Nonmotor symptoms common in early-stage PD

By Lauretta Ihonor, medwireNews reporter

Nonmotor symptoms (NMS) occur in nearly all individuals with Parkinson's disease (PD), Italian study results suggest.

And the use of conventional dopamine agonists does not appear to have a marked effect on these symptoms, which remain stable throughout the early stages of PD, add the authors.

The assessment of NMS in 91 newly diagnosed PD patients (mean age 57.6 years) revealed the presence of one or more NMS in 98% of the group before they started dopamine agonist therapy (baseline).

The NMS rate remained similar at 2 years after the introduction of dopaminergic therapy, at a rate of 96%, report Paolo Barone (University of Salerno) and team. This, say the authors, indicates that dopamine replacement therapy does not have as noticeable an effect on NMS as it does on motor impairment.

NMS seen among the group included orthostatic hypotension, nausea, hallucinations, sleep disturbance, and psychosis. Sleep disturbance and neuropsychiatric complaints remained most common throughout the study period.

Of note, all patients included in the study had PD defined using the UK Parkinson's Disease Society Brain Bank Diagnostic Criteria, a clinical PD history of less than 2 years, and no history of dopaminergic therapy.

As reported in the Journal of Neurology, Neurosurgery, and Psychiatry, although the rates of most NMS remained stable over the 2-year study period, the proportion of patients with weight change increased significantly from 7.7% at baseline to 18.7% by the study end.

"This result is in line with previous studies suggesting a close relationship between dopamine agonist use and weight gain," say the authors.

The frequency of self-reported depression fell from 43.9% at baseline to 21.1% at 2 years after dopaminergic therapy introduction. The authors say that this finding supports existing theories that dopamine agonist-related activation of limbic dopamine D3 receptors produces noticeable antidepressant effects.

"Further longitudinal studies are required to assess both NMS occurrence and severity in larger samples of PD patients, and their correlation to dopaminergic therapy," conclude Barone et al.

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