Neuroimaging in sleep medicine

Functional and structural neuroimaging provide a means to understand brain function in patients affected by sleep disorders. Herein, we describe neuroimaging findings of primary sleep disorders, including types of dyssomnia related to intrinsic sleep impairments (i.e., idiopathic insomnia, narcolepsy, and obstructive sleep apnea) and abnormal motor behaviors during sleep (i.e., periodic limb movement disorder, restless legs syndrome and rapid-eye-movement sleep behavior disorder). We also include functional neuroimaging studies in sleep complaints secondary to specific psychiatric disorders. Functional neuroimaging may address different kinds of issues in sleep medicine. Functional and structural neural changes can have a causal role in the pathophysiology of sleep disorders. Other changes in brain structure or regional activity can be considered as secondary consequences of long-term sleep disruption. Neuroimaging studies can help to better understand the cognitive and neural responses to various therapeutic approaches. In the future, neuroimaging studies will probably lead to modify the nosography of sleep disorders on the basis of their underlying and characteristic neural correlates.