Although the MSLT is currently the best available test to diagnose EDS in general, the MSLT protocol lacks the ability to document the extended, unrefreshing daytime naps that often occur in idiopathic hypersomnia. Complicating the matter, several groups of researchers have found normal MSLT results in patients who otherwise seem to have idiopathic hypersomnia. Therefore, when idiopathic hypersomnia is suspected, researchers suggest appending a 24-hour continuous polysomnography to the standard overnight/MSLT study in order to record total sleep time.[20] Alternatively, an assay of the patient's cerebrospinal fluid (CSF) can be performed in order to test for an adequate level of hypocretin (to exclude narcolepsy with cataplexy) and to determine whether the patient’s CSF abnormally boosts GABAA receptor sensitivity (thought to underlie many cases of idiopathic hypersomnia and narcolepsy without cataplexy).[8] Globally, there are very few labs capable of performing the CSF assays referenced above.