Causes of Muffled Hearing Muffled hearing can be associated with various factors such as earwax impaction, otitis externa, otitis media, and sudden hearing loss. Earwax Impaction: Earwax, commonly referred to as “ear wax,” is a substance secreted by the ceruminous glands in the outer ear canal. Under normal circumstances, this material naturally exits the ear while talking, chewing, or opening the mouth. However, when there is an excessive secretion of earwax or when its expulsion is obstructed, it can gradually form clumps, blocking the outer ear canal and thus leading to muffled hearing. Otitis Externa: Otitis externa, often caused by... Learn more