Transcranial direct current stimulation of the left prefrontal cortex improves attention in patients with traumatic brain injury: a pilot study.

OBJECTIVE To determine whether a single session of anodal transcranial direct current stimulation to the left dorsolateral prefrontal cortex improves attention in patients with traumatic brain injury. DESIGN Double-blinded, cross-over design. PATIENTS Nine patients with attention deficit after traumatic brain injury. METHODS Patients underwent a computerized contrast reaction time task before and after the administration of real transcranial direct current stimulation (2 mA for 20 min) or sham transcranial direct current stimulation (2 mA for 1 min) to the left dorsolateral prefrontal cortex in a double-blind, crossover manner. RESULTS Immediately post-stimulation, the transcranial direct current stimulation group showed a tendency of shortened reaction time relative to baseline (87.3 ± 7.8%), whereas the sham stimulation group (122.4 ± 715.5%) did not (p = 0.056). However, this difference was not significant 3 or 24 h after stimulation (p > 0.05). The numbers of correct responses were not changed at any time after stimulation. CONCLUSION Anodal transcranial direct current stimulation applied to the left dorsolateral prefrontal cortex improves attention compared with sham stimulation in patients with traumatic brain injury, which suggests a potential role for this intervention in improving attention during cognitive training after traumatic brain injury. A further prospective randomized trial is required to confirm the benefits conferred by transcranial direct current stimulation in this patient population.