My 17 months baby has blank stares for 3-5 seconds more than 5-10 times a day and discontinues it with physical intervention. no eeg.absense epilepsy?

Unlikely: abscence epilepsy usually presents between 4 to 12 years old. seizures cannot be aborted with physical stimulation so the fact these spells do points away from a seizure. your baby could be daydreaming but if still very concerned, EEG capturing the spell would help clarify if this is an epileptic event vs a benign 17 month old pondering of his/her existance. hope its the 2nd one.