Resting-state electroencephalography (EEG) routinely reveals increased slow-wave activity and reduced alpha power in schizophrenia, but the regional distribution across finer frequency bands in adolescent-onset cases is less well characterized. This preprint analyzed region-specific relative power (RP) across nine frequency bands in male adolescents with schizophrenia to identify localized alterations, with a particular focus on occipito-parietal differences.
The dataset included 45 male adolescents with schizophrenia (SCZ; mean age 12.3 ± 1.2 years) and 39 age- and sex-matched healthy controls (CON; mean age 12.3 ± 1.3 years). EEG was recorded using 16 scalp electrodes placed according to the 10–20 system. The source is a publicly available resting-state EEG dataset reported in the preprint.
Raw EEG underwent standard preprocessing steps before spectral analysis: band-pass filtering, artifact subspace reconstruction, spline interpolation, average re-referencing, and independent component analysis. Following preprocessing, relative power (RP) was computed for nine frequency bands. RP values were analyzed within five predefined cortical regions: frontal, central, parietal, temporal, and occipital.
The analysis used nine frequency bands; the report highlights findings in the delta band and the alpha2 sub-band (noting dissociation from alpha1). RP was aggregated regionally for frontal, central, parietal, temporal, and occipital cortices based on the 16-electrode montage.
Group differences were assessed using a three-way repeated-measures analysis of variance (ANOVA). Post-hoc pairwise comparisons were performed using estimated marginal means (emmeans) with Bonferroni false discovery rate (FDR) correction for multiple comparisons. Reported group differences met an FDR threshold of < 0.001 for the key findings.
Compared with controls, adolescents with schizophrenia exhibited significantly higher delta RP in multiple cortical regions. Significant increases were observed in the frontal, parietal, and occipital regions. Topographic visualizations indicated a widespread enhancement of delta activity in the SCZ group. The greatest regional delta increase was reported in the occipital cortex with an effect size of |Cohen's d| = 0.82.
The SCZ group showed significantly reduced alpha2 RP that was dissociable from alpha1. Decreases in alpha2 RP were observed in central, parietal, temporal, and occipital regions (all FDR < 0.001). The largest reduction in alpha2 RP occurred in the occipital cortex (|Cohen's d| = 0.73), described as a moderate-to-large effect.
Topographic maps reported in the study demonstrated two prominent spatial patterns in the SCZ group: widespread delta power enhancement and attenuated occipito-parietal alpha2 activity. Effect sizes for the strongest regional differences (occipital delta and alpha2) were moderate to large (|d| ≈ 0.73–0.82), indicating robust group-level effects in these regions.
These findings indicate region-specific alterations in resting-state EEG relative power in male adolescent schizophrenia, with a notable occipital predominance: increased slow-wave (delta) activity and reduced alpha2 power. The authors propose that regional RP, especially occipital RP abnormalities, may serve as a neurophysiological feature useful for characterizing or detecting early-onset schizophrenia. Such regional spectral markers could inform future biomarker development or stratification efforts in adolescent populations.
This report is a preprint and has not undergone peer review. The authors declared no competing interests. The source did not report certain potentially relevant details in the summarized abstract, including symptom severity measures, diagnostic subtypes, duration of illness, medication or treatment status, comorbidities, or longitudinal follow-up. Any methodological specifics beyond the listed preprocessing steps (for example, epoch length, exact frequency band boundaries, or artifact rejection thresholds) were not detailed in the abstract and therefore are not described here.
In this sample of male adolescents, schizophrenia was associated with region-specific alterations in resting-state EEG RP: elevated delta RP and reduced alpha2 RP, with the largest effects localized to the occipital cortex. The authors suggest these regional RP changes may be promising neurophysiological features for early-onset schizophrenia, but findings are preliminary pending peer review and further clarification of clinical and methodological variables.