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)

The Pennsylvania Alcohol Craving Scale (PACS) consists of 5 items, each rated on a scale from 0 to 6. The scale comprehensively assesses the frequency, intensity, and duration of alcohol craving, as well as the individual's ability to resist drinking. The total score ranges from 0 to 30, with a score of 20 or higher indicating a level consistent with a substance use disorder.

To evaluate changes in alcohol craving before and after a 5-week brain stimulation intervention using the Penn Alcohol Craving Scale (PACS). The study will compare the change in craving scores across three groups: combined stimulation (tPBM+taVNS), tPBM-only, and taVNS-only.

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

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

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

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.

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.

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.

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.

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.

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").

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.

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").

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.

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.

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.

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.