Annals of Neurology
September 22, 2016
Silvia Casarotto, Angela Comanducci, Mario Rosanova et al.
504 citations
A brain-based measure called the Perturbational Complexity Index (PCI) can reliably distinguish conscious from unconscious individuals, even when they cannot speak or move. The index was first validated in 150 healthy and brain-injured people who could report their conscious state, achieving perfect accuracy in separating conscious from unconscious conditions. Applied to 81 noncommunicative patients, PCI correctly identified 94.7% of those in a minimally conscious state and revealed that 9 of 43 patients diagnosed as vegetative had PCI values overlapping with conscious individuals. These findings suggest that some behaviorally unresponsive patients may retain hidden conscious capacity.
Clinical EEG and Neuroscience
January 1, 2014
Simone Sarasso, Mario Rosanova, Adenauer G. Casali et al.
164 citations
Consciousness requires both functional integration and differentiation in the brain, a property termed brain complexity. Transcranial Magnetic Stimulation combined with electroencephalography (TMS/EEG) can quantify this complexity. Studies consistently show that the complexity of the cortical response to TMS collapses during loss of consciousness in deep sleep, anesthesia, and vegetative state after severe brain injury. Complexity recovers when consciousness returns during wakefulness, dreaming, the minimally conscious state, or locked-in syndrome. This approach may help understand the pathophysiology of disorders of consciousness and requires careful methodological attention.
Nature and science of sleep
January 1, 2025
David R Schreier, Matteo Fecchio, Christian S Guay et al.
Dexmedetomidine (DEX) is a sedative that produces a sleep-like state and offers a way to study shifts in consciousness using behavior, EEG, and TMS-evoked EEG responses. Little is known about how repeated DEX exposure affects recovery. This pilot trial plans to sedate 12 healthy volunteers twice, one week apart, monitoring responsiveness with an auditory click task. It will compare time to return of responsiveness between visits, explore sex differences, and assess state transitions via EEG signatures, TMS-evoked complexity, and cognitive tests. The study also evaluates the feasibility of TMS-EEG during DEX sedation and reports on sleep quality and experiences.