Electrical treatment of reduced consciousness: Experience with coma and Alzheimer's disease

Abstract

The right median nerve can be stimulated electrically to help arouse the central nervous system for persons with reduced levels of consciousness. The mechanisms of central action include increased cerebral blood flow and raised levels of dopamine. There is 11 years of experience in the USA of using nerve stimulation for acute coma after traumatic brain injury. There is a much longer period of experience by neurosurgeons in Japan with implanted electrodes on the cervical spinal cord for persons in the persistent vegetative state (PVS). But the use of right median nerve electrical stimulation (RMNS) for patients in the subacute and chronic phases of coma is relatively new. Surface electrical stimulation to treat anoxic brain injury as well as traumatic brain injury is evolving.Novel applications of electrical stimulation in Amsterdam have produced cognitive behavioural effects in persons with early and mid-stage Alzheimer's disease employing transcutaneous electrical nerve stimulation (TENS). Improvements in short-term memory and speech fluency have also been noted.Regardless of the aetiology of the coma or reduced level of awareness, electrical stimulation may serve as a catalyst to enhance central nervous system functions. It remains for the standard treatments and modalities to retrain the injured brain emerging from reduced levels of consciousness.

Effect of Right Median Nerve Stimulation on Level of Consciousness in Traumatic Brain Injury Subjects

“…Existence of electrophysiological relationship between nucleus of the levator palpebrae muscle and ascending reticular activating system in brainstem is also evident 25 . The right median nerve not only stimulate the brain stem and cerebrum to increase awareness but also better pattern of speech and abilities to calculate have been observed after right median nerve electrical stimulation 26,27 . As Broca's speech area is in the left frontotemporal region, this area has been shown to become more active in positron emission tomography when a subject moves his or her hand 28 .…”

Vegetative State and Minimally Conscious State: A Review of the Therapeutic Interventions

“…The right median nerve, according to Cooper et al [23] , can serve as a peripheral portal to the central nervous system because the spinoreticular component of the median nerve pathway synapses with neurons of the ascending reticular activating system. Putative mechanisms of action include increased cerebral blood flow, raised levels of dopamine and norepinephrine, and activation of Broca's area.…”

“…Putative mechanisms of action include increased cerebral blood flow, raised levels of dopamine and norepinephrine, and activation of Broca's area. The supporters of median nerve stimulation stress that therapy has to be initiated early because brain atrophy is in progress and it may be too late to achieve a recovery of brain function at a later stage [23] . It is suggested that some months or even years are needed in the chronic DOC [23] .…”

“…Median nerve stimulation has been tested in 1 patient only, who satisfied our inclusion criteria [23] .…”

Estimating the Effects of Right Median Nerve Stimulation on Memory in Alzheimer's Disease: A Randomized Controlled Pilot Study

“…In clinical studies, RMNS has only been applied to coma patients and appeared to accelerate awakening from deep coma (Cooper, Jane, Alves, & Cooper, 1999;Peri et al, 2001;Liu et al, 2003). Similar to the TENS studies in AD, the rationale underlying the coma studies is that RMNS stimulates the ARAS (Cooper et al, 1999;Cooper, Scherder, & Cooper, 2005). Based on the positive effects of RMNS in coma, we investigated in the present study whether RMNS could improve memory in patients with probable AD.…”