A diner scans the menu with her eyes while strands of conversation and random noise – from her party, from other customers, from the kitchen – bombard her ears. She leans in but deciphering what’s being said just across the table can be challenging, if not impossible.
Sensory episodes like this unfold every day in crowded bars and restaurants.
While this scenario, oft-dubbed “cocktail party deficit,” can signal normal age-related hearing loss, especially for people over 50, it could also be a sign of central auditory processing disorder (CAPD). The condition, which currently has no U.S. Food and Drug Administration (FDA)-approved therapeutic treatment, affects about 60 million Americans and 800 million people worldwide.
What are symptoms of CAPD?
- Difficulty understanding speech in noisy environments
- Trouble focusing on conversations in groups
Researchers at the University of Colorado Anschutz are offering hope to this population with a groundbreaking treatment. The lab of Achim Klug, PhD, recently enrolled the first patient in a clinical trial of a novel combination therapy that aims to reverse age-related CAPD.
Preclinical animal models of age-related CAPD have shown the Klug Lab’s combination therapy – an oral FDA-approved drug with a proprietary acoustic therapy – produced near-complete reversal of central hearing deficit within 30 days.
Hearing loss is a risk factor for dementia
Just as doctors have long singled out obesity as a major risk factor for cancer, diabetes, heart disease and other serious conditions, Klug notes, the loss of hearing has a similar central position in mental health.
The 2024 Lancet Commission on Dementia Prevention identifies untreated hearing loss as the single largest modifiable risk factor for dementia.
Key points:
- Age-related central auditory processing disorder (CAPD) affects approximately 800 million people worldwide, including about 60 million Americans.
- A CU Anschutz-led new therapy combines an oral drug with an engineered acoustic therapy that has reversed CAPD in animal models.
- The Klug Lab recently enrolled the first patient in a clinical trial of the novel combination therapy.
“If somebody has hearing loss and it’s untreated, they’re at higher risk for not just dementia, but also Alzheimer’s, depression and a lot of other mental health diseases,” said Klug, a professor of physiology and biophysics at the CU Anschutz School of Medicine.
Because central hearing loss is a neurological condition, he said, hearing aids do not address the biological cause.
Brain circuits change with age
“Everybody knows about hearing loss at the level of the ear, and that’s when you need a hearing aid,” Klug said. “But there is a brain attached to the ear that processes all that information. Older people have a lot of trouble in the crowded-restaurant scenario, and it’s not because they need a hearing aid. It’s because the brain circuits have changed, and they don’t process that information as effectively as young people do. So that’s what we’re aiming to treat.”
Samuel Budoff, PhD, a postdoctoral fellow in the Klug Lab, is the CEO of Parley Neurotech, Inc., a startup that announced the enrollment of patients in the CAPD-LOOT (localized oligodendrocyte optimization therapy) clinical trial.
He notes that one in 12 cases of dementia could have been prevented with adequate hearing treatments.
When a person loses the ability to filter and focus on relevant speech in noisy settings, “more often than not they are going to self-isolate,” Budoff said. “So, they remove themselves from social or professional settings where they’re using their brain writ large. And that’s how we think about this longer-term problem that we’re trying to stave off.”
Clinical trial overview
What is being tested: A combination therapy using clemastine fumarate (oral drug) and engineered acoustic therapy.
Trial design:
- Phase I/II randomized, double-blind, placebo-controlled study
- Up to 344 participants
- Ages 45-65
- Four treatment arms
Goal: To restore myelination in brain circuits involved in auditory processing and reverse CAPD symptoms.
Why it matters: CAPD affects approximately 800 million people globally and is the leading modifiable risk factor for dementia.
Additional testing: Parley Neurotech, Inc., plans expanded access testing in Montana under the state’s Right to Try law. The law allows patients in Montana to use experimental treatments that have not yet received FDA approval.
In the following Q&A, Klug and Budoff discuss the biological causes of CAPD, research into possible therapies, CU Anschutz’s bench-to-bedside ecosystem, and the combination therapy that shows promise to reverse CAPD.
The interview has been edited for length and clarity.
Photo at top: A man sits in the engineered acoustic therapy room at the University of Colorado Anschutz.
