Intracranial Pressure and Brain Function: Effects of Head Down Tilt Upon Brain Perfusion and Cognitive Performance (IPCog)

The aim of the study is to understand the relationship between intracranial pressure regulation, cerebral tissue oxygenation and cognitive functioning. More specifically, the study tests the hypothesis that head down tilt will increase intracranial pressure (not measured in this study, but demonstrated in previous studies), will induce venous congestion and facial swelling, decrease intracranial tissue oxygenation and hamper brain functioning. The objectives of the study therefore are to assess young healthy people during head-down tilt (HDT), and to assess cognitive brain functioning, cerebral tissue oxygenation (non-invasively), frontal skin thickness, cerebral perfusion and neuronal functioning via event-related potentials.

Study Overview

• Status: Completed
• Conditions: Intracranial Hypertension
• Intervention / Treatment: Other: 12° head down tilt

• Study Type: Interventional
• Enrollment (Actual): 13
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Cologne, Germany, 51147
    • DLR German Aerospace Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Physically and mentally healthy male test subjects that are able and declare in writing their willingness to participate in the entire study and successfully passed the psychological and medical screening
• Aged between 18-55 years old with a Body Mass Index (BMI) of 20-28 kg/m2, weight between 65-100 kg, and a height between 158-195 cm
• Demonstrable medical insurance and official certificate of absence of criminal record

Exclusion Criteria:

• Inability to sleep on the back
• Drug, medication or alcohol abuse (regular consumption of more than 20-30 g alcohol/day)
• Smoking within the past 6 months prior to study commencement
• Migraine or other chronic head aches
• Previous psychiatric illness
• Subjects suffering from weak concentration
• History of psychological or central nervous disorders
• Hiatus hernia
• Gastro-oesophageal reflux
• Diabetes mellitus
• Pronounced orthostatic intolerance (< 10 min standing)
• Kidney disorder: deviations from normal values for creatinine in plasma. (Normal value: Creatinine < 1.20 mg/dl)
• Thyroid gland disorder: deviations from normal values for thyroid stimulating Hormone (TSH) in plasma. (Normal range: TSH 0.55-4.80 mUnits/l)
• Anaemia: Hb under normal values (Normal values of Hb for men: 13.5-17.5 g/l)
• Elevated risk of thrombosis
• High likelihood of coagulopathy assessed by a clinical standard questionnaire
• Chronic back complaints
• History of lumbar surgery
• History of lumbar spine trauma
• Motor or sensory deficits as assessed by neurological examination
• Contraindications against MRI
• Imprisoned at the time of the study
• Taking medications that may impair cognitive function, autonomic function or any of the study procedures
• Ophthalmological conditions including glaucoma, retinopathy, severe cataracts, eye trauma or implants
• Any other medical condition that the investigators consider a contraindication to the study procedures that would make it unsafe or confound the measurements.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: NONE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
NO_INTERVENTION: Horizontal; Subjects will be in horizontal supine Position for 21 hours
EXPERIMENTAL: -12° head down tilt; Subjects will be in 12° head down supine Position for 21 hours	Other: 12° head down tilt; supine head down tilt

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in cognitive test battery score	The test battery includes sensomotoric speed, psychomotor vigilance, visual analysis of items, abstract thinking and mathematical processing	Twice at baseline, and 30 minutes and 20 hours after starting the intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in mid cerebral artery blood flow velocity	Transcranial Doppler measurements	Twice at baseline, and 10 minutes and 19 hours after starting the intervention
Change in cerebral tissue oxygenation	Near-infrared measurement	Twice at baseline, and 10 minutes and 19 hours after starting the intervention
Magnetic resonance Imaging: Change in cerebral blood flow	Magnetic resonance imaging will be performed in order to gain information about intracranial blood flow.	Once at baseline, and 2 and 19 hours after starting the intervention
Magnetic resonance Imaging: Change in resting state functional MRI (fMRI)	Magnetic resonance imaging will be performed to assess resting state functional MRI.	Once at baseline, and 2 and 19 hours after starting the intervention
Magnetic resonance Imaging: Change in fMRI Response to decision task	Magnetic resonance imaging will be performed in order to assess functional MRI during a decision task combing a reaction time test using a visual stimulus.	Once at baseline, and 2 and 19 hours after starting the intervention
Change in jugular vein filling	Conventional Imaging ultrasound from jugular veins veins will be used to assess vein cross sections	Once at baseline, and 10 minutes and 19 hours after starting the intervention
Change in frontal vein filling	Conventional Imaging ultrasound from the frontal veins will be used to assess vein cross sections	Once at baseline, and 10 minutes and 19 hours after starting the intervention
Change in P-300	P-300 will be assessed via an EEG electrode during cognitive test battery	Twice at baseline, and 30 minutes and 20 hours after starting the intervention
Change in sleep effectiveness	Polysomnographic recordings	over the entire intervention night
Change in total sleep time	Polysomnographic recordings	from 22:00 until 6:00 in all nights

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in frontal skin thickness	Conventional Imaging ultrasound will be used to assess Skin thickness at the frontal skull	Once at baseline, and 10 minutes and 19 hours after starting the intervention
Change in arterial blood pressure	arterial blood pressure will be assessed non-invasively from a finger artery during transcranial doppler measurements	Twice at baseline, and 10 minutes and 19 hours after starting the intervention
Change in heart rate	ECG will be recorded during transcranial doppler measurements	Twice at baseline, and 10 minutes and 19 hours after starting the intervention

Collaborators and Investigators

• Sponsor: DLR German Aerospace Center
• Collaborators: University of Cologne; University Hospital, Umeå; Forschungszentrum Juelich
• Investigators: Principal Investigator: Jörn E Rittweger, MD, German Aerospace Center

Publications and helpful links

General Publications

• Boschert AL, Elmenhorst D, Gauger P, Li Z, Garcia-Gutierrez MT, Gerlach D, Johannes B, Zange J, Bauer A, Rittweger J. Sleep Is Compromised in -12 degrees Head Down Tilt Position. Front Physiol. 2019 Apr 16;10:397. doi: 10.3389/fphys.2019.00397. eCollection 2019.

Study record dates

Study Major Dates

• Study Start: March 1, 2016
• Primary Completion (ACTUAL): November 1, 2016
• Study Completion (ACTUAL): November 1, 2016

Study Registration Dates

• First Submitted: November 18, 2016
• First Submitted That Met QC Criteria: November 23, 2016
• First Posted (ESTIMATE): November 29, 2016

Study Record Updates

• Last Update Posted (ACTUAL): March 3, 2017
• Last Update Submitted That Met QC Criteria: March 1, 2017
• Last Verified: March 1, 2017

More Information

Terms related to this study

• Keywords: cerebral perfusion; Cognitive functioning; Brain tissue oxygenation; head down tilt
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Intracranial Hypertension
• Other Study ID Numbers: IPCog

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED