ePoster

ACUTE ANT-DBS RECONFIGURES SCALP EEG SPECTRA AND APERIODIC DYNAMICS: REPRODUCIBLE ON–OFF EFFECTS ACROSS YEARS

Elaheh Sabbaghiand 4 co-authors

Tampere University

FENS Forum 2026 (2026)
Barcelona, Spain
Board PS02-07PM-338

Presentation

Date TBA

Board: PS02-07PM-338

Poster preview

ACUTE ANT-DBS RECONFIGURES SCALP EEG SPECTRA AND APERIODIC DYNAMICS: REPRODUCIBLE ON–OFF EFFECTS ACROSS YEARS poster preview

Event Information

Poster Board

PS02-07PM-338

Abstract

Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is an established therapy for drug-resistant epilepsy, yet its acute large-scale cortical effects in humans remain incompletely characterized. We quantified DBS-locked changes in oscillatory and aperiodic (1/f) EEG components using scalp EEG (64 channels, high-dynamic-range acquisition) from five patients recorded at two time points (2018/2019; 10 patient-years) during a 1 s stimulation ON / 5 s OFF cycling paradigm. After rigorous preprocessing and quality control to mitigate stimulation-related artefacts, we compared DBS-ON segments against five time-matched OFF windows (OFF1–OFF5) within each cycle. Spectral power was estimated using power spectral density (PSD) and time–frequency decomposition, and aperiodic parameters were quantified via parametric spectral modelling (slope = −exponent). Group-level effects were assessed with paired, cluster-corrected permutation statistics across sensors and frequency–time bins and summarized as prevalence maps (fraction of significant sensors) for positive and negative effects. ANT-DBS produced a reproducible broadband spectral reconfiguration: increased high-frequency/gamma activity with concomitant suppression in lower frequencies (theta range), alongside a systematic flattening of the aperiodic component (reduced 1/f exponent). Cycle-resolved aperiodic dynamics referenced to late OFF (OFF5) showed a rapid ON-locked shift followed by recovery across OFF windows. These convergent oscillatory and aperiodic effects indicate a robust, DBS-locked change in cortical network state that replicates across years, supporting candidate EEG biomarkers for mechanistic monitoring of thalamic neuromodulation in epilepsy.

ANT-DBS EEG summary figure: PSD ON vs OFFmean, aperiodic slope cycle (ON/OFF1–OFF5), and positive/negative STF prevalence heatmaps.

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