Neural, Behavioural, and Clinical Effects of tDCS in PDOC; Feasibility Study

Sham-controlled, Double-blind, Randomised Crossover Study of the Neural, Behavioural, and Clinical Effects of Transcranial Direct Current Stimulation in Patients With a Prolonged Disorder of Consciousness; Feasibility Study

This study evaluates the feasibility of an experimental protocol that combines advanced multi-modal imaging of the brain with clinical and behavioural scales to characterise the neural, behavioural, and clinical effects of transcranial direct current stimulation (tDCS) for rehabilitation in PDOC

Patients with prolonged disorders of consciousness (PDOC) have very limited therapeutic options, and they often show little to no progress over time. Here, the investigators will assess whether transcranial direct current stimulation can improve patients' responsiveness. The investigators will use a protocol designed to target specific brain networks that have been shown to play a key role in explaining the lack of voluntary responses in PDOC. The study will focus on characterising the mechanisms of action of tDCS and the bases for potential individual differences in responsiveness to the stimulation across participants. This feasibility study is the first step towards developing personalised tDCS interventions to restore external responsiveness in PDOC patients. Its results will inform the design of a future trial fully powered for characterising neural, behavioural, and clinical effects of tDCS in PDOC as well as the mechanisms underlying individual differences in responsiveness.

Inclusion Criteria:

• Aged 18 years or older
• Receiving care at a recruitment site, with a consensus clinical diagnosis of PDOC from any aetiology (i.e. traumatic or non-traumatic injury).
• Stable and with no need of mechanical support (i.e. respirator, etc.)

Exclusion Criteria:

• Scalp skin sores or any skin damage at the electrode sites
• Metallic implants in the face or skull
• Craniectomy or cranioplasty
• No evidence of auditory startle in clinical observations, or absent brainstem auditory evoked potentials in recent clinical history (if data available)
• MRI incompatible: metal plates incompatible with MRI scanners, pacemaker, inability to lay flat for prolonged periods of time, aneurysm clips, neurostimulators, brain/subdural electrodes, etc. (MRI stream ONLY)