Disorders of Consciousness and Electrophysiological Treatment Strategies: A Review of the Literature and New Perspectives

Andrea      Guerra; Emanuele   Maria   Costantini; Sara      Maatta; David      Ponzo; Florinda      Ferreri

Abstract

The last years have witnessed a significant increase in our understanding of brain functions in survivors of severe brain injuries with disorders of consciousness (DOC). Despite there is currently no effective standardized treatment for DOC patients, in the past decade many potential pharmacological as well as non-pharmacological therapies have been proposed. A promising and increasingly growing field of non-pharmacological therapeutic trials has been supported by the application of electrophysiological techniques. This article reviews the most relevant studies in the literature in order to provide the reader with a clear picture of the current available neurophysiological instruments that could be used to treat DOC patients. We will hereinafter briefly discuss the basic principles of deep brain stimulation (DBS), repetitive transcranial magnetic stimulation (rTMS), spinal cord stimulation (SCS) and peripheral nerve stimulation (MNS) that are the main techniques now used by researchers as a treatment and we will explain the rationale of these therapies. Then, we will outline the more relevant studies regarding their application in DOC patients. Finally, due to the fact that only a moderate amount of individual or clinically-dependent approaches are available, we conclude that more standardized studies are necessary to address the role of electrophysiological treatment strategies in DOC as well as to further elucidate their therapeutic effects and define optimal stimulation parameters. Undoubtedly, at present the multidimensional approach is the most interesting.

Keywords: Disorders of consciousness, arousal, awareness, consciousness, vegetative state, minimally conscious state, locked-in syndrome, coma, deep brain stimulation, spinal cord stimulation, transcutaneous electric nerve stimulation, median nerve stimulation, DBS, rTMS, SCS, TENS, DOC, PVS, MCS, LIS.