Glucose metabolism and brain perfusion in patients with insomnia

Background . Insomnia is one of the most common sleep disorders. Cerebral hyperarousal is considered to be the main component in the pathogenesis of insomnia detected at all levels in patients with chronic insomnia. The search for mechanisms of hyperarousal is underway in order to apply target therapy to correct insomnia disorder. Objective . The objective of this study was to determine features of glucose metabolism and cerebral perfusion in adult patients with insomnia using fluorodeoxyglucose F18 and 13N-ammonia. Design and methods . The sample included 58 people — 41 patients with chronic insomnia and 17 volunteers without sleep disorders. Objective assessment of sleep was performed using full polysomnography. PET/CT with the following radiopharmaceuticals was used as a neuroimaging technique: 18F-fluorodeoxyglucose to assess brain metabolism and 13N-ammonium to assess brain perfusion and indirectly evaluate the activity of the glutamatergic system. Results . A decrease in glucose metabolism was found in the left prefrontal medial cortex and in the right inferior parietal lobe. Brain perfusion was higher in the right and left prefrontal cortex, anterior cingulate cortex, right parietal lobe, and right and left sensorimotor cortex. Conclusions . The results of this study demonstrate the objective nature of sleep disturbances and changes in brain metabolism and its perfusion in patients with complaints of insomnia, which may be related to sleep deprivation and constitute a manifestation of hyperarousal.