Clinical Characteristics of Late-Onset Parkinson Disease

Recently, Diederich et al¹ reported greater motor impairment and a less aggressive treatment strategy in patients with Parkinson disease (PD) who had old-age onset compared with middle-age onset. To test whether these findings applied to a different population with comparable characteristics, we carried out a similar analysis in a group of patients from the PD registry of the Department of Neurology at the University Hospital of Patras (Patras, Greece).

Forty patients with PD who had old-age onset (mean ± SD age at onset, 76.1 ± 3.7 years; range, 74-89 years; mean ± SD duration of PD, 4.5 ± 4.0 years; 65% men) were matched for sex and disease duration (within ±2 years) with 40 patients with PD and middle-age onset (mean ± SD age at onset, 56.1 ± 6.8 years; range, 46-66 years; mean ± SD duration of PD, 4.7 ± 4.0 years). The diagnosis of PD was made according to criteria from the Parkinson's Disease Society brain bank.²

In agreement with the findings of Diederich et al,¹ the Unified Parkinson's Disease Rating Scale (UPDRS)³ motor and axial impairment scores were higher in patients with PD who had old-age onset compared with middle-age onset. Patients with old-age onset tended to have higher rigidity and bradykinesia scores than those with middle-age onset, but it did not reach statistical significance (Table 1). The UPDRS II and UPDRS total scores were also significantly higher in patients with old-age onset compared with middle-age onset. Hoehn and Yahr scale⁴ and Schwab and England scale⁵ scores did not differ significantly between patients with earlier or later onset. Similar to the results of Diederich and colleagues, patients with old-age onset were more likely to receive levodopa monotherapy and less likely to receive dopamine agonists alone. However, combination therapy was almost equally prescribed in all patients. Dyskinesias were more frequent in patients with middle-age onset, in agreement with other studies.⁶ The specific comorbidities recorded in our study did not differ significantly between the 2 groups. Auditory and visual deficits, which accounted for most of the difference between comorbidities in the study by Diederich and colleagues were not recorded. Dementia was more frequently diagnosed in patients with old-age onset, whereas depression was encountered almost equally in the 2 groups.

Our results seem to confirm that the course of PD in patients who have old-age onset is not milder compared with that of patients with an onset in middle age. Although neurologists in our department appear reluctant to prescribe dopamine agonists alone in elderly patients, they use them frequently as an additional treatment, which probably reflects a local prescribing pattern. A higher proportion of patients with dementia (although not statistically significant) in the late-onset group may merely reflect the higher prevalence of dementia in the elderly population. The identification of different clinical features in patients with old-age onset could be important for identifying treatment options and prognosis because such patients are frequently excluded from randomized controlled trials.