Nocebo Effects on Muscular Performance - An Experimental Study About Clinical Situations

Area of Science:

• Medical Psychology
• Clinical Physiology

Background:

• Nocebo effects, triggered by negative communication, are prevalent in clinical settings.
• Objective data on the impact of negative communication on physiological responses is limited.

Purpose of the Study:

• To quantify the immediate effects of verbal and non-verbal medical communication on muscular performance.
• To identify specific communication elements that induce nocebo effects and test alternative phrasings.

Main Methods:

• An experimental study involving 46 volunteers using dynamometry to measure maximal muscle strength (arm abduction).
• Exposure to 18 verbal and non-verbal suggestions, comparing negative formulations with positive alternatives.
• Baseline strength was compared to performance after suggestion exposure.

Main Results:

• Verbal and non-verbal suggestions significantly reduced maximal muscle strength, primarily through weakening effects.
• Negative communication, such as discussing risks, pain, or medical procedures, decreased strength (e.g., risk info to 91.4%, pain/nausea to 89.4%).
• Positive or neutral alternatives and specific non-verbal cues (e.g., face-to-face induction, landscape view) mitigated or eliminated strength reduction.

Conclusions:

• A simple, objective test using muscle strength can identify and quantify negative suggestions (nocebo effects).
• Muscle strength is a relevant clinical parameter affected by negative communication, potentially reflecting a general 'weakening effect'.
• This method aids in developing and verifying communication strategies to prevent nocebo effects and improve patient care.