BlueCross BlueShield of Tennessee Medical Policy Manual

Navigated Transcranial Magnetic Stimulation


Navigated transcranial magnetic stimulation (nTMS) is a noninvasive imaging method used in individuals with brain lesions to aid in the localization of eloquent areas of the brain to reduce damage to verbal and motor functions during surgery. Transcranial magnetic pulses are delivered to the individual as a navigation system calculates the strength, location, and direction of the stimulating magnetic field. The locations of these pulses are registered to a magnetic resonance image of the individual’s brain. Surface electromyography (EMG) electrodes are attached to the various limb muscles of the individual. Moving the magnetic stimulation source to various parts of the brain causes the EMG electrodes to respond, which indicates the part of the cortex involved in particular muscle movements.

Surgical management of brain tumors necessitates mapping to preserve brain tissue and essential brain function. Mapping is considered to be most accurately achieved with direct cortical stimulation (DCS), which is performed intraoperatively.




Limited studies of nTMS evaluating language areas have shown high false-positive rates (low specificity) and sensitivity that may be insufficient for clinical use. The evidence is insufficient to determine the effects of the technology on health outcomes.


BlueCross BlueShield Association. Evidence Positioning System Medical. (6:2018). Navigated transcranial magnetic stimulation (2.01.90). Retrieved September 24, 2018 from (23 articles and/or guidelines reviewed)

Frey, D., Schilt, S., Strack, V., Zdunczyk, A., Rosler, J., Niraula, B., et al. (2014). Navigated transcranial magnetic stimulation improves the treatment outcome in patients with brain tumors in motor eloquent locations. Neuro-Oncology, 16 (10), 1365-1372. (Level 3 evidence)

Hendrix, P., Senger, S., Simgen, A., Griessenauer, C., & Oertel, J. (2017). Preoperative rTMS language mapping in speech-eloquent brain lesions resected under general anesthesia: a pair-matched cohort study. World Neurosurgery, 100, 425-433. Abstract retrieved October 19, 2017 from PubMed database.

Krieg, S. M., Sollmann, N., Hauck, T., Ille, S., Meyer, B., & Ringel, F. (2014). Repeated mapping of cortical language sites by preoperative navigated transcranial magnetic stimulation compared to repeated intraoperative DCS mapping in awake craniotomy. BMC Neuroscience, 15 (1), 20. (Level 3 evidence)

Sollmann, N., Hauck, T., Hapfelmeier, A., Meyer, B., Ringel, F., & Krieg, S. (2013). Intra- and interobserver variability of language mapping by navigated transcranial magnetic brain stimulation. BMC Neuroscience, 2013, 14: 150. (Level 3 evidence)

Takahashi, S., Vajkocy, P., & Picht, T. (2013). Navigated transcranial magnetic stimulation for mapping the motor cortex in patients with rolandic brain tumors. Neurosurgical Focus, 34 (4), 1-7. (Level 5 evidence)

U. S. Food and Drug Administration. (2011, September). Center for Devices and Radiological Health. 510(k) Premarket Notification Database. K112881. Retrieved May 16, 2016 from

Winifred S. Hayes, Inc. Hayes Brief. The clinical utility of navigated transcranial magnetic stimulation for presurgical planning for brain tumors. Retrieved October 19, 2017 from (19 articles and/or guidelines reviewed)




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