Medical and surgical treatments in disorders of consciousness

Ever since a 2012 landmark study showed positive effects of amantadine in people with disorders of consciousness (DOC), there has been a shift in research efforts from merely improving diagnostics and prognostication of DOC to also include therapeutic trials, in the quest to improve consciousness recovery after brain injury. Stimulation of residual consciousness in the intensive care unit is critical because failure to do so may lead to unwarranted pessimistic prognosis and premature withdrawal of life-sustaining therapies. Similarly, it is crucial to harvest the potential of chronic DOC patients for late consciousness recovery, which is increasingly reported. To this end, medical and nonpharmacologic, including surgical, treatment strategies are being tested. These include dopaminergic and GABAergic drugs (medical), vagal nerve stimulation (noninvasive or surgical), and deep brain stimulation (surgical). In addition, transcranial magnetic stimulation, transcranial direct current stimulation, and low-intensity ultrasound (nonpharmacologic and nonsurgical) are covered in another chapter in this volume of the Handbook. Although overall, DOC treatment studies are subject to small sample sizes, unblinded protocols, and limited follow-up, this will likely change in the foreseeable future with the advent of adequately powered multicenter studies, randomized, double-blind, placebo-controlled designs, and standardized outcome measures. This chapter discusses the present state and outlooks of the field of medical and surgical options to boost arousal and awareness in patients with DOC, indicating the future of DOC treatment is bright.