Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach (Substudy 4 of 7)

Systematically Assessing Effects of Colored Light on Humans With a Multi-modal Approach

NOTE: This is the fourth of in total 7 sub-studies related to the Ethics Committee of the Canton of Bern Ref. No. KEK-BE 2016-00674. This sub-study includes 50 participants and 8 arms, in total 350 participants will be assessed in all 7 sub-studies.

General study information: This is a randomized, cross-over, quantitative study, which investigates physiological variables, mood, and affect of healthy participants in response to colored light exposure. The Participants take part in 5-8 arms and are exposed to colored light only, or are additionally asked to solve cognitive tasks during the colored light exposure. Primary aim is to measure the change in several physiological variables, mood, and affect during colored light exposure of 15 or 45 minutes. The risk for the participants is negligible and comparable to the risk during daily life.

Study Overview

• Status: Completed
• Conditions: Exposure to Man-made Visible Light
• Intervention / Treatment: Other: Visible light exposure

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Bern, Switzerland, 3012
    • University of Bern, Institute of Complementary Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Normal color vision
• Right handed
• Written informed consent

Exclusion Criteria:

• Smoking
• Any kind of diagnosed sleep disorder or neurological or psychiatric disorder in the last 3 months
• Acute severe traumas
• Chronic diseases with the necessity for medication
• Use of recreational drugs
• Regular intake of medication that would affect the outcome measures
• Regular excessive alcohol use (> 18 standard units / week)
• Transmeridian travel in the last month (crossed > 1 time zone border)
• Night shift word during the last month

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

8

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Visible light exposure cognitive Red; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to red LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive Orange; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to orange LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive Yellow; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to yellow LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive Green; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to green LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive Cyan; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to cyan LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive Blue; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to blue LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive Violet; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to violet LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.
Experimental: Visible light exposure cognitive White; The participants will be tested for cognitive performance (verbal fluency task, arithmetic task, word repetition task) during exposure to white LED light at a fixed illuminance for 15 minutes. The colored light exposure will be preceded by sitting 8 minutes in darkness and followed by sitting 20 minutes in darkness. The participants will additionally perform hyperventilation and hypoventilation tasks.	Other: Visible light exposure; Subjects will be exposed to visible colored light for 15 minutes. The visible light will be generated by red-green-blue light emitting diodes light cans.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in cerebral tissue oxygen saturation during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in variables of the heart rate variability during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in variables of the electro-dermal activity during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the blood pressure during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the partial pressure of carbon dioxide during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the respiration rate during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the heart rate during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the pulse-respiratory quotient during colored light exposure compared with a baseline and a recovery period	The pulse-respiratory quotient will be calculated as heart rate divided by the respiration rate.	43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change of the arterial oxygen saturation during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)
Change in cerebral hemoglobin concentrations during colored light exposure compared with a baseline and a recovery period		43 minutes (8 min baseline, 15 min colored light exposure, 20 min recovery)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in verbal fluency task performance during exposure to different colors.	A word repetition task will serve as control condition.	1-4 weeks
Change in arithmetic task performance during exposure to different colors.	A word repetition task will serve as control condition.	1-4 weeks
Difference in brain activity evoked from the verbal fluency task for the different colored light conditions.	A word repetition task will serve as control condition.	1-4 weeks
Difference in brain activity evoked from the arithmetic task for the different colored light conditions.	A word repetition task will serve as control condition.	1-4 weeks

Collaborators and Investigators

• Sponsor: University of Bern
• Investigators: Principal Investigator: Ursula Wolf, Prof. Dr., University of Bern

Publications and helpful links

General Publications

• Weinzirl J, Wolf M, Nelle M, Heusser P, Wolf U. Colored light and brain and muscle oxygenation. Adv Exp Med Biol. 2012;737:33-6. doi: 10.1007/978-1-4614-1566-4_5. No abstract available.
• Weinzirl J, Wolf M, Heusser P, Nelle M, Wolf U. Effects of changes in colored light on brain and calf muscle blood concentration and oxygenation. ScientificWorldJournal. 2011 Jun 9;11:1216-25. doi: 10.1100/tsw.2011.118.

Helpful Links

• Link to further information on the study

Study record dates

Study Major Dates

• Study Start (Actual): August 18, 2017
• Primary Completion (Actual): October 8, 2018
• Study Completion (Actual): January 18, 2020

Study Registration Dates

• First Submitted: August 24, 2016
• First Submitted That Met QC Criteria: September 27, 2016
• First Posted (Estimate): September 29, 2016

Study Record Updates

• Last Update Posted (Actual): September 17, 2021
• Last Update Submitted That Met QC Criteria: September 16, 2021
• Last Verified: September 1, 2021

More Information

Terms related to this study

• Keywords: blood pressure; functional near-infrared spectroscopy; heart rate variability; mood; affect; respiration; cerebral oxygen metabolism; partial pressure of carbon dioxide; systematic randomized cross-over study; systemic physiology; electro-dermal activity; pulse-respiratory quotient
• Other Study ID Numbers: COLOR10_d

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Access to research data and documents will be handled according to the Manifesto to advance Data Access and Research Transparency (DART) in Switzerland, formulated at the workshop on "Improving DART in Switzerland" in Bern, November 7th, 2014.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No