Effects of tDCS on Cognitive Flexibility and EEG Oscillations in Orthorexia Nervosa

NCT07141979 · tracked via the Priya Life Science Turkey tracker

Sponsor

Istanbul Medipol University Hospital

Phase

Not applicable

Started

2025-11-01

Last updated

2026-04-01

Condition(s) studied

Orthorexia Nervosa

Investigational drug(s) / intervention(s)

Active tDCSSham tDCS

Active tDCS: 20 min, 2 milliampere (mA), Anodal tDCS in left DLPFC

Sham tDCS: 20 min, left DLPFC Sham tDCS

Study summary

Orthorexia Nervosa (ON); is a condition characterized by individuals being overly focused on healthy eating habits, constantly checking and classifying the foods they will consume. ON has not yet been clinically defined as an eating disorder or in a different category, and has not been included in DSM-5. Cognitive flexibility can be defined as a person's ability to quickly change their thinking and behaviors to adapt to different situations and changing conditions. It has been reported that cognitive flexibility skills are impaired in ON. There is evidence that tDCS, a neuromodulation method, increases cognitive flexibility skills. On the other hand, although there are EEG studies on eating disorders, there is no EEG study directly studying ON, and there is no information on the EEG profiles of individuals with high ON scores. For this reason, EEG studies on eating disorders and obsessive behaviors are generally generalized to orthorexia nervosa and are interpreted. This study aims to compare the EEG oscillations and cognitive flexibility skills of individuals with high ON scores with a control group and to examine the effects of anodal tDCS application on these two variables. For this purpose, a total of 48 individuals, 24 healthy and 24 high ON scores, will be included in the study. Participants will be randomly assigned to tDCS experimental and control groups. Therefore, 48 participants will be divided into 4 different subgroups of 12 people each. Data collection tools will be Informed Consent Form, Demographic Information Form, Beck Depression Inventory, Orthorexia Nervosa Test (TON-17), Cognitive flexibility task. First, participants will be subjected to a cognitive flexibility task by taking simultaneous EEG recordings, then tDCS stimulation will be initiated (active or sham) and after stimulation, a cognitive flexibility task will be performed by taking simultaneous EEG recordings again. EEG analyses will be performed using the Brain-Vision Analyzer program. Repeated Measures Analysis of Variance (within-group and between-groups) will be used in statistical analyses.

Eligibility

Sex

ALL

Min age

18 Years

Max age

40 Years

Healthy volunteers

Accepted

Inclusion Criteria: * Being between the ages of 18-40, * Having a score of 17 or less on the Beck Depression Inventory * Having a score of 61 or more on the Test for Orthorexia Nervosa (TON-17) for the orthorexia group Exclusion Criteria: * Having a history of serious neurological and psychiatric illness, * Currently taking medication that alters the cortical excitability level, * Having visual defects that cannot be corrected with glasses * Use of intracranial metal objects, implanted stimulating devices or pacemakers

Primary outcome measure(s)

Change in EEG Oscillations in individuals with Orthorexia Nervosa for active vs. sham stimulation — Baseline, 5 minutes after completion of the active/sham stimulation
The EEG oscillations recording the event brain oscillations during the cognitive flexibility task from pre and post measurements. There are the five frequencies band which are Delta (0.5-3,5 Hz), Theta (4-7 Hz), Alpha (8-13 Hz), Beta (15-30 Hz) and Gamma (30-100 Hz). Data will be record simultaneously and analyzed. The analysis will be done with the BrainVisionAnalyzer program and power analysis will be made in Delta, Theta, Alpha, Beta, Gamma bands and the averages will be compared. Oscillations will be evaluated in terms of averages changing as an indicator of the effect of the neuromodulation preceding it.
Change in Cognitive Flexibility Task score in individuals with Orthorexia Nervosa for active vs. sham stimulation — Baseline, 20 minutes after completion of the active/sham stimulation
A structured task-switching paradigm will be used to measure cognitive flexibility skills from pre and post test score in individuals with Orthorexia Nervosa \* The paradigm consists of two conditions: trials with a task switch and trials without a task switch. The experiment will include two blocks, with a total of 320 trials. Each block will contain 160 phases, consisting of 80 trials with a task switch and 80 trials without a task switch. Score averages will compare between pre and post test. Data will be record Excel by Psychopy program simultaneously. Performance will be evaluated for accuracy as an indicator of the effect of the neuromodulation preceding it.

Trial sites (1)

Facility	City	Region	Status
Istanbul Medipol University	Istanbul	Turkey (Türkiye)	Recruiting

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Official registry record

This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.

View NCT07141979 on ClinicalTrials.gov ↗ ← All trials in Turkey