Background: The investigation of disease progression provides important information on the dynamics of cell death in Parkinson disease (PD).Objective: To determine the progression of dopaminergic impairment in PD with the use of positron emission tomography (PET).Design: Longitudinal prospective cohort study with a follow-up period of 64.5 ± 22.6 months (mean ±SD).Setting: University hospital. Patients: A consecutive sample of patients with PD (N=31; age at symptom onset, 53.6 ± 11.3 years) with a wide range of symptom duration and severity at the time of study entry. Interventions: Investigation by serial fluorodopa F 18 ([ 18 F]fluorodopa) PET as a marker for striatal dopaminergic function. Main Outcome Measures: Changes in caudate and putaminal [ 18 F]fluorodopa influx constant (K i ) values.Results: In patients with PD, the decline rate of putaminal [ 18 F]fluorodopa K i correlated inversely with disease duration before study inclusion (r=−0.46, P =.01) and positively with baseline K i values (r =0.44, P =.01), indicating a negative exponential loss of dopamine neurons. Annual disease progression rates ranged from 4.4% in the caudate nucleus to 6.3% in the putamen. A mean preclinical period of 5.6±3.2 years was calculated with symptom onset at a putaminal K i threshold of 69% from controls. Assuming nonlinear progression kinetics, the required sample size to prove neuroprotection with the use of [ 18 F]fluorodopa PET was found to increase strongly with the preceding symptom duration of study subjects. Conclusion:These data suggest that the neurodegenerative process in PD follows a negative exponential course and slows down with increasing symptom duration, contradicting the long-latency hypothesis of PD.

Summary: Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a highly effective surgical treatment in patients with advanced Parkinson's disease (PD). Because the STN has been shown to represent an important relay station not only in motor basal ganglia circuits, the modification of brain areas also involved in nonmotor functioning can be expected by this intervention. To determine the impact of STN-DBS upon the regional cerebral metabolic rate of glucose (rCMRGlc), we performed positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) in eight patients with advanced PD before surgery as well as in the DBS on-and off-conditions 4 months after electrode implantation and in ten age-matched healthy controls. Before surgery, PD patients showed widespread bilateral reductions of cortical rCMRGlc versus controls but a hypermetabolic state in the left rostral cerebellum. In the STN-DBS on-condition, clusters of significantly increased rCMRGlc were found in both lower thalami reaching down to the midbrain area and remote from the stimulation site in the right frontal cortex, temporal cortex, and parietal cortex, whereas rCMRGlc significantly decreased in the left rostral cerebellum. Therefore, STN-DBS was found to suppress cerebellar hypermetabolism and to partly restore physiologic glucose consumption in limbic and associative projection territories of the basal ganglia. These data suggest an activating effect of DBS upon its target structures and confirm a central role of the STN in motor as well as associative, limbic, and cerebellar basal ganglia circuits.

Background and Purpose-Pneumonia has been estimated to occur in about one third of patients after acute stroke. Only limited data are available on stroke-associated pneumonia (SAP) in specialized neurological intensive care units (NICUs). Methods-We enrolled 124 patients with acute stroke who were treated at our university hospital NICU in a prospective observational study. Incidence rates and risk factors of SAP and long-term clinical outcome were determined. Results-SAP incidence was 21% with a spectrum of pathogens, which is comparable to previously published data on general ICU patients. Mechanical ventilation, multiple location, and vertebrobasilar stroke, as well as dysphagia and abnormal chest x-ray findings, were identified as risk factors for the disease. SAP patients showed higher mortality rates than nondiseased subjects (acute, 26.9% versus 8.2%; long-term, 35.3% versus 14.3%) and a significantly poorer long-term clinical outcome (Barthel Index, 50.5Ϯ42.4 versus 81.5Ϯ27.8; Rankin Scale, 3.5Ϯ1.7 versus 2.2Ϯ1.6). Conclusions-Our data underline the considerable epidemiological and prognostic impact of SAP for the treatment of acute stroke patients in a specialized NICU setting. They demonstrate that the occurrence of SAP deteriorates clinical outcome in these patients. Our results allow us to identify high-risk stroke patients at time of NICU admission in whom the use of preventive treatment strategies is most promising.

A kindred from South Tyrol (northern Italy) with familial, adult-onset parkinsonism of pseudo-dominant inheritance and mutations in the parkin gene was recently described. To gain insight into basal ganglia dysfunction in this form of hereditary parkinsonism, positron emission tomography (PET) with 18-fluorodopa (FDOPA) and 11C-raclopride (RAC) was performed in 5 affected family members and 5 asymptomatic relatives with proven compound heterozygous or heterozygous parkin mutations. Results were compared to findings in healthy control subjects and patients with typical sporadic, idiopathic Parkinson's disease. Similar to findings in the sporadic Parkinson's disease group, presynaptic striatal FDOPA storage was decreased in patients with compound heterozygous parkin mutations, with the most prominent reduction in the posterior part of the putamen. Along with the presynaptic lowered FDOPA uptake, we found a uniform reduction of the striatal 11C-raclopride binding index in all affected family members as compared to asymptomatic family members carrying a heterozygous parkin mutation, sporadic Parkinson's disease, and control subjects. Our PET data provide evidence that parkinsonism in this family is associated with presynaptic dopaminergic dysfunction similar to idiopathic Parkinson's disease pathophysiology, along with alterations at the postsynaptic D2 receptor level. In asymptomatic carriers of a single parkin mutation with an apparently normal allele, we found a mild but statistically significant decrease of mean FDOPA uptake compared to control subjects in all striatal regions. These data indicate a preclinical disease process in these subjects.

Mutations in DJ-1 are less frequent than mutations in Parkin in EOPD patients but should be considered as a possible cause of EOPD. The effect of single heterozygous mutations in DJ-1 on the nigrostriatal system, as described for heterozygous changes in Parkin and PARK6, remains to be elucidated.