Decreased Delta/Beta ratio index as the sleep state-independent electrophysiological signature of sleep state misperception in Insomnia disorder: A focus on the sleep onset and the whole night
Elisabetta Fasiello,
Maurizio Gorgoni,
Andrea Galbiati,
Marco Sforza,
Francesca Berra,
Serena Scarpelli,
Valentina Alfonsi,
Ludovica Annarumma,
Francesca Casoni,
Marco Zucconi,
Vincenza Castronovo,
Luigi Ferini-Strambi,
Luigi De Gennaro
Affiliations
Elisabetta Fasiello
Faculty of Psychology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy; Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy; Corresponding author at: Faculty of Psychology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy.
Maurizio Gorgoni
Department of Psychology, University of Rome Sapienza, Via dei Marsi, 78, 00185, Rome, Italy; Body and Action Lab, IRCCS Fondazione Santa Lucia, Rome, Italy
Andrea Galbiati
Faculty of Psychology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy; Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Marco Sforza
Faculty of Psychology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy; Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Francesca Berra
Faculty of Psychology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy; Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Serena Scarpelli
Department of Psychology, University of Rome Sapienza, Via dei Marsi, 78, 00185, Rome, Italy
Valentina Alfonsi
Department of Psychology, University of Rome Sapienza, Via dei Marsi, 78, 00185, Rome, Italy
Ludovica Annarumma
Department of Psychology, University of Rome Sapienza, Via dei Marsi, 78, 00185, Rome, Italy
Francesca Casoni
Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Marco Zucconi
Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Vincenza Castronovo
Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Luigi Ferini-Strambi
Faculty of Psychology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy; Department of Clinical Neurosciences, Neurology-Sleep Disorders Center, IRCCS San Raffaele Scientific Institute, Via Stamira d'Ancona, 20, 20127, Milan, Italy
Luigi De Gennaro
Department of Psychology, University of Rome Sapienza, Via dei Marsi, 78, 00185, Rome, Italy; Body and Action Lab, IRCCS Fondazione Santa Lucia, Rome, Italy
Purpose: Sleep State Misperception (SSM) is described as the tendency of Insomnia Disorder (ID) patients to overestimate Sleep Latency (SL) and underestimate Total Sleep Time (TST). Literature exploring topographical components in ID with SSM is scarce and does not allow us to fully understand the potential mechanisms underlying this phenomenon. This study aims to evaluate the existence of sleep EEG topography alterations in ID patients associated with SSM compared to Healthy Controls (HC), focusing on two distinct periods: the Sleep Onset (SO) and the whole night. Methods: Twenty ID patients (mean age: 43.5 ± 12.7; 7 M/13F) and 18 HCs (mean age: 41.6 ± 11.9; 8 M/10F) underwent a night of Polysomnography (PSG) and completed sleep diaries the following morning upon awakening. Two SSM indices, referring to the misperception of SL (SLm) and TST (TSTm), were calculated by comparing objective and subjective sleep indices extracted by PSG and sleep diary. According to these indices, the entire sample was split into 4 sub-groups: ID +SLm vs HC –SLm; ID +TSTm vs HC –TSTm. Results: Considering the SO, the two-way mixed-design ANOVA showed a significant main effect of Groups pointing to a decreased delta/beta ratio in the whole scalp topography. Moreover, we found a significant interaction effect for the sigma and beta bands. Post Hoc tests showed higher sigma and beta power in anterior and temporo-parietal sites during the SO period in IDs +SLm compared to HC –SLm.Considering the whole night, the unpaired t-test revealed in IDs +TSTm significantly lower delta power during NREM, and lower delta/beta ratio index during NREM and REM sleep compared to HCs –TSTm.Finally, we found diffuse significant negative correlations between SSM indices and the delta/beta ratio during SO, NREM, and REM sleep. Conclusion: The main finding of the present study suggests that higher SL overestimation and TST underestimation are both phenomena related to diffuse cortical hyperarousal interpreted as a sleep state-independent electrophysiological correlate of the SSM, both during the SO and the whole night.
