Bibliographic record
Abstract
INTRODUCTION Major depressive disorder (MDD) affects approximately 15% of adolescents, and is linked with impairment in social, family and academic functioning. Current treatment options are limited. Repetitive transcranial magnetic stimulation (rTMS) represents a novel avenue for treatment of depression; utilizing magnetic pulses to stimulate specific brain regions thought to underlie MDD. However, beneficial response to rTMS is not universal. Identifying baseline biomarkers that correlate to treatment response will allow professionals to apply a more personalized and effective treatment program and will be more cost-effective for the health care system. Therefore, the aim of this project is to investigate cortical thickness as a baseline structural predictor of rTMS treatment response in MDD children and youth. METHODS Participants (n=15, age range 16 - 21; mean 18.43 ± 1.41) were recruited using advertisement and referral. Inclusion criterion included resistance to antidepressants for at least 8 weeks. Exclusion criteria were additional neurological or psychiatric diagnoses, previous seizures or epilepsy, hypertension, left handedness, pregnancy or braces. The Hamilton Rating Scale for Depression (Ham-D) was used to measure depression severity. A cut-off of a 30% post-treatment reduction in HAM-D was used to distinguish between responders and non-responders. 10 responders and 5 non-responders were not significantly different into terms of sex, age, IQ or baseline HAM-D. The rTMS treatment was applied for 5 days a week for 3 weeks. Participants underwent a baseline MRI scan. Cortical thickness was analyzed using FreeSurfer software. RESULTS We observed increased thickness in the left Broca’s Area, left frontal pole, and right lateral orbitofrontal gyrus in non-responders versus responders. Conversely, the left caudal anterior cingulate cortex was thicker in responders versus non-responders (Table 1). DISCUSSION AND CONCLUSIONS Our current findings match our previous studies showing a thicker anterior cingulate and frontal in MDD versus controls [1,2]. Other studies have indicated structural differences in lateral orbitofrontal gyrus in MDD [3]. This preliminary data suggests that these regions may act as baseline structural biomarkers for rTMS treatment responders, and may influence future MDD treatment protocols. FUTURE DIRECTIONS To further validate these results, a study should be conducted with a larger sample size, especially for rTMS non-responders. Identifying baseline biomarkers for the use of rTMS will enable professional to maximize the potential of this novel therapy in treating MDD and other mental health disorders in children and youth.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.009 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".