The ROLE of BRAIN in HEARING LOSS

Notes from a 2/15/03 SHHH-CA presentation by Dr. Robert Sweetow, Head of Audiology, UCSF 

as recorded by Laine Waggoner, MA, MS and Joan Ireland

Our brains:

We hear in our brains not our ears. The auditory cortex of the brain processes sound at different levels.  The brain’s nerves take on different functions in hearing loss because the ear has lost it’s fine tuning ability.

Brain functioning continuously changes over time: the brain is structurally inflexible, but functionally flexible.  The brain tries to compensate for the confusing high-frequency sounds provided by the new hearing aids.  These plastic changes can create a learning catastrophe, called “bad listening syndrome”.  What sometimes appears to be cognitive loss or dementia may actually be a problem with plasticity of the brain.

It is possible to train the brain: to alter the “brain map”.

What hearing aids CAN do:

• Increase audibility

• Maintain comfortable sound levels

• Minimize feedback to noise

• Amplify high pitched sounds which the brain has forgotten how to process.

What hearing aids CANNOT or MIGHT NOT do:

• Resolve all frequency resolution problems.

• Rectify temporal resolution: separating sounds by time.

• Undo “bad listening” syndrome.

• Automatically induce neural plasticity (molding brain’s patterns).

Current hearing aid facts:

• Costs are up 35%- mostly among the digital aids. 

• Dr. Sweetow anticipates that in five years all digital aids will cost less.

• More insurance companies will now reimburse for hearing aids.

• Digital aids are the latest in hearing aids: a mini computer converts sound into numbers. This is not necessarily better sound than analog aids which run sound through filters.  

• An experimental “IN-SOUND” aid is in the works, which will be inserted deeply in the ear canal by a physician using a microscope. It may avoid ear wax problems. It requires little amplification and no feedback. It could be used for 3-4 months.

Major digital features include: 

(1) Feedback canceling control allowing more amplification before feedback occurs.  (2) Multiple microphones available in all but the smallest in-the ear (ITE) or in-the-canal (ITC) aids.  

(3) Possible noise suppression.

Expected future developments in the practice of audiology:

• There will be more auditory training or audiological rehabilitation-with or without hearing aids.

• Retraining the brain may be more effective than constantly reprogramming hearing aids.

• Realistic expectations will be stressed, such as the fact that even the most advanced hearing aid technology may not be able to compensate for certain limitations of an individual’s brain.

• Practice in communication will be important, much like physical therapy for a body injury. At UCSF, study subjects are practicing a variety of sentences 30 minutes a day, five days a week for four weeks.

• There will, hopefully, be more counseling in the use of hearing aids, assistive listening devices and communication strategies.

• Training in enhancing listening skills will include techniques for effective hearing, attending, understanding and remembering what is said.

Laine Waggoner is the Director of HEAR (Hearing-loss Education And Relationships), which conducts support groups, facilitates seminars, and provides private coaching for individuals who are experiencing hearing loss.  Email: LaineWaggoner@dc.rr.com