Repetitive transcranial magnetic stimulation in traumatic brain injury: evidence from animal and human studies

We provide here the first systematic review on the studies dealing with repetitive transcranial magnetic stimulation (rTMS) for traumatic brain injury (TBI) in animals and humans. Several experimental studies in animal models have explored with promising results the use of rTMS to enhance neuroprotection and recovery after TBI. However, there are surprisingly few studies that have obtained substantial evidence regarding effects of rTMS in humans with TBI, many of them are case reports investigating the heterogeneous conditions linked to TBI. The most studies have investigated the effects of rTMS in subjects with post-traumatic depression and variable effects have been observed. rTMS has been proposed as an experimental approach for the treatment of disorders of consciousness (DOC), but in subjects with TBI therapeutic effects on DOC have also been variously documented. Beneficial effects have been reported in subjects with cognitive/emotional disturbances and auditory dysfunction (tinnitus and hallucinations), although the results are somewhat conflicting. rTMS applied over the left prefrontal cortex may relieve, at least transiently, post-traumatic headache. Isolated rTMS studies have been performed in TBI patients with motor impairment, chronic dizziness or pain. Especially whether provided in combination, rTMS and neurorehabilitation may be synergistic in the potential to translate experimental findings in the clinical practice. In order to reach definitive conclusions, well-designed randomized controlled studies with larger patient samples, improved design and optimized rTMS setup, are warranted to verify and corroborate the initial promising findings.