Current cohort


The study was launched in 2009/2010 (first assessment). The first follow-up (second assessment) has been completed in 2012, the second follow-up (third assessment) has been completed in April 2014. The third follow-up (fourth assessment) has started in February 2015. Currently, the study cohort comprises approximately 1200 individuals aged over 50 years with either one or several of the prodromal risk-markers (RBD, hyposmia and depression) or none of these markers. The latter serve as control group.


 Study protocol


Biannually participants are assessed according to a standardized protocol, that is continuously adapted based on current scientific knowledge. Each individual is investigated for 3.5 hours where 8 different and independent assessments are performed, while the TREND investigators are blinded to the results of the other assessments. In the following assessments of the baseline and first follow-up are summarized.


Neurological examination

Examination includes cranial nerve status, motor and sensory function, coordination and reflex status.


Duration: 10 minutes



Blood collection includes samples for DNA, serum and plasma.


Duration: 5 minutes


Transcranial sonography (TCS)

TCS is a simple non-invasive ultrasound-based method to image different structures of the brain at different levels..


Duration: 13 minutes


Intima-media thickness of the carotid artery

The thickness of the innermost two layers of the carotid artery wall is measured by ultrasound. A relation between the carotid intima-media thickness and the presence and severity of atherosclerosis has been documented.


Duration: 2 minutes


Autonomic testing

Participants are asked about occurrence of incontinence, obstipation and orthostatic dysregulation. In addition, heart rate variability, blood pressure as well as sympathetic skin responses are tested quantitatively over a time period of several minutes. 


Duration: 10 minutes


Olfactory testing

The sense of smell is tested with "Sniffin'Sticks". Individuals have to identify a specific odor out of four choices.


Duration: 10 minutes


Medical history

Family history and demographic data.


Duration: 15 minutes


Archimedes Spiral Test

This test examines fine motor control and identifies different tremor types. The participant draws a spiral pattern with the right and left hand respectively.


Duration: 2 minutes


Purdue Pegboard Test

This test measures dexterity and slowing of distal movements. The participant places pins with the right hand, the left hand and with both hands together in pin holes of the Pegboard as fast as possible.


Duration: 8 minutes


Cognitive testing

Cognitive functions are investigated by a structured interview combined with different tests including the CERAD battery.


Duration: 30 minutes


Color vision

Color vision is tested with the Roth 28-Hue test.


Duration: 10 minutes


Distal motor testing

Distal movements such as finger tapping, lifting an object as well as rest and postural tremor are quantitatively assessed.


Duration: 25 minutes


Axial motor testing

Via a motion sensor positioned at the lower back of the participants axial motor testing is performed under challenging conditions including tasks such as the Timed-up-and-Go test, functional reach test, sway assessments and walking along a corridor with and without dual tasking situations.


Duration: 15 minutes


Vagus somatosensory evoked potentials

This method measures the activity of vagus brain stem nuclei. This activity has been shown to be altered during early neurodegenerative processes as they occur in Alzheimer’s disease.


Duration: 25 minutes


Near-infrared spectroscopy (NIRS)

NIRS is a non-invasive method to indirectly measure brain activation during task performance. Specifically, during cognitive performance (verbal fluency) changes in blood-oxygen levels in brain structures under the scull are recorded by light emitters and detectors arranged in a cap on the participant's head. Difficulties in effortful word retrieval are among the earliest cognitive symptoms of Alzheimer's Disease.


Duration: 20 minutes




Questionnaires assessing aspects such as sleep quality, mood, activities of daily living and other aspects are included in the study protocol.