Could acoustic neuroma cause permanent hearing loss?

Yes: The majority cause unilateral or asymmetric hearing loss as the first and sometimes only symptom. This hearing loss is always permanent.

Yes: Acoustic neuroma grows on the auditory nerve deep in the auditory canal. Surgery to remove the tumor often will cause disruption of the nerve. The surgeon will do all he can to preserve hearing the best he can. Usually severe and permanent hearing loss is a result.