What Is Auditory Processing Disorder (APD)?

Auditory processing disorder (APD) is a condition that affects children’s ability to take in verbal information. Even though there’s nothing wrong with their hearing, children with APD have trouble registering—or registering correctly—what people are saying and remembering what they hear. This can make it hard for them to learn to read and express themselves clearly, as they often confuse the sounds of different words.

Children with auditory processing disorder have normal hearing, but for some reason, they are weak in basic skills for decoding language that most kids develop naturally.

“The kids we see are having difficulty following directions,” explains Rachel Cortese, a speech-language pathologist. “They ask for repetition a lot. They seem to just kind of miss things in conversations. From testing, we know that their ear is hearing the signal. It’s attending to the auditory information. But they have glitches when the brain is not assigning meaning—or the right meaning—to that signal.”

Specific symptoms of auditory processing disorder include:

• Difficulty following directions and needing frequent repetition
• Trouble distinguishing between similar sounds, like “bat” and “pat”
• Weak auditory memory, making it hard to remember songs or instructions
• Mixing up the sequence of sounds or numbers
• Struggling to filter out background noise, especially in classrooms

There are four basic skills involved in auditory processing disorder, and kids who have these problems may be weak in one or more of them.

Auditory discrimination is the ability to notice and distinguish between distinct and separate sounds. This is crucial in being able tell similar but different words apart, like bat and pat, or seventy and seventeen. A lot of times, kids with auditory processing difficulties might miss information or misunderstand what you say because they mishear words,” says Cortese. “They’re not detecting the subtle differences in sounds.” They may also find it harder to learn to read and to express themselves clearly.

When they’re speaking, they may mix up similar sounds because they don’t perceive the difference—say befs instead of best—and drop syllables out of words. Experts call this “syllable attenuation,” and it’s something kids often do when they’re learning languages but these kids continue to do it after most have begun to speak accurately.

Kids with auditory processing disorder also have trouble rhyming, because their brain are not detecting that these are words that sound the same. For a lot of them, Cortese explains, that’s because they’re tuning in only to the beginning of the word, not the end.

This is the ability to differentiate important sounds from background noise, to follow verbal instructions or pick out one voice from the auditory clutter. In a classroom, a child who is weak in this figure-to-ground discrimination might have trouble being able to focus on what the teacher is saying rather than other sounds in the classroom. “It’s like a filtering problem,” Cortese adds. “What do I need to attend to? What do I need to filter out?”

Auditory memory includes the ability to remember things we hear, in both the short-term and the long-term. Children weak in auditory memory have trouble remembering nursery rhymes and song lyrics, learning things through recitation, and remembering information unless it’s written down.

This is the ability to understand and recall the order of sounds. A child with weakness in auditory sequencing will mix up numbers with the same digits in different order (84 and 48) and may switch the sequence of sounds in a word (ephelant instead of elephant). She may also have trouble recalling information presented in lists, and difficulty following instructions in sequence.

While most experts call this condition auditory processing disorder, you may also hear it referred to as “central auditory processing disorder,” which is an earlier name.

That name, explains Matthew Cruger, PhD, director of the Learning and Development Center at the Child Mind Institute, implies that the brain is like a computer. “In that theoretical model there is some single auditory processing unit in the mind that does this work,” he notes. “But we haven’t been able to find a central auditory processor, so we’re still struggling to understand it.”

There is disagreement among experts about whether auditory processing disorder should be understood as a distinct disorder, because it overlaps with other learning and attention disorders.

Dr. Cruger notes that auditory processing problems can be diagnosed in two different groups of kids:

One group, he explains, seem to have profound disruption in those foundation skills for processing auditory information. “They struggle with a wide range of linguistic tasks, ” he says, “including making sense of what words mean and how they are used, grammar and syntax, semantics and meaning, putting all that together.” These kids have trouble with language on a lot of fronts, and they are likely to also be diagnosed as having language disorders.

But there’s another group of kids identified as having auditory processing weaknesses whose higher level language skills are intact, Dr. Cruger says. “But there’s some breakdown in foundation skills for sound processing that leads to some errors.” These kids just show weakness in the skills listed above, and struggle to take in information in some environments. These kids are also often described as having attention issues, make it hard to distinguish between auditory processing and ADHD.

Kids in that second group may also grow out of their problems as the auditory fibers or pathways in the mind develop, which strengthens the capacity to process signals from the ear within the brain, notes Dr. Cruger. Since these fibers and these connections aren’t finished developing until adolescence, it’s possible that some APD is a delay in development, rather than a deficit.