By Maurice H. Miller
When we deny our hearing aid patients effective programs of rehabilitation, we render them unable to function in a variety of important real-life listening situations. We also increase their isolation from loved ones and society. We may be giving them more sophisticated hearing aids with adjustable digital circuitry and almost infinitely variable microphone circuits. But, are we giving them functional hearing in difficult listening situations that are important in their everyday lives? All too often, the answer is no.
Rehabilitation has become, if not the new “magic” word in patient care, certainly a recognized, essential concept of patient care, especially for our increasingly elderly population. Even non-specialized dictionaries define the purpose of rehabilitation as restoring some or all of the patient’s physical, mental, and sensory capabilities that have been lost to injury, illness, or disease. To those we should add aging, although there are some who believe that aging per se does not result in loss of function. Rehabilitation aims to assist the patient in compensating for deficits that cannot be medically reversed.
Rehabilitation now pervades virtually every aspect of expanded health (not just medical) care. Earlier this year, I faced a life-or-death health crisis as a result of a massive infection. Hospitalization was followed by rehabilitation in a nursing-rehab center, where I was given, in addition to wound care, physical and occupational therapy on a regular, intensive basis. As I write this, my 80-year-old brother-in-law is in a rehab facility to help him relearn to walk and to achieve independence following a fall that required knee surgery.
Thousands of persons, mostly elderly, undergo knee and hip replacement surgery, and all expect and receive a period of rehab following the surgery.
AUDIOLOGY IS LAGGING BEHIND
Despite the growing role of rehab in other areas of healthcare, audiologic rehabilitation (AR) does not occupy a central role in the practice of audiology, the profession where during World War II AR began and saw much of its most productive development.
Robert Sweetow, one of our most distinguished audiologists and a leading advocate for AR, has observed that, regrettably, it is the device and not the rehab that is the center of what we do for our patients. Despite the recent proliferation of papers and presentations about AR, it is not yet not ingrained as the centerpiece of our work–which is what it should be.
HOW AUDIOLOGY EVOLVED
More than 50 years ago, when ASHA (the American Speech-Language-Hearing Association) was the only professional organization for audiologists, I was one of a small group of audiologists who attempted, at the invitation of the association’s executive secretary, Ken Johnson, to develop principles and practices for audiologists to follow in dispensing hearing aids. I remember that Johnson stated that once the “professionals,” i.e., audiologists, started dispensing, the need for AR would diminish significantly.
Johnson led ASHA for over 20 years. During most of this tumultuous period it was not accepted practice for audiologists to dispense hearing aids. He defended this posture for most of his career until it became apparent that preventing audiologists from dispensing hearing aids was a restraint of trade and would lead to legal action against the organization.
How many readers of this blog were practicing audiology when ASHA strictly prohibited them from dispensing hearing aids? Back then, the audiologist did a hearing aid evaluation (HAE) to determine which aid was “best” for a particular patient. The patient was then referred to a hearing aid dealer of his choice, who sold the aid to the patient and referred him back (sometimes) to the referring audiologist.
So we had a system in which the audiologist had no direct involvement in the actual fitting and adjustment of the hearing aid. Instead, someone who often had no more than a high school diploma or its equivalent was responsible for the fitting and adjustment (and any circuit modifications he felt appropriate).
THE CARHART METHOD
How did audiologists decide which hearing aid to recommend? It was largely based on the Carhart method of hearing aid evaluation (HAE).1
The audiologist took aided and unaided sound field measurements with several hearing aids. Measurements included the SRT (speech-recognition threshold), WRS (word-recognition score) in quiet and in background noise, MCL (most comfortable loudness) and UCL (uncomfortable loudness level), range of comfortable loudness, and a subjective determination of how the aid sounded to the patient. On the basis of which instrument performed and sounded best, the audiologist made a recommendation and the patient was sent to a local dealer.
The Carhart HAE procedure was fraught with serious errors of both validity and reliability. First, how did we know if the audiologist’s clinic stocked the best aid for a given patient? Also, the aid that scored “best” or that the patient liked best on the initial test often did not prove to be the “best” on repeat testing (frequently not done by the audiologist).
HAEs on elderly patients often showed diminishing performance with successive hearing aids because of fatigue, regardless of which aid was being evaluated. And patients (both then and now) often preferred the hearing aid circuit that reproduced their own distorted hearing pattern, not the one that provided the best speech discrimination.
There were more problems: The hearing aid fitted by the dealer on the patient often differed significantly electroacoustically from the one with which the patient was evaluated by the audiologist. And, unbeknownst to the audiologist, the dealer often made changes in the circuitry to improve the patient’s amplification performance.
ARTICLE NOTED WEAKNESSES OF THE CARHART PROCEDURE
I subjected some of these problems to a clinical investigation and wrote an article illustrating the serious limitations of the Carhart procedure, which was used in one form or another in clinics throughout the country. The article was accepted for publication by one of the most respected otolaryngology journals.
The distinguished Dr. Raymond Carhart, one of the founders of audiology, learned about my article, and I still shake as I recall his words warning me that my article would do irreparable harm to the profession. In a state of fear (and being very young at the time), I withdrew the article. Since the publisher had already incurred considerable expense preparing the article for publication, I agreed to reimburse the publisher, which was not easy for a novice in the field with a small salary.
I did present a 15-minute summary of the paper at an ASHA Convention in 1958. It was greeted with approbation by a number of distinguished audiologists in the audience, including Ira Hirsh. The article that I had withdrawn from the otolaryngology journal was summarized in the annual convention issue of the association’s publication Asha, with no corrections suggested.
And so Ken Johnson’s belief that audiologists allowed to dispense hearing aids for a profit would not survive never met the test of reality. In fact, for many audiology clinics dispensing hearing aids has become their most financially productive component, as reimbursement for some diagnostic procedures has diminished significantly.
THE IMPORTANCE OF AR IS ONLY GROWING
Clearly, the availability of better hearing aids has not eliminated the need for intensive, high-quality audiologic rehabilitation. In fact, it has reinforced that need. Today’s hearing aids may be more adaptable, but our patients are not.
The aging of our population is accompanied by a variety of central processing deficits. The questions of which comes first, the CANS (central auditory nervous system) or the auditory disorder, and what is the synergistic interaction between the two lead to interesting speculation. But the combination of deficits makes successful adjustment to amplification a far more formidable challenge than ever before.
Johnson was wrong when he postulated that better hearing aids fitted by professionals with advanced degrees and training would reduce the need for AR. It was probably true for some younger members of the military and some veterans, but it hardly applies to the age and combined disabilities of the population we now serve.
The use of DVDs alone will not meet the challenge. Many patients must be provided with intensive, individual AR if we are to achieve truly successful rehabilitation.
1. Carhart R: Tests for selection of hearing aids. Laryngoscope. 1946;56:780-794.
Maurice H. Miller, PhD (Columbia, 1956), is Professor Emeritus of Audiology, New York University Steinhardt School of Culture, Education and Human Development, and former Chair of the Department of Speech-Language Pathology and Audiology. He is a Fellow of ASHA and recipient of Lifetime Career Awards from the American Academy of Audiology and New York University. He is the author of five books, the latest of which is the Hearing Disorders Handbook, co-authored with Dr. Jerome D. Schein and published by Plural.
Dr. Miller dedicates this Hearing View article to Dr. Schein, “one of the world’s great authorities on the deaf community, who tragically died last year and was my co-author of articles and books. His unique abilities will never be replaced.”