MRI findings in narcolepsy.
The neuropathology of narcolepsy is unknown. Recently, Plazzi et al. (1) reported magnetic resonance imaging (MRI) abnormalities in the pontine tegmentum of three patients with long-standing idiopathic narcolepsy. Considering the localization of the neuroradiological findings in the pontine reticular formation, where rapid eye movement (REM) sleep is generated, the authors suggested a causal relationship between narcolepsy and MRI abnormalities. Frey and Heiserman, however, found pontine MRI abnormalities in only two of 12 patients with narcolepsy both of whom had long-standing hypertension (2). Pullicino et al. noted similar pontine MRI abnormalities in patients with subcortical arteriosclerotic encephalopathy-like ischemic rarefaction of the pons (3). Thus, the changes noted by Plazzi et al. may have been caused by small-vessel disease rather than narcolepsy. To assess whether altered pontine MRI signals are a regular feature of idiopathic narcolepsy, we selected randomly from our database seven patients with narcolepsy with cataplexy. Of these seven, three agreed to have brain MRIs; their cases are described below. None had pontine MRI abnormalities.
Bassetti
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Department of Neurology, University of Michigan Medical Center, Ann Arbor 48109-0316, USA.
Aldrich
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Quint
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D000328:Adult; D001161:Arteriosclerosis / Q000473:pathology; D002545:Brain Ischemia / Q000473:pathology; D000697:Central Nervous System Stimulants / Q000627:therapeutic use; D005260:Female; D015802:HLA-DR2 Antigen / Q000276:immunology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009290:Narcolepsy / Q000175:diagnosis* / Q000276:immunology; D011149:Pons / Q000098:blood supply / Q000473:pathology; D011175:Positive-Pressure Respiration; D012154:Reticular Formation; D012891:Sleep Apnea Syndromes / Q000628:therapy; D012895:Sleep, REM
D000697:Central Nervous System Stimulants; D015802:HLA-DR2 Antigen