Could there be an association between head trauma and narcolepsy w/ cataplexy?

Definitely.: This is well documented with both narcolespy with cataplexy and narcolepsy without cataplexy.

Rare : Limiting the answer to the adult patient population, narcolepsy can be a sequel of head trauma. This is commonly referred to as secondary narcolepsy. However, would expect to see other obvious neurologic deficits and not just narcolepsy.