A 15-year-old school girl c/o feeling excessive sleepiness but not amounting to Narcolepsy esp. in the morning after getting up from the bed. lasts for 3-4hrs, for the past 6 months.she is otherwise very healthy n intelligent  girl. No past h/o any major illness.No h/o of migraine No h/o any regular drug intake. Food habits are normal. Studying habits are normal.

School is near home. No need for long travel. No late nite studying.sleeps 10pm to 5am. Her basic metabolic parameters, CBC, Electrolytes, TFT are normal.Hb 13gm%.Ophthalmic evaluation is normal. Kindly suggest further investigations possible diagnosis and management.