Diagnostic accuracy of Parkinson's disease and atypical parkinsonism in nursing homes

α-Synuclein conformers reveal link to clinical heterogeneity of α-synucleinopathies

α-Synucleinopathies, such as Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy, are a class of neurodegenerative diseases exhibiting intracellular inclusions of misfolded α-synuclein (αSyn), referred to as Lewy bodies or oligodendroglial cytoplasmic inclusions (Papp-Lantos bodies). Even though the specific cellular distribution of aggregated αSyn differs in PD and DLB patients, both groups show a significant pathological overlap, raising the discussion of whether PD and DLB are the same or different diseases. Besides clinical investigation, we will focus in addition on methodologies, such as protein seeding assays (real-time quaking-induced conversion), to discriminate between different types of α-synucleinopathies. This approach relies on the seeding conversion properties of misfolded αSyn, supporting the hypothesis that different conformers of misfolded αSyn may occur in different types of α-synucleinopathies. Understanding the pathological processes influencing the disease progression and phenotype, provoked by different αSyn conformers, will be important for a personalized medical treatment in future.

Assisted Diagnosis of Parkinsonism Based on the Striatal Morphology

Parkinsonism is a clinical syndrome characterized by the progressive loss of striatal dopamine. Its diagnosis is usually corroborated by neuroimaging data such as DaTSCAN neuroimages that allow visualizing the possible dopamine deficiency. During the last decade, a number of computer systems have been proposed to automatically analyze DaTSCAN neuroimages, eliminating the subjectivity inherent to the visual examination of the data. In this work, we propose a computer system based on machine learning to separate Parkinsonian patients and control subjects using the size and shape of the striatal region, modeled from DaTSCAN data. First, an algorithm based on adaptative thresholding is used to parcel the striatum. This region is then divided into two according to the brain hemisphere division and characterized with 152 measures, extracted from the volume and its three possible 2-dimensional projections. Afterwards, the Bhattacharyya distance is used to discard the least discriminative measures and, finally, the neuroimage category is estimated by means of a Support Vector Machine classifier. This method was evaluated using a dataset with 189 DaTSCAN neuroimages, obtaining an accuracy rate over 94%. This rate outperforms those obtained by previous approaches that use the intensity of each striatal voxel as a feature.

Parkinsonism in a population-based study of individuals aged 75+ years: The Pietà study

INTRODUCTION

Parkinsonism is one of the most prevalent neurological syndromes in the elderly. There are only a few epidemiological studies focusing on parkinsonism in oldest-old individuals, particularly in Latin America. This study aims to investigate the prevalence and characteristics of parkinsonism in subjects aged 75 + years living in the community.

METHODS

The Pietà study is a population-based investigation on brain aging conducted in Caeté, southeast Brazil. A sample composed of 610 community-dwelling individuals aged 75 + years (48.7% of the total population within this age range) underwent clinical, neurological, cognitive and functional assessments.

RESULTS

The sample comprised mostly women (61.5%), with mean age of 83.3 years and mean schooling of 2.5 years. Parkinsonism was identified in 65 subjects (crude prevalence = 10.7%). Parkinson's disease, Parkinsonism + dementia syndrome, drug-induced parkinsonism, vascular parkinsonism and Lewy-body dementia were identified in, respectively, 19 (29.2%), 19 (29.2%), 8 (12.3%), 4 (6.1%) and 1 (1.5%) subjects. In 14 individuals (21.5%), the etiology of parkinsonism could not be determined. The most important vascular risk factor was hypertension (64.6%). Cognitive evaluation disclosed dementia in 37 (56.9%) subjects. Mean Pfeffer's functional activities questionnaire score was 12.2 points and 22 (33.8%) subjects were impaired in basic activities of daily living.

CONCLUSION

Parkinsonism was common in this oldest-old population, being associated with dementia and vascular risk factors, particularly hypertension. Different confounders, such as concomitant dementia and exposure to anti-dopaminergic drugs, were present in this population, challenging the definition of causes of parkinsonism.

Functional Status of Elderly Nursing Home Residents With Parkinson's Disease

BACKGROUND

Parkinson's disease (PD) is a debilitating neurological disorder that has a significant impact on activities of daily living (ADL). Limited data exists regarding the functional status of nursing home residents with PD.

OBJECTIVE

The study examined the nature, extent, and predictors of limitation of ADL in patients with PD residing in nursing homes.

METHODS

This study used cross-sectional design involving data from the National Nursing Home Survey (NNHS). The dependent variable was the total number of ADL for which the patient needed assistance. Assistance for ADL comprised of five items of transferring, dressing, eating, toileting and bathing. Multivariable linear regression was used to examine the individual, biological and environmental factors associated with assistance needed for ADL.

RESULTS

The nationally representative study sample was of 98,093 nursing home residents with PD for an overall prevalence of 6.57%. The mean age of the study sample was 81.03±0.34 years. Mood symptoms (45%), behavioral symptoms (24%)and dementia (8%) were common among PD patients. Assistance needed for each ADL ranged from 68.24% for eating to 99.25% for bathing. Older age, being married, living in metropolitan statistical area (MSA), living in other place prior to admission, and presence of mood symptoms were positively related to assistance for ADL. Presence of behavioral symptoms and use of levodopa combination therapy were negatively related to assistance for ADL.

CONCLUSIONS

Majority of the nursing home residents with PD had disability in all the five items of ADL. Various individual, environmental and biological factors were associated with ADL in nursing home residents with PD.

"Atypical" atypical parkinsonism: Critical appraisal of a cohort

BACKGROUND

Atypical parkinsonian conditions such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), corticobasal syndrome (CBS) and Dementia with Lewy bodies (DLB) comprise 10-15% of parkinsonian syndromes. Misdiagnosis with Parkinson disease (PD) and within the entities is common, given the absence of reliable biomarkers. However a correct diagnosis is not only important in clinical practice, but also crucial for any trial attempting to identify biomarkers or new treatments.

METHODS

Consecutive patients, who were referred to our tertiary center with a diagnosis of a particular AP were included and the medical records were reviewed retrospectively. We applied each set of current diagnostic research criteria to the respective cohort to see which features fit in and if there are any additional atypical features "outside" the classic definition.

RESULTS

Sixty-nine patients were recruited between January 2013 and May 2015 clinically presenting with one of the following phenotypes: 14 MSA, 24 PSP, 19 CBS and 12 DLB. Up to 49% showed additional "atypical" features and approximately 10% eventually received an alternative diagnosis, in half of whom this being based on genetic testing.

CONCLUSIONS

In a subset of our patients, despite the final diagnosis of an AP being maintained, there were additional "atypical" features. It remains to be seen if these reflect the clinical heterogeneity of APs, or should prompt a search for an alternative diagnosis. The search for biomarkers is more likely to be successful in homogenous groups of "typical" patients, hence the importance of recognizing "atypical" features.