A Comprehensive Guide to Auditory Processing Disorder and Autism

Key Take-Away Messages

What does Auditory Processing Disorder (APD) look like in Autism Spectrum Disorder (ASD)?

APD in children with ASD can manifest as either hypersensitivity or, less commonly, hyposensitivity to sounds. It might also appear as delayed responses to sounds, difficulty noticing changes in speech tones, or a tendency to focus more on nonspeech sounds than on actual speech.

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Introduction

Challenges with communication, language, and social interaction are core features of Autism Spectrum Disorder (ASD). If your child has autism, you might often see them get upset in loud places, cover their ears to block out sounds that don’t usually bother others, or get distracted by minor noises.

Abnormal responses to sound are a core characteristic among children with autism. In addition, recent studies show that many struggle to process and understand sounds (auditory processing) [1]. Experts believe this difficulty with processing sounds could be the cause of speech and language delays in children with autism [2]. 

This article explores the link between auditory processing disorder and autism and how to identify APD in autism.

The Relationship Between APD and ASD

Autism is a developmental disability where differences in the brain affect how they behave, interact with others, communicate and learn. Meanwhile, APD is a condition where changes in the brain affect its ability to make sense of sounds.

It’s well-known that nearly all autistic children have sensory processing difficulties [3]. However, difficulty processing and interpreting auditory information is the most common across all sensory domains [4,5]. Because of this, many associate auditory processing disorder and autism. Here’s a comparison of symptoms between the two:

ASD Symptoms [6]

APD Symptoms [7]

Social communication/interaction –       Rarely makes eye contact –       Doesn’t show interest in objects or activities with others –       Struggles with conversational give-and-take –       Gestures and facial expressions don’t align with spoken words –       Has trouble understanding others’ perspectives or actions –       Slow to respond to name-calling or verbal bids for attention –       Difficulty adapting behavior to different social settings  Restrictive, repetitive behaviors –       Show unusual behaviors such as repeating words (echolalia) –       Express intense, prolonged interest in specific topics –       Shows a strong focus on certain items, such as moving objects –       Either hypersensitive or underresponsive to sensory stimuli like sounds, light, and textures

●          Find it difficult to understand spoken language, especially in noisy environments ●          May find noisy environments overwhelming or distressing ●          Gets easily distracted by sounds ●          Finds it hard to tune out sounds from the environment ●          Exhibit long delays before responding to others ●          Struggle with activities that require listening ●          Find it difficult to pay attention ●          Face challenges with reading, spelling, and learning ●          Experience learning problems ●          Have trouble following rapid speech ●          Frequently ask for repetitions ●          Find it difficult to follow complex directions ●          Mishear or misunderstand messages

How common is APD in Autism?

Despite numerous studies highlighting that many children with autism also have central auditory processing disorder (CAPD), there is no clear data on exactly how many children with autism spectrum disorder (ASD) also experience APD [8]. 

The available information only indicates auditory processing difficulties. For instance, a 2016 study reported that the lifetime prevalence of decreased sound tolerance (i.e., the inability to tolerate everyday sounds) in autism is 86.6% [9]. Meanwhile, another study showed that it is more common for people with ASD who are minimally or low verbal to display more abnormal behavioral responses to sound compared to those who are verbally fluent [10].

What are the causes of APD in Autism?

The exact cause linking APD to autism is still unknown. However, there are many theories that try to explain the connection.

Research has shown that autistic children have problems with their central auditory processing, both at the brainstem and cortical level [11]. A 2015 study found children with ASD have a delayed reaction to sounds, demonstrating a delayed maturation in their auditory system [12]. Meanwhile, a 2024 study explained how abnormalities in the structure and function of the hippocampus, a brain area important for learning, language ability, emotional regulation, and memory, play a role in the problems seen in ASD [13].  

A study that assessed auditory processing in higher-functioning autism mentioned that there may be less differentiation between the neural pathways they use to process speech and environmental sounds compared to typically developing individuals [14].  It also found that those with ASD focus more on low-level sound characteristics, whether relevant or not, and are less attuned to the sounds (phonemic categories) of their native language.

Another study theorized that their speech and language difficulties stem from their slowed attention shifting and tendency not to pay attention to certain sounds [15]. They found out that while children with ASD have good sound processing and discrimination as their neurotypical peers, they have a difficult time detecting sound changes related to speech sounds (vowels). 

How to diagnose APD in Autism

Diagnosing APD involves using a series of auditory processing disorder tests to assess the integrity of the child’s central auditory nervous system (CANS). This typically requires a multidisciplinary approach consisting of physicians, audiologists, speech-language therapists and psychologists. 

In addition to thorough history taking, an accurate diagnosis typically includes the following [16]:

• Linguistic, cognitive, and memory assessments
• Speech and language assessments
• Psychological assessment
• Behavioral tests
• Neuroimaging

Diagnosing APD can be a challenge due to the limitations caused by the child’s verbal and cognitive abilities. Fortunately, electrophysiological tests can be done regardless of these hurdles. These imaging tests monitor the brain’s responses and activity in response to different sounds and look at differences in sound perception relative to background noise.

Treatment and Management Strategies

Both auditory processing disorder therapies and treatments for autism have the ultimate aim of minimizing symptoms and improving their ability to function more effectively in daily life. Here are the treatment interventions used for both conditions:

ASD Treatment [17]

APD Treatment [7]

–       Behavioral interventions like applied behavioral analysis (ABA) –       Developmental approaches like OT, sensory integration therapy, and speech therapy which aim to improve developmental skills and performance in daily life –       School-based and educational therapies –       Social-relational approaches like social skills training, social stories, and DIR Floortime –       Medications to address co-occurring symptoms like self-harming behaviors, anxiety, and seizures –       Cognitive-behavior therapy –       Complementary and alternative treatments like art therapy and relaxation therapy

–       Direct skills remediation: targets specific auditory processing skill deficits like auditory and phoneme discrimination and sound localization and lateralization through computer-based training and exercises –       Compensatory strategies: utilize higher-order skills like attention and memory to address a child’s learning, communication, listening, and social skills –       Environmental modifications: includes adaptations in the environment and tools that can help child access sounds better

Since the central auditory system is affected in both auditory processing disorder and autism, treatments that target this area of the brain can be helpful. Programs like Soundsory® and Forbrain® capitalize on the brain’s ability to change and adapt (neuroplasticity) and use special technology to modify sounds to grab the brain’s attention, helping it learn to better process and integrate auditory information.

Soundsory^® involves a combination of movement exercises and specially processed music to stimulate the brain. Forbrain^®, on the other hand, modifies a child’s own voice, enhancing it and then sending it back to the child through both air and bone conduction, which helps improve their auditory processing skills. 

Tips for Parents and Educators

Below are some tips for parents and educators handling children with APD and autism:

• Adjust your speech. Speak slowly and give them enough time to process what you said.
• Adapt the environment. Processing sounds amid competing sounds can be overwhelming and confusing. If possible, move to a quieter place or remove sound sources like fans and television. The same is true for other sensory stimuli.
• Provide support. Using assistive hearing technologies like frequency modulation (F/M) systems can help a child listen better during classes. These allow a child to hear their teacher’s voice directly through an earpiece.
• Stick to a routine. Having a regular schedule can help a child feel organized and know what to expect next, which makes it easier for them to adjust their behavior as needed.
• Provide breaks. Continuous listening and processing of spoken information can be draining. Breaks throughout the day can help the child relax and avoid sensory overload.

Conclusion

Although much is still unknown about how APD  and autism are connected, it’s clear that auditory processing disorder in autism can make their everyday life more difficult – struggling to understand, organize, and remember sounds can make it harder for them to interact, communicate, and learn.

Getting a proper diagnosis can help parents better understand their children’s needs and find more effective ways to support them. Since auditory processing disorder in autism involves deficits in the central auditory system, treatments designed for one condition may also benefit the other. Specifically, targeting specific auditory skill deficits, making changes to the environment, and using existing skills to compensate for auditory skill challenges can help children with autism improve their language, communication, and social skills.

FAQs 

Is auditory processing disorder part of autism?

Yes. According to electrophysiological studies, CAPD is one of the characteristic features of ASD [8].

Are auditory processing issues common in the autistic community?

Yes. About 90% of autistic individuals experience sensory processing issues. Of these, auditory hypersensitivity is the most common[5].

Can someone have both APD and Autism?

Yes. The majority of individuals with autism also have auditory processing disorder due to problems with their central auditory nervous system (CANS).

References 

1.     Danesh, A. A., Howery, S., Aazh, H., Kaf, W., & Eshraghi, A. A. (2021). Hyperacusis in Autism Spectrum Disorders. Audiology research, 11(4), 547–556.

2.     Marco, E. J., Hinkley, L. B. N., Hill, S. S., & Nagarajan, S. S. (2011). Sensory processing in autism: A review of neurophysiologic findings. Nature News. 69, 48–54

3.     Kong, M. & Moreno, M. (2018). Sensory processing in children. JAMA Pediatrics, 172(12),1208.

4.     O’Connor, K. (2012). Auditory processing in autism spectrum disorder: A review. Neuroscience and Behavioral Reviews, 26(2), 836-854 

5.     Rotschafer, S. (2021). Auditory discrimination in autism spectrum disorder. Frontiers in Neuroscience, 15

6.     National Institute of Mental Health. (2024). Autism Spectrum Disorder. https://www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd

7.     American Speech-Language-Hearing Association (ASHA). Central auditory processing disorder. https://www.asha.org/practice-portal/clinical-topics/central-auditory-processing-disorder/

8.     Ocak, E., Eshraghi R.,Danesh, A., Mittal, R., & Eshraghi, A. (2018).  Central auditory processing disorders in individuals with autism spectrum disorders. Balkan Med J, 35, 362-372

9.     Williams, Z. J., He, J. L., Cascio, C. J., & Woynaroski, T. G. (2021). A review of decreased sound tolerance in autism: Definitions, phenomenology, and potential mechanisms. Neuroscience and biobehavioral reviews, 121, 1–17. https://doi.org/10.1016/j.neubiorev.2020.11.030

10.  Schwartz, S, Wang, L, Shinn-Cunningham, B., & Tager-Flusberg, H. (2020). Atypical perception of sounds in minimally and low verbal children and adolescents with autism as revealed by behavioral and neural measures. Autism Research, 13(10)

11.  Gonçalves, L. F., Paiva, K. M., Patatt, F. S. A., Stolz, J. V., & Haas, P. (2021). Association between autism spectrum disorder and changes in the central auditory processing in children. Revista da Associacao Medica Brasileira (1992), 67(1), 156–162. https://doi.org/10.1590/1806-9282.67.01.20200588

12.  Edgar, J. C., Fisk Iv, C. L., Berman, J. I., Chudnovskaya, D., Liu, S., Pandey, J., Herrington, J. D., Port, R. G., Schultz, R. T., & Roberts, T. P. (2015). Auditory encoding abnormalities in children with autism spectrum disorder suggest delayed development of auditory cortex. Molecular autism, 6, 69. https://doi.org/10.1186/s13229-015-0065-5

13.  Long, J., Lee, H., Liu, Y., Liao, X., Tang, Z., Han, K., Chen, J., & Xhang, H. (2024). Insights into the structure and function of the hippocampus: implications for the pathophysiology and treatment of autism spectrum disorder.Frontiers in Psychiatry, 15

14.  dePape, A., Hall G., Tillman, B & Trainor, L. (2012). Auditory processing in high-functioning adolescents with autism spectrum disorder. PLoS ONE 7(9): e44084

15.  Čeponienė, R., Lepistö, T., Shestakova, A., Vanhala, R., Alku, P., Näätänen, R.  & Yaguchi, K. (2003). Biological Sciences, 100 (9) 5567-5572

16.  Aristidou IL, Hohman MH. (2024). Central auditory processing disorder.StatPearls [Internet]. Treasure Island (FL). https://www.ncbi.nlm.nih.gov/books/NBK587357/

17.  Centers for Disease Control and Prevention. (2022). Treatment and intervention services. https://www.cdc.gov/ncbddd/autism/treatment.html