Hearing Aid Signal Processing for Alzheimer's Disease

Recruiting at 1 trial location

Overseen By Kendra Marks, Au.D.

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Northwestern University

Disqualifiers: Unstable medical conditions, Stroke, Schizophrenia, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 6-10 weeks

20 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how different types of hearing aid signal processing affect individuals with Alzheimer's dementia or its early stage, amnestic mild cognitive impairment. Researchers aim to determine if simpler hearing aid settings are more effective for those with reduced memory and thinking skills. Participants will test two hearing aid setups: one with advanced signal processing and another with basic signal processing. The trial seeks individuals diagnosed with Alzheimer's or mild cognitive impairment who live at home and experience hearing difficulties that impact daily communication.

As an unphased trial, this study provides a unique opportunity to contribute to understanding how hearing aid settings can enhance communication for those facing cognitive challenges.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It is best to discuss this with the trial coordinators or your doctor.

What prior data suggests that these hearing aid signal processing strategies are safe for older adults with Alzheimer's dementia?

Research has shown that the way hearing aids process sound, whether they alter the sound significantly or minimally, is generally safe. Studies suggest that features like reducing background noise and adjusting sound frequencies are well-tolerated. Although these studies do not highlight specific problems, the methods used in these hearing aids are common and have not raised major safety concerns in past research. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores how different levels of hearing aid signal manipulation might impact Alzheimer's disease. Unlike existing treatments for Alzheimer's, which often focus on medication to slow cognitive decline, this approach investigates auditory stimulation as a potential method to enhance brain function. By varying the signal manipulation, researchers hope to discover whether specific auditory processing techniques can improve cognitive outcomes, potentially leading to a non-invasive, supportive therapy for individuals with Alzheimer's.

What evidence suggests that this trial's treatments could be effective for Alzheimer's disease?

Research has shown that hearing aids can support brain function in older adults. In this trial, participants will experience two levels of signal manipulation in hearing aids. One study found that hearing aids with minimal sound changes, which participants will experience in one arm of this trial, might slow mental decline by keeping sounds natural and easier for the brain to process. However, strong evidence is lacking to prove that hearing aids directly improve thinking skills in people with Alzheimer's. For hearing aids that significantly alter sounds, which participants will experience in another arm of this trial, the benefits remain unclear. Some experts believe they might not be as helpful for those with very low mental abilities. Overall, while hearing aids can improve hearing, more research is needed to understand their effect on brain function. ^{1 6 7 8 9}

Who Is on the Research Team?

Pam Souza, PhD

Principal Investigator

Northwestern University

Are You a Good Fit for This Trial?

This trial is for older adults with Alzheimer's dementia or its precursor, amnestic mild cognitive impairment. Participants must speak English, have normal vision or corrected-to-normal vision, sensorineural hearing loss within specific parameters, and a certain level of cognitive function. They should live at home and be able to consent to the study.

Inclusion Criteria

Minimum Grade 10 education

You have slight or mild problems with memory, thinking, and daily activities.

My vision is normal or corrected to normal (20/40).

Exclusion Criteria

You have had a serious mental illness like schizophrenia or severe untreated depression.

You are also participating in other studies focused on improving hearing, language, or communication.

You currently use a hearing aid for at least 4 hours a day on most days in the past year.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants will use two different hearing aid signal processing strategies, each for 3-5 weeks

6-10 weeks

Multiple visits for fitting and assessment

Follow-up

Participants are monitored for changes in speech intelligibility and conversation analysis after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• High level of signal manipulation
• Low level of signal manipulation

Trial Overview

The study tests two types of signal manipulation in hearing aids: one with high levels of alteration and another with low levels. It aims to determine which strategy benefits those with Alzheimer's dementia more by providing clearer sound without too much processing.

How Is the Trial Designed?

Group I: Hearing Aid Fitting Order B Experimental Treatment 2 Interventions

Participants wear hearing aids with a low level of signal manipulation, followed by a high level of signal manipulation

Group II: Hearing Aid Fitting Order A Experimental Treatment 2 Interventions

Participants wear hearing aids with a high level of signal manipulation, followed by a low level of signal manipulation

Who Is Running the Clinical Trial?

Northwestern University

Lead Sponsor

Trials

1,674

Recruited

989,000+

National Institute on Deafness and Other Communication Disorders (NIDCD)

Collaborator

Trials

377

Recruited

190,000+

Published Research Related to This Trial

In a study of 43 Alzheimer's disease patients and 50 control subjects, no significant differences in hearing thresholds or word recognition scores were found between the two groups, suggesting that peripheral hearing dysfunction is similar in both populations.

The results indicate that hearing loss in Alzheimer's patients does not correlate with cognitive impairment as measured by the Mini-Mental State Examination (MMSE), implying that hearing issues may not be directly related to the severity of dementia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Hearing impairment in senile dementia of Alzheimer's type]. Wang, NY., Yang, HJ., Su, JF., et al.[2006]

The review outlines a comprehensive six-stage framework to understand how hearing aids impact speech understanding, highlighting factors from the acoustic content of the signal to the listener's ability to identify speech sounds.

Two new assessment techniques are introduced: acoustic analysis of speech at the hearing aid's output and auditory evoked potentials, which can help clinicians better evaluate hearing aid performance and the effects of hearing loss on speech processing.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

New perspectives on assessing amplification effects. Souza, PE., Tremblay, KL.[2019]

Hearing aids use advanced technologies like directional microphones and noise reduction to help people with hearing impairment understand speech better, especially in noisy environments.

However, the effectiveness of these technologies can vary based on individual differences in working memory capacity, meaning that some users may find it harder to process the enhanced signals, which could hinder their listening experience.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cognition and hearing aids. Lunner, T., Rudner, M., Rönnberg, J.[2009]

Digital hearing aids (HAs) offer advanced features like adaptive filtration and signal reconstruction, which significantly improve speech perception in noisy environments for individuals with hearing loss.

These digital HAs are designed using effective signal processors that enhance their performance and reliability, making them a superior option compared to traditional analog hearing aids.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Ways of using digital signal processing for expanding the potentials of hearing aids]. Babkina, LN., Molchanov, AP.[2006]

In a study involving 49 older adults with mild-to-moderate hearing loss, the effectiveness of hearing aids with different signal processing settings was influenced by individual factors such as age and working memory, with older participants showing decreased speech recognition in noisy environments when using stronger signal processing.

Participants with lower working memory struggled with speech intelligibility regardless of the signal processing used, while those with higher working memory performed better with mild signal processing, highlighting the importance of tailoring hearing aid settings to individual characteristics for optimal performance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Understanding Variability in Individual Response to Hearing Aid Signal Processing in Wearable Hearing Aids. Souza, P., Arehart, K., Schoof, T., et al.[2023]

A new method to evaluate hearing improvement from hearing aids has been successfully used on 200 patients over 2 years, focusing on how well patients can understand speech in quiet and noisy environments.

Key metrics for assessing hearing aid effectiveness include the improvement in speech reception thresholds in silence, the maximum tolerable noise level, and the noise level at which hearing aids become less effective than not using them.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Evaluation of hearing improvement due to hearing aids]. Welzl-Müller, K., Sattler, K.[2007]

In a study involving 10 patients with Alzheimer's disease and mild hearing loss, a delay of 3 milliseconds in low-frequency sounds significantly improved their speech understanding compared to normal speech tests.

The improvement in speech intelligibility is attributed to compensating for the disrupted function of the cochlea's traveling wave, which is affected by hair cell loss in these patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Speech comprehension by patients with Alzheimer disease. Possibilities for improvement]. Boelen, HJ., Veen, C.[2012]

In a study involving 24 participants (12 children and 12 adults) with bilateral sensorineural hearing loss, the new frequency-lowering strategy called frequency composition (FC) showed similar speech perception and listening effort compared to conventional hearing aid processing, indicating that both methods are effective in making high-frequency sounds audible.

Despite no significant improvement in speech recognition, some participants preferred the FC method for its sound quality, highlighting the importance of subjective experiences in evaluating hearing aid technologies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Listener Performance with a Novel Hearing Aid Frequency Lowering Technique. Kirby, BJ., Kopun, JG., Spratford, M., et al.[2022]

Modern hearing aids have advanced significantly due to micro-electronics and digital signal processing, allowing for better customization and flexibility in addressing various types of hearing impairments.

Enhanced understanding of the auditory system and cognitive functions has led to technological improvements that help individuals with a wide range of hearing losses, from mild to severe.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Modern hearing-aids at the cutting edge of microelectronics. Increased possibilities for individual customization]. Arlinger, S.[2012]

A meta-analysis of six studies involving 171 Alzheimer's Disease (AD) patients and 222 age-matched controls found that individuals with AD have significantly poorer hearing, with an average increase of 2.3 dB HL at lower frequencies (0.5-2 kHz) and 4.5 dB HL at higher frequencies (0.5-4 kHz).

This study highlights the importance of quantifying hearing loss in AD patients, suggesting that hearing impairment may serve as a potential biomarker for earlier diagnosis and treatment strategies for Alzheimer's Disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pure Tone Audiometry and Hearing Loss in Alzheimer's Disease: A Meta-Analysis. Kwok, SS., Nguyen, XT., Wu, DD., et al.[2023]

Hearing aid technology has seen steady improvements in user benefits through advancements in amplification, feedback suppression, noise reduction, and adaptation to different listening situations.

Effective hearing aid solutions require individualized assessments of hearing loss, particularly for bilateral and binaural devices, to address the various acoustic, neurosensory, and cognitive impacts of sensorineural hearing impairment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Functionality of hearing aids: state-of-the-art and future model-based solutions. Kollmeier, B., Kiessling, J.[2019]

Hearing aids are essential for patients with noncorrectable hearing loss, aiming to amplify speech for better understanding, enhance environmental sound awareness, and support language development in children with early hearing loss.

The article reviews the current technology of hearing aids, highlighting their benefits and limitations, while also addressing important medical considerations for fitting these devices in patients' ears.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Hearing aid evaluation and fitting. Popelka, GR., Gates, GA.[2012]

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Hearing Aid Signal Processing for Alzheimer's Disease

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