An Exploratory Preliminary Study on the Effect of Combined Transcranial Photobiomodulation(tPBM)-Transauricular Vagus Nerve Stimulation(taVNS) on Alcohol Craving and Neurophysiological Marker in Drinkers (in South Korea)

Change in EEG-Based Neurophysiological Markers

To evaluate changes in EEG signals (e.g., power spectral density, event-related potentials) before and after 5 weeks of intervention.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Heart Rate Variability (HRV)

To assess autonomic nervous system changes through time-domain and frequency-domain HRV parameters.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Alcohol Use Measured by Alcohol Use Disorders Identification Test (AUDIT)

The AUDIT is a 10-item questionnaire designed to assess alcohol consumption, drinking behaviors, and alcohol-related problems. Higher scores indicate more severe alcohol-related issues. A score of 8 or above suggests hazardous or harmful alcohol use. Score Range: 0-40

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Drinking Motives Measured by Drinking Motives Questionnaire-Revised (DMQ-R)

The DMQ-R is a drinking motives scale developed to measure adult drinking motives. This tool consists of four subscales: enhancement motives, coping motives, conformity motives, and social motives, with a total of 20 items. Each drinking motive is assessed with 5 items, totaling 20 items overall, and each item is rated on a 5-point scale from 1 "Not at all" to 5 "Very much so." Higher scores in each drinking motive subscale indicate a stronger motivation for that particular type of drinking.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Depressive Symptoms Measured by Beck Depression Inventory (BDI).

The Beck Depression Inventory (BDI) is a self-report questionnaire developed based on clinical symptoms of depression to assess the severity of depressive symptoms across 21 areas, including emotional, cognitive, and motivational aspects. Each item is rated on a 4-point scale (0 to 3), with total scores ranging from 0 to 63. A total score of 0-9 indicates no depression, 10-23 indicates moderate depression, and a score of 24 or above indicates severe depression.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Anxiety Symptoms Measured by Beck Anxiety Inventory (BAI).

The Beck Anxiety Inventory (BAI) is a tool designed to measure the severity of anxiety, encompassing cognitive, emotional, and physical aspects of anxiety. It consists of 21 items. The BAI was primarily developed to distinguish anxiety from depression. Each item is rated on a 4-point scale (0 to 3), with total scores ranging from 0 to 63. A total score of 21 or below indicates minimal anxiety, 22-26 indicates moderate anxiety, 27-31 indicates severe anxiety, and a score of 32 or above indicates extreme anxiety.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Sleep Quality Measured by Pittsburgh Sleep Quality Index (PSQI).

The Pittsburgh Sleep Quality Index (PSQI) is a self-report questionnaire that assesses subjective sleep quality over the past month. It evaluates sleep quality across seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Impulsivity Measured by Barratt Impulsiveness Scale (BIS).

The Korean version of the Barratt Impulsiveness Scale-11 (BIS-11) is one of the most widely used self-report questionnaires for measuring impulsivity. It consists of three subcomponents: cognitive impulsivity, motor impulsivity, and non-planning impulsivity. The scale includes 30 self-report items, including 11 reverse-scored items. Each item is rated on a 4-point Likert scale ranging from 1 ("Not at all true") to 4 ("Always true"). Scores are calculated by summing the items, taking into account the reverse-scored items. Higher total scores indicate greater impulsivity.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in readiness to change measured by the Korean version of the Stages of Change Readiness and Treatment Eagerness Scale (SOCRATES-K).

The SOCRATES was originally designed to assess motivation for change in problem drinkers. The Korean version (SOCRATES-K) was adapted to better reflect the Korean context and is used to assess motivation for change in individuals with alcohol dependence or abuse. It consists of 19 items, each rated on a 5-point Likert scale ranging from 1 ("Not at all true") to 5 ("Always true").

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Interoceptive Awareness Measured by Multidimensional Assessment of Interoceptive Awareness (MAIA).

The Korean version of the Multidimensional Assessment of Interoceptive Awareness (MAIA) is a self-report questionnaire that reflects recent approaches such as mindfulness and acceptance, focusing on how individuals relate to internal experiences, including bodily sensations. It consists of 32 items related to interoceptive awareness. Each item is rated on a 7-point Likert scale ranging from 0 ("Not at all true") to 6 ("Always true"). Higher total scores, calculated by summing item scores, indicate greater interoceptive awareness.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Craving and Metacognitive Control Measured by Meta Cognitions Questionnaire (MCQ).

The Korean version of the Metacognitions Questionnaire consists of 30 items and assesses metacognitive beliefs across five domains: positive beliefs about worry, negative beliefs about the uncontrollability and danger of worry, cognitive confidence, need to control thoughts, and cognitive self-consciousness. Each item is rated on a 4-point Likert scale ranging from 0 ("Do not agree") to 3 ("Strongly agree").

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Credit Assignment Task (CAT)

Participants will choose between two options, with rewards delivered after variable and unpredictable temporal delays. This task assesses participants' learning strategy and ability to infer the causal relationship between actions and outcomes when feedback is delayed, probing their capacity for temporal credit assignment.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Delay Discounting Task (DDT)

Participants will complete a computer-based binary choice task in which they repeatedly choose between smaller immediate rewards and larger delayed rewards. The task is designed to assess delay discounting - the degree to which individuals devalue rewards as a function of delay.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Loss Aversion Task (LAT)

A binary choice procedure will be used to assess individual sensitivity to loss aversion, where participants choose between mixed gambles involving potential gains and losses versus a certain outcome. This task quantifies the relative weighting of losses compared to gains.

Time frame: Administered at baseline (V1), five weeks (V2)

Change in Choice under Risk and Ambiguity Task (CRAT)

A binary choice procedure will be conducted in which, on certain trials, the probability of winning will be hidden in order to assess decision making under ambiguity, as compared to decision making under risk.

Time frame: Administered at baseline (V1), five weeks (V2)