Non-invasive brain stimulation to promote alertness and awareness in chronic patients with disorders of consciousness: Low-level, near-infrared laser stimulation vs. focused shock wave therapy.

In order to promote alertness and awareness in patients with severe disorders of consciousness (DOC) frontal near infrared laser stimulation (N-LT) or transcranial focused shock wave therapy (F-SWT) might be an option. The study compared both techniques in severe chronic DOC patients.

Sixteen DOC patients were allocated to two groups (A and B). A three week baseline either followed a frontal N-LT (0,1 mJ/mm2, 10 min per session), five times a week over four weeks (group A), or a F-SWT (0,1 mJ/mm2, 4000 stimuli per session) three times a week over four weeks (group B). The primary variable was the revised Coma Recovery Scale (r-CRS, 0-23), blindly assessed.

Both groups improved in the r-CRS over time, but revealed no differences between groups. One patient of group B had a focal seizure in the third therapy week. One patient with akinetic mutism improved most and three patients with global hypoxia did not improve at all.

Both options might be an option to increase alertness and awareness of chronic DOC patients. An akinetic mutism seems to be a positive and severe cerebral hypoxia a negative predictor. Epileptic seizures are a potential unwanted side effect. More clinical studies are warranted.