Doctors seek better way to measure real-world cochlear implant outcomes

Thousands of people get cochlear implants each year, totaling more than 96,000 people in the United States using implants to help them hear better. Yet there isn’t a comprehensive method for measuring how much the implants help people in day-to-day life, said Ted McRackan, M.D., a physician-scientist in the ear, nose and throat department at MUSC Health. 

“There’s a very low correlation between how patients perceive they’re doing and how they’re performing on the speech recognition test,” he said. 

The problem is that patients are assessed in a closed environment – an audio booth in which they listen to recorded sentences spoken in clear, proper English, McRackan said. They’re graded based on how many words they hear correctly in the sentence. But real-life speech rarely lives up to the audio booth standard. And the audio booth test only assesses the percentage of words the patient can identify. It doesn’t take into account how much effort the patient had to expend to understand the words or how well they’re able to maintain a social life. McRackan and his colleagues realized there was a disconnect between what was being tested and what ought to be tested.  

“It got us thinking, ‘How good of a job are we doing evaluating outcomes in this population?’” he said. 

Now, with a $605,000 grant from the National Institute on Deafness and Other Communication Disorders, McRackan is working on building a new quality-of-life instrument to evaluate patient outcomes. He said once they better understand the findings, they can then use that information to figure out how to improve patient care. 

McRackan, who got initial funding from the South Carolina Clinical and Translational Research Institute at MUSC as well as the American Cochlear Implant Alliance, said the work started with focus groups of cochlear implant patients. Although McRackan admits to having been a bit skeptical of using focus groups at first, he now says they were key to the entire project. 

“We really learned a tremendous amount. It really did inform the future direction of the research,” he said.  

“They gave us tremendous insight into how their hearing loss affected their social lives and how they were really retreating from society, backing off, not being engaged, not going to movies, not going to church, were fearful of interacting with people.”

 

Dr. Ted McRackan

What the investigators needed to hear from the focus groups was how much their hearing loss affected them socially and emotionally. 

“They gave us tremendous insight into how their hearing loss affected their social lives and how they were really retreating from society, backing off, not being engaged, not going to movies, not going to church, were fearful of interacting with people,” McRackan said. 

The investigators were also surprised by how important environmental sounds were to patients – being able to hear the birds chirping, kids playing basketball outside or a car coming down the street. 

From the focus groups, the investigators developed a bank of statements to include on the evaluation. Typical statements might include: 

• I am able to have a conversation without asking the other person to repeat him/herself. 

• I am able to have a conversation with three or more people in a noisy place. 

• I am able to understand what someone is saying without reading his/her lips.

 “A lot of them didn’t realize how much lip reading they were doing before they had a cochlear implant,” McRackan said of the focus group participants. 

The new evaluation also attempts to measure listening effort. There’s a clear association between hearing loss and dementia, McRackan said, and some early research suggests that listening effort – how much mental energy a person expends in hearing – may play a role. 

The questions were then tested on more than 300 people at 25 centers across the U.S. and then compared to traditional evaluations. From this information, the new Cochlear Implant Quality of Life (CIQOL) instrument was developed.

In addition to static quality of life instruments, the research team is now developing a computerized adaptive test. Adaptive testing is when an algorithm chooses the next question based on how the test-taker answered the previous question. McRackan said the ACI Alliance is funding the development of the computerized adaptive test. 

The next step entails a longitudinal study of patients starting from before they get the implants. There’s a great deal of variability in how much the implants help, McRackan said, so this study will look at everything from the patients’ socioeconomic status, employment level and region of the country to whether they have one or two implants. 

McRackan and his colleagues plan to develop an “expectations” instrument so, hopefully, they can align a patient’s expectations with the likely reality before the surgery takes place. They’ll also develop their instruments into health economic tools to determine the health economic impact of cochlear implants and look at whether there are simple interventions that could improve how well the implant works. For example, he said, there are currently online and telephone services for patients to practice their listening skills, as well as audio books. But no one really knows whether patients are using those resources or if they actually help, he said. 

McRackan said he’s fortunate to have lots of help here on campus, citing Judy Dubno, Ph.D., director of the Hearing Research Program; Craig Velozo, Ph.D., director of the Division of Occupational Therapy, who has been working on the instrument development; and Kit Simpson, DrPH, who will work on the health economic instrument. 

There’s a definite need for this work, said McRackan, adding that he receives several inquiries each month from clinicians and researchers who are interested in using the new CIQOL instrument.

“It’s exciting, because this is really the beginning of the research,” he said.