Multiple system atrophy is distinguished from idiopathic Parkinson's disease by the arginine growth hormone stimulation test.

OBJECTIVE: Multiple system atrophy (MSA) may be difficult to distinguish from idiopathic Parkinson's disease (PD). Our aim was to evaluate the accuracy of the arginine growth hormone (GH) stimulation test in distinguishing between MSA and PD in large populations of patients. METHODS: We measured the GH response to arginine in 69 MSA (43 MSAp [parkinsonism as the main motor feature] and 26 MSAc [cerebellar features predominated]) patients, 35 PD patients, and 90 healthy control subjects. We used receiver-operating curve analysis to establish the arginine cutoff value that best differentiated between MSA and PD. RESULTS: The GH response to arginine was significantly lower (p < 0.01) in MSA than in either PD patients or control subjects. At a cutoff level of 4 microg/L, arginine distinguished MSAp from PD with a sensitivity and specificity of 91% and MSAc from PD with a sensitivity of 96% and specificity of 91%. The arginine test had a positive predictive value for MSA of 95%. The GH response to arginine was not affected by disease duration or severity, MSA motor subtype, pyramidal signs, response to dopaminergic therapy, or magnetic resonance imaging findings. INTERPRETATION: The GH response to arginine differentiates MSA from PD with a high diagnostic accuracy. The results suggest an impairment of cholinergic central systems modulating GH release in MSA.

Pramipexole versus sertraline in the treatment of depression in Parkinson's disease: a national multicenter parallel-group randomized study.

In addition to treating the motor symptoms of Parkinson's disease, the dopamine agonist pramipexole has shown an antidepressant effect. The trials, however, included patients with motor complications, raising the question of whether the antidepressant benefit represented only a treatment-related motor improvement. To address this issue, we have conducted a 14-week randomized trial comparing pramipexole with an established antidepressant in patients without motor complications. At seven Italian centers, 67 Parkinsonian outpatients with major depression but no history of motor fluctuations and/or dyskinesia received open-label pramipexole (at 1.5 to 4.5 mg/day) or sertraline (at 50 mg/day). In both groups, the Hamilton Depression Rating Scale (HAM-D) score decreased throughout 12 weeks of treatment, but in the pramipexole group the proportion of patients who recovered, as defined by a final HAM-D score

The long-acting dopamine receptor agonist cabergoline in early Parkinson's disease: final results of a 5-year, double-blind, levodopa-controlled study.

OBJECTIVES: Cabergoline is an ergoline derivative with a very long half-life that allows once-daily administration and the potential for more continuous stimulation of dopaminergic receptors than is possible with other dopamine receptor agonists (DAs). The aim of this study was to evaluate whether the possible advantage resulting from a more sustained dopaminergic effect of cabergoline would translate into delayed onset of motor complications, compared with levodopa, in patients with newly diagnosed Parkinson's disease. STUDY DESIGN AND METHODS: This study was a double-blind, multicentre trial that compared cabergoline and levodopa as initial therapy for Parkinson's disease. A total of 419 levodopa-, DA- and selegiline-naive patients with newly diagnosed Parkinson's disease were randomised to receive either cabergoline (n = 211) or levodopa (n = 209). Treatment was titrated to an optimal dose over a period of up to 24 weeks and then continued at this dose until the study endpoint (confirmed motor complications) or up to a maximum of 5 years. At years 1-5, the cabergoline group was receiving cabergoline at average daily doses ranging from 2.8-2.9 mg, with added levodopa at mean daily doses ranging from 322 mg at year 1 to 431 mg at year 5; over the same period, the levodopa group was receiving daily levodopa doses of 784 mg. Thus, patients in the cabergoline group received <50% levodopa than patients in the levodopa group. RESULTS: Motor complications were significantly delayed (p = 0.0175) and occurred less frequently in cabergoline-treated patients than in levodopa-treated patients (22.3% vs 33.7%). Cox model proportional hazards regression analysis showed that the relative risk of developing such complications was >50% lower (0.46; p < 0.001) in the cabergoline group compared with the levodopa group. In particular, development of dyskinesias was markedly delayed in the cabergoline group and occurred in 9.5% of patients compared with 21.2% in the levodopa group (p < 0.001). Among patients not requiring supplemental levodopa, the frequency of motor complications was three times higher with levodopa (15.5% of 110 patients) than with cabergoline (5.3% of 76 patients). Among patients who did need supplemental levodopa, motor complications were more frequent in the levodopa arm (54.1% of 98 patients) than in the cabergoline arm (31.9% of 135 patients). Consistent improvements relative to baseline in average Unified Parkinson's Disease Rating Scale (UPDRS) daily living activities and motor function sections, and in Clinical Global Impression severity of illness and physician- and patient- rated global improvement scores, were seen in both treatment groups, with maximal effects occurring within 2 years. However, levodopa treatment was associated with a significantly (p < 0.001) greater improvement in motor disability (as measured by the UPDRS motor score) over time, with mean values of 13.8 versus 12.9 in the cabergoline versus levodopa arm recorded at 1 year, 18.6 versus 17.2 at 3 years and 19.2 versus 16.3 at 5 years, respectively. While the overall frequency of adverse events was similar in the two groups, the cabergoline-treated group experienced marginally, but not significantly, higher frequencies of nausea, vomiting, dyspepsia and gastritis (37.4% vs 32.2% in the levodopa group) and of dizziness and postural hypotension (31.3% vs 24% in the levodopa group). Cabergoline-treated patients also experienced a significantly higher frequency of peripheral oedema (16.1% vs 3.4%, respectively; p < 0.0001). The cabergoline and levodopa groups had similar rates of sleepiness (17.5% vs 18.3%, respectively) and hallucinations (4.8% vs 4.4%, respectively); in an elderly population subset, hallucinations were reported in 7.1% and 6.5% of patients taking cabergoline and levodopa, respectively. Adverse events generally occurred more frequently in female patients (with the exception of dyskinesias, hyperkinesias and hallucinations, which occurred more frequently in men) and in the elderly. CONCLUSION: This study showed that, compared with levodopa, initial therapy with cabergoline in patients with Parkinson's disease is associated with a lower risk of response fluctuations at the cost of a marginally reduced symptomatic improvement and some tolerability disadvantages that are mostly limited to a significantly higher frequency of peripheral oedema.