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Anodal tDCS Over Left PPC Enhances Visuospatial Attention and Alpha Power Among Young Adults

3. juni 2026 opdateret af: Halime Avunc, Medipol University

Background: Visuospatial attention enables individuals to detect and process relevant stimuli efficiently. The posterior parietal cortex (PPC), a core hub of the dorsal attention network, exerts top-down control over visual scanning and is closely linked to alpha-band oscillations (8-13 Hz), which index attentional allocation and inhibition of distractors. Transcranial direct current stimulation (tDCS) offers a noninvasive method to alter cortical excitability transiently, but evidence for its effects on PPC-mediated attention and alpha power remains mixed.

Objective: This randomized, single-blind trial examined whether anodal tDCS over the left PPC modulates visuospatial attention and resting-state alpha power in young adults, and whether EEG changes predict behavioral performance.

Method: Thirty-two healthy participants (18-40 years) were randomized to anodal (2 mA, 20 min; n=15) or sham (n=17) stimulation. Cancellation Test performance and resting-state EEG were assessed pre- and post-stimulation. EEG analyses focused on artifact-free alpha power; regression models probed associations between neural and behavioral changes.

Studieoversigt

Undersøgelsestype

Interventionel

Tilmelding (Faktiske)

32

Fase

  • Ikke anvendelig

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiesteder

    • İ̇stanbul
      • Beykoz, İ̇stanbul, Tyrkiet (Türkiye), 34820
        • Istanbul Medipol University

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

  • Voksen

Tager imod sunde frivillige

Ja

Beskrivelse

Inclusion Criteria:

  • Age between 18 and 40 years
  • Score of 21 or higher on the Montreal Cognitive Assessment Scale (MoCA)

Exclusion Criteria:

  • History of neurological or psychiatric illness
  • Uncorrected visual impairments
  • MoCA score of 21 or lower
  • Use of medications affecting cortical excitability
  • History of seizures or epilepsy
  • Presence of intracranial metal objects, implanted stimulating devices, or pacemakers

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Grundvidenskab
  • Tildeling: Randomiseret
  • Interventionel model: Parallel tildeling
  • Maskning: Enkelt

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Eksperimentel: Anodal tDCS Group
Anodal tDCS Protocol: In the Anodal tDCS participant group, a direct current of 2 mA was applied for 20 minutes in accordance with the safety guidelines. To provide cortical stimulation, the superficial anodal electrode of the device was placed on the P3 region (left PPC), which is located in the left superior parietal lobe, corresponds to Brodmann area (BA) 40, and is associated with the dorsal visual pathway according to the international 10-20 EEG system. The reference electrode was placed on the contralateral (opposite) shoulder.
Sham-komparator: Sham tDCS Group
Sham tDCS Protocol: The anode superficial electrode of the device was placed on the P3 region (left PPC), located in the left superior parietal lobe, corresponding to Brodmann area (BA) 40, and associated with the dorsal visual pathway according to the international 10-20 EEG system. The reference electrode was placed on the contralateral (opposite) shoulder. In the Sham tDCS group, a single 20-minute sham session was administered over the left posterior parietal cortex (P3) without delivering current, in accordance with the safety guidelines.

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
EEG recording and power in alpha band
Tidsramme: Before and immediately after applying tDCS
EEG recordings were acquired in a semi-dark, electrically shielded Faraday room using a BrainAmp 32-Channel DC System (Brain Products, Munich, Germany). Signals were sampled at 500 Hz with a 0.01-250 Hz bandpass filter and recorded using BrainVision Recorder software. A 32-channel Ag/AgCl electrode cap (Easycap) was positioned according to the international 10-20 system. Resting-state EEG data were collected for 4 minutes with eyes open and 4 minutes with eyes closed. Numerical evaluation of artifact-free EEG data for power density calculation is performed using Fast Fourier Transform (FFT) with 0.5 Hz frequency resolution, and alpha (8-13 Hz) bands were calculated and then averaged over these power spectrum values. The amplitude values, measured from peak to peak, were recorded for each individual, and the necessary data for statistical analysis were collected.
Before and immediately after applying tDCS
Cancellation Test
Tidsramme: Before and immediately after applying tDCS
The Cancellation Test is one of the most widely used tools for assessing visuospatial attention. IT consists of four subtests arranged on A4-sized sheets. Each subtest includes 60 target stimuli distributed among 300 total stimuli. For each subtest, separate scores are calculated for the right and left sides, including the number of correctly marked targets (IT1), omitted targets (IT2), incorrectly marked letters/shapes (IT3), total error score (IT4), and scanning time (IT5). The total error score is calculated as the sum of omitted targets and incorrectly marked letters/shapes. Achieving a high score (i.e., a high number of correctly marked targets and a low number of errors) and a short completion time (time score) indicate better performance. İn the present study, the paper-and-pencil version of the Cancellation Test was chosen to reliably assess visuospatial attention and subtle tDCS-induced changes.
Before and immediately after applying tDCS

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Efterforskere

  • Studieleder: Lütfü Hanoğlu, Professor, Medipol University
  • Studiestol: Mevhibe Sarıcaoğlu, PhD, Medipol University
  • Studieleder: Miray Budak, PhD, Rutgers University-Newark
  • Studiestol: Fatma Aydın, MsC, Medipol University

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Faktiske)

1. februar 2021

Primær færdiggørelse (Faktiske)

1. juli 2021

Studieafslutning (Faktiske)

1. november 2021

Datoer for studieregistrering

Først indsendt

22. maj 2026

Først indsendt, der opfyldte QC-kriterier

3. juni 2026

Først opslået (Faktiske)

4. juni 2026

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

4. juni 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

3. juni 2026

Sidst verificeret

1. maj 2026

Mere information

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