*6.2.1 Diagnostic and prognostic tool*

Single-pulse TMS has been used to stimulate motor cortex to produce motor response since its first introduction in 1985 [1]. With the successful production of motor response, it proves the integrity of motor pathway, from neurons in motor cortex via corticospinal tract to muscle fibers. Disruption in any part along the tract causes failure of motor response production. This property has been used to evaluate the severity of the insult for both diagnosis and estimation of prognosis and to monitor the progress of rehabilitation [59, 60].

### *6.2.2 Cortical mapping*

FDA first cleared the use of nTMS in cortical mapping in 2009. It can be used for both motor and language mapping. Intraoperative direct cortical stimulation has been the gold standard for cortical mapping. nTMS has been shown to have good accuracy (<10 mm) in motor mapping compared to direct cortical stimulation [61, 62]. The accuracy of nTMS is comparable or even better than functional MRI according to the results from some studies [61]. nTMS has been in used in preoperative planning in neurosurgical operations to maximize the resection of tumors in eloquent areas while preserving neurological functions [63, 64].
