Minimally Conscious

The mass media have recently pointed out the likelihood of diagnostic errors in post-coma patients. Late recoveries of consciousness, even after 20 years, might indicate hidden misdiagnoses that are not corrected over a long period of time. The rate of misdiagnoses of patients in a vegetative state is very high when based on behavioral assessment strategies alone. An extremely restrictive motor repertoire, as occurs in locked-in patients, seems to be the major factor responsible for diagnostic confusion. Functional neuroimaging techniques are regarded as promising tools in unearthing covert awareness in behaviorally unresponsive patients who are unable to produce any motor output. However, unless we believe that these patients persistently live in an unconvincing Cartesian-like state, in which thinking and acting are mutually dissociated, we have to admit that a new taxonomy for low responsive states is called for. This taxonomy should take into account the possible syndromic overlap between disorders of consciousness and locked-in syndrome. We should suspect a "locked-in state" in behaviorally unresponsive patients unless we reach strong evidence that such is not the case; this is the only way to avoid dramatic misdiagnoses.

Families share their experiences of having a relative in a long-term ‘coma’ on the award-winning website healthtalk.org - a resource to support families and health care practitioners, and inform communication and policy.  Access the new resource here: http://healthtalkonline.org/peoples-experiences/nerves-brain/family-experiences-vegetative-and-minimally-conscious-states/topics

Objective: To assess the efficacy of transcranial direct current stimulation (tDCS) on improving consciousness in patients with persistent
unresponsive wakefulness syndrome (UWS) (previously termed persistent vegetative state [PVS]) or in a minimally conscious state (MCS).
Design: Prospective, case series trial with follow-up at 12 months.
Setting: General and research hospital.
Participants: Inpatients in a PVS/UWS or MCS (NZ10; 7 men, 3 women; age range, 19e62y; etiology: traumatic brain injury, nZ5; anoxia,
nZ4; postoperative infarct, nZ1; duration of PVS/UWS or MCS range, 6moe10y). No participant withdrew because of adverse effects.
Intervention: All patients received sham tDCS for 20 minutes per day, 5 days per week, for 1 week, and real tDCS for 20 minutes per day, 5 days
per week, for 2 weeks. An anodal electrode was placed over the left primary sensorimotor cortex or the left dorsolateral prefrontal cortex, with
cathodal stimulation over the right eyebrow. One patient in an MCS received a second round of 10 tDCS sessions 3 months after initial
participation.
Main Outcome Measure: JFK Coma Recovery Scale-Revised.
Results: All patients in an MCS showed clinical improvement immediately after treatment. The patient who received a second round of tDCS 3
months after initial participation showed further improvement and emergence into consciousness after stimulation, with no change between
treatments. One patient who was in an MCS for <1 year before treatment (postoperative infarct) showed further improvement and emergence into
consciousness at 12-month follow-up. No patient showed improvement before stimulation. No patient in a PVS/UWS showed immediate
improvement after stimulation, but 1 patient who was in a PVS/UWS for 6 years before treatment showed improvement and change of status to an
MCS at 12-month follow-up.
Conclusions: tDCS seems promising for the rehabilitation of patients with severe disorders of consciousness. Severity and duration of pathology
may be related to the degree of tDCS’ beneficial effects.