## 2 Materials and Methods
### Recruiting Subjects and the CES-D Survey  
Participants were recruited through QR code posters placed on building walls, directing them to a pre-test survey location. The survey employed was the Center for Epidemiologic Studies Depression Scale (CES-D), developed by [PERSON] to assess depressive symptoms [40]. A total of 56 individuals volunteered to participate in this study. All participants were fully informed of the study's objectives and procedures and provided written consent prior to participation. The CES-D survey, in addition to demographic questions, comprised 20 items, with scores categorized as follows: scores below 16 indicated no depression, scores between 16 and 24 indicated moderate depression, and scores above 25 indicated severe depression.  
Sixteen participants scored 25 or higher, indicating a severe level of depressive symptoms. These participants were right-handed, without any psychiatric history or physical issues related to mobility or vision. The CES-D scale demonstrated reliability, with a Cronbach's \(\alpha\) of 0.71. The selected participants had a mean age of 24.31 years (SD = 2.3), with a gender distribution of 18.8% male and 81.3% female. Each participant received USD 20 as compensation. This study adhered to ethical standards, with approval from the Institutional Review Board (IRB No. 1044396-202303-HR-043-01). EEG measurements were conducted following the 10-20 electrode placement system, as recommended by the American Society of Clinical Neurophysiology [41; 42].  
During EEG measurements, participants were seated approximately 60 cm from the monitor, in line with prior studies [43; 44]. The experimental setup involved two laptops: one driving a 24-inch LG LCD monitor (LG, Seoul, Republic of Korea) (2560 \(\times\) 1440 res  
Figure 1: Structure of the neural network model with input, two hidden, and output layers.  
olution, SDR RGB color space, 8-bit), powered by an MSI Pulse 15B13V with an Intel Core i7-1370H processor (Intel, Santa Clara, CA, USA), and a second Macbook Pro 16-inch (Apple Inc., Los Altos, CA, USA) with an M1 Max processor and 32 GB memory for pre- and post-experiment surveys. Participants entered a quiet, 8-square-meter room, where a research assistant provided a 5 min briefing on the study protocol. Using the survey laptop, participants completed the pre-experiment survey. They were then exposed to two conditions of ANN-optimized EMDR stimuli for 30 s each, alternating between an eye-open (EO) and eye-close (EC) state.  
EEG measurements were taken using the Neuro Harmony device (Panatos, Republic of Korea), which specializes in two-channel frontal lobe assessments. This device has demonstrated high reliability, with a correlation of 0.916 (\(p<0.001\)) compared to the Grass System (USA) for \(\alpha\), \(\beta\), and \(\theta\) waves [42; 45; 46]. For frontal lobe measurements, electrodes were placed at Fp1 and Fp2, with the left earlobe as the reference. EEG data were processed using NeuroSpec V.S20 software (Panatos, Republic of Korea), converting raw EEG data into two- and three-dimensional Fast Fourier Transform (FFT) graphs to identify frequency components. Stimulus blocks were categorized as EO and EC, following established frequency ranges: delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-32 Hz), and gamma (\(>\)32 Hz) [47].  
To minimize noise, EEG data with frequencies below 48 Hz and a duration of 120 s were included in the analysis. Additionally, the square root of the EEG signal's absolute magnitude was calculated in microvolts (\(\mu\)V). The relative power for each EEG frequency band was computed by dividing the power of a specific frequency range by the total power across all ranges.