I think the
audiologist's recommendation that you follow up with your
doctor is a good one. There are several possible causes of hearing loss, and these are usually grouped into where in the ear (outer, middle, or inner ear) that the reasons for the hearing loss is occurring.
To give some examples, a build up of ear wax in the ear canal would be a cause of "outer ear" hearing loss. A buildup of fluid behind the ear drum, for example from an
ear infection, would be a cause of "middle ear" hearing loss.
In your case, the audiologist, based on the tests performed, feels that the cause of hearing loss is in the "inner ear." This may also be referred to as sensorineural hearing loss or cochlear pathology. By far the most common cause of sensorineural hearing loss in your age range would simply be presbycusis, or age related hearing loss. Although this does tend to occur in both ears, this may not always be the case. There is a long list of other inflammations, infections, and various conditions other than presbycusis which can also cause sensorineural hearing loss, and your doctor will be able to help you figure out which is the likely cause.