Neurophysiological Mechanisms of Placebo and Nocebo Effects in Sports - a Protocol Paper

NCT06835777 | Not Yet Recruiting

• 1 other identifier: ETH2324-0198
• Study Type: interventional
• Target: 56
• Locations: 1 country
• Sites: 1

Brief Summary

This clinical trial aims to investigate the neurophysiological mechanisms of placebo and nocebo effects on sports performance, using Electroencephalography (EEG) and isometric strength testing of the lower extremities. The primary objective of this trial is to identify temporal mechanisms and cortical regions and networks involved in generating placebo and nocebo effects before (expectation) and at onset of athletic performance (perception). The trial will include four groups, two of them experimental, one an active control and one natural history, meaning participants in this group will receive no intervention and won't be EEG controlled. Data will be collected on two occasions with baseline data for EEG, expectations and performance as well as key participant characteristics being collected on day one. On day two, in a deceptive process, participants in the two experimental groups will take an inert substance presented as either performance enhancing or inhibiting and subsequently experience a reinforcement of beliefs via exposure to explicit adjectives. EEG data will be collected during reinforcement of beliefs. In the active control group, participants will receive no substance, but this group will follow the same procedure as the experimental groups with neutral adjectives. Participants will then perform isometric strength and fatigue resistance tests on an isometric dynamometer. EEG data as well as subjective data on expectations and rating of perceived exhaustion will be collected.

Conditions

Placebo Effect; Nocebo Effect

Keywords

EEG; Placebo; Nocebo; Sports Performance

Outcome Measures

Primary Outcomes (3)

• EEG data - performance

  Temporal neurophysiological data measured by EEG. The Continuous Negative Variation (CNV), an Event Related Potential (ERP), will be used to differentiate positive and negative expectations as well as motor preparation before and at onset of isometric strength testing.

  From collection of baseline data on day one to the end of day two of data collection.

• EEG data - reinforcement of beliefs

  Event related potentials (ERP) will be investigated during the reinforcement of beliefs, specifically the late positive potential (LPP) and the late positive component (LPC).

  From collection of baseline data on day one to the end of day two of data collection.

• EEG, exploratory source analysis

  In addition to ERP data, Low-Resolution Electromagnetic Tomography (LORETA) will be used in an exploratory approach to identify specific neural origins associated with placebo and nocebo responses.

  From collection of baseline data on day one to the end of day two of data collection

Secondary Outcomes (7)

• Performance Output, Isometric Forces

  From collection of baseline data on day one to the end of day two of data collection.

• Performance Output, Force Consistency

  From collection of baseline data on day one to the end of day two of data collection.

• Performance Output, Endurance Hold and Fatigue Resistance

  From collection of baseline data on day one to the end of day two of data collection.

• Performance Output, Recovery Capacity

  From collection of baseline data on day one to the end of day two of data collection.

• Heartrate

  From collection of baseline data on day one to the end of day two of data collection.

Other Outcomes (8)

• Questionnaires - Anxiety

  From collection of baseline data on day one to the end of day two of data collection.

• Questionnaires - Motivation and Perception of Ability

  From collection of baseline data on day one to the end of day two of data collection.

• Questionnaires - Optimism

  From collection of baseline data on day one to the end of day two of data collection.

Study Arms (4)

positive-expectations

EXPERIMENTAL

The positive-expectations intervention will consist of two inert pills filled with cornstarch and a manipulation of beliefs regarding the given substance and it's effects. Participants will be informed that the inert pills are neurostimulants, usually used in the context of depression and other mental health issues and that they can positively affect sports performance. Participants will be reinforced about these effects throughout testing via implicit adjectives regarding potential sensations they might experience after pill intake. Reinforcement of beliefs and subsequent strength testing will be EEG controlled.

Combination Product: Positive Expectation

negative-expectations

EXPERIMENTAL

The negative-expectations intervention will consist of two inert pills filled with cornstarch and a manipulation of beliefs regarding the given substance and it's effects. Participants will be informed that the inert pills are neuro-depressants, which relieve anxiety and can negatively affect sports performance. Participants will be reinforced about these effects throughout testing via implicit adjectives regarding potential sensations they might experience after pill intake. Reinforcement of beliefs and subsequent strength testing on day two will be EEG controlled.

Combination Product: Negative Expectation

control

ACTIVE COMPARATOR

The control intervention consists of the same testing procedure as the other intervention groups, but no pills or manipulation of beliefs will be administered. Participants will be given a neutral presentation on the testing procedure of the isometric strength testing. Neutral adjectives will be presented instead of a reinforcement of beliefs. Presentation of adjectives and subsequent strength testing will be EEG controlled.

Other: Control

natural history

NO INTERVENTION

Participants will neither receive an EEG nor any sort of intervention. They will do the isometric strength testing on two different occasions like the other groups and will not receive any sort of manipulation of beliefs.

Interventions

Positive Expectation COMBINATION_PRODUCT

The lead researcher will deliver a short presentation (8 minutes) to participants informing them about the deceptive substance, presenting it as a performance enhancing neurostimulant,. Participants will be given the opportunity to ask questions and will receive a handout of the key points of the presentation. After the presentation, participants will be set up with a high-density EEG and given two inert pills filled with cornstarch. Participants will be reminded of the performance enhancing qualities of the deceptive substance by implicit adjectives on a screen. Afterwards, experimental performance outcomes will be collected using a dynamometer.

positive-expectations

Negative Expectation COMBINATION_PRODUCT

The lead researcher will deliver a short presentation (8 minutes) to participants informing them about the deceptive substance, presenting it as a performance inhibiting neuro-depressant. Participants will be given the opportunity to ask questions and will receive a handout of the key points of the presentation. After the presentation, participants will be set up with a high-density EEG and given two inert pills filled with cornstarch. Participants will be reminded of the performance inhibiting qualities of the deceptive substance by implicit adjectives on a screen. Afterwards, experimental performance outcomes will be collected using a dynamometer.

negative-expectations

Control OTHER

The lead researcher will deliver a short presentation (8 minutes) to participants informing them about EEG research and set ups and give general information about isometric strength testing. They will be shown neutral adjectives unrelated to performance instead of implicit adjectives related to performance (experimental groups). EEG set up and strength testing remains the same as the experimental groups.

control

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy adult participants (18+)
• physically active (WHO, 2020)
• no medical history pf psychological disorders/mental health issues
• no acute or regular medication intake
• no severe injury to the lower limb within the last 6 months
• proficient in english
• normal or corrected eyesight

Sponsors & Collaborators

• Canterbury Christ Church University: lead

Study Sites (1)

Canterbury Christ Church University

Canterbury, Kent, CT1 1QU, United Kingdom

Location

Central Study Contacts

Janina Hanssen, M.Sc.

CONTACT

07553606641; JH1718@canterbruy.ac.uk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD Candidate

Model Details: randomised controlled trail, four parallel arms (positive-expectations, negative-expectations, control , natural history)

Study Record Dates

• First Submitted: February 10, 2025
• First Posted: February 19, 2025
• Study Start: March 1, 2025
• Primary Completion: December 31, 2025
• Study Completion: December 31, 2025
• Last Updated: February 19, 2025

Record last verified: 2025-02

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)