Brain stimulation will consist of 4 types of intervention:

• real transcranial direct current stimulation (two weeks, five days a week)
• a week of wash-out
• Sham transcranial direct current stimulation (two weeks, five days a week)
• two weeks of wash-out
• real repetitive transcranial magnetic stimulation (two weeks, four days a week)
• a week of wash-out
• Sham repetitive transcranial magnetic stimulation (two weeks, three days a week)

Stimulations will be counterbalanced between patients.

2 mA of intensity, 20 minutes of stimulation over the left fronto-temporal prefrontal cortex.

EEG will be filtered between 0.5 and 30Hz by elliptic filters. Fast Fourier Transformation will be performed on 2 sec-epochs. For each stimulation site, coherence values will be estimated within four frequency bands: Delta (0.5-3.5 Hz), Theta (4-7.5 Hz), Alpha (8-12.5 Hz), and Beta (13-30 Hz). Each coherence map will be proportionally thresholded, preserving 50% of the strongest coherence values, to produce a weighted adjacency matrix. The estimated functional connectivity patterns will be characterized by means of two global network metrics derived from graph theory: modularity and global efficiency. Modularity measures how the network is organized into modules with high level clustering. Global efficiency measures how efficient the network is in exchanging information at the global level.

This scale is developed to assess cognitive function in severely impaired head-injured adults and to monitor and predict change in slow-to-recover patients.