Furthermore, unlike the polysomnography, it is less expensive and non-invasive.An actigraphy over several days can show longer sleep periods, which are characteristic for idiopathic hypersomnia. Actigraphy is also helpful in ruling out other sleep disorders, especially circadian disorders, leading to an excess of sleepiness during the day, too. The maintenance of wakefulness test (MWT)
The maintenance of wakefulness test (MWT) is a test that measures the ability to stay awake. It is used to diagnose disorders of excessive somnolence, such as hypersomnia, narcolepsy or obstructive sleep apnea. During that test, patients sit comfortably and are instructed to try to stay awake. The Stanford sleepiness scale (SSS)
The Stanford sleepiness scale (SSS) is a self-report scale that measures the different steps of sleepiness. For each statement, patients report their level of sleepiness using a 7-point scale, going from very alert to excessively sleepy. Researchers found that the SSS was highly correlated with performances to monotonous and boring tasks, which are found to be very sensitive to sleepiness. These results suggest that the SSS is a good tool to assess sleepiness in patients. The Epworth sleepiness scale (ESS)
The Epworth sleepiness scale (ESS) is also a self-reported questionnaire that measures the general level of sleepiness in a day  The patients have to rate specific daily situations by means of a scale going from 0 (would never doze) to 3 (high chance of dozing). The results found in the ESS correlate with the sleep latency indicated by the Multiple Sleep Latency Test.
In fact, two studies showed no correlation between PLMS and objective measures of excessive daytime sleepiness. In addition, EDS in these patients is best treated with psychostimulants—and not with dopaminergic agents known to suppress PLMS. "Neuromuscular diseases and spinal cord diseases often lead to sleep disturbances due to respiratory dysfunction causing sleep apnea, and they may also cause insomnia related to pain. "Other sleep alterations, such as periodic limb movement disorders in patients with spinal cord disease, have also been uncovered with the widespread use of polysomnography. "Primary hypersomnia in diabetes, hepatic encephalopathy, and acromegaly is rarely reported, but these medical conditions may also be associated with hypersomnia secondary to sleep apnea and periodic limb movement disorder (PLMD).Chronic fatigue syndrome and fibromyalgia can also be associated with hypersomnia. Chronic fatigue syndrome is "characterized by persistent or relapsing fatigue that does not resolve with sleep or rest. Polysomnography shows reduced sleep efficiency and may include alpha intrusion into sleep EEG. It is likely that a number of cases labeled as chronic fatigue syndrome are unrecognized cases of upper airway resistance syndrome" or other sleep disorders, such as narcolepsy, sleep apnea, PLMD, etc.As with chronic fatigue syndrome, fibromyalgia may be associated with anomalous alpha wave activity (typically associated with arousal states) during NREM sleep. Also, researchers have shown that disrupting stage IV sleep consistently in young, healthy subjects causes a significant increase in muscle tenderness—similar to that experienced in "neurasthenic musculoskeletal pain syndrome".