Description of longitudinal cohorts focused on prodromal neurodegeneration in Czechia and Slovakia

Summary

Aim: The aim of this study was to describe existing longitudinal cohort studies in Czechia and Slovakia that focus on prodromal neurodegeneration, describe their design, and evaluate opportunities for data sharing and protocol harmonization. Material and methods: A standardized questionnaire was distributed to centers conducting cohort studies of prodromal neurodegeneration. The questionnaire inquired about cohort focus, inclusion/exclusion criteria, sample sizes of followed patient groups, follow-up frequency, and applied methodologies. Results: Six centers located in Prague, Brno, Ostrava, and Košice collectively manage seven cohorts initiated between 2007 and 2020. In total, they include 285 individuals with Parkinson’s disease, 1,000 with Alzheimer’s disease, 72 with dementia with Lewy bodies, 210 with isolated REM sleep behavior disorder, 603 with mild cognitive impairment, 500 with subjective cognitive decline, 133 with hyposmia, 101 with substantia nigra hyperechogenicity on transcranial sonography, 20 carriers of genetic risk variants, and 523 healthy controls. Clinical follow-up intervals range from 1 to 5 years, with a maximum follow-up duration of 17 years. Most cohorts employ longitudinal cognitive and motor assessments, questionnaires addressing depression, anxiety, sleep, autonomic functions, and quality of life, olfactory testing, brain MRI, transcranial sonography, and biobanking of biological material. Conclusion: A robust network of cohorts focused on prodromal neurodegeneration exists in Czechia and Slovakia, covering a broad spectrum of diagnoses and offering substantial potential for multicenter studies.

Keywords:

cohort studies – Parkinson’s disease – hyposmia – REM sleep behavior disorder – Metadata – Alzheimer’s disease – prodromal neurodegeneration – Lewy body dementia

This is an unauthorised machine translation into English made using the DeepL Translate Pro translator. The editors do not guarantee that the content of the article corresponds fully to the original language version.

Introduction

Neurodegenerative diseases have a long pre-diagnostic period during which molecular neuropathology is detectable, but clinical manifestations are mild and/or nonspecific. This prodromal stage of neurodegeneration can last up to several decades with minimal progression, thus representing an ideal window for initiating neuroprotective interventions [1,2].

Symptoms of the prodromal stages of a -synucleinopathies—Parkinson’s disease (PD) and dementia with Lewy bodies (DLB)—may include a loss of smell, orthostatic hypotension, constipation, or behavioral disturbances during REM (rapid eye movement) sleep. A known risk factor for the development of PD is the presence of hyperechogenicity in the substantia nigra detected by transcranial sonography. Based on the presence of these signs, research diagnostic criteria for prodromal PD have been defined [3]. Prodromal symptoms of Alzheimer’s disease (AD) include subjective cognitive decline or mild cognitive impairment manifested by deficits in episodic memory and, to a lesser extent, language or visuospatial abilities [4]. Another example of individuals at risk for the prodromal stage of neurodegeneration are carriers of pathogenic genetic variants with autosomal dominant inheritance (SNCA, LRRK2), or strong risk variants (GBA) in the case of a -synucleinopathies [5] and APP, PSEN1, or PSEN2 in the case of AD [6].

Longitudinal cohort studies that collect data on specific populations over time provide highly valuable information on symptom progression from a very early stage and enable the identification of diagnostic, progression, and predictive biomarkers, as well as risk factors for the diseases under study. We expect prodromal cohorts to resolve key challenges in planning clinical trials at this stage, namely selecting the optimal study design in the absence of clinical symptoms, defining criteria for enrolling suitable patients, and validating biomarkers for assessing efficacy.

Some longitudinal studies examine various aspects of aging in a random population sample, which makes it possible to estimate the incidence and prevalence of cognitive impairments and neurodegenerative diseases in the population [7]; the Atlas of Longitudinal Datasets catalogs these projects [8]. In Europe, for example, this includes the Survey of Health, Ageing, and Retirement in Europe –⁠ European Research Infrastructure Consortium (SHARE-ERIC) [9], which is also being conducted in Czechia [10]. However, for more detailed research, studies are needed that specifically identify individuals with symptoms indicating a high probability of prodromal neurodegeneration, such as REM sleep behavior disorder [11], hyposmia [12], or mild cognitive impairment [13]. Since individuals with these symptoms do not typically seek medical attention on their own, recruitment is difficult, the number of participants in individual studies is relatively low, and only the analysis of data from multiple cohorts (a so-called “meta-cohort”) provides sufficient statistical power to analyze biomarkers or risk factors [14,15]. Efforts to harmonize and optimize data collection have led to the publication of recommendations or, directly, to the establishment of multicenter studies for the prodromal phases of a number of neurodegenerative diseases, such as PD [16,17], AD [18], or frontotemporal dementia [19]. Recently, several national consortia have also been established to study REM sleep behavior disorder (RBD), such as NAPS in the U.S. and Canada and FARPRESTO in Italy [20,21].

The aim of this study is to map existing longitudinal cohort studies in Czechia and Slovakia that focus on prodromal neurodegenerative disorders, describe their design, scope, and the range of data collected, and evaluate opportunities for data sharing and protocol harmonization. Another objective is to inform clinical neurologists about ongoing studies with regard to the possibility of enrolling suitable patients, as well as to provide guidance for designing protocols for future studies of prodromal neurodegeneration.

 

Data Set and Methodology

A standardized questionnaire was distributed electronically to centers conducting cohort studies of prodromal neurodegeneration in Czechia and Slovakia. The selection criterion for the contacted centers was the existence of previous publications or presentations based on their own longitudinally followed cohort of individuals with prodromal neurodegeneration. Centers were sought among institutions affiliated with the National Center for Neurological Research [22] and the international research group on REM sleep behavior disorder [23]. Furthermore, publications by authors with Czech or Slovak affiliations were searched in PubMed using the query (czech*[Affiliation] OR slovak*[Affiliation]) AND (prodromal[Title/Abstract] OR “REM sleep behav*”[Title/Abstract] OR hyposm*[Title/Abstract] OR MCI[Title/Abstract] OR “mild cognitive impairment”[Title/Abstract]) for the period 01/2015–12/2025. Data were collected and managed using REDCap (Research Electronic Data Capture) electronic data capture tools [24], developed at Vanderbilt University (Nashville, TN, USA) and hosted at St. Anne’s University Hospital in Brno.

The questionnaire included information on the cohort’s focus, inclusion and exclusion criteria, the prodromal and clinically manifest diagnostic groups under study, their prevalence, demographics, and the frequency of follow-up. In addition, detailed information was obtained on the cognitive tests and clinical instruments used to assess olfaction, autonomic function and motor function, as well as questionnaires evaluating depression, anxiety, quality of life, and sleep. Regarding imaging data, the use of MRI—including the protocol—as well as nuclear medicine methods such as single-photon emission computed tomography (SPECT) and PET, and transcranial sonography was recorded. Finally, information on biobanking of biological material was collected. The completed questionnaires were evaluated by the lead author (P.D.), who contacted the administrators at the individual centers directly in cases of ambiguity.

 

Results

All six contacted centers responded; together, they manage seven cohort studies launched between 2007 and 2020. These include the Biomarkers of Parkinson’s Disease (BIO-PD/RBD) study conducted at the First Faculty of Medicine of Charles University and the General University Hospital in Prague [20,21], the Czech Brain Aging Study (CBAS) at Motol University Hospital in Prague and the International Clinical Research Center (ICRC) in Brno [25], the Subjects at Risk of Parkinson’s Disease Development (SR-PDD) study at the Faculty of Medicine of the University of Ostrava, the Prodromal Lewy Body Disease (P-LBD) study at the Central European Institute of Technology (CEITEC) at Masaryk University [26,27], as well as two studies—the RBD-based Prodromal Parkinson’s Disease Biomarker Study (PDBIOM) and the Parkinson’s Disease-Associated Colonic Alpha-Synuclein Biomarker Study (PARCAS)—being conducted at the Faculty of Medicine of Pavol Jozef Šafárik University in Košice [28–31], and the Degeneration Risk Evaluation Associated with iRBD and Medication-associated RBD (DREAM) study at the National Institute of Mental Health in Klecany. The individual studies focus on the prodromal stages of AD, PD, DLB, and a -⁠ synucleinopathies in general, with inclusion criteria including subjective or mild cognitive impairment, REM sleep behavior disorder, idiopathic hyposmia, hyperechogenic substantia nigra, or other prodromal markers according to the research criteria for prodromal PD (Table 1) [25–33].

Since their inception, a total of 285 individuals with PD, 1,000 with AD, 72 with DLB, 210 with idiopathic/isolated RBD, 603 with mild cognitive impairment (including 67 cases of the variant with Lewy bodies), 500 with subjective cognitive decline, 133 with idiopathic hyposmia, 101 with hyperechogenic substantia nigra, 20 carriers of genetic risk variants, and 523 healthy controls. The interval between clinical follow-up visits ranges from 1 to 5 years, with a maximum follow-up duration of 17 years (Table 2).

The most commonly used cognitive tests are the Montreal Cognitive Assessment (MoCA) for screening, the National Adult Reading Test (NART) for assessing premorbid intelligence, the Trail Making Test part A (TMT-A) for evaluating attention, the TMT-B and the Stroop Test for evaluating executive functions, and verbal fluency tests for evaluating language functions (Table 3).

The most commonly used depression questionnaires are the Beck Depression Inventory-II (BDI-II) and the Geriatric Depression Scale (GDS); sleep parameters are assessed using the REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ) and the Epworth Sleepiness Scale (ESS). Autonomic function is typically assessed using an orthostatic test and the Scale for Outcomes in Parkinson’s Disease-Autonomic (SCOPA-AUT) questionnaire. Among olfactory tests, Sniffin’ Sticks and the University of Pennsylvania Smell Identification Test (UPSIT) are used with nearly equal frequency. Motor assessment is routinely performed using the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) (Table 4). The use of neurophysiological and imaging examinations, as well as information on stored biological material, is summarized in Table 5.

 

Discussion

We have mapped longitudinal cohort studies in Czechia and Slovakia, including their protocols and the number of enrolled participants. Five centers are investigating prodromala -synucleinopathies, and one center, as part of a more broadly defined project, focuses primarily on cognitive disorders in old age, particularly AD. The combined of more than 1,500 individuals with prodromal neurodegeneration is substantial by international standards.

This questionnaire-based study showed that there is consensus among the individual centers regarding the domains under investigation, in line with current trends and analogous studies worldwide [17,18], but the specific instruments and tests often vary. This is partly due to the focus of individual studies on specific diagnoses, for which the optimal tests may differ. Other factors include harmonization with collaborating foreign institutions within the framework of multicenter studies, historical experience with specific tests, and the availability of complementary tools at individual centers.

Some questionnaires are used by most centers, due to the availability of validated Czech/Slovak versions, such as the BDI-II [34], SCOPA-AUT [35], RBDSQ [36], or ESS [37]. To assess motor status, specifically the presence of parkinsonism, four centers use the updated MDS-UPDRS scale, while one uses the older UPDRS. This discrepancy does not prevent multicenter analyses, as scores between the two versions can be converted [38]. Similarly, scores can be converted between the two tests used to assess the sense of smell, UPSIT and Sniffin’ Sticks [39].

Regarding cognitive testing, there is broad consensus among centers on the use of the MoCA, TMT-B, and verbal fluency tests. In contrast, there is potential for harmonization in the testing of memory, attention, and visuospatial functions. Published recommendations exist for harmonizing cognitive function assessment protocols for both dementia syndrome and cognitive impairment in PD [40–42].

Scores from questionnaires, cognitive tests, and olfactory tests used by most centers can be used to create a normative database for the Czech and Slovak populations and to establish optimal cutoff values for defining abnormal findings for individual diagnoses. In the future, we will strive to include a basic, harmonized set of questionnaires and cognitive tests in all studies involving prodromal neurodegeneration.

All centers use neuroimaging techniques. While specialized methods, such as DaTscan™ or amyloid PET, are typically used only for a subset of participants, transcranial sonography and brain MRI are performed on all participants in most cohorts. Given advances in the capabilities for retrospective analysis of harmonized multicenter MRI data [43], it is now possible to analyze a vast number of scans from different centers. MRI protocols should therefore ideally include at least 3D Magnetization Prepared Rapid Gradient Echo (3D-MPRAGE) and high-resolution 3D T2-weighted scans, which enable quantitative morphometric analyses.

Recently, the use of biological markers to confirm specific neuropathological processes in the prodromal stage of neurodegeneration has become standard practice [44,45]. In the case of a -synucleinopathies, this primarily involves the detection of abnormal a -synuclein in cerebrospinal fluid using the real-time quaking-induced conversion (RT-QuIC) method or in skin tissue using immunohistochemical methods [46]. In the case of AD, this involves a positive result on an amyloid PET scan or abnormal levels of certain tau protein isoforms in plasma, particularly p-tau217 [47]. Further development of biological markers is expected in the future; therefore, it is recommended to preserve blood samples, and possibly other biological material, for future analyses [48]. One way to facilitate the sharing of biological samples is to organize a so-called virtual biobank, where information about samples physically stored in local biobanks is listed and shared [49]. A similar approach can also be applied to neuroimaging data. Ideally, a neuropathological examination confirming the underlying proteinopathy will be performed in the event of a study participant’s death. Since 2021, Thomayer University Hospital in Prague has operated a brain bank that handles the formal and practical aspects of brain donation [50].

In conclusion, we note that Czechia and Slovakia have a robust network of longitudinally followed cohorts focused on research into prodromal neurodegeneration, covering the most common diseases. Most studies are still actively recruiting new participants. The harmonized aspects of cognitive testing, biomarker protocols, and neuroimaging parameters have the potential to facilitate multicenter studies; however, we have also identified several areas with potential for further harmonization. We present detailed protocols as inspiration for future cohort studies and believe that this article will contribute to stimulating a discussion on improving organization and inter-center collaboration in research on prodromal neurodegeneration in Czechia and Slovakia.

 

Acknowledgments

We would like to thank Terezie Poláčková, B.A., and Petra Weselá, Ph.D., for their technical assistance.

Funding

Created within the framework of the National Institute for Neurological Research (Neur-IN), supported by project no. LX22NPO5107 (Ministry of Education, Youth and Sports): Funded by the European Union –⁠ Next Generation EU. The project was also supported by the Slovak Agency for the Support of Science and Research (APVV) under grant No. APVV-22-0279 and the EU Recovery and Resilience Plan “Major Projects for Excellent Researchers” under grant No. 09I03-03-V03-00007.

 

Conflict of Interest

The authors declare that they have no conflict of interest in connection with the subject of the study.

 

Table 1. List of cohorts.
Study Name	Biomarkers of Parkinson's Disease	Czech Brain Aging Study	Subjects at Risk for the Development of Parkinson's Disease	Prodromal Lewy Body Disease	RBD-Based Prodromal Parkinson's Disease Biomarker Study	PARkinson's Disease-Associated Colonic Alpha-Synuclein Biomarker Study	Evaluation of Degeneration Risk Associated with iRBD and Medication-Associated RBD
Acronym	BIO-PD/RBD	CBAS	SR-PDD	P-LBD	PDBIOM	PARCAS	DREAM
Year the study began	2015	2007	2020	2020	2018	2014	2020
Department	First Faculty of Medicine, Charles University, and General University Hospital in Prague	Motol University Hospital, Prague; ICRC, FNUSA, and Faculty of Medicine, Masaryk University, Brno	Faculty of Medicine, University of Ostrava	CEITEC, Masaryk University, Brno	Faculty of Medicine, Pavol Jozef Šafárik University and University Hospital, Košice	Faculty of Medicine, Pavol Jozef Šafárik University and University Hospital, Košice	National Institute of Mental Health, Klecany
Inclusion criteria	Newly diagnosed, untreated PD; iRBD confirmed by PSG	subjective cognitive decline, mild cognitive impairment	idiopathic hyposmia; hyperechogenicity of the substantia nigra on transcranial sonography	mild cognitive impairment with Lewy bodies (MCI-LB)	Suspected iRBD based on a score of ≥ 5 on the REM Sleep Behavior Disorder Screening Questionnaire	At least 1 prodromal marker according to the MDS research criteria for prodromal PD*	iRBD confirmed by PSG
Data retention	RedCap	RedCap	Microsoft Excel	Microsoft Excel	RedCap/Microsoft Excel	RedCap/Microsoft Excel	Microsoft Excel
The cohort is still recruiting new participants	Yes	Yes	Yes	Yes	Yes	no	yes
Study Information	Dusek et al. [25,26]	Sheardova et al. [27]	–	Zeleznikova et al. [28]; Mitterova et al. [29]	Toth et al. [32]; Kulcsarova et al. [33]	Kulcsarova et al. [30]; Skorvanek et al. [31]	–
*The prodromal markers include hyposmia, depression, constipation, and suspected RBD based on the RBD1Q; CEITEC –⁠ Central European Institute of Technology; FNUSA –⁠ St. Anne’s University Hospital; ICRC –⁠ International Clinical Research Center; iRBD –⁠ idiopathic REM sleep behavior disorder; MDS –⁠ Movement Disorders Society; ; PD –⁠ Parkinson’s disease; PSG –⁠ polysomnography; TCS –⁠ transcranial sonography

 

 

Table 2. Numbers, diagnoses, and demographic data at study enrollment.
	BIO-PD/RBD	CBAS	SR-PDD	P-LBD	PDBIOM	PARCAS	DREAM
Parkinson's disease	157	40	80	–	4	4	–
Alzheimer's disease	–	1,000	–	–	–	–	–
Lewy Body Dementia	–	70	–	–	2	–	–
REM Sleep Behavior Disorder	117	2	–	–	38	3	50
Mild cognitive impairment	–	500	–	103*	–	–	–
Subjective cognitive decline	–	500	–	–	–	–	–
Hyposmia	–	–	82	–	1	50	–
Hyperechogenic substantia nigra	–	–	95	–	–	6	–
Genetic risk variants	–	20	–	–	–	–	–
Healthy controls	109	80	68	111	34	101	20
Age of participants	33–86 (average 62)	50–98	18–84 (average 58)	55–84 (average 68)	41–82 (average 63)	40–85 (average 62)	45–84 (average 62)
Interval of follow-up visits	1 year	1–2 years	1 year	1 year	2–5 years	5 years	1 year
Follow-up period for study participants	1–10 years (average 4 years)	1–17 years	1–5 years (average 3 years)	1–4 years	2–7 years	2–8 years	3 years
*67 meets the criteria for mild cognitive impairment with Lewy bodies

 

 

 

Table 3. Methodology for testing cognitive functions.

BIO-PD/RBD

CBAS

SR-PDD

P-LBD

PDBIOM

PARCAS

DREAM

screening

MoCA

MMSE, MoCA, Uniform Data Set

ALBA*, POBAV*, ACE-III*

MoCA

MoCA

MoCA***

MoCA

premorbid intelligence

NART**

NART

–

NART, WAIS-III (vocabulary)

–

–

–

memory

RAVLT**

RAVLT, Logical Memory (WMS-III)

–

PVLT, BVMT-R

WMS, WAIS-III

–

–

Attention

TMT-A**, SDMT**, DS-F**

TMT-A, DSST, DS-F

–

DSST

TMT-A

–

–

executive functions

TMT-B**, DS-B, Stroop Test**, TOL**

TMT-B, DS-B

TOL*

TMT-B, Stroop Test, WAIS-III (Picture Arrangement)

TMT-B, Stroop Test

–

–

speech functions

BNT**, Verbal Fluency**

BNT, Verbal Fluency

–

Verbal fluency

Verbal fluency

–

–

visuo-spatial functions

–

ROCFT, CDT, B-JoL

–

B-JoL

ROCFT

–

–

*only at the initial examination; **only at the initial examination and the retest in the 5th year; ***not examined at baseline ACE –⁠ Addenbrooke's Cognitive Examination; ALBA –⁠ Amnesia Light and Brief Assessment; B-JoL –⁠ Benton Judgment of Line Orientation; BNT –⁠ Boston Naming Test; BVMT-R –⁠ Brief Visuospatial Memory Test –⁠ Revised; CDT –⁠ Clock Drawing Test; DS-B –⁠ Digit Span –⁠ Backward; DS-F –⁠ Digit Span –⁠ Forward; DSST –⁠ Digit Symbol Substitution Test; POBAV –⁠ Picture Naming and Recall; PVLT –⁠ Philadelphia Verbal Learning Test; MMSE –⁠ Mini-Mental State Examination; MoCA –⁠ Montreal Cognitive Assessment; NART –⁠ National Adult Reading Test; RAVLT –⁠ Rey Auditory Verbal Learning Test; ROCFT –⁠ Rey-Osterrieth Complex Figure Test; SDMT –⁠ Symbol Digit Modalities Test; TMT –⁠ Trail Making Test; WAIS –⁠ Wechsler Adult Intelligence Scale; TOL –⁠ Tower of London; WMS –⁠ Wechsler Memory Scale

 

 

 

Table 4. Questionnaires and specific tests.
	BIO-PD/ RBD	CBAS	SR-PDD	P-LBD	PDBIOM	PARCAS		DREAM
Depression and Anxiety Questionnaires	BDI-II, STAI-X-1/2	GDS, HAM-A	BDI-II*	GDS	BDI-II, PAS	BDI-II***, PAS***		BDI-II, BAI
Quality of Life and Functional Status Questionnaires	PDQ-39/8, FAQ, SCD-Q	EQ-5D, FAQ	EQ-5D*	–	PDQ-39/8	PDQ-39/8		SF-36*
Sleep Quality/Sleepiness Questionnaires	RBDSQ, FSS*, ESS, ISI	Mayo Sleep Q	RBDSQ*	RBDSQ, ESS	RBDSQ, ESS, PDSS-2, PSQI	RBDSQ, ESS***, PDSS-2***		RBDSQ*, FSS, ESS, ISI, iRBD-SSS
Autonomic Function	Orthostatic test, SCOPA-AUT	Orthostatic test	–	SCOPA-AUT‡	Orthostatic Test, SCOPA-AUT, NMSS	Orthostatic Test***, SCOPA-AUT***, NMSS***		Orthostatic Test, SCOPA-AUT
Olfactory testing	Sniffin’ Sticks Identification 16, Threshold/UPSIT †	UPSIT	Sniffin’ Sticks identification 16, discrimination*, olfactory evoked potentials‡	UPSIT	Sniffin’ Sticks identification 16	Sniffin’ Sticks identification 16		Sniffin’ Sticks identification 16
Motor tests	MDS-UPDRS, TUG, Grooved Pegboard**	UPDRS	MDS-UPDRS	MDS-UPDRS	MDS-UPDRS, Purdue Pegboard	MDS-UPDRS		MDS-UPDRS
*only at the initial examination; **only at the initial examination and the retest in the 5th year; ***not assessed at baseline; ‡ in a subset of the cohort; † in a subset of the UPSIT cohort, in a subset of the Sniffin’ Sticks cohort BAI –⁠ Beck Anxiety Inventory; BDI-II –⁠ Beck Depression Inventory II; GDS –⁠ Geriatric Depression Scale; EQ-5D –⁠ EuroQoL-5 Dimension Questionnaire; ESS – Epworth Sleepiness Scale ; FAQ –⁠ Functional Activities Questionnaire; FSS –⁠ Fatigue Severity Scale; HAM-A –⁠ Hamilton Anxiety Rating Scale; iRBD-SSS –⁠ International REM Sleep Behavior Disorder Study Group Symptom Severity Scale; ISI –⁠ Insomnia Severity Index; (MDS-)UPDRS –⁠ (Movement Disorder Society-) Unified Parkinson's Disease Rating Scale ; NMSS –⁠ Non-Motor Symptom Scale; PAS –⁠ Parkinson Anxiety Scale; PDQ –⁠ Parkinson's Disease Questionnaire; PDSS-2 –⁠ Parkinson’s Disease Sleep Scale, 2nd Version; PSQI –⁠ Pittsburgh Sleep Quality Index; RBDSQ – REM Sleep Behavior Disorder Screening Questionnaire ; SCD-Q –⁠ Subjective Cognitive Decline Questionnaire; SCOPA-AUT – Scale for Outcomes in Parkinson’s Disease-Autonomic ; SF-36 –⁠ Short Form 36-Item Health Survey; STAI-X1/2 –⁠ State-Trait Anxiety Inventory; TUG –⁠ Timed Up and Go test; UPSIT – University of Pennsylvania Smell Identification Test

 

Table 5. Electrophysiological, instrumental, imaging, and laboratory tests.
	BIO-PD/RBD	CBAS	SR-PDD	P-LBD	PDBIOM	PARCAS	DREAM
Neurophysiological Tests
Polysomnography	Yes	–	–	–	Yes	yes (part of the cohort)	yes
Accelerometers	Yes (during gait assessment)	–	–	Yes (at home)	Yes (at home—part of the cohort)	–	yes (at home)
Acoustic speech analysis	Yes	–	–	Yes	Yes (part of the cohort)	–	–
Handwriting analysis	yes	–	–	yes	–	–	–
Instrumental gait analysis	Yes	–	–	–	–	–	–
Imaging Methods
Brain MRI (protocol)	MPRAGE/ FLAIR/ DTI/ rsFMRI/ QSM	MPRAGE/ FLAIR/ DTI	Clinical protocol	MPRAGE/FLAIR/DTI/rsfMRI/QSM/NMS	clinical protocol	clinical protocol	Clinical Protocol
DaTscan™	yes	Yes (DLB)	–	–	Yes (part of the cohort)	Yes (part of the cohort)	Yes (part of the cohort)
MIBG SPECT	–	Yes (DLB)	–	–	–	–	–
Amyloid PET	–	Yes (part of the cohort)	–	–	–	–	–
FDG PET	–	–	–	–	–	–	–
Transcranial sonography	yes	–	yes	yes	yes	yes	–
Biological material (biobanking)
Blood (serum/plasma)	Yes	Yes	Yes	Yes	yes	yes	yes
Cerebrospinal fluid	Yes (part of the cohort)	yes	–	–	Yes (part of the cohort)	–	–
DNA	yes	yes	–	–	yes	–	Yes
Skin biopsy	–	–	–	–	Yes (part of the cohort)	yes (part of the cohort)	–
DLB –⁠ dementia with Lewy bodies; DTI –⁠ diffusion tensor imaging; FDG –⁠ fluorodeoxyglucose; FLAIR –⁠ fluid-attenuated inversion recovery; MIBG –⁠ metaiodobenzylguanidine; MPRAGE –⁠ magnetization-prepared rapid gradient echo  ; NMS –⁠ neuromelanin-sensitive sequence; QSM –⁠ quantitative susceptibility mapping; rsFMRI –⁠ resting-state functional magnetic resonance imaging; SPECT –⁠ single-photon emission computed tomography