Brief communication Altered interaction between cardiac vagal influence and delta sleep EEG suggests an altered neuroplasticity in patients suffering from major depressive disorder Jurysta F, Kempenaers C, Lancini J, Lanquart J-P, van de Borne P, Linkowski P. Altered interaction between cardiac vagal influence and delta sleep EEG suggests an altered neuroplasticity in patients suffering from major depressive disorder. Objective: Major depressive disorder (MDD), which is associated with altered neuroplasticity and increased relative cardiac sympathic activity, enhances the risk of cardiovascular pathologies. Interaction between cardiac sympatho-vagal indexes and delta sleep power is probably altered in MDD. Method: Sleep characteristics and cardiac sympatho-vagal indexes of 10 depressive patients were compared to 10 control men across the first three non-rapid eye movement (NREM)–REM cycles. Interaction between normalized high frequency (HF) and delta power bands was studied using coherence analysis. Results: Patients showed increased sleep latency, stage 1 and wake durations. No differences in heart rate variabilities were observed: Total power, HF and RR-interval decreased from NREM to REM sleep and wakefulness in both groups. Gain value was lower in patients while coherence and phase shift were similar between groups. Modifications in HF appear 8 min before modifications in delta. Conclusion: Major depressive disorder is related to an altered link between cardiac vagal influence and delta sleep, suggesting disorders in cardiovascular controls and an altered neuroplasticity. F. Jurysta 1 , C. Kempenaers 1 , J. Lancini 1 , J.-P. Lanquart 1 , P. van de Borne 2 , P. Linkowski 1 1 Sleep Laboratory and Psychiatric Research Laboratory, Department of Psychiatry and 2 Department of Cardiology and Hypertension Clinic, Erasmus Academic Hospital of Free University of Brussels, Brussels, Belgium Key words: depression; delta sleep; cardiac sympatho- vagal influence; coherence; neuroplasticity Fabrice Jurysta, Sleep Laboratory and Psychiatric Re- search Laboratory, Department of Psychiatry, Erasmus Academic Hospital, Free University of Brussels, 1070 Brussels, Belgium. E-mail: fabrice.jurysta@erasme.ulb.ac.be Accepted for publication August 19, 2009 Significant outcomes • The first study of the interaction between cardiac sympatho-vagal activity and delta sleep EEG in patients suffering from major depressive disorder. • Patients were free from somatic, psychiatric or sleep comorbidities, and did not take any psychotropic drug since 14 days at least. • Changes in the link between cardiac sympatho-vagal activity and delta sleep could be related to increased cardiovascular disorders in MDD. Limitations • This study involved low number of subjects and a large spread of their ages. • Patients with very high scores on HDRS or with important suicidal risk were not included. • This study would be extended by functional imagery investigations. • In the absence of studies concerning other psychiatric disorder, results are limited to major depressive disorder. Acta Psychiatr Scand 2010: 121: 236–239 All rights reserved DOI: 10.1111/j.1600-0447.2009.01475.x Ó 2009 John Wiley & Sons A/S ACTA PSYCHIATRICA SCANDINAVICA 236