Longitudinal evolution of non-motor symptoms according to age at onset in early Parkinson's disease.

OBJECTIVE

To investigate the longitudinal change of non-motor symptoms according to the age at onset in Parkinson's disease (PD).

METHODS

This cohort study using the Parkinson's Progression Markers Initiative data included 405 patients with early PD. They were classified into late-onset (age at onset ≥ 70 years, n = 63), middle-onset (50 to 69 years, n = 268), and young-onset (<50 years, n = 74) groups. Non-motor symptoms were assessed with well-validated instruments covering neuropsychiatric, sleep-related, and autonomic symptoms yearly over 5 years of follow-up. Dopamine transporter imaging was also performed at baseline and the 1-, 2-, and 4-year follow-up visits.

RESULTS

The late-onset group had a mean decrease of 0.35 more points per year in the Montreal Cognitive Assessment (MoCA) scores (p = 0.008) and increases of 0.32 more points in the 15-item Geriatric Depression Scale scores (p = 0.002) and 0.72 more points in the State-Trait Anxiety Inventory-state scores (p = 0.022) compared to the middle-onset group. The young-onset group had a mean decrease of 0.22 fewer points per year in the MoCA scores (p = 0.002) than the middle-onset group. The other non-motor progression did not differ among the groups. No significant differences were found between the late-onset, middle-onset, and young-onset groups in the changes of striatal DAT binding ratios.

CONCLUSION

Compared to middle-onset PD, late-onset PD showed a faster progression of cognitive impairment along with depression and anxiety, and young-onset PD showed a slower progression of cognitive impairment in the early phases of the disease. These differences do not appear to be associated with the longitudinal changes in striatal dopaminergic activities.