Alterations of Attention in POTS Depending on Body Position and Hydration
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT03253120 |
Recruitment Status :
Active, not recruiting
First Posted : August 17, 2017
Last Update Posted : February 10, 2022
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
The Postural Tachycardia-Syndrome (POTS) is a form of autonomic dysregulation, typically accompanied by symptoms of orthostatic intolerance (OI). OI is defined by the inability to tolerate the upright position and is improved by lying down. POTS is considered a syndrome that may include a number of several disorders. Symptoms should be persistent for at least 6 months to reach a diagnosis. It is characterized by a sustained heart rate (HR) increment of 30 beats/min or more within 10 min of standing or head-up tilt (HUT) in adults, in the absence of orthostatic hypotension and with the presence of symptoms of OI. In children and adolescents a diagnosis requests a HR increment of at least 40 beats/min. The increment in HR when moving to an upright posture is often a response to a reduction in venous return, causing excessive blood pooling in the lower limbs. The symptoms present in POTS vary greatly. Typical symptoms are lightheadedness, dizziness, blurred vision, mental clouding ("brain fog") or cognitive dysfunction. Other symptoms may present as palpitations or chest pain. Additional symptoms consist of postural headaches, nausea, sleep disturbances, fatigue and gastrointestinal dysfunction. The manifestation of symptoms in POTS varies in severity, frequency and combination, resulting in POTS being a very heterogenous and subjective disorder. Symptoms can be severe and often make simple daily activities difficult to an extent that compromises the patients quality of life. Typically symptoms exacerbate in the mornings, after physical activity, after eating and during menstruation.
This study objective is to examine the occurrence, mechanisms and causes of impaired attention in POTS as well as to test the effect of acute water ingestion for attention in POTS. The investigators therefore conduct a study including patients with POTS and healthy volunteers.
All participants will receive a dossier of five self-assessment questionnaires after giving informed consent. Clinical examination includes 2 HUT-tests while standing for 15 minutes, conventional measuring of blood pressure, continuous recording of NIRS signals during testing, determination of pupil size, the diameter of the optic nerve and Neuropsychological testing (Test of Attentional Performance, mobility version" (TAP-M), Go/NoGo Test, Divided Attention Test)
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Postural Tachycardia Syndrome | Other: Water | Not Applicable |

Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 30 participants |
Allocation: | Non-Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Patients will drink 5dl of water. Healthy volunteers will drink 5dl of water. |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Alterations of Attention in Patients With Postural Tachycardia Syndrome and Healthy Controls Depending on Body Position and Hydration |
Actual Study Start Date : | September 11, 2017 |
Estimated Primary Completion Date : | October 31, 2022 |
Estimated Study Completion Date : | March 31, 2023 |

Arm | Intervention/treatment |
---|---|
Patient
Patients will drink 5dl of water.
|
Other: Water
Patient/ Healthy volunteer will drink 5dl of Water |
Healthy volunteer
Healthy volunteers will drink 5dl of water.
|
Other: Water
Patient/ Healthy volunteer will drink 5dl of Water |
- Numerical variables reaction time and/or hits resp. misses in the subtests "alertness" from the automated test battery "Test of Attentional Performance, mobility version" [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]"Alertness" is designed to assess tonic alertness, which is defined as the ability to maintain a high level of responsiveness in anticipation of a test stimulus. The alertness test measures the simple reaction time in response to a visual stimulus (a cross presented on the monitor)
- Numerical variables reaction time and/or hits resp. misses in the subtest "Go/NoGo" from the automated test battery "Test of Attentional Performance, mobility version" [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]The "Go/NoGo" task for assessing the specific ability of subjects to suppress undesired responses. Reaction times and errors are recorded in a simple test with two stimuli
- Numerical variables reaction time and/or hits resp. misses in the subtest "divided attention" from the automated test battery "Test of Attentional Performance, mobility version" [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]In the Test of Attentional Performance a visual and an auditory task must be processed in parallel
- Diameter of the optic nerve [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]The diameter of the optic nerve is measured with a 7-15 MHz linear array transducer in transorbital B-mode ultrasound .
- Brain perfusion measured with NIRS [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]All parameters of brain perfusion will be assessed using NIRS.
- Heart rate [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]For autonomic function testing, beat-to-beat BP and HR are measured with the Finometer device.
- Blood pressure [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]For autonomic function testing, beat-to-beat BP and HR are measured with the Finometer device.
- Pupil diameter [ Time Frame: After change body position and 5dl of water, up to 30 minutes ]Determination of pupil size will be performed with a rubber cup covering the measured eye and the operator's hand covering the nonmeasured eye. A brief 2- to 3-second pause allows the pupil to dilate briefly at which time the measurement will be taken. Pupil size is the average diameter for the entire measurement time, which is typically 3 to 4 seconds.
- Scores of the questionnaires (composite endpoint) [ Time Frame: Through study completion an average of 1 day ]Beck's Depression Inventory II (BDI-II) for assessing depression, Short Form (36) Health Survey (SF-36) for assessing health-related quality of life, Pittsburgh Sleep Quality Index (PSQI) for assessing sleep quality, International Physical Activity Questionaire

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years to 60 Years (Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
For patients:
- Informed consent
- Patients with diagnosed POTS (for criteria, see above)
- Age: ≥18 years and ≤ 60 years
For healthy volunteers:
- Informed consent
- Age: ≥18 years and ≤ 60 years
Exclusion Criteria:
For patients:
- Pregnancy and Breastfeeding
- Due to clinical reasons the current medication for POTS can not be discontinued
For healthy volunteers:
- Pregnancy and Breastfeeding
- Intake of vasoactive medication or known, non-treated arterial hypertension
- Known vasovagal syncope in medical history

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03253120
Switzerland | |
Inselspital Bern | |
Bern, Switzerland, 3010 |
Principal Investigator: | Werner Z'Graggen, MD | Inselspital Bern, Department of Neurosurgery and Neurology |
Responsible Party: | University Hospital Inselspital, Berne |
ClinicalTrials.gov Identifier: | NCT03253120 |
Other Study ID Numbers: |
2017-01368 |
First Posted: | August 17, 2017 Key Record Dates |
Last Update Posted: | February 10, 2022 |
Last Verified: | February 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Postural Orthostatic Tachycardia Syndrome Tachycardia Syndrome Disease Pathologic Processes Arrhythmias, Cardiac Heart Diseases |
Cardiovascular Diseases Cardiac Conduction System Disease Orthostatic Intolerance Primary Dysautonomias Autonomic Nervous System Diseases Nervous System Diseases |