The Dutch Parkinson and Cognition Study

University Medical Center Groningen150 enrolled

Overview

Parkinson Disease (PD) is a heterogeneous, progressive neurodegenerative disorder which is characterized by a variety of motor and non-motor symptoms. The DUPARC study is a single-centre longitudinal cohort study aimed at deeply phenotyping newly diagnosed PD patients. The main aim is to investigate the relationship between cognitive impairment and both cholinergic and dopaminergic neurodegeneration in the early stages of the disease. In addition, gastrointestinal and visual system dysfunction in PD and their role in the underlying pathology are further explored in a longitudinal setup. Treatment-naïve participants will undergo extensive motor- and non-motor assessment, imaging, and microbiome assessment at time of diagnosis, and will be followed for at least 3 years.

Rationale: Parkinson's disease (PD) is characterized by both motor and non-motor symptoms, including cognitive decline. Mild cognitive impairment (PD-MCI) is already present at time of diagnosis in 24-36% of PD patients. Cognitive impairment in PD is associated with both cholinergic and dopaminergic deficiencies in the brain. Although dopaminergic neuronal degeneration is quite well established in relationship to the motor impairment, the rate and extent of the cholinergic neuronal degeneration in the course of PD is unknown. It is also unclear how cholinergic and dopaminergic degeneration contributes to cognitive deficits found in early and more advanced PD and its role in the progression over time. Objectives: The primary objective is to establish the relationship between cognitive impairment and cholinergic neurodegeneration in de novo PD patients, by studying cholinergic imaging using \[ 18 F\]Fluoroethoxy-Benzovesamicol (\[18F\]FEOBV) positron emission tomography (PET) and neuropsychological performance over time. Secondary objectives include: (1) the investigation of possible predictive factors using optical coherence tomography and (2) to determine the relative contributions of PD diagnosis and dopaminergic medication use to the changes in microbiota composition observed in PD patients. Study design: At baseline patients will undergo the following investigations and questionnaires: Demographics, detailed medical history, neuropsychological assessment, imaging including MRI brain, dopaminergic Fluoro-18-L-Dihydroxyphenylalanine (18F-FDOPA) and cholinergic FEOBV PET, optical coherence tomography (OCT) and microbiota composition. At one year follow-up subjects will undergo motor-, neuropsychological, and microbiota assessment. At 3 year follow up baseline measurements will be repeated in its entirety with the exception of the genetic and gastrointestinal assessments. Study population: 150 de novo PD patients, recruited from the neurological practices in the northern area of the Netherlands and healthy control subjects. Healthy age-,sex- and constipation-matched controls will be assessed on microbiota composition Assessment and endpoints related to gastroenterological assessment have been approved under a separate research protocol (NL61123.042.17 - CCMO) and has been officially linked to the overall protocol.

Outcomes

Primary Outcomes

[18F]FEOBV PET

Cortical and subcortical cholinergic innervation as measured by \[18F\] FEOBV PET imaging

Time frame: Baseline

Secondary Outcomes

Cognitive screening

General cognitive performance will be assessed using a cognitive screening; the Montreal Cognitive Assessment (MOCA). The MOCA test covers the important cognitive domains including memory, attention, executive function, language and visuospatial abilities, resulting in one total score of cognitive performance. MOCA score ranges between 0 and 30, with higher scores representing better performance.

Time frame: baseline

Memory performance

Memory performance will be calculated as an average Z-score of two cognitive tests; the Rey auditory verbal learning test for measuring verbal memory and the location learning test for measuring visual memory. Based on established normative data, a z-score for each test outcome will be calculated, representing performance compared to an age-, gender- and educational level-matched control group. A Z-score of 0 (zero) represents a performance similar to the normative data. A positive z-score represents better performance, while a negative z-score represents worse performance. There is no minimum or maximum z-score. These z-scores from both tests will be averages to form one outcome measurement representing memory performance.

Time frame: baseline

Attention and working memory performance

Attention performance will be calculated as an average Z-score of three cognitive tests; the Stroop color-word test, the digit span and the Vienna test system reaction time measurement. Based on established normative data, a z-score for each test outcome will be calculated, representing performance compared to an age-, gender- and educational level-matched control group. A Z-score of 0 (zero) represents a performance similar to the normative data. A positive z-score represents better performance, while a negative z-score represents worse performance. There is no minimum or maximum z-score. These z-scores from all three tests will be averages to form one outcome measurement representing attention performance.

Time frame: baseline

Executive function performance

Executive function performance will be calculated as an average Z-score of four cognitive tests; the trail making test, the Wisconsin card sorting test, the Hayling Sentence completion test and the letter fluency test. Based on established normative data, a z-score for each test outcome will be calculated, representing performance compared to an age-, gender- and educational level-matched control group. A Z-score of 0 (zero) represents a performance similar to the normative data. A positive z-score represents better performance, while a negative z-score represents worse performance. There is no minimum or maximum z-score. These z-scores from all tests will be averages to form one outcome measurement representing executive performance.

Time frame: baseline

Visouspatial abilities

Cognitive visuospatial abilities will be calculated as an average Z-score of two cognitive tests; the Judgement of line orientation and the Map search subtest of the test of everyday attention. Based on established normative data, a z-score for each test outcome will be calculated, representing performance compared to an age-, gender- and educational level-matched control group. A Z-score of 0 (zero) represents a performance similar to the normative data. A positive z-score represents better performance, while a negative z-score represents worse performance. There is no minimum or maximum z-score. These z-scores from all tests will be averages to form one outcome measurement representing visuospatial abilities.

Time frame: baseline

Language performance

Language performance will be calculated as an average Z-score of two cognitive tests; the Boston Naming test and the verbal fluency test. Based on established normative data, a z-score for each test outcome will be calculated, representing performance compared to an age-, gender- and educational level-matched control group. A Z-score of 0 (zero) represents a performance similar to the normative data. A positive z-score represents better performance, while a negative z-score represents worse performance. There is no minimum or maximum z-score. These z-scores from all tests will be averages to form one outcome measurement representing language performance.

Time frame: baseline

Social cognition

Social cognition abilities will be represented as a z-score calculated from the performance on the FEEST; Facial Expression of Emotion Stimuli and tests. Based on established normative data, a z-score of the test outcome will be calculated, representing performance compared to an age-, gender- and educational level-matched control group. A Z-score of 0 (zero) represents a performance similar to the normative data. A positive z-score represents better performance, while a negative z-score represents worse performance. There is no minimum or maximum z-score. These z-scores from the FEEST test represents social cognition performance.

Time frame: baseline

Brain grey matter volume

Grey matter volume as measured by structural MRI.