Multisensorial IMmersive Experiences (MIME) in Disorders of Consciousness

Overview

Disorder of consciousness (DoC) is a state in which consciousness is altered because of brain damage and can occur under a variety of conditions: in fact, the most frequent causes of DoC are vascular disease, head trauma, and cerebral hypoxia. DoCs result from the loss of regulation of neural function of the two components of consciousness, alertness and awareness. Depending on the patient's behavior and responsiveness, DoCs can be identified in different states, from coma to persistent vegetative state (VS) to intermittent minimally conscious state (MCS). Regarding the prognosis of recovery, in patients with DoC the chance of having functional improvement decreases with time, although some positive functional changes have been observed in chronic patients. Therapies for DoC include some drugs, such as dopaminergic, GABAergic and amantadine drugs, which work to facilitate the recovery of consciousness. Neurorehabilitation, however, seems to be the most recognized intervention that aims to strengthen, in uninjured brain regions, the spontaneous neuroplasticity that occurs to compensate for lost function. Simultaneous stimulation of multiple senses, such as hearing, sight and smell, provides the neural network with more stimuli that are more effective than a single stimulus. In fact, multisensory stimuli can more easily activate attention because cortical processing is predominantly multimodal. As for content, it would seem that those with autobiographical and emotionally salient character could engage multiple brain networks and have priority access to attention. Numerous trials show that stimulus-containing content led to increased behavioural activity, improving self-awareness in patients with DoC. Considering that a communication system that can combine both visual and auditory channels proves to be more effective than a "single-sense" channel, multisensory stimulation is likely to provide simultaneous activation of different brain areas by enhancing plasticity processes. Furthermore, the intensity of stimulation could be one of the main variables with greater impact on the patient: in fact, higher intensity would correspond to a greater effect on the brain.

It can be hypothesized that sensory stimulation, or "Multisensorial IMmersive Experiences" (MIME), enhanced by high-quality video images, a larger screen size, and qualitatively better sound, may have a greater impact on the patient than the same image or video played on a small screen. The purpose of the study is to evaluate (i) whether MIMEs can clinically modify the vigilance of DoC patients during administration; (ii) whether there is SNA activation during the administration of MIMEs; and (iii) whether patients treated daily with MIMEs have any benefits in terms of vigilance modification. Twenty patients of both sexes with DoC will be recruited, evaluated and treated at the UOC of High Intensity Neurorehabilitation at the Fondazione Policlinico Universitario Gemelli IRCCS in Rome. All study participants will undergo MIME treatment once a day for 5 days a week, for a total of 10 sessions. Patients will perform, in addition to MIME therapy, conventional rehabilitation as a daily routine. Patients will be divided into two groups: one part will perform MIME treatment concurrently with transcranial direct current stimulation (tDCS, G-Mt) and as many will undergo MIME treatment alone (G-M), as described below. In the case of epileptic subjects, these due to contraindications to tDCS may be subjected to MIME therapy only.