Hypersomnia

• Feeling sleepy during the day, even after a good night's sleep. 
• Difficulty waking up after you have been asleep at night or for a nap.
• Fatigue
• The need to sleep can strike at any time, including when you are driving a car or working.

• Insufficient sleep
• Low thyroid levels
• Obesity
• Depression and psychiatric disorders
• Medications that have sedating effects
• Certain neurologic disorders, such as Parkinson Disease or Multiple Sclerosis.

In addition to taking a detailed medical history, listening to the patient describe symptoms, and conducting a physical exam, the healthcare provider may also recommend:

• Epworth Sleepiness Scale. Your doctor may ask you to rate your sleepiness with this tool to help determine how sleep affects your daily life.
• Sleep diary. Your doctor may ask you to keep a sleep diary in which you log your daily sleep and wake times to help show your sleep amounts and pattern.
• Polysomnogram. In this test, you stay in a sleep center overnight. A polysomnogram monitors your brain activity, eye movements, leg movements, heart rate, breathing functions and oxygen levels as you sleep.
• Multiple sleep latency test. This measures your sleepiness and the types and stages of sleep you go through during daytime naps. This test is generally conducted the day after a polysomnogram.

Sleep specialist might recommend a regular nighttime sleep schedule that would include avoiding alcohol and certain medications that can affect your sleep. 

However, because the cause of hypersomnia isn't always known, the treatment is aimed at easing symptoms. Stimulant medication might be prescribed to help you stay awake during the day.