In the course of Parkinson's disease (PD), the enteric nervous system (ENS) and parasympathetic nerves are amongst the structures earliest and most frequently affected by alpha-synuclein pathology. Accordingly, gastrointestinal dysfunction, in particular constipation, is an important non-motor symptom in PD and often precedes the onset of motor symptoms by years. Recent research has shown that intestinal microbiota interact with the autonomic and central nervous system via diverse pathways including the ENS and vagal nerve. The gut microbiome in PD has not been previously investigated. We compared the fecal microbiomes of 72 PD patients and 72 control subjects by pyrosequencing the V1-V3 regions of the bacterial 16S ribosomal RNA gene. Associations between clinical parameters and microbiota were analyzed using generalized linear models, taking into account potential confounders. On average, the abundance of Prevotellaceae in feces of PD patients was reduced by 77.6% as compared with controls. Relative abundance of Prevotellaceae of 6.5% or less had 86.1% sensitivity and 38.9% specificity for PD. A logistic regression classifier based on the abundance of four bacterial families and the severity of constipation identified PD patients with 66.7% sensitivity and 90.3% specificity. The relative abundance of Enterobacteriaceae was positively associated with the severity of postural instability and gait difficulty. These findings suggest that the intestinal microbiome is altered in PD and is related to motor phenotype. Further studies are warranted to elucidate the temporal and causal relationships between gut microbiota and PD and the suitability of the microbiome as a biomarker.

http://www.wilson-disease.org/Editor/eWebeditor/uploadfile/20150831170701195.pdf

Gut microbiota are related to Parkinson's disease and clinical phenotype.

The correct diagnosis of Parkinson's disease is important for prognostic and therapeutic reasons and is essential for clinical research. Investigations of the diagnostic accuracy for the disease and other forms of parkinsonism in community-based samples of patients taking antiparkinsonian medication confirmed a diagnosis of parkinsonism in only 74% of patients and clinically probable Parkinson's disease in 53% of patients. Clinicopathological studies based on brain bank material from the UK and Canada have shown that clinicians diagnose the disease incorrectly in about 25% of patients. In these studies, the most common reasons for misdiagnosis were presence of essential tremor, vascular parkinsonism, and atypical parkinsonian syndromes. Infrequent diagnostic errors included Alzheimer's disease, dementia with Lewy bodies, and drug-induced parkinsonism. Increasing knowledge of the heterogeneous clinical presentation of the various parkinsonisms has resulted in improved diagnostic accuracy of the various parkinsonian syndromes in specialised movement-disorder units. Also genetic testing and various other ancillary tests, such as olfactory testing, MRI, and dopamine-transporter single-photon-emission computed-tomography imaging, help with clinical diagnostic decisions.

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474-4422(05)70285-4.pdf

The diagnosis of Parkinson's disease

Background
A Task Force was convened by the EFNS/MDS-ES Scientist Panel on Parkinson's disease (PD) and other movement disorders to systemically review relevant publications on the diagnosis of PD.

Methods
Following the EFNS instruction for the preparation of neurological diagnostic guidelines, recommendation levels have been generated for diagnostic criteria and investigations.

Results
For the clinical diagnosis, we recommend the use of the Queen Square Brain Bank criteria (Level B). Genetic testing for specific mutations is recommended on an individual basis (Level B), taking into account specific features (i.e. family history and age of onset). We recommend olfactory testing to differentiate PD from other parkinsonian disorders including recessive forms (Level A). Screening for pre-motor PD with olfactory testing requires additional tests due to limited specificity. Drug challenge tests are not recommended for the diagnosis in de novo parkinsonian patients. There is an insufficient evidence to support their role in the differential diagnosis between PD and other parkinsonian syndromes. We recommend an assessment of cognition and a screening for REM sleep behaviour disorder, psychotic manifestations and severe depression in the initial evaluation of suspected PD cases (Level A). Transcranial sonography is recommended for the differentiation of PD from atypical and secondary parkinsonian disorders (Level A), for the early diagnosis of PD and in the detection of subjects at risk for PD (Level A), although the technique is so far not universally used and requires some expertise. Because specificity of TCS for the development of PD is limited, TCS should be used in conjunction with other screening tests. Conventional magnetic resonance imaging and diffusion-weighted imaging at 1.5 T are recommended as neuroimaging tools that can support a diagnosis of multiple system atrophy (MSA) or progressive supranuclear palsy versus PD on the basis of regional atrophy and signal change as well as diffusivity patterns (Level A). DaTscan SPECT is registered in Europe and the United States for the differential diagnosis between degenerative parkinsonisms and essential tremor (Level A). More specifically, DaTscan is indicated in the presence of significant diagnostic uncertainty such as parkinsonism associated with neuroleptic exposure and atypical tremor manifestations such as isolated unilateral postural tremor. Studies of [123I]MIBG/SPECT cardiac uptake may be used to identify patients with PD versus controls and MSA patients (Level A). All other SPECT imaging studies do not fulfil registration standards and cannot be recommended for routine clinical use. At the moment, no conclusion can be drawn as to diagnostic efficacy of autonomic function tests, neurophysiological tests and positron emission tomography imaging in PD.

Conclusions
The diagnosis of PD is still largely based on the correct identification of its clinical features. Selected investigations (genetic, olfactory, and neuroimaging studies) have an ancillary role in confirming the diagnosis, and some of them could be possibly used in the near future to identify subjects in a pre-symptomatic phase of the disease.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/ene.12022

EFNS/MDS‐ES recommendations for the diagnosis of Parkinson's disease

Parkinson's disease (PD) is associated with abnormal activity in spatially distributed neural systems mediating the motor and cognitive manifestations of this disorder. Metabolic PET studies have demonstrated that this illness is characterized by a set of reproducible functional brain networks that correlate with these clinical features.The time at which these abnormalities appear is unknown, as is their relationship to concurrent clinical and dopaminergic indices of disease progression. In this longitudinal study, 15 early stage PD patients (age 58.0 � 10.2 years; Hoehn and Yahr Stage 1.2 � 0.3) were enrolled within 2 years of diagnosis. The subjects underwent multitracer PET imaging at baseline, 24 and 48 months. At each timepoint they were scanned with ( 18 F)-fluorodeoxyglucose (FDG) to assess longitudinal changes in regional glucose utilization and in the expression of the PD-related motor (PDRP) and cognitive metabolic covariance patterns (PDCP). At each timepoint the subjects also underwent PET imaging with ( 18 F)-fluoropropyl CIT (FP-CIT) to quantify longitudinal changes in caudate and putamen dopamine transpor- ter (DAT) binding. Regional metabolic changes across the three timepoints were localized using statistical para- metric mapping (SPM). Longitudinal changes in regional metabolism and network activity, caudate/putamen DAT binding, and Unified Parkinson's Disease Rating Scale (UPDRS) motor ratings were assessed using repeated measures analysis of variance (RMANOVA). Relationships between these measures of disease progression were assessed by computing within-subject correlation coefficients. We found that disease progression was associated with increasing metabolism in the subthalamic nucleus (STN) and internal globus pallidus (GPi) (P50.001), as well as in the dorsal pons and primary motor cortex (P50.0001). Advancing disease was also associated with declining metabolism in the prefrontal and inferior parietal regions (P50.001). PDRP expression was elevated at baseline relative to healthy control subjects (P50.04), and increased progressively over time (P50.0001). PDCP activity also increased with time (P50.0001). However, these changes in network activity were slower than for the PDRP (P50.04), reaching abnormal levels only at the final timepoint. Changes in PDRP activity, but not PDCP activity, correlated with concurrent declines in striatal DAT binding (P50.01) and increases in motor ratings (P50.005). Significant within-subject correlations (P50.01) were also evident between the latter two progression indices. The early stages of PD are associated with progressive increases and decreases in regional metabolism at key nodes of the motor and cognitive networks that characterize the illness. Potential disease-modifying therapies may alter the time course of one or both of these abnormal networks.

Changes in network activity with the progression of Parkinson's disease.

FDG PET in the differential diagnosis of parkinsonian disorders

BACKGROUND AND PURPOSE: Quantitative evaluation of midbrain atrophy may be useful in differentiating progressive supranulear palsy (PSP) from Parkinson disease (PD); however, this finding is not specific of PSP, and quantitative measurements are not always practical. We determined whether an abnormal superior midbrain profile (flat or concave aspect) is a more practical diagnostic parameter for PSP. METHODS: MR imaging studies of 25 patients with PSP and 27 with PD were reviewed by means of five parameters: midbrain superior profile on midsagittal T1-weighted images, midbrain atrophy, tegmental abnormal T2 hyperintensity, abnormal T2 putaminal hypointensity or hyperintensity on axial proton density–weighted images. We also measured the anteroposterior diameter of the midbrain on axial T2-weighted sections at the level of the superior colliculus. RESULTS: The finding of an abnormal superior profile of the midbrain had 68% sensitivity and 88.8% specificity. Midbrain atrophy had 68% sensitivity and 77.7% specificity. Tegmental T2 hyperintensity had 100% specificity but poor sensitivity (28%). Only 14.8% of patients with PD and 24% of those with PSP had abnormal putaminal T2 hypointensity; none had proton-density hyperintensity. With PSP, the average midbrain diameter was smaller than that with PD, but an important overlap was observed. Reader discordance was lower for the midbrain superior profile sign (eight of 52 cases); this was similar for tegmental hyperintensity (nine of 52 cases) and higher for midbrain atrophy (16 of 52 cases). CONCLUSION: An abnormal superior profile of the midbrain facilitates the distinction of PSP from PD and may support the clinical differential diagnosis of parkinsonism.

http://www.ajnr.org/content/ajnr/25/6/927.full.pdf

MR Imaging of the Superior Profile of the Midbrain: Differential Diagnosis between Progressive Supranuclear Palsy and Parkinson Disease

Positron emission tomography (PET) and network analysis have been used to identify a reproducible pattern of regional metabolic covariation that is associated with idiopathic Parkinson's disease (PD). The activity of this PD-related pattern can be quantified in individual subjects and used to discriminate PD patients from atypical parkinsonians. Because PET is not commonly available, we sought to determine whether similar discrimination could be achieved using more routine single photon emission computed tomography (SPECT) perfusion methods. Twenty-three subjects with PD (age, 63 ± 9 years), 22 subjects with multiple system atrophy (MSA; age, 64 ± 7 years), and 20 age-matched healthy controls (age, 62 ± 13 years) underwent SPECT imaging of regional cerebral perfusion with Tc-99m ethylene cysteinate dimer (ECD). Using network analysis, we determined whether a PD-related pattern existed in the SPECT data, and whether its expression discriminated PD from MSA patients. Additionally, we compared the accuracy of group discrimination achieved by this pattern with that of the PET-derived PD-related pattern applied to the SPECT data. Network analysis of the SPECT data identified a significant pattern characterized by relative increases in cerebellar, lentiform, and thalamic perfusion covarying with decrements in the frontal operculum and in the medial temporal cortex. Subject scores for this pattern discriminated PD patients from controls (P < 0.01) and from MSA patients (P < 0.03). Subject scores for the PET-derived PD-related pattern computed in the individual SPECT scans more accurately distinguished PD patients from controls (P < 0.005) and from MSA patients (P = 0.0002). A significant PD-related covariance pattern can be identified in SPECT perfusion data. Moreover, the disease related pattern identified previously with PET can be applied to individual SPECT perfusion scans to provide group discrimination between PD patients, healthy controls, and individuals with MSA. Because of significant individual subject overlap between groups, however, the clinical utility of this method in the differential diagnosis of Parkinsonism remains uncertain. © 2002 Movement Disorder Society

Tc-99m ethylene cysteinate dimer SPECT in the differential diagnosis of parkinsonism

The dietary habits of 45 Italian patients with Parkinson's disease (PD) and their spouses were investigated using the EPIC food frequency questionnaire. Average daily energy intake was similar, but PD patients consumed significantly more vegetable proteins and carbohydrates (both +18%; P = 0.01 and P = 0.001, respectively). Daily protein intake, which interferes with levodopa absorption, was 50% higher than the recommended daily allowance (1.2 vs. 0.8 g/kg) in both PD patients and spouses and was significantly higher in patients with moderate/severe symptoms (1.27 ± 0.29 vs. 1.07 ± 0.28 g/kg; P < 0.001). In patients taking levodopa, there was a correlation between daily levodopa dosage and protein intake (P = 0.027). Dietary habits of patients with advanced and/or fluctuating PD should always be checked, with particular reference to protein intake. © 2006 Movement Disorder Society

Protein intake in Parkinsonian patients using the EPIC food frequency questionnaire

Protein intake interferes with levodopa therapy. Patients with advanced Parkinson's disease (PD) should restrict daily protein intake and shift protein intake to the evening. For further reduction of protein intake in the first part of the day, special low-protein products (LPP) should be used instead of normal food products at breakfast and lunch. We studied the efficacy of LPP on postprandial off periods, in PD patients on levodopa therapy. The methods included a randomized, cross-over, single-blind, pilot clinical trial comparing a 2-month balanced diet with a 2-month LPP diet in 18 PD patients with motor fluctuations. The off phases were significantly shorter after LPP diet than after balanced diet (postprandial off, 49 +/- 73 min vs. 79 +/- 72 min and total off, 164 +/- 148 min vs. 271 +/- 174 min, both P < 0.0001). Moreover, a reduction in total off time during LPP diet (3.3 +/- 2.7 hr vs. 4.7 +/- 3.3 hr, P < 0.0001), occurred also in the 9 patients who did not experience subjective benefit. No significant changes in hematological and biochemical variables or body composition were recorded; a slight reduction in body weight (mean, -1.8%) was observed. Consumption of LPP in the first part of the day ameliorates off periods in PD patients, but additional studies including pharmacokinetics are needed.

Special low-protein foods ameliorate postprandial off in patients with advanced Parkinson's disease

Purpose Signal abnormalities within the putamen in MRI have been related to tissue degeneration in the striatonigral variant of multiple system atrophy (MSA-P). While previous work demonstrated the high specificity of these MR findings, sensitivity rates were unsatisfactory. We evaluated the specificity and sensitivity of an acquisition protocol using thin section MRI to differentiate MSA-P from Parkinson disease (PD). Method Axial 3-mm-thick conventional T2 and proton density spin echo images at the level of basal ganglia were acquired at 1.5 T in 24 patients with MSA-P and 27 patients with PD. Results We found an abnormal putaminal T2 hypointensity in 21 of 24 MSA-P patients (87.5% sensitivity) and a proton density hyperintensity in 20 of 24 MSA-P patients (83.3% sensitivity). Three among 27 PD patients had an abnormal putaminal T2 hypointensity (88.8% specificity) and there were no proton density abnormalities (100% specificity). Conclusion Our thin section conventional spin echo protocol showed a substantial increase in MR sensitivity compared with previous reports. We believe that a better depiction of even mild signs of degeneration in the putamen may allow a more widespread use of this technique in the differential diagnosis of parkinsonisms.

Roberta De Notaris

Papers

MR Imaging of the Superior Profile of the Midbrain: Differential Diagnosis between Progressive Supranuclear Palsy and Parkinson Disease

Tc-99m ethylene cysteinate dimer SPECT in the differential diagnosis of parkinsonism

Protein intake in Parkinsonian patients using the EPIC food frequency questionnaire

Special low-protein foods ameliorate postprandial off in patients with advanced Parkinson's disease

Thin section MR study of the basal ganglia in the differential diagnosis between striatonigral degeneration and Parkinson disease.