Document Type : Original article
Authors
1
Department of Cognitive Neuroscience Faculty of Educational Sciences and Psychology, University of Tabriz, Tabriz, Iran
2
Department of Cognitive Neuroscience, Faculty of Educational Sciences and . Psychology, University of Tabriz, Tabriz, Iran.
3
Department of Educational Sciences, Faculty of Educational Sciences and Psychology, University of Tabriz, Tabriz, Iran
4
Psychiatrist, University of Tabriz, Tabriz, Iran.
5
Department of Biomedical Engineering, Faculty of Engineering, Shahed University, Tehran, Iran.
10.22037/sjrm.2025.117415.3343
Abstract
Background and Aims: Generalized Anxiety Disorder (GAD) is a chronic psychiatric condition characterized by excessive and uncontrollable worry, which significantly impairs both cognitive and emotional functioning. Empirical evidence has indicated that heightened anxiety levels are commonly associated with deficits in attention and concentration. Furthermore, neurophysiological studies have highlighted that absolute theta power plays a crucial role in attentional processes, whereas both alpha and theta absolute power are critically involved in anxiety regulation. Based on these findings, the present study aims to evaluate the efficacy of transcranial Direct Current Stimulation (tDCS) in modulating the absolute power of alpha and theta brainwaves and enhancing visual and auditory attention in individuals with GAD.
Materials and Methods: This clinical study was conducted as a single-blind, randomized trial involving 24 patients diagnosed with GAD, using a pre-test/post-test control group design. The study took place in Tabriz, Iran, during the years 2023 and 2024. Participants, aged between 18 and 40 years, were recruited from medical centers in Tabriz. Following clinical evaluations by a psychiatrist and screening with the Generalized Anxiety Disorder 7-item (GAD-7) scale, which assesses the impact of GAD on individual, social, familial, and occupational functioning, participants were randomly assigned to either the experimental group (n=12) or the control group (n=12). Both groups completed the Integrated Visual and Auditory Continuous Performance Test (IVA-2) and quantitative electroencephalography (qEEG) to evaluate visual and auditory attention and to measure absolute power in alpha and theta brainwave bands, respectively, both before and after the intervention. The experimental group received transcranial Direct Current Stimulation (tDCS) over 10 sessions, administered every other day. Each session involved 30 minutes of stimulation at an intensity of 2 mA, targeting the orbitofrontal cortex with electrodes placed at Fp1 (anode) and Fp2 (cathode). The control group received sham stimulation using the same electrode placements. Post-intervention, alpha and theta absolute power were recorded via qEEG, and attentional performance was reassessed using the IVA-2. Data were analyzed using the Statistical Package for the Social Sciences (SPSS).
Results: The statistical analyses revealed a significant relationship between the activity of theta and alpha brainwaves and visual and auditory attention in individuals with GAD. Specifically, the absolute power of theta waves showed a notable decrease from 108.28 to 85.89, while the absolute power of alpha waves increased from 73.66 to 175.33. In parallel, visual attention scores improved significantly from 596.86 to 1836.34, and auditory attention scores increased from 503.57 to 1850.3 following the intervention.
Conclusion: The findings of this study demonstrate the effectiveness of tDCS in modulating the absolute power of alpha and theta brainwaves, aimed at enhancing visual and auditory attention performance in individuals with GAD. Further research is warranted to optimize tDCS protocols and investigate the long-term effects of this neuromodulation technique.
Keywords
Main Subjects
)