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

NCT ID: NCT07141979

Last Updated: 2025-08-26

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

48 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-09-01

Study Completion Date

2026-07-31

Brief Summary

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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.

Detailed Description

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Measurement instruments:

Informed Voluntary Consent Form Demographic Information Form Edinburgh Hand Preference Survey Beck Depression Scale Test of Orthorexia Nervosa (TON-17) Cognitive Flexibility Task EEG and tDCS devices Statistics: Statistical analyses will be conducted using SPSS 25.0 (Statistical Package for Social Sciences) for Windows, and EEG data will be analyzed using the Brain-Vision Analyzer software.

Descriptive statistics for group variables such as age and education will be presented as means and standard deviations, while gender will be reported as frequency and percentage.

The normality of the distribution of variables will be assessed using the Kolmogorov-Smirnov test, and appropriate parametric or non-parametric tests will be applied based on the results.

To evaluate pre-test and post-test data for cognitive flexibility and EEG measures in the experimental and control groups, Repeated Measures Analysis of Variance (within- and between-subjects) or its non-parametric equivalent, the Friedman Test, will be used.

For all statistical tests, a significance level of p \< 0.05 will be considered as the threshold for statistical significance.

Conditions

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Orthorexia Nervosa

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

It is an experimental, randomised controlled trial. The data will be collected with the convenience sampling method from volunteer healthy people and individuals with orthorexia nervosa. The matched-group design method will be used.
Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Participants
Participants will not know that which group they will be in

Study Groups

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Experimental group

Participants will take active tDCS stimulation

Group Type ACTIVE_COMPARATOR

Active tDCS

Intervention Type DEVICE

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

Control group

Participants will take sham tDCS stimulation

Group Type SHAM_COMPARATOR

Sham tDCS

Intervention Type DEVICE

20 min, left DLPFC Sham tDCS

Interventions

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Active tDCS

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

Intervention Type DEVICE

Sham tDCS

20 min, left DLPFC Sham tDCS

Intervention Type DEVICE

Eligibility Criteria

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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
Minimum Eligible Age

18 Years

Maximum Eligible Age

40 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Istanbul Medipol University Hospital

OTHER

Sponsor Role lead

Responsible Party

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Bahar Güntekin

Prof. Dr., Principal Investigator

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

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Istanbul Medipol University

Istanbul, , Turkey (Türkiye)

Site Status

Countries

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Turkey (Türkiye)

Central Contacts

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Saliha Şahintürk Şentürk, PhD

Role: CONTACT

+90 531 566 03 22

Melek Özden, PhD

Role: CONTACT

+90 5079771646

Facility Contacts

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Saliha Şahintürk Şentürk, PhD

Role: primary

+90 531 566 03 22

References

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Emek Savas DD, Yerlikaya D, G Yener G, Oktem Tanor O. Validity, Reliability and Normative Data of the Stroop Test Capa Version. Turk Psikiyatri Derg. 2020 Spring;31(1):9-21. doi: 10.5080/u23549. English, Turkish.

Reference Type BACKGROUND
PMID: 32594475 (View on PubMed)

Du M, Peng Y, Li Y, Zhu Y, Yang S, Li J, Zou F, Wang Y, Wu X, Zhang Y, Zhang M. Effect of trait anxiety on cognitive flexibility: Evidence from event-related potentials and resting-state EEG. Biol Psychol. 2022 Apr;170:108319. doi: 10.1016/j.biopsycho.2022.108319. Epub 2022 Mar 22.

Reference Type BACKGROUND
PMID: 35331781 (View on PubMed)

Dong G, Wang Y, Chen X. Anodal occipital tDCS enhances spontaneous alpha activity. Neurosci Lett. 2020 Mar 16;721:134796. doi: 10.1016/j.neulet.2020.134796. Epub 2020 Jan 30.

Reference Type BACKGROUND
PMID: 32006627 (View on PubMed)

Donaldson PH, Kirkovski M, Yang JS, Bekkali S, Enticott PG. High-definition tDCS to the right temporoparietal junction modulates slow-wave resting state power and coherence in healthy adults. J Neurophysiol. 2019 Oct 1;122(4):1735-1744. doi: 10.1152/jn.00338.2019. Epub 2019 Aug 28.

Reference Type BACKGROUND
PMID: 31461371 (View on PubMed)

Darna M, Stolz C, Jauch HS, Strumpf H, Hopf JM, Seidenbecher CI, Schott BH, Richter A. Frontal theta oscillations and cognitive flexibility: Age-related modulations in EEG activity. Aging Brain. 2025 Jun 24;8:100142. doi: 10.1016/j.nbas.2025.100142. eCollection 2025.

Reference Type BACKGROUND
PMID: 40620518 (View on PubMed)

Chrysikou EG, Hamilton RH, Coslett HB, Datta A, Bikson M, Thompson-Schill SL. Noninvasive transcranial direct current stimulation over the left prefrontal cortex facilitates cognitive flexibility in tool use. Cogn Neurosci. 2013;4(2):81-9. doi: 10.1080/17588928.2013.768221.

Reference Type BACKGROUND
PMID: 23894253 (View on PubMed)

Cavinato M, Genna C, Formaggio E, Gregorio C, Storti SF, Manganotti P, Casanova E, Piperno R, Piccione F. Behavioural and electrophysiological effects of tDCS to prefrontal cortex in patients with disorders of consciousness. Clin Neurophysiol. 2019 Feb;130(2):231-238. doi: 10.1016/j.clinph.2018.10.018. Epub 2018 Nov 29.

Reference Type BACKGROUND
PMID: 30580246 (View on PubMed)

Borwick C, Lal R, Lim LW, Stagg CJ, Aquili L. Dopamine depletion effects on cognitive flexibility as modulated by tDCS of the dlPFC. Brain Stimul. 2020 Jan-Feb;13(1):105-108. doi: 10.1016/j.brs.2019.08.016. Epub 2019 Aug 31.

Reference Type BACKGROUND
PMID: 31494070 (View on PubMed)

Berchio C, Annen LC, Bouamoud Y, Micali N. Temporal dynamics of cognitive flexibility in adolescents with anorexia nervosa: A high-density EEG study. Eur J Neurosci. 2023 Mar;57(6):962-980. doi: 10.1111/ejn.15921. Epub 2023 Feb 7.

Reference Type BACKGROUND
PMID: 36683346 (View on PubMed)

Alizadehgoradel J, Nejati V, Sadeghi Movahed F, Imani S, Taherifard M, Mosayebi-Samani M, Vicario CM, Nitsche MA, Salehinejad MA. Repeated stimulation of the dorsolateral-prefrontal cortex improves executive dysfunctions and craving in drug addiction: A randomized, double-blind, parallel-group study. Brain Stimul. 2020 May-Jun;13(3):582-593. doi: 10.1016/j.brs.2019.12.028. Epub 2020 Jan 3.

Reference Type BACKGROUND
PMID: 32289681 (View on PubMed)

Aboulafia-Brakha T, Manuel AL, Ptak R. Prefrontal transcranial direct current stimulation facilitates affective flexibility. Neuropsychologia. 2016 Jun;86:13-8. doi: 10.1016/j.neuropsychologia.2016.03.030. Epub 2016 Mar 30.

Reference Type BACKGROUND
PMID: 27039163 (View on PubMed)

Other Identifiers

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E-10840098-202.3.02-35.59

Identifier Type: -

Identifier Source: org_study_id

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