By Lauren McGrath
This April, Hearing Health Foundation (HHF) draws your attention to Auditory Processing Disorder (APD), a condition that causes impairments in sound localization—the ability to identify sound sources—and has been closely linked to autism. April 4 is recognized as APD Awareness Day in some regions of the U.S. and April is Autism Awareness Month nationwide.
APD occurs when the central nervous system has difficulty processing verbal or auditory information, specifically in noisy, social environments. Individuals with APD do not necessarily have a diagnosed hearing loss; in fact, many have normal audiogram results. With APD and typical hearing, the inner ear properly sends signals to the brain, but, once received, the brain fails to interpret and analyze these sounds accurately, resulting in jumbled messages.
In the U.S., it is estimated five percent of school-age children, or 2.5 million children, have APD. Individuals with APD are often unable to hear sounds as words and have learning problems, including difficulty in reading, spelling, and language comprehension. It is vital to review the symptoms, demographics, and treatments of APD, should you suspect it in yourself or a loved one.
Individuals with APD have trouble distinguishing between words or syllables that sound alike (auditory discrimination) and recalling what they heard (poor auditory memory). They show delayed responses to verbal requests and instructions and will often ask someone to repeat what has been said. APD is commonly misdiagnosed as ADD/ADHD, dyslexia, or hearing loss.
Demographically, APD is a common secondary diagnosis for children with autism; most children diagnosed with autism have auditory processing disorders or auditory difficulties. HHF Emerging Research Grants (ERG) recipient Elizabeth McCullagh, Ph.D.’s 2017 published work in The Journal of Comparative Neurology examines the strong connection between Fragile X Syndrome (FXS), the most common genetic form of autism, and difficulties with sound localization.
Additionally, APD is prevalent in individuals with neurological problems, including those who have experienced head injuries or strokes. Older adults, who are more susceptible to some cognitive decline, are also at greater risk for APD.
Military veterans who have been repeatedly exposed to blasts are another community disproportionately affected by APD. An estimated 15% of all returning military personnel live with APD. HHF’s ERG recipient Edward Bartlett, Ph.D., explains that the changes to the central auditory system may account for the behavioral issues that veterans experience, such as problems with memory, learning, communication, and emotional regulation.
Retired U.S. Army Colonel John Dillard of HHF’s Board of Directors remarks, “It is truly unfortunate that our veterans, after making such honorable sacrifices, are forced to live with APD, often alongside tinnitus and/or hearing loss. I am hopeful that future scientific advancements will better the lives of veterans and all Americans.”
There are no cures for APD, but there are many treatments that aim to improve the effectiveness of everyday communication. These include environmental modifications, addressing functional deficits, and improving listening and spoken language comprehension. Pursuing treatment for APD as early as possible is imperative, McCullagh explains, because hearing is vital to social and educational interactions. “Those with APD often develop issues with language development, hearing in noise, and sound localization. Risks associated include not being able to participate in noisy environments which can often result in depression and anxiety.”
Much more research of APD is needed to improve the accuracy of methodologies for diagnosis and to determine the best interventions for each child or adult. Even though there are available strategies to treat APD, researchers, including those funded by HHF, largely through the generosity of the Royal Arch Masons Research Assistance, are hard at work finding alternative treatments that will improve the lives of those with APD.