Effects of taVNS Combined With tACS on Adolescents With Non-Suicidal Self-Injury

Adolescent Non-suicidal Self-injury Assessment Questionnaire (ANSAQ) reduction in the frequency of self-injury

The ANSAQ is a brief, self-report tool specifically designed for adolescents aged 12-18 to quantify non-suicidal self-injury (NSSI) over the past year. It is used both to screen for clinically relevant self-harm and to track changes in self-injury frequency after an intervention. Higher frequencies indicate more severe NSSI behavior.

Brief Barratt Impulsiveness Scale (BBIS)

The BBIS is an 8-item, self-report subset of the well-known Barratt Impulsiveness Scale. Each item (e.g., "I act on the spur of the moment") is answered on a 4-point scale: 1 = rarely/never, 2 = occasionally, 3 = often, 4 = almost always/always. Total scores range 8-32; higher scores indicate greater impulsivity. Total score: 32. Higher scores indicate greater impulsivity.

Eye movement index-fixation counts

A free-viewing paradigm consisting of 60 images was employed, with eye movements recorded using an SMI-RED eye-tracking system. Each trial comprised a four-image array: three neutral stimuli and one NSSI-related stimulus, presented for 4000 ms. A dot-probe paradigm consisting of 204 trials was employed, with eye movements recorded using an SMI-RED eye-tracking system. Each trial comprised a pair of images: one neutral stimulus and one NSSI-related stimulus, presented for either 200 ms or 500 ms.The region of interest (ROI) was defined as the area containing the NSSI-related cue. 'Dwell time' was operationalized as the total duration (in milliseconds) that the eyes remained fixated within the ROI during image presentation. Values were averaged across all NSSI-related cue images at baseline (Day 0) and post-intervention (Day 8). A clinically relevant improvement in inhibitory control was defined as a ≥20% reduction in total dwell time on NSSI-related cues relative to baseline.

Stop Signal Task（SST）

The experiment consisted of 192 trials (64 × 3), preceded by a 20-trial practice phase. Each trial began with a 1.5-second fixation cross, followed by a left- or right-pointing arrow (maximum duration: 2 seconds), to which participants responded as quickly and accurately as possible. In approximately 25% of trials, an auditory stop signal was presented after a variable delay, requiring participants to inhibit their response. The stop-signal delay (SSD) was dynamically adjusted using a staircase procedure (initial delay: 250 ms; ±50 ms based on performance) to index inhibitory control. The inter-trial interval was fixed at 30 seconds.

Hamilton Depression Scale (HAMD-17) score

The Hamilton Depression Rating Scale (HAMD) is a clinician-administered questionnaire widely used to assess the severity of depressive symptoms. The 17-item version (HAMD-17) is the most commonly used, with total scores ranging from 0 to 52. Higher scores indicate greater severity of depression

Hamilton Anxiety Scale (HAMA-14) score

The Hamilton Anxiety Rating Scale (HAMA-14) is a clinician-administered scale assessing the severity of anxiety symptoms. It comprises 14 items, with total scores ranging from 0 to 56. Higher scores indicate greater anxiety severity.

the score of PANSI

14-item self-report that gauges both protective (positive) and risk-related (negative) aspects of suicide ideation in adolescents. Items are rated 1-5; higher totals on the 6-item Positive Ideation sub-scale (range 6-30) indicate greater resilience, while higher totals on the 8-item Negative Ideation sub-scale (range 8-40) signal increased suicide risk.

The score of Ruminative Responses Scale (RRS)

The Ruminative Responses Scale (RRS) is a self-report measure assessing rumination, defined as repetitive and passive thinking about negative emotions and their causes. The 22-item version yields total scores from 22 to 88, with higher scores indicating more frequent rumination.