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Completed

NCT Number: NCT07550556

Neural Basis of the Effect of EMDR Therapy

This study aimed to investigate the effects of a single session of Butterfly Tapping (BT), a self-administered form of alternating bilateral stimulation, on emotional reactivity and its neurophysiological correlates. 46 participants will be randomly assigned to an experimental (Exp) or control (Con) group. The Exp group performed a 15-minute session of BT. Emotional reactivity was assessed before and after the stimulation using a detection task with emotional visual stimuli, presented during electroencephalographic (EEG) recording. EEG analyses were conducted using the event-related potential (ERP) method, specifically focusing on the differential amplitude (negative minus neutral) of the Late Positive Potential (LPP), a centro-parietal component associated with sustained processing of emotionally salient stimuli. Results revealed a significant LPP reduction in the Exp group at T1 compared to T0, whereas no change emerged in the Con group. The topographical distribution of the modulation was predominantly central, consistent with models implicating the LPP in higher-order integrative and evaluative processes. These findings provide preliminary neurophysiological evidence that BT may reduce cortical reactivity to negative emotional stimuli in young clinical populations, supporting its potential as a simple and accessible strategy capable of modulating affective responsiveness.

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Key information

Conditions

PTSD - Post Traumatic Stress Disorder Behavior Combat Disorders Emotional Regulation Mental Disorders Self-Control Social Behavior Stress Disorders, Post-Traumatic Stress Disorders, Traumatic Trauma and Stressor Related Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Rome Foro Italico

Rome, RM, 00135, Italy

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • normal or corrected-to-normal vision; full right-handedness

Exclusion criteria

  • neurological or other psychiatric disorders tha PTSD; current use of psychoactive medications.

Treatment and study plan

Butterfly Tapping (BT)

Behavioral

Participants adopted the traditional butterfly hug posture: arms crossed over the chest, fingertips placed below the clavicles.

They delivered alternating left-right rhythmic taps (~1 Hz) on their shoulders. Eyes remained closed, and participants were instructed to keep the emotional content active by mentally recalling previously viewed negative images, ensuring sustained affective engagement.

Duration: 15 minutes, structured in four blocks of 3 minutes with short pauses. No auditory pacing was provided to preserve spontaneous rhythmicity.

Targeted Mechanism Bilateral tactile stimulation aiming to modulate cortico-limbic processing, interhemispheric communication, and sustained emotional reactivity, as indexed by LPP amplitude during ta emotional simple response task

Other names: Alternating Bilateral Stimulation

No intervention control

Behavioral

Participants will adopt the same butterfly-hug position, with arms crossed and hands placed on the chest.

No rhythmic tapping or movements will be performed. Eyes are closed for the entire session, as in the experimental arm. Participants will held the emotional images in mind just as in the experimental arm.

Duration: 15 minutes, identical block structure and timing as the BT condition.

Targeted Mechanism

Serves as a posture-matched and expectancy-matched control, ruling out effects of:

simple stillness, emotional recall, attentional focus, physical posture, general relaxation effects.

Other names: static position, Static Posture Control, No Alternating Stimulation

Primary outcomes

  1. LPP

    Time frame: Baseline, End of Treatment (8-12 weeks), and Follow-up (8 weeks after treatment completion)

    Late Positive Potential (LPP) Differential Amplitude (Negative - Neutral) The primary neurophysiological outcome will be the modulation of the centro-parietal Late Positive Potential (LPP), extracted from EEG recordings during the Emotional Simple Response Task (E-SRT). The LPP is a well-established marker of sustained attentional and evaluative processing of emotional stimuli. For each participant and time point (T0, T1, T2), ERP waveforms willbe computed separately for negative and neutral images, and difference waves (negative minus neutral) were used to isolate emotion-specific neural reactivity.

    Primary analyses focused on mean amplitudes in the experimentally defined cLPP time window (456-552 ms) over the centro-parietal electrode cluster (Cz, C1, C2, CP1, CPz, CP2).

    The primary contrast of interest was the Group × Time interaction, assessing whether a single session of Butterfly Tapping selectively reduced the LPP differential amplitude relative to the static control condition.

Secondary outcomes

  1. Frontal positivity

    Time frame: Baseline, End of Treatment (8-12 weeks), and Follow-up (8 weeks after treatment completion)

    Frontal Positivity (188-228 ms). Is sn exploratory secondary marker, indexing early evaluative or response-related processing, quantified over the frontal region (F1, Fz, F2, FC1, FCz, FC2).

  2. Behavior

    Time frame: Baseline, End of Treatment (8-12 weeks), and Follow-up (8 weeks after treatment completion)

    Behavioral Performance:

    Response Time (RT) to emotional images Omission Rate (OM) Both extracted from the E-SRT before and after stimulation.

  3. Self-report

    Time frame: Baseline, End of Treatment (8-12 weeks), and Follow-up (8 weeks after treatment completion)

    Self-Reported Emotional State:

    State Anxiety (STAI-Y1) Emotional Discomfort (VAS) Collected immediately after each task block to assess subjective affective changes.

Sponsors and collaborators

Lead sponsor

University of Rome Foro Italico

Other

Registry information

Official study title

Neural Basis of the Effect of Eye Movement Desensitization and Reprocessing (EMDR) Therapy on Cognition in Patients With Post-Traumatic Stress Disorder

Acronym: EMDR-NEURO

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Apr 24, 2026
Registry last updated
May 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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