Brain MRI findings in patients with idiopathic hypersomnia.

OBJECTIVE: Proper diagnosis of idiopathic hypersomnia necessitates the exclusion of neurologic or medical causes of sleepiness that better explain the clinical syndrome. However, there are no formal guidelines regarding the use of neuroimaging to identify such secondary causes of symptoms. We sought to characterize brain MRI findings in a series of patients with idiopathic hypersomnia.

METHODS: We reviewed medical records on a consecutive series of 61 patients diagnosed with idiopathic hypersomnia to determine the frequency and results of brain magnetic resonance imaging (MRI).

RESULTS: One-third of patients had undergone brain MRI, with focal neurologic signs or symptoms being the most common indication for neuroimaging. Although seven patients had an identifiable finding on neuroimaging (e.g., chronic microvascular ischemic changes), clinical management was changed as a result of imaging in only three cases. In all three, the imaging finding was predated by clear clinical abnormalities.

CONCLUSIONS: Neuroimaging may be a complementary part of an idiopathic hypersomnia evaluation, but the decision to pursue imaging should be made on a case-by-case basis.