The neural mechanisms underlying the development of the most common
intrinsic sleep disorders are not completely known. Therefore, there is a great need for noninvasive tools which can be used to better understand the pathophysiology of these diseases.
Transcranial magnetic stimulation (TMS) offers a method to noninvasively investigate the functional integrity of the motor cortex and its corticospinal projections in neurologic and
psychiatric diseases. To date, TMS studies have revealed cortical and corticospinal dysfunction in several
sleep disorders, with cortical hyperexcitability being a characteristic feature in some disorders (i.e., the
restless legs syndrome) and cortical hypoexcitability being a well-established finding in others (i.e.,
obstructive sleep apnea syndrome narcolepsy). Several research groups also have applied TMS to evaluate the effects of pharmacologic agents, such as dopaminergic agent or
wake-promoting substances. Our review will focus on the mechanisms underlying the generation of abnormal TMS measures in the different types of
sleep disorders, the contribution of TMS in enhancing the understanding of their pathophysiology, and the potential diagnostic utility of TMS techniques. We also briefly discussed the possible future implications for improving therapeutic approaches.