Disorders of consciousness (DOC) diagnosis suffers from the difficulty to measure the level of consciousness due to the variability associated with behavioural assessments and the difficulty in detecting the residual level of consciousness in patients who do not show any behavioural signs during the behavioural assessment. This issue could be overcome by using instrumental tools, that are expensive and not always available in clinical settings. The ultrasound-based techniques could represent a valid low-cost and more feasible alternative to deep the knowledge about physio-pathological mechanisms underlying DOC and their chronicization. These techniques could be tailored to treat acute and chronic DOC patients from a personalised medicine perspective. Improving the knowledge, management and care pathways of DOC patients and finding new therapeutic options would benefit not only patients but also public health systems.

After acquired brain injuries, Disorders of Consciousness (DOC) may occur and persist for up to many years. DOC range from Unresponsive Wakefulness Syndrome (UWS; presence of reflexive behaviours) to the emergence from Minimally Conscious State (eMCS; presenting signs of functional communication and/or object use). A correct diagnosis affects the legal decisions, prognosis, and potential therapeutic and rehabilitative interventions. Although DOC diagnosis relies on behavioural assessment (Coma Recovery Scale-Revised; CRS-R), several studies highlight the importance of instrumental tools (e.g., neuroimaging and electrophysiology) for improving diagnosis and prognosis despite their complexity, high costs, and low availability. The ultrasound techniques can represent a valid alternative, allowing both to acquire bedside structural and functional data with low costs and less invasiveness, and perform stimulation to boost consciousness improvement and/or recovery. However, limited evidence exists to date about the use of ultrasound techniques for clinical characterization of DOC patients, and only one registered trial is exploring the effectiveness of ultrasound stimulation for consciousness recovery in this clinical population. For these reasons, we aim to explore the brain functioning and morphology with direct ultrasound (US) in DOC patients, providing both anatomical and functional information in real-time. Specifically, the measures extracted from US examination might provide data regarding DOC's physiopathology in a bedside and affordable manner. Moreover, although clinical trials with low-intensity ultrasound modulation of subcortical structures and thalamic nuclei are already in progress, targeting is still empirical. Thus, understanding US parameters in DOC could provide the ground to improve deep brain structures' targeting, tailoring low-intensity ultrasound parameters according to patient's specific needs for improving their level of consciousness.

Aim 1

Inclusion criteria:

• an established diagnosis of DOC (UWS or MCS according to the CRS-R criteria and/or a CRS-R total score ≤22) following severe acquired brain injury;
• age>18 years old;
• written informed consent obtained from each patient's representative.

Exclusion criteria:

• previous psychiatric, neurological, or drug abuse history;
• on-going mechanical ventilation.

From the population enrolled for aim 1, we plan to select ten patients

Inclusion criteria:

• 18\