Neuroimaging of Narcolepsy and Kleine-Levin Syndrome.

Narcolepsy is a chronic neurologic disorder with the abnormal regulation of the sleep-wake cycle, resulting in excessive daytime sleepiness, disturbed nocturnal sleep, and manifestations related to rapid eye movement sleep, such as cataplexy, sleep paralysis, and hypnagogic hallucination. Over the past decade, numerous neuroimaging studies have been performed to characterize the pathophysiology and various clinical features of narcolepsy. This article reviews structural and functional brain imaging findings in narcolepsy and Kleine-Levin syndrome. Based on the current state of research, brain imaging is a useful tool to investigate and understand the neuroanatomic correlates and brain abnormalities of narcolepsy and other hypersomnia.

Feeling unreal: a functional imaging study in patients with Kleine-Levin syndrome.

Kleine-Levin syndrome is characterized by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, derealization and behavioural disturbances. Between episodes, patients have normal sleep, mood and behaviour. Functional imaging studies performed in small series of patients with Kleine-Levin syndrome with visual or semi-quantitative, uncontrolled analysis yielded equivocal brain changes. Using whole brain voxel-based group analysis, we compared brain perfusion scintigraphy during and between episodes in consecutive patients with Kleine-Levin syndrome versus healthy control subjects and correlated perfusion changes with disease severity and symptoms, focusing on less studied but disabling symptoms, such as apathy and derealization. During asymptomatic periods, 41 patients (mean age of 22.3 ± 8.1 years, 56.1% male) and 15 age- and sex-matched healthy control subjects underwent single-photon emission computed tomography scanning with technetium-99m ethyl cysteinate dimer. Eleven patients repeated the test during a symptomatic period. Compared with controls, patients during asymptomatic periods had persistent hypoperfusion in the hypothalamus, the thalamus (mainly the right posterior part), the caudate nucleus, and cortical associative areas, including the anterior cingulate, (Brodmann area 25), the orbito-frontal (Brodmann area 11) and the right superior temporal cortices (Brodmann area 22), extending to the insula (P < 0.001 in all area). Two additional hypoperfused areas emerged during symptomatic periods (P < 0.001), located in the right dorsomedial prefrontal cortex (Brodmann area 8) and the right parieto-temporal junction (Brodmann areas 22 and 39). These two areas were more affected between episodes, when the mean episode duration was longer (r = -0.53; P < 0.001). The score for the Depersonalization/Derealization Inventory during symptomatic periods strongly correlated with the hypoperfusion of the right (r = -0.74, P < 0.001) and left (r = -0.59, P < 0.005) parieto-temporal junctions. No hyperperfusion was found. Because the parieto-temporal junction (including the angular gyrus) is involved in cross-modal association between somatosensory (body knowledge), auditory and visual information, the robust hypoperfusions and correlations observed in this area may underlie the striking derealization reported by patients during episodes. Defects in the dorsomedial prefrontal cortex may cause apathy. Persistent hypoperfusion in the diencephalic and associative cortical area during asymptomatic periods is a marker of the disease, suggestive of a scenario wherein patients compensate for these deficient circuitries.

Kleine-Levin syndrome: a case report and review of literature.

BACKGROUND: Kleine-Levin syndrome presents with recurrent hypersomnia along with a number of other neuropsychiatric features, of which hyperorality has not been described frequently. METHOD: We report a male adolescent who presented with recurrent hypersomnia, hypersexuality, and hyperorality. Magnetic resonance imaging of the brain and overnight polysomnography followed by a multiple sleep latency tests were ordered. Excessive daytime sleepiness was assessed with the Epworth Sleepiness Scale. RESULTS: Magnetic resonance imaging of the brain did not reveal any abnormality. Overnight video-synchronized polysomnography and multiple sleep latency tests ruled out narcolepsy. Epworth Sleepiness Scale score at baseline was 22. He was prescribed lithium carbonate 300 mg twice a day. The symptoms improved within a week after starting lithium carbonate therapy. CONCLUSION: Kleine-Levin syndrome may present with hyperorality, and our patient responded well to lithium carbonate therapy.

Kleine-Levin syndrome with brain atrophy.

Kleine-Levin syndrome (KLS) is commonly described as a self-limiting disorder exhibiting episodes of hypersomnia and psychiatric symptoms, but without any enduring disabilities. Recently, reports have shown that persistent or even progressive memory deficits can also be associated with the disorder. Nevertheless, little has been reported about cognitive disturbances in KLS. Our report describes a rare patient with KLS and prominent brain atrophy. A 24-year-old woman developed severe neurological and psychiatric features 12 years previously, 2 weeks after she was hit in the head. Although she has had no recurrence of the primary KLS symptoms, she continues to have a cognitive disorder, verbal disability, and whole brain atrophy.

Clinical features of Kleine-Levin syndrome with localized encephalitis.

We report the clinico-pathological findings regarding a 9 year-old girl with some clinical features of Kleine-Levin syndrome who died suddently as a result of pulmonary embolism in the course of femoro-iliac thrombophlebitis. Neuropathological examination provided evidence of perivascular inflammatory infiltrates and microglial proliferation of nodular type located in the diencephalon and midbrain. These findings suggest that a localized encephalitis may be the underlying condition in Kleine-Levin syndrome.