As evidence linking hearing loss to cognitive decline and dementia mounts, researchers and clinicians are starting to explore whether automated, self-administered cognitive screening tests should be added to routine workups of patients seen in busy otolaryngology practices. Whether the technology behind these automated tests is ready for everyday use depends on whom you ask.
What is not up for debate is the reason behind the intense interest in cognitive screening: the epidemiologic data underpinning the connection between hearing loss and brain function. “Whether you look at Frank Lin’s work with the Baltimore Longitudinal Study of Aging or the more recent work by The Lancet Commission on Aging, it’s now clear that hearing loss and cognitive decline are strongly associated,” said Jed Grisel, MD, an otolaryngologist in practice at Texoma ENT & Allergy in Wichita Falls, Texas. “That has profound implications for what we should be doing as a profession to identify these patients and intervene as early as possible.”
There is plenty of research that backs up the link. A recent scientific statement from the American Heart Association underscored the important role adequate hearing plays in a patient’s ability to maintain healthy brain function (Stroke 2021;52:e295-e308). And The Lancet study Dr. Grisel cited, first published in 2017 and updated in 2020 (Lancet 2020;396:413-446), used meta-analyses to identify risk factors for dementia. The investigators found that age-related hearing loss may account for between 8% and 9% of all cases of dementia.
“That’s an incredible number,” said Dr. Grisel. “It far outstripped other risk factors in The Lancet report that many of us typically think of when it comes to dementia contributors, such as hypertension [2%], traumatic brain injury [3%], and smoking [5%].”
That correlation, albeit strong, does not necessarily mean causation, Dr. Grisel stressed. More research needs to be done to prove that treating patients who have hearing loss actually prevents or mitigates cognitive decline. “But we have to start with at least the assumption that it will prove to be the case, and act accordingly with more aggressive cognitive screening,” he said. “This really is a public health mandate, given our aging population and the high stakes involved.”
Frank R. Lin, MD, PhD, the director of the Cochlear Center for Hearing and Public Health and a professor of otolaryngology, medicine, mental health, and epidemiology at Johns Hopkins Medicine in Baltimore, said his work in this area first germinated when he read a 1989 paper linking the two conditions in the Journal of the American Medical Association (1989;261:1916-1919).
“I knew this was just a preliminary finding,” said Dr. Lin. “But it really piqued my interest, in part because it offered a possible explanation for what I was beginning to see in my surgical practice: patients with hearing loss suffering some level of cognitive overload from trying to discern sounds with a steadily diminished ability to do so. This often leads to them feeling isolated from family members and having compromised mental capacity as a result.”
It certainly should become part of our counseling about preventing noise exposure and when discussing the benefits of treating a hearing loss. —Hinrich Staecker, MD, PhD
That’s when Dr. Lin and his colleagues at the National Institute on Aging (NIA) decided to embark on an analysis of data from the NIA’s Baltimore Longitudinal Study of Aging to determine if hearing loss documented in study participants in the early 1990s was associated with the risk of being diagnosed with dementia over the next 15 years (Arch Neurol. 2011;68:214-220). “What we found is that individuals with mild, moderate, and severe hearing loss had a two-fold, three-fold, and five-fold increased risk for dementia, respectively, compared with patients who had normal hearing,” he said.
As for which cognitive screens are best suited to a busy otolaryngology practice, Dr. Grisel said he feels very strongly that self-administered, automated tests are the way to go because they offer several advantages over the paper-based screening tests typically employed by neurologists and other specialists. Whether it’s the Montreal Cognitive Assessment (MoCA) or the Saint Louis Mental Status Examination (SLUMS), among others, he noted, these tests “tend to be cumbersome and time-consuming for a patient to navigate. By the time a patient is done with one of these tests, a good chunk of your typical clinical visit can be gone. Also, you arguably have to have a professional present to administer these tests. That isn’t a viable staffing option for most otolaryngology practices.”
An Argument for Testing
Dr. Grisel has been using a kiosk-based, self-administered test marketed by Cognivue in his practice for about a year and has found it to be an effective alternative. The testing unit is similar in design to a laptop, but with a top and two side panels that help the user focus on the front screen of the unit without distraction. The device weighs less than 8 pounds, which facilitates folding it up and moving it between exam rooms. The test takes between five and 10 minutes to complete, according to the company’s website.
A clinical validation study of 401 patients showed “good agreement” between Cognivue screening test results and SLUMS (World J Psychiatr. 2020;10:1-11; bit.ly/3p0NG3u). The device has been cleared for use by the FDA.
Dr. Grisel said Cognivue controls for many of the key variables that make paper-based testing problematic. If a patient has poor vision, for example, the test can detect that problem and adjust the cognition-related tasks accordingly.
In his own practice, Dr. Grisel administers a cognitive test to any patient who is being considered for a hearing intervention. “But we’re certainly not screening everyone; we aren’t a neurology clinic. Rather, we try to focus on this incredibly important interaction between hearing loss and cognitive decline.”
Dr. Grisel noted that there are reimbursement codes one can use to get paid for administering the test. “We’ve certainly gotten payment for it,” he said. “It isn’t much, but that’s not really why we’re doing it.” The real impetus for adding cognitive screenings, he noted, is to be part of the solution to the growing problem of cognitive decline in patients with a hearing impairment.
“Remember: When we address hearing health, we’re addressing a key pillar to successful aging—to be able to age with intact cognition and brain function,” Dr. Grisel said. “If you’re going to help patients do that, you need to be able to identify their cognitive decline early, before several of the later stages of dementia have developed.”
However, he acknowledged that these are early days for determining optimal workflow and protocols for automated, self-administered cognitive screening. Indeed, the number of otolaryngology practices using this technology “is probably only in the dozens right now,” he said. “As with any new medical technology, it takes time to catch on.”
An Argument Against Testing
In the absence of widespread experience, can a strong case still be made to add some type of cognitive screening to a busy otolaryngology practice? Not according to the epidemiologist who has done pioneering work in this area.
“To be honest, I don’t think there’s much of a role for such screening at this point, at least for me, as a surgical otologist and ENT specialist,” said Dr. Lin, who was also a co-investigator for the Baltimore Longitudinal Study of Aging (Arch Neurol 2011;68:214-220) that Dr. Grisel cited as being so critical to the profession’s understanding of the link between hearing loss and cognition.
Remember: When we address hearing health, we’re addressing a key pillar to successful aging—to be able to age with intact cognition and brain function. —Jed Grisel, MD
“Cognitive impairment is a very broad condition, and it exists on a spectrum in terms of brain function; it isn’t linear,” Dr. Lin said. “One day you might perform poorly on a cognitive test, and another day you might score well. So, whether someone has a clinically significant cognitive impairment or not, it’s rarely something you ever diagnose by one simple 10-minute screening test.
“That being said, it does sometimes come up with my patients,” he continued. “Often, they’ve read that I’ve done research into the link between hearing loss and cognitive decline. If they ask me about it, I reassure them that just because they have some hearing loss, it doesn’t mean they’re doomed to develop dementia.”
However, if there are some significant reg flags for cognitive decline, Dr. Lin takes it seriously. “I’ll usually refer them to one of my colleagues at the Johns Hopkins Memory and Alzheimer’s Treatment Center, where they typically will review the whole set of other factors that can contribute to cognitive decline, including nutritional deficiencies, polypharmacy, etc.,” he says. “That’s a more effective approach than any screening test I could administer in my own practice.”
A Neurologist’s Perspective
Dave Bissig, MD, PhD, an assistant clinical professor in the department of neurology at the University of California at Davis in Sacramento, has a more positive but still measured view of cognitive screening tests, based in part on a study he coauthored that assessed a free, public-domain, self-administered, and automatically scored cognitive screening test known as SATURN (Self-Administered Tasks Uncovering Risk of Neurodegeneration). The 30-point computer-based screening test assesses a wide range of markers for cognitive function adapted from SLUMS and other assessments of visuospatial function and memory (Alzheimers Dement (NY) 2020;6:e12116).
For the study, 75 participants, including 23 patients from a dementia clinic, were given SATURN and the results were compared with the paper- or app-based MoCA test. Dr. Bissig and his coinvestigators found that SATURN and MoCA scores were highly correlated (P<.00001). Both tests also correlated well with clinical dementia rating scale scores (P<0.00001). Most participants (83%) reported that SATURN was easy to use, and most either preferred SATURN over the MoCA (47%) or had no preference (32%).
Asked whether such results support use of SATURN in an otolaryngology or other specialist’s clinic, Dr. Bissig offered some caveats based on his own experience with the test. He first noted that SATURN and most of the other tests in this field have not yet been fully validated in enough numbers to make definitive conclusions about their clinical utility. Moreover, they should not be given too much weight on their own. “I view SATURN and MoCA scores with the same caution: These tests have to be interpreted in the context of age, education level, any disturbances to mood or sleep, polypharmacy, etc.,” he said.
Finally, SATURN shares a limitation with several other automated, self-administered tests, in that certain physical conditions can compromise results. In the case of SATURN, the test “will be of limited use in those with poor vision or low baseline literacy,” Dr. Bissig said. “In regular clinical practice, when a patient is unable to read the initial stimulus, an alternative and appropriately normed test should be selected.”
The Value of Patient Discussions
Hinrich Staecker, MD, PhD, the David S. and Marylin M Zamierowski Professor in Skull Base Oncology in the department of otolaryngology–head and neck surgery at the University of Kansas School of Medicine, in Kansas City, acknowledged the potential that automated, self-administered tests have in certain clinical settings.
In the case of the Cognivue test, for example, Dr. Staecker said, “The device is fascinating, and as pharmacologic interventions for dementia are developed, these types of tests will play a valuable role in identifying candidate patients.” But he also expressed some caveats about using such screens routinely in otolaryngology practices.
“Both dyslipidemia and diabetes are independently associated with hearing loss, but we don’t do additional screening for those disorders, which could, of course, be mitigated to decrease a patient’s risk for further hearing loss,” said Dr. Staecker. “We could go through a long list of disorders a patient could be screened for during an otolaryngology visit.”
If the goal of adding cognitive screening to otolaryngology practices is to convince patients of the dangers of untreated hearing loss, and to treat that hearing loss as early as possible, Dr. Staecker believes that a more useful approach would be to improve access to hearing screening through tools such as the hearing handicap inventory and tablet-based audiometer systems, and then to educate patients about the associated risk of dementia.
These discussions are critical, Dr. Staecker stressed, given the “explosion” of epidemiologic data linking hearing and cognition. And that’s not just based on the findings of The Lancet Commission. “The first studies are also emerging that suggest that amplification or cochlear implantation can mitigate the risk for cognitive decline,” he said. One recent study, for example, showed improvements in several cognitive subdomains in older patients fitted with the implants (Otol Neurotol [published online ahead of print Mar. 26, 2021]). “It’s an extremely important topic for otolaryngologists to be aware of,” he said. “It certainly should become part of our counseling about preventing noise exposure and when discussing the benefits of treating a hearing loss.”
David Bronstein is a freelance medical writer based in New Jersey.
Financial disclosures: Dr. Grisel reported that he is a paid consultant for Cochlear Americas and Cognivue Inc. Dr. Lin reported that he is a consultant to Frequency Therapeutics and is the director of a public health research center funded in part by a philanthropic gift from Cochlear, Ltd., to the Johns Hopkins Bloomberg School of Public Health. Dr. Staecker reported that he is on the surgical advisory board for MED-EL. Dr. Bissig reported no relevant financial relationships.
Aging and Cognitive Health Evaluation in Elders Trial
Demonstrating that hearing loss is a strong predictor for dementia is all well and good, but the real breakthrough would be to show that treating hearing loss actually makes a difference—that it mitigates cognitive decline, according to Frank R. Lin, MD, PhD, the director of the Cochlear Center for Hearing and Public Health and a professor of otolaryngology, medicine, mental health, and epidemiology at Johns Hopkins Medicine in Baltimore. “If we can make that case, then prioritizing screening for and treating hearing loss in older adults makes a lot more sense,” he said.
This is exactly what Dr. Lin and his colleagues at the Johns Hopkins Bloomberg School of Public Health and six other institutions hope to accomplish with their ACHIEVE (Aging and Cognitive Health Evaluation in Elders) trial (ClinicalTrials.gov Identifier: NCT03243422). Supported by the National Institute on Aging, the $20 million study has recruited nearly 1,000 older adults between the ages of 70 and 84, all of whom have mild to moderate hearing loss. Participants will be randomized 1:1 to the hearing intervention (hearing needs assessment, fitting of hearing devices, education/counseling) or a successful aging education control intervention (individual sessions with a health educator covering healthy aging topics). Post baseline, participants will be followed semi-annually for three years to assess various domains of cognitive impairment and dementia. Results from the ACHIEVE trial are expected in 2023.
“As an epidemiologist, I have no idea of what the results might be, as the trial is completely blinded, and I’ve seen too many research hypotheses fail to be supported by large-scale studies,” said Dr. Lin. “But, as a clinician, my hope is that I’ll see confirmed what I have observed in my personal surgical experience: that when we intervene and treat hearing loss, whether with hearing aids or cochlear implants, the treatments often make a huge difference in patients’ lives. They no longer have to spend so much of their cognitive bandwidth on trying to hear, and instead can reconnect with family and friends and become much less isolated.”
Financial disclosure: Dr. Lin reported that he is a consultant to Frequency Therapeutics and is the director of a public health research center funded in part by a philanthropic gift from Cochlear, Ltd., to the Johns Hopkins Bloomberg School of Public Health.