You’re Assessing for Dyslexia. Should You Test for Auditory Processing Disorder, Too?
Wednesday, April 16, 2025
Auditory processing disorder (APD), also known as central auditory processing disorder (CAPD), is a disruption in the processing of sound signals in the brain. Some experts have described auditory processing as “what we do with what we hear” (Alanzi, 2023). People with auditory processing difficulties have trouble detecting, focusing on, interpreting, or remembering sound information (Aristidou & Hohman, 2023). Around 70% of students with dyslexia have auditory processing deficits.
If you work with students or clients who have dyslexia, understanding auditory processing disorder may help you understand and address some of the specific abilities and challenges they face. It may also help you determine whether the behaviors and abilities you’re observing arise from auditory processing disorder, dyslexia, or another neurodevelopmental condition.
Some experts recommend screening for auditory processing disorders whenever you’re evaluating a child for a neurodevelopmental condition such as dyslexia (Aristidou & Hohman, 2023). Identifying these difficulties early in the evaluation process can help you tailor instruction and interventions to address all the underlying factors affecting a student’s ability to read.
Effects of Auditory Processing Disorder
Auditory processing disorder is not a distinct diagnosis within the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition Text Revision (DSM-5-TR). For that reason, there isn’t a list of specific diagnostic criteria for the condition. Impairments in auditory processing can be present on their own, or they may co-occur with neurodevelopmental conditions such as:
- dyslexia
- developmental language disorder (DLD)
- autism
- aphasia
- attention-deficit hyperactivity disorder (ADHD)
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Speech–language pathologists often identify auditory processing difficulties as they relate to language. By contrast, audiologists typically identify auditory processing disorders using assessments that measure how the auditory system detects, interprets, and transfers sound information (American Speech Language and Hearing Association, n.d.) |
For students with auditory processing disorders, it can be harder to:
- understand speech in noisy settings
- determine where a sound is located
- recognize sound patterns
- remember auditory information
- sense the timing of sounds
- follow complicated sets of directions
- comprehend and respond to fast speech
- pay attention to speech for longer periods
- learn from verbal communication without visual cues
These challenges can be present with or without hearing loss, and they can lead to learning difficulties, frustration, a sense of isolation, and anxiety.
Auditory Processing and Learning to Read
The ability to read begins with understanding spoken language. Most children develop this ability without having to be taught; they simply listen to the language spoken around them. One part of this innate process is learning to detect breaks in the flow of sound—the places where phonemes, syllables, and words start and stop. Children also learn what the sound breaks mean.
From infancy, children can usually sense differences in the pitch and duration of a sound, even when sounds are changing quickly. Typically, babies can perceive the rising and falling in speech—even in noisy places. They’re especially adept at recognizing the sounds of their primary language.
The ability to hear a sound and identify it as speech is foundational to learning to read. That’s because when we learn to read, we practice connecting individual speech sounds (phonemes) to written letters that represent those sounds (graphemes). This process, which is sometimes called orthographic mapping, doesn’t happen quickly or easily for children with auditory processing issues.
Researchers use mismatch negativity tasks to measure auditory processing abilities in children and adults with dyslexia. In these tasks, people are asked to identify which sounds differ in a patterned sequence of sounds. Studies have repeatedly shown that people with dyslexia react more slowly and with less accuracy in these tasks, whether the sounds have a different tone, frequency, or intensity. Researchers think these difficulties may be related to the phonological awareness deficits that are often seen in dyslexia (Gu & Bi, et al., 2020).
Learn more about how babies process sound here.
Speech Sounds in Noise
The connections between auditory processing and reading abilities have been studied for some time. Studies have shown that auditory processing, especially the ability to process speech sounds in noisy conditions, is a reliable predictor for the development of literacy skills. In 2015, researchers looked at the brain-behavior connections of 37 four-year-old students and found that those who could accurately identify consonants in noise had better scores in these early literacy skills:
- memory for spoken sentences
- rapid naming
One year later, researchers tested phonological processing skills in the same group of students and found that their original auditory processing scores also predicted their abilities in sight word reading, spelling, and overall reading competence. Based on these findings, researchers said the ability to identify consonants in noise was a reliable biomarker for difficulties in early literacy skills.
In the same study, researchers looked at school-age children and found that the ability to accurately “code” consonants in noise predicted scores in these literacy skills:
- reading competence
- sight word reading
- non-word reading
- spelling
- oral reading efficiency
- phonological processing
In this study, the ability to identify consonants in noisy conditions predicted which older students had a diagnosis of specific impairment of reading, or dyslexia (White-Swoch et al., 2015).
It’s important to note that the ability to process sound cues in noisy environments keeps developing into adulthood, so difficulties in early childhood may improve. There’s evidence that this skill matures quickly until around age nine (Bertels et al., 2023).
Download our Dyslexia Assessment Tool Kit here.
Amplitude Rise Times
Researchers have also found a link between another auditory processing measurement and dyslexia. A 2025 study looked at auditory processing in 78 school-age children with dyslexia and 32 school-age children with typical development. Researchers focused on one listening skill: distinguishing amplitude rise times.
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Amplitude rise time is the amount of time it takes a sound wave to reach its peak. People of all ages use it to distinguish speech from other kinds of sound, and to tell when each unit of speech starts and stops. Amplitude rise times help us pick up on the rhythms in speech. |
In this study, researchers found that people with developmental dyslexia had trouble detecting amplitude rise times. Difficulty with amplitude rise times was also linked to impairments in reading abilities. These difficulties were connected to differences in brain structures. Brain imaging showed that students who were better at detecting differences in amplitude rise times had more folds in an area of the brain known as the superior temporal gyrus (Qi et al., 2025).
Tone Perception
People with dyslexia may also perceive tone differently than those with typical development. In a 2022 study, researchers looked at the ability to distinguish between four different tones of Mandarin speech. They found that students with dyslexia had a harder time telling the difference between high and low tones. Students with dyslexia also showed differences in musical tasks, singing tasks, Mandarin pronunciation tasks, and tasks that required them to recognize sound-syllable tones. It took students with dyslexia longer to perform some of these tasks (Christiner et al., 2022).
Researchers look at tone because the ability to pick up on subtle differences in the sounds within words is key to learning how to read and spell.
Auditory Working Memory
Working memory is the ability to remember information you need while completing a task. Some researchers view working memory as a cluster of related skills rather than a single ability. Two components of working memory that are especially important to the development of early literacy are the phonological loop and the visuospatial sketchpad.
The phonological loop allows you to store the sounds of a letter or word briefly, and to silently rehearse those sounds. The visuospatial sketchpad allows you to recognize the shape of letters and remember their position in a word. Both abilities operate as children learn to map sounds to letters, remember spelling patterns, and find meaning in texts (Schvartsman & Shaul, 2023).
Auditory memory is often disrupted in children with auditory processing difficulties (Drosos et al., 2024). Researchers have also found that teens with auditory processing difficulties have trouble with working memory (Jain et al., 2023). The connections between dyslexia, auditory processing, and working memory need to be clarified by further research.
Learn more about conditions that co-occur with dyslexia here.
Key Message
Auditory processing deficits can make it harder for people to learn spoken language. They can keep people from being able to detect breaks and subtle changes in sound, including variations in tone. They can also impact the ability to learn to read, since reading depends in part on speech and language skills.
People with auditory processing disorder may have trouble identifying some letter and word sounds and may have to work harder to link sounds to the letters that represent them. Since many children and adults with dyslexia have auditory processing difficulties, it’s important to assess auditory skills as part of a holistic dyslexia evaluation.
Read more in this series: You’re Assessing for Dyslexia. Should You Test Executive Function, Too?
Research and Resources:
Alanazi, A. A. (2023). Understanding auditory processing disorder: A narrative review. Saudi Journal of Medicine & Medical Sciences, 11(4), 275–282. https://doi.org/10.4103/sjmms.sjmms_218_23
American Speech Language Hearing Association. (n.d.). Central auditory processing disorder. https://www.asha.org/practice-portal/clinical-topics/central-auditory-processing-disorder/
Aristidou, I.L., Hohman, M.H. (Updated 2023, March 1). Central Auditory Processing Disorder. In: StatPearls. Treasure Island (FL) https://www.ncbi.nlm.nih.gov/books/NBK587357/
Bertels, J., Niesen, M., Destoky, F., Coolen, T., Vander Ghinst, M., Wens, V., Rovai, A., Trotta, N., Baart, M., Molinaro, N., De Tiège, X., & Bourguignon, M. (2023). Neurodevelopmental oscillatory basis of speech processing in noise. Developmental Cognitive Neuroscience, 59, 101181. https://doi.org/10.1016/j.dcn.2022.101181
Christiner, M., Serrallach, B. L., Benner, J., Bernhofs, V., Schneider, P., Renner, J., Sommer-Lolei, S., & Groß, C. (2022). Examining individual differences in singing, musical and tone language ability in adolescents and young adults with dyslexia. Brain Sciences, 12(6), 744. https://doi.org/10.3390/brainsci12060744
Drosos, K., Papanicolaou, A., Voniati, L., Panayidou, K., & Thodi, C. (2024). Auditory processing and speech-sound disorders. Brain Sciences, 14(3), 291. https://doi.org/10.3390/brainsci14030291
Gu, C., & Bi, H. Y. (2020). Auditory processing deficit in individuals with dyslexia: A meta-analysis of mismatch negativity. Neuroscience and Biobehavioral Reviews, 116, 396–405. https://doi.org/10.1016/j.neubiorev.2020.06.032
Jain, C., Ghosh, P. G. V., Chetak, K. B., & Lakshmi, A. (2023). Relationship between central auditory processing abilities and working memory during adolescence. Indian Journal of Otolaryngology and Head and Neck Surgery, 75(1), 1–7. https://doi.org/10.1007/s12070-022-03126-w
Qi, T., Mandelli, M. L., Pereira, C. L. W., Wellman, E., Bogley, R., Licata, A. E., Chang, E. F., Oganian, Y., & Gorno-Tempini, M. L. (2024). Anatomical and behavioral correlates of auditory perception in developmental dyslexia. Brain, 148(3), 833–844. https://doi.org/10.1093/brain/awae298
Shvartsman, M., & Shaul, S. (2023). The role of working memory in early literacy and numeracy skills in kindergarten and first grade. Children (Basel, Switzerland), 10(8), 1285. https://doi.org/10.3390/children10081285
White-Schwoch, T., Woodruff Carr, K., Thompson, E. C., Anderson, S., Nicol, T., Bradlow, A. R., Zecker, S. G., & Kraus, N. (2015). Auditory processing in noise: A preschool biomarker for literacy. PLoS Biology, 13(7), e1002196. https://doi.org/10.1371/journal.pbio.1002196