Transcranial Direct Current Stimulation Effects in Patients With Chronic Consciousness Disorders

Consciousness disorders have high impact on society and national health system. One of these disorders is vegetative condition in which, as in coma, there isn't any self or environmental consciousness but there is alertness, whereas in minimal state of consciousness at least part of awareness is conserved.

In Emilia Romagna region about 80 people per million of inhabitants are hospitalized after cerebral damage, and after discharge about 1/5 of patients are stabilized in a consciousness disorder.

The diagnosis of these disorders is based on neurobehavioural tests, for example JFK Coma Recovery Scale Revised (CRS-R).

In these patients recovery of state of consciousness is one of the main challenges. There are very little evidences about treatment, it has been proposed the use of therapies that could modulate central nervous system activity, like specific drugs, neuroimaging and neuromodulation techniques such as transcranial magnetic stimulation and repetitive transcranial current stimulation.

A non invasive neuromodulation technique is transcranial direct current stimulation (tDCS) which can modulate cortical excitability: cathodic current reduces excitability whereas anodic current increases it.

In conclusion, tDCS is an easy technique to use, it's not invasive and it's an efficient tool for the modulation of cortical excitability that demonstrated reliable results in healthy subjects.

As the tDCS can modulate cortical excitability it is likely that the combination of this stimulation tool with transcranial magnetic stimulation for the registration of cortical excitability could give important information about cerebral damage in patients with consciousness disorders and to test new treatments. It is also likely that the modification of cortical excitability could induce neurobehavioural changes.

Inclusion criteria

• males and females aged >18 years old and <70 years old
• diagnosis of disorders of consciousness classified as MCS according to criteria of American Academy of Neurology1.
• traumatic etiology (>12 months after the acute injury)

Exclusion criteria

• contraindications to single pulse TMS (TMS will be used to measure cortical excitability) such as metal head implants, history of seizures, metal in the head, implanted brain medical devices.
• contraindications to tDCS such as metal in the head, implanted brain medical devices.