Transcranial Low-Level Laser Therapy May Improve Alertness and Awareness in Traumatic Brain Injured Subjects with Severe Disorders of Consciousness: a Case Series


  • Stefan Hesse
  • Cordula Werner
  • Manuela Byhahn



Brain stimulation, traumatic brain injury, minimal conscious state, near-infrared light, transcranial low-level laser therapy, revised coma recovery scale


Background: Transcranial low-level laser therapy (T-LLT) proved promising in acute stroke studies and in single traumatic brain injured subjects (TBI). It was assumed to increase cortical mitochondrial energy production and/or vasodilatation.

Objective: Within this case series the potential of transcranial lowlevel laser therapy in improving the alertness and awareness in TBI subjects with severe disorders of consciousness will be investigated.

Methods: Following a 21-day baseline, the forehead of fie patients, four chronic in a state of unresponsive wakefulness or minimal consciousness, one subacute in the state of akinetic mutism, was stimulated with the T-LLT (785 nm, 10 mW/cm2, CW mode, 21 emitting diodes) for 10 min every workday for six weeks. Follow-up was four weeks after end of intervention. Primary variable was the revised version of the Coma Recovery Scale (r-CRS, 0-23), blindly assessed by an external reviewer with the help of videos.

Results: The r-CRS, almost stable during baseline, improved in all patients during the intervention, from 3 to 12, 9 to 12, 8 to 12 and 5-12 in the chronic, and from 6 to 21 in the subacute patient. Follow-up revealed a sustained effect. The patient in the state of akinetic mutism improved her competence in the activities of daily living and mobility status. Single epileptic fis occurred in two patients during the intervention.

Conclusion: T-LLT improved the patients’ alertness and awareness; epileptic fis were potential side effects. Sham-controlled studies including the quantitative assessment of awareness should follow the case series.

Author Biography

Stefan Hesse

Medical Park Berlin, Neurological Rehabilitation, Charité – University Medicine Berlin.