UCSF clinicians publish results of a comparative study of NBS for motor mapping in Journal of Neurosurgery

HELSINKI, Finland – July 11, 2012 -- Nexstim announces availability of a new paper "Preoperative Multi-modal Motor Mapping: A Comparison of Magnetic Source Imaging, Navigated Transcranial Magnetic Stimulation, and Direct Cortical Stimulation" from the Departments of Neurological Surgery and Radiology, University of California, San Francisco, California.

In their paper, Tarapore et al. note that preoperative, noninvasive motor mapping is becoming increasingly accurate, with magnetic source imaging (MSI) having been extensively validated but navigated TMS less so, while direct cortical stimulation (DCS) remains the gold-standard technique for motor mapping during craniotomy. In order to compare navigated TMS with DCS and MSI, the clinicians performed Navigated Brain Stimulation (NBS) mapping and MSI on 24 patients with tumors in proximity to primary motor cortex. Patients were subsequently mapped with DCS during neurosurgery. The clinicians found a median distance between NBS and DCS motor sites of 2.1 ± 0.29mm; and a median distance between NBS and MSI motor sites of 4.71 ± 1.08mm.

The results represent extremely close concordance between presurgical NBS mapping and intraoperative DCS for motor site localization. Importantly, in no patients did DCS motor mapping reveal a motor site that was unrecognized by NBS mapping. In their conclusion, the authors noted that maps of the motor system generated with the NBS System correlate well with those generated by both MSI and DCS. Negative NBS mapping also correlates with negative DCS mapping. Finally the authors state that "Navigated TMS is an accurate modality for noninvasively generating preoperative motor maps".