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Parkinson's disease (PD) is preceded by a premotor phase of unknown duration. Dopaminergic degeneration during this phase may lead to subtle cognitive and behavioural changes, such as decreased novelty seeking. Consequently, premotor subjects might be most comfortable in jobs that do not require optimal dopamine levels, leading to an overrepresentation in structured and predictable occupations, or an underrepresentation in artistic occupations. In a case-control study, 750 men with PD (onset ≥40 years) and 1300 healthy men completed a validated questionnaire about their lifetime occupational status. Occupations were classified using the RIASEC model. Odds ratios (ORs) were calculated for the conventional and artistic categories, both for the most recent occupation before symptom onset, and for the very first occupation. Because farming has been associated with a PD risk, ORs were calculated separately for farming. A reduced risk of PD was found for men with an artistic occupation late in life (OR 0.14, 95% CI 0.04-0.53), while an artistic first occupation did not prevent PD (OR 0.72, CI 0.32-1.59). Conventional occupations showed no increased risk (recent: OR 1.07, CI 0.70-1.64; first: OR 1.14, CI 0.77-1.71). In support of previous reports, farming was associated with an increased risk of PD (recent: OR 2.6, CI 1.4-4.6; first: OR 2.7, CI 1.6-4.5). PD patients were older than controls, but various statistical corrections for age all lead to similar results. Artistic occupations late in life are associated with a reduced risk of subsequent PD, perhaps because this reflects a better preserved dopaminergic state. No initial occupation predicted PD, suggesting that the premotor phase starts later in life.

Various ancillary investigations can assist clinicians in the differential diagnosis of patients with parkinsonism. It is unknown which test offers greatest diagnostic value in clinical practice. We included 156 consecutive patients with parkinsonism, but with an initially uncertain diagnosis. At baseline, all patients underwent extensive clinical testing and the following ancillary investigations: brain magnetic resonance imaging (MRI); (123)I-iodobenzamide single photon-emission computed tomography (IBZM-SPECT); analysis of cerebrospinal fluid (CSF); and anal sphincter electromyography (EMG). The final diagnosis was established after 3-year follow-up by two movement disorder specialists, according to international consensus criteria. We determined the diagnostic value by comparing the baseline clinical parameters and ancillary studies with the final diagnosis. Out of a potential 138 parameters, univariate analysis identified 35 parameters that discriminated Parkinson's disease (PD, n = 62) and atypical parkinsonism (AP, n = 94), with AUC of 0.55-0.81. Stepwise logistic regression showed that the combination of tandem gait, axial UPDRS subscore, slow saccadic eye movements and dysphagia yielded an AUC of 0.93, adjusted for optimism. The combination of tandem gait and axial UDPRS subscore yielded an AUC of 0.90. None of the ancillary investigations alone or in combination with clinical testing improved this clinically based diagnostic accuracy, not even in a subgroup of patients with the greatest diagnostic uncertainty at baseline. Our study demonstrates that a comprehensive set of clinical tests provides good accuracy to differentiate PD from AP. Our results also suggest that routine MRI, IBZM-SPECT, CSF analysis and anal sphincter EMG do not improve this diagnostic accuracy. Future work should evaluate the possible diagnostic value of more advanced diagnostic tests.

Various signs on routine brain MRI can help differentiate between Parkinson's disease (PD) and the various forms of atypical parkinsonism (AP). Here, we evaluate what routine brain MRI contributes to the clinical diagnosis, in both early and advanced disease stages. We performed a prospective observational study in 113 patients with parkinsonism, but without definite diagnosis upon inclusion. At baseline, patients received a structured interview, comprehensive and standardized neurological assessment, and brain MRI. The silver standard diagnosis was made after 3 years of follow-up (PD n = 43, AP n = 57), which was based on disease progression, repeat standardized neurological examination and response to treatment. The clinical diagnosis was classified as having either 'low certainty' (lower than 80%) or 'high certainty' (80% or higher). The added diagnostic yield of baseline MRI results were then studied relative to clinical neurological evaluation at presentation, and at follow-up. Sensitivity and specificity for separating AP from PD were calculated for all potentially distinguishing MRI abnormalities described previously in the literature. MRI abnormalities showed moderate to high specificity but limited sensitivity for the diagnosis of AP. These MRI abnormalities contributed little over and above the clinically based diagnosis, except when the clinical diagnosis was uncertain. For these patients, presence of putaminal or cerebellar atrophy was particularly indicative of AP. Routine brain MRI has limited added value for differentiating between PD and AP when clinical certainty is already high, but has some diagnostic value when the clinical diagnosis is still uncertain.

Patients with Parkinson's disease (PD) are likely to become physically inactive, because of their motor, mental, and emotional symptoms. However, specific studies on physical activity in PD are scarce, and results are conflicting. Here, we quantified daily physical activities in a large cohort of PD patients and another large cohort of matched controls. Moreover, we investigated the influence of disease-related factors on daily physical activities in PD patients. Daily physical activity data of PD patients (n = 699) were collected in the ParkinsonNet trial and of controls (n = 1,959) in the Longitudinal Aging Study Amsterdam (LASA); data were determined using the LAPAQ, a validated physical activity questionnaire. In addition, variables that may affect daily physical activities in PD were recorded, including motor symptoms, depression, disability in daily life, and comorbidity. Patients were physically less active; a reduction of 29% compared to controls (95% CI, 10-44%). Multivariate regression analyses demonstrated that greater disease severity, gait impairment, and greater disability in daily living were associated with less daily physical activity in PD (R (2) = 24%). In this large study, we show that PD patients are about one-third less active compared to controls. While disease severity, gait, and disability in daily living predicted part of the inactivity, a portion of the variance remained unexplained, suggesting that additional determinants may also affect daily physical activities in PD. Because physical inactivity has many adverse consequences, work is needed to develop safe and enjoyable exercise programs for patients with PD.

Drooling (saliva loss) is a frequently reported symptom in patients with Parkinson's disease (PD), but an accurate estimate of the prevalence of drooling is lacking. The aim of this study was to systematically review the prevalence of drooling in published research papers. A systematic PubMed and CINAHL search was done, including studies published until January 2009. Eight studies were found, presenting prevalence rates of drooling based on responses of PD patients to questionnaires. The statistical heterogeneity was highly significant (P < 0.0001), with prevalence rates ranging from 32 to 74%. The pooled prevalence estimate with random effect analysis was of 56% (95% CI 44-67) for PD patients and 14% (95% CI 3-25) for healthy controls; the pooled relative risk (RR) with random effect analysis was 5.5 (95% CI 2.1-14.4). All studies reported data of community dwelling idiopathic PD patients, with a mean age around 65 years and mild PD in 50-60% of the cases. Heterogeneity was mainly caused by differences in definition or frequency of drooling. The highest prevalence rates included nocturnal drooling where others noted only diurnal drooling. Analysis of the data of two studies showed that drooling is reported frequently by 22-26% of the patients. Prevalence rates were lower in milder PD patients. The summarized findings demonstrate that drooling can be present in half of all PD patients. In about a quarter of PD patients, drooling appears to be a frequently occurring problem. We recommend to report drooling in future studies with more detailed consideration of severity, frequency and nocturnal versus diurnal complaints.

We examined the effect of bilateral subthalamic nucleus stimulation on levodopa-resistant balance impairment in 14 patients with Parkinson's disease and 18 matched controls. Instability was quantitatively assessed using standardized multidirectional dynamic posturography. Patients were tested after taking a suprathreshold dose of levodopa, both with stimulators turned on and off. Patients with stimulators turned off were more unstable than controls following backward directed perturbations. Overall, patients' instability did not improve with STN stimulation, and considerable inter-individual variability was noted. Of note, marked levodopa- resistant axial motor symptoms before surgery correlated with an adverse treatment effect. We conclude that STN stimulation does not alleviate levodopa-resistant postural instability in Parkinson's disease.

Background: To determine the diagnostic value of the clapping test, which has been proposed as a reliable measure to differentiate between progressive supranuclear palsy (where performance is impaired) and Parkinson's disease (where performance should be normal)., Methods: Our study group included a large cohort of consecutive outpatients including 44 patients with Parkinson's disease, 48 patients with various forms of atypical parkinsonism and 149 control subjects. All subjects performed the clapping test according to a standardized protocol., Results: Clapping test performance was normal in all control subjects, and impaired in 63% of the patients with atypical parkinsonism. Unexpectedly, we also found an impaired clapping test in 29% of the patients with Parkinson's disease., Conclusion: Although the proportion with an abnormal clapping test was significantly higher in atypical parkinsonism, the clapping test did not discriminate well between Parkinson's disease and atypical parkinsonism.

Earlier studies on the association between health systems' economic performance and public satisfaction were based on between-countries comparisons. This approach can be challenged as it ignores the fact that subjective measures like 'satisfaction' might be relative. Cohort analysis is a way of dealing with this issue as it focuses on within-countries comparisons. The association between change in satisfaction with health care systems and change in economic performance, determined by an output-orientated constant returns to scale DEA Malmquist model over the period 1995 to 2000/2002 using OECD data, is explored. The results show that a health care systems' economic performance is not associated with public satisfaction.

Myositis specific autoantibodies (MSAs) are proven to be specific for myositis compared with other inflammatory connective tissue diseases. Their specificity compared, however, with other neuromuscular disorders, which are included in the differential diagnosis of patients in whom the diagnosis myositis is under consideration, is unknown. We prospectively screened sera from 107 patients with various neuromuscular disorders for the most common MSAs and compared the results with the findings in a group of 97 myositis patients, published previously. Special attention was paid to patients with facioscapulohumeral muscular dystrophy (FSHD), an autosomal dominant muscle disease with marked inflammation in skeletal muscle tissue. Only one patient in the neuromuscular disorders group tested positive for an MSA, compared with 41 in the myositis group, resulting in a specificity of 99%. None of the FSHD patients tested positive. We conclude that the tested MSAs are highly specific for myositis and that they are not merely associated with muscle inflammation.