Steffen Rex

KU Leuven

2 papers in the library · 359 citations · publishing 2019-2026

Papers

The spectral exponent of the resting EEG indexes the presence of consciousness during unresponsiveness induced by propofol, xenon, and ketamine

NeuroImage January 11, 2019 Michele Colombo, Martino Napolitani, Mélanie Boly et al. 359 citations

During anesthesia, people may still be conscious even though they do not respond. A marker of consciousness based on the decay rate of the power spectral density (PSD) of resting EEG—measured by the spectral exponent β—was tested in healthy participants under xenon, propofol, or ketamine anesthesia (n=5 per group). Delayed reports indicated whether consciousness was present or absent. Xenon and propofol, which abolish consciousness, caused a steeper PSD decay (more negative β) compared to wakefulness. Ketamine, which preserves consciousness, showed a PSD decay similar to wakefulness overall but a flattening in high frequencies (20–40 Hz). The spectral exponent correlated strongly with the Perturbational Complexity Index (PCI), supporting its use as a marker of consciousness.

DOI: 10.1016/j.neuroimage.2019.01.024 Ketamine Propofol Xenon Exponent +9

Sustained mood improvement with laughing gas exposure (SMILE): a randomised, placebo-controlled pilot trial of nitrous oxide for treatment-resistant depression: commentary, Kalmar et al

BJPsych Open July 1, 2026 Alain F. Kalmar, Pascal Sienaert, Filip Bouckaert et al.

Nitrous oxide, a potent greenhouse gas, is being explored as a treatment for therapy-resistant depression, but its environmental costs are often ignored. A single one-hour treatment produces about 150 kilograms of CO2-equivalents, and a year of treatment for one patient generates roughly 7.8 metric tons of CO2-equivalents. The authors argue that these environmental externalities should be factored into assessments of the therapy's overall value.

DOI: 10.1192/bjo.2026.12040 Full text Nitrous oxide Greenhouse gas Mood Externality +5