I have ob.sleep apnea & am using a cpap nightly. i sleep 8-9 hrs/night. still tired. sleep studies also show alpha wave intrusion.how is this treated?

Other causes: Alpha wave intrusions have not been shown to be a problem by themselves, and do not need treatment. Assuming the CPAP is set correctly, controls the apnea, and you are using it every night all night, i would look for other causes of sleepiness (including narcolepsy and idiopathic hypersomnia). Sometimes sleepiness from sleep apnea gets better with CPAP but not completely, and stimulants may help.

Stimulants: In most cases of sleep apnea, CPAP treatment does not completely eliminate sleepiness. Stimulants can be used if symptoms remain a problem. Other issues can contribute. Your sleep doctor might have more answers for you.