable Parkinson's disease (PD) is unknown. The aim of this study was to evaluate associations between striatal dopaminergic neuron losses that occur with aging and gait in healthy adults. Forty healthy subjects aged 21-85 years old underwent [(11)C]-beta-CFT dopamine transporter (DAT) positron emission tomography (PET). Subjects were also asked to walk in a gait laboratory at their own pace. Gait variables of interest included average general spatiotemporal characteristics of walking patterns and their standard deviation reflecting gait variability. Segmented nonlinear models were used to investigate the relationship between striatal DAT activity and gait while controlling for age. Gait speed, cadence, and single and double support durations were significantly slower than age-based predictions in adults with lower striatal DAT activity (P < 0.05). After controlling for age, striatal DAT activity was not significantly associated with average step length and step width and with gait variability. We conclude that dopaminergic physiology influences certain aspects of gait independent of age-related changes. The findings of this study may augur novel therapeutic approaches to treating gait disorders in the elderly.