Audiology Convention Keynote Addresses Current Issues in Amplification ASHA Convention Coverage
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ASHA Convention Coverage  |   January 01, 2005
Audiology Convention Keynote Addresses
Author Notes
  • Pam Mason, director of professional practices in audiology, can be reached at pmason@asha.org.
    Pam Mason, director of professional practices in audiology, can be reached at pmason@asha.org.×
  • Marat Moore, managing editor of The ASHA Leader, can be reached at mmoore@asha.org.
    Marat Moore, managing editor of The ASHA Leader, can be reached at mmoore@asha.org.×
Article Information
Hearing Disorders / ASHA Convention Coverage
ASHA Convention Coverage   |   January 01, 2005
Audiology Convention Keynote Addresses
The ASHA Leader, January 2005, Vol. 10, 1-17. doi:10.1044/leader.ACC1.10012005.1
The ASHA Leader, January 2005, Vol. 10, 1-17. doi:10.1044/leader.ACC1.10012005.1
Audiologists filled the daily keynote sessions offered at the Audiology Convention at ASHA, held Nov. 18–20, 2004 in Philadelphia. Each keynote panel featured three well-known speakers addressing different aspects of the keynote topic. Coverage of the first keynote presentation on Nov. 18, which focused on hair cell rescue, repair and regeneration, appeared in the Dec. 14 issue of The ASHA Leader. Below is a summary of the second set of presentations given Nov. 19. Addressing “Current Issues in Amplification,” speakers offered data-based insights into the potentials and limitations of current amplification systems used to compensate for reduced hearing ability. The session was sponsored by Energizer Battery.
A Chronology of Amplification
Ruth Bentler, a professor in the department of speech-language pathology and audiology at the University of Iowa and a former clinical audiologist, reviewed the historical development of amplification by outlining the “eras” that mark technological advances.
  • Era 1: “Electronic Hearing Aids.” This era saw major advances but they included unwanted side effects, such as signal distortion, narrow bandwidth, poor comfort. The newer technologies actually introduced worsening conditions for the hearing aid user.

  • Era 2: “Industry knew best.” This period spanned the 1970s to the1990s and included Wide Dynamic Range Compression (WDRC), as well as programmable devices, multi-channels and the first generation of digital signal processing. Audiologists began to utilize the manufacturers’ “First Fit” software based solely on audiometric data. “Buzz words” and marketing campaigns predominated and caused unrealistic expectations in hearing aid users. In addition, all control was removed from patients; no volume controls and no t-coils existed in many devices during this era.

  • Era 3: “Online processing.” Directional mics (d-mics), reduced power consumption (longer battery life), noise management and controls on feedback developed during this period. Hearing aids contained multiple small computer chips that allowed for precision control. D-mics with multiple microphones are used to increase speech intelligibility. They can be switchable—the patient can flick a switch to change the mic from omni to directional—limiting the pick-up from behind the head. From switchable d-mics came adaptive d-mics, which continuously process and adapt to changing environments. “Despite good lab results, we can’t predict success in the real world,” Bentler said, adding that audiologists cannot rely on slope of loss, or self-report scales, to predict directional advantage. Bentler conducted research that focused on real-world assessment but noted the inconclusive results, saying, “one-third of the subjects liked the omni mic, a third liked the fixed d-mic and a third liked the adaptive mic.”

  • Era 4: “Digital Signal Processing (DSP) Noise Reduction.” In the current period—with adjustable gain reduction, varying onsets, and varying algorithms—manufacturers’ philosophies differ on what most effectively reduces noise and feedback. In Bentler’s view, the potential pitfalls of the current era include: reverberation and multiple noises in the environment (directional mics don’t work that well); “good noise” versus “bad noise” (perception); reduced audibility (feedback reduction); cascading features (the potential of one factor to override or affect the other); and the human factor.

Will technology advances improve outcomes? “Through these developments in amplification, we have made significant advances—lower distortion, WDRC, d-mics, noise reduction, feedback reduction (with online processing), verification of fittings, and ear mold technology,” Bentler said.
“What remains unresolved is how to predict human success.”
Measuring Outcomes of Audiological Interventions
Terry Hnath Chisolm, from the University of South Florida was the second presenter. She replaced Michael Valente on the program and addressed measurement of outcomes of audiological interventions.
She noted that outcomes should be similar between similar patients and not dependent on clinician or location. To achieve this goal, clinicians must engage in evidence-based practice. “We must systemize hearing aid evaluation and fitting practices to achieve optimal outcomes,” she said.
She described how the World Health Organization’s International Classification of Functioning, Disability and Health (WHO-ICF) could be used as a conceptual model for selecting goals and identifying appropriate outcome measures. The WHO-ICF discusses the impact of diseases and disorders in terms of impairments of body structure and function, activity (i.e., what a person can or cannot do in a controlled situation) and participation (i.e. what a person does or does not do in real life). All of these factors are influenced by personal and environmental contextual factors.
In applying the WHO-ICF to audiology, the most common goal of hearing aid intervention addresses the WHO-ICF code “d320—listening to—receiving—spoken messages.” At the level of activity soundfield, speech recognition testing provides appropriate outcome measures. At the level of participation, a self-report measure such as the Abbreviated Profile of Hearing Aid Benefit is a suitable choice.
In addition to improving activity and participation, clinicians need to be concerned with patient satisfaction. “Satisfaction is a universally agreed upon outcome. It is achieved when the audiologist must meet or exceed patient expectations. To do this, it is important for patients not to be oversold on or have unrealistic expectations of amplification,” Chisolm said.
Chisolm talked about a new generic health-related quality-of-life outcome measure—the WHO’s Disability Assessment Schedule II (WHO-DAS II). It includes two items relevant to audiology: understanding what people say, and starting and maintaining a conversation. Chisolm worked on a multi-site VA study with Dr. Harvey Abrams, Chief of Audiology and Speech-Language Pathology Services at the VAMC-Bay Pines, Florida, which demonstrated the sensitivity of the WHO-DAS II to hearing aid intervention.
“Why should audiologists care about generic measures?” she asked. “In the economic domain, they allow us to show economic viability of intervention.” For example, Chisolm and Abrams found that intervention through hearing aid intervention alone cost about $60 per quality-adjusted-life year (QALY) gained, while it was only $31.91 per QALY-gained when a four-week aural rehabilitation program was implemented. “Compared to other health care interventions, aural rehabilitation provides a high benefit at a low cost,” Chisolm concluded.
Non-Audiological Factors and Hearing Aid Outcomes
Patricia Kricos, the third presenter, discussed “Influence of Non-Audiological Variables on Hearing Aid Outcomes: What Have We Learned in the Last 10 Years?”
Kricos opened with a series of questions related to hearing aid use. “Why do only one in five adults fitted with hearing aids continue to wear them?” she asked. “What is the influence of non-auditory variables on hearing aid outcomes, and how can we better predict patient success? Audiologists need to think of the whole person,” she said.
In 1994, research by Gatehouse found that audiological variables aren’t the most important in predicting outcomes. He conducted regression analysis for social and psychological factors, and found that none of the audiological variables contributed to the perceived hearing aid benefit. Other significant factors affecting hearing aid use are hysteria, depression, sickness and anxiety, Kricos said.
Regarding gender, she noted that women tend to be more sensitive to health-related concerns and have greater problem awareness. One study conducted in Wales in 2003 found that women were less able to manipulate hearing aids than men, and were less satisfied with them.
Age affects outcomes in multiple ways. Old age is often accompanied by chronic disease and disabilities, vision problems, side effects of medications, compromised manual dexterity, and problems with working and long-term memory.
Psychologically, the level of motivation of the patient or communication partner is “hugely important,” she said, noting her research has shown that pressure from a family member or caregiver on a patient to seek treatment does not negatively affect outcomes.
A study of hearing aid users between 16 and 97 years of age showed the youngest and oldest had the greatest difficulty adjusting to hearing aids. “Younger people reported feeling that they had more of a handicap than elders,” Kricos said, adding that elders often passively accept hearing loss and don’t have as many communication demands placed upon them as do younger people.
Cognitively compromised patients received less benefit from hearing aids. “We should be doing a cognitive screen,” Kricos said.
One interesting study she suggested that audiologists read is “Modeling and Predicting Hearing Aid Outcomes,” Humes (2003).
Self-efficacy research has proved useful in other health care fields, but has not yet been conducted in relation to hearing aid outcomes. Research has shown that patients can have a domain-specific competency. “In other words, competency can vary according to the specific activity. You could have a confident person who has low confidence about her ability to use a hearing aid, for example,” Kricos said. “We need to do this research, especially related to aural rehabilitation outcomes.”
She wrapped up by saying, “Audiologists must do a better job at evaluating the non-auditory issues and predicting success for their patients.”
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January 2005
Volume 10, Issue 1