Auditory processing disorders (APD), also known as central auditory processing disorders (CAPD), occur when the brain is unable to process sounds. APD is the result of impaired neural function. It is distinct from hearing loss. A person with APD can hear sounds; in fact, many have typical audiogram results. With APD, the way the brain translates those sounds is disrupted, resulting in jumbled messages.

The umbrella term describes a heterogeneous group of disorders of central auditory processing identified in an ever increasing population, spanning infancy through the elderly and of diverse etiology due to various underlying pathologies, all leading to difficulties in making sense of the sounds that one hears.

These include challenges in recognizing which sounds are important and which are background noise; telling one sound apart from another; locating where sounds are coming from; remembering sounds in the order they are heard; and experiencing additional difficulties in understanding after exposure to loud noises.

The hearing difficulties associated with APD occur despite typical hearing thresholds, thus audibility of sounds per se is not the cause. Consequently, it remains challenging to diagnose, manage and treat, given the wide variety of symptoms grouped under the label, the complex relationship between APD and other disorders and disabilities, and uncertainties about its cause(s). 

Learn More:

Auditory Skills
Signs & Symptoms of APD
APD Demographics
Treatments for APD
Our Research on Auditory Processing Disorders

Auditory Skills

Individuals with APD often are unable to hear sounds as words and have learning problems, including difficulty in reading, spelling, and language comprehension. They 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 often will ask someone to repeat what has been said.

Here are more details about the four types of auditory skills essential to processing what one hears, and which may be compromised with APD:

1. Auditory discrimination is the ability to notice, compare, and distinguish the distinct and separate sounds in words. If a child has difficulty with auditory discrimination, he or she may confuse similar words like seventy and seventeen, have trouble learning to read, and be unable to follow directions even when the child appears to be paying attention.

2. Auditory figure-ground discrimination is the ability to pick out important sounds from a noisy background. A child who struggles with auditory figure-ground discrimination may be unable to filter background conversations and noises to focus on what is important. For example, a child may miss lessons in class if he or she cannot filter extraneous background noise in the classroom.

3. Auditory memory is the ability to recall what is heard after a period of time and includes both short-term and long-term memory. Difficulties associated with auditory memory may include remembering people’s names, memorizing telephone numbers, following multi-step directions, and recalling stories or songs.

4. Auditory sequencing is the ability to understand and recall the order of words. Difficulties with auditory sequencing may include confusing numbers like 93 for 39 and confusing lists and sequences. For example, a child with auditory sequencing problems may not be able to complete a series of tasks in the right order. He or she may fail to be able to do so even when appearing to have heard and understood the directions.

Learn More:

Auditory Skills
Signs & Symptoms of APD
APD Demographics
Treatments for APD
Our Research on Auditory Processing Disorders

Signs and Symptoms of Auditory Processing Disorders

There are many behaviors that may point to APD. Individuals with APD demonstrate a poor ability to:

• Direct or divide attention

• Discriminate subtle differences in sounds and words

• Read, spell, write, understand vocabulary, or learn a foreign language

• Understand rapid speech

• Hear in noisy, social environments

• Recognize and integrate a sequence of sounds into words or other combinations

• Remember and/or comprehend spoken information

• Understand instructions

• Follow long conversations

• Follow multi-step directions

• Maintain focus on an activity if other sounds are present

• Take written notes from speech

• Complete verbal math problems

• Learn songs or rhymes

Because these symptoms overlap with other disorders, auditory processing disorder cannot be diagnosed from this list of symptoms alone. The condition can only be diagnosed by audiologists, who use tests that measure specific auditory processing functions.

Symptoms like difficulty listening, remembering information, or understanding spoken language, make APD commonly confused with Attention Deficit Hyperactivity Disorder (ADHD) or dyslexia, but it is distinct from both.

With ADHD and dyslexia, there is no impairment of the processing of auditory input in the central nervous system.

Children with ADHD tend to exhibit inattention, distractibility, and hyperactivity in any environment, while children with APD usually don’t have difficulty focusing and paying attention in quiet environments.

While those with dyslexia also have difficulty memorizing, spelling, thinking and/or understanding, these difficulties do not exist because of an inability to hear clearly. Unlike APD, dyslexia is a language-based learning disability.

See more information at American Speech-Language-Hearing Association.

Learn More:

Auditory Skills
Signs & Symptoms of APD
APD Demographics
Treatments for APD
Our Research on Auditory Processing Disorders

Auditory Processing Disorders Demographics

• In a 2021 Frontiers in Neurology paper, the authors write: “The prevalence of APD was calculated to be 1.94 per 1,000 children by a 2016 retrospective study based on referrals and diagnoses made in a national audiology clinic. [In a 2011 paper] Hind et al. estimated a prevalence of APD as 0.5–1% in the general population, based on a prevalence of normal audiometric findings. [As cited in the same paper] APD was prevalent in 5% of children and 0.9% of adults of all ages who were referred to a general audiology clinic. However, these estimates may be affected by ascertainment bias and the prevalence of APD is yet to be determined.”

• People with autism spectrum disorder (ASD) often show difficulties with auditory processing. Autism is a developmental disability that can cause significant social, communication, and behavioral challenges. Processing auditory information is critical to social communication, and people with autism spectrum disorders typically have problems processing information received from verbal communication. APD is a common secondary diagnosis for children with autism.

• Studies have shown a strong link between Fragile X Syndrome (FXS), the most common genetic form of autism, and difficulties with sound localization. FXS is characterized by impaired cognition, hyperactivity, seizures, attention deficits, and hypersensitivity to sensory stimuli, specifically auditory stimuli.

• An estimated 15% of military veterans live with APD due to blast exposure. HHF’s Emerging Research Grants 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.

• Older adults, including those with typical or near-typical hearing, may exhibit age-related central auditory processing deficits. Scientists have confirmed that changes in both the peripheral and central auditory systems occur as a result of aging. These changes can impact auditory and cognitive processing abilities that are important for speech understanding. Such individuals experience reduced speed of information (sensory and mental) processing, which, can affect listening comprehension. Speech understanding especially in adverse or challenging environments has been related to listeners' working memory capacity.

• Individuals with neurological disorders as a result of brain injuries (e.g., stroke, traumatic brain injury, tumors, epilepsy) are more susceptible to APD because of damage to the central nervous system.

Sources: Autism Research Institute; Journal of Rehabilitation Research & Development; National Institute on Deafness and Other Communication Disorders; Seminars in Hearing

Learn More:

Auditory Skills
Signs & Symptoms of APD
APD Demographics
Treatments for APD
Our Research on Auditory Processing Disorders

Treatments for Auditory Processing Disorders

The following is general information only. HHF does not offer medical advice. Please consult your hearing care professional with any specific questions about your auditory health and healthcare.

There are no cures for APD, but there are many treatments that aim to improve the effectiveness of everyday communication. As it is a neurological problem, it cannot be treated with medication.

A successful treatment plan for APD incorporates many different approaches.

Environmental modifications: These modifications fall into two types, bottom-up and top-down, and aim to create a redundant listening and learning environment.

• Bottom-up environmental modifications, which are acoustic-based, include: hearing assistive technology, architectural interventions to reduce reverberation, and preferential seating away from adverse noise.

• Top-down environmental modifications, which change how information is imparted, include: checking for comprehension, complementing verbal speech with visual cues, slowing the speaking rate, repeating key information, providing written instructions, and providing a notetaker.

Speech-language pathology (speech therapy): Because children with APD struggle with sound discrimination—differentiating between similar sounds—speech-language pathologists (SLPs) can help them perceive these sounds better and more clearly. SLPs can also help children improve perception of individual sounds (phonemes) in words, which can help with reading, employ active listening skills, and use appropriate language in social situations.

Compensation strategies: Individuals with APD can be taught skills to compensate for weak listening ability. Examples include teaching the patient to be more proactive when in a learning environment, such as requesting clarification, asking a person to repeat directions, or using a recording device.

Auditory training: This intervention directly attempts to improve the function of the affected auditory process(es) by addressing auditory skills. Training can be formal or informal:

• Formal auditory training uses recorded stimuli (e.g., tones, noise, speech, digits) presented via an audio device. The stimuli may be routed through an audiometer for control. Performance is scored periodically and training difficulty is modified to bring performance closer to the criterion.

• Informal auditory training does not use stimulus control with an audiometer; instead they are presented face-to-face rather than played from a recording on a device.

HHF offers general information only and does not offer medical advice. Please consult your hearing care professional with any specific questions about your auditory health and healthcare.

Sources: American Speech-Language-Hearing Association; Child Mind Institute; Seminars in Hearing; Strickland Ear Clinic; Understood.org

Learn More:

Auditory Skills
Signs & Symptoms of APD
APD Demographics
Treatments for APD
Our Research on Auditory Processing Disorders

Auditory Processing Disorders News and Research

Thanks to the generosity of Royal Arch Research Assistance, Hearing Health Foundation funds groundbreaking research to advance our scientific understanding of central auditory processing disorders. We are pleased to have worked with RARA to fund the most promising CAPD research.

Grants focused on CAPD are awarded annually to promising scientific investigators through the Emerging Research Grants program.

Learn More

Learn More:

Auditory Skills
Signs & Symptoms of APD
APD Demographics
Treatments for APD
Our Research on Auditory Processing Disorders