Slow wave traveling in First-Episode Psychosis: an early measure of brain disconnectivity?

Poster B7, Friday, October 21, 11:30 am - 1:00 pm, Le Baron

Anna Castelnovo1,3, Armando D'Agostino1, Cecilia Casetta1, Simone Sarasso2, Brady A. Riedner3, Armand Mensen3, Giulio Tononi3, Fabio Ferrarelli4; 1Department of Health Sciences, Università degli Studi di Milano, 20142 Milan, Italy, 2Department of Biomedical and Clinical Sciences "L. Sacco", Università degli Studi di Milano, Milan 20157, Italy, 3University of Wisconsin School of Medicine and Public Health, Department of Psychiatry, Madison WI 53706, USA, 4Department of Psychiatry, University of Pittsburgh, Pittsburgh PA 15213, USA.

Background and rationale: Sleep slow-waves, the hallmark of stage 3 sleep, arise from the cortico-cortical and thalamo-cortical synchronization of slow oscillations in the membrane potentials of millions of neurons. As slow-waves travel across the brain, their travelling properties represent an ideal paradigm to study pathological conditions interfering with brain connectivity. We hereby test the hypothesis that disconnectivity is a core abnormality in schizophrenia from the earliest manifestations of the disease. Methods: Five drug-naïve, First-Episode Psychosis and five age- and gender-matched healthy control subjects were recorded in a sleep laboratory setting using a 256 channel EEG system. One patient was re-tested after eight months of continuous antipsychotic (AP) therapy. A toolbox recently developed by one of the authors (AM) was used for slow wave visualization and detection. Results: Patients and control subjects spent the same amount of time in stage 3 of sleep. Slow-waves density, amplitude and wave-lengths did not differ between groups. Slow wave travelled distance (measured as the line of longest displacement), and globality (measured as the number of channels involved by each wave) were significantly reduced in patients relative to controls (p < 0.001 and p < 0.04, respectively). One patient who was retested after 8 months of AP therapy showed a normalization of slow wave travelled distance. Conclusions: These preliminary results suggest that the travelling of slow waves changes during psychotic episodes and that the early administration of AP therapy may reverse this effect after the first psychotic episode. Future research is needed to confirm these results.

Topic Area: Electrophysiology

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