There are a few key reasons.
1. The brain processes sound differently
Studies show that many autistic people process sound differently, even with normal hearing. The brain may:
• Take a bit longer to respond to sound
• Find it harder to pick out speech from background noise
• React more strongly (or less strongly) to certain sounds
These are exactly the skills that can be weak in APD. For many autistic children and adults, an APD diagnosis is really describing one part of a broader autistic sensory profile – how the brain deals with sound.

2. Sensory overload in noisy places
Many autistic people are very sensitive to noise:
• Classrooms, open-plan offices, shopping centres and parties can quickly feel overwhelming.
• They might cover their ears, shut down, mask and then crash later, or avoid certain places altogether.
When someone is in sensory overload, it’s much harder to:
• Focus on what’s being said
• Hold instructions or information in mind
• Join in conversations
From the outside, this looks just like APD: “can’t hear in noise”, “misses instructions”, “zones out”.
So autism + sensory overload + noisy environments often leads to APD-type listening problems, even when the ears themselves are fine.

3. Language, attention and learning all affect listening
APD tests don’t measure “hearing” alone. They also depend on:
• Language – understanding words and sentences
• Attention – staying focused on the task
• Memory – holding sounds or instructions in mind
Autistic people are more likely to also have:
• Language delays or differences
• ADHD or attention challenges
• Learning difficulties, anxiety, or working-memory issues
So they’re more likely to struggle on APD tests and with listening in everyday life. Difficulties are usually a mix of auditory, language, attention and sensory factors, which increases the chance of an APD diagnosis.

4. Shared early-life influences
Some things that increase the chance of APD also show up more often in autistic people, such as:
• Family history (genetics)
• Premature birth or early medical complications
• Long periods of glue ear or repeated ear infections in early childhood
These early influences can affect overall development and how the brain processes sound, so autism and APD sometimes grow out of the same early roots.

What this means for autistic people and families

The most important point:

Listening difficulties are real – not laziness, not “bad behaviour”, not a character flaw.

For parents of autistic kids, and for autistic adults themselves, it is reasonable to:

• Take listening struggles and noise sensitivity seriously
• Ask for classroom, workplace or university adjustments
• Consider a full hearing assessment and, if appropriate, an APD assessment with an audiologist who understands autism
• Work with the wider team – speech pathologist, occupational therapist, psychologist, teachers, support workers – to build a joined-up plan

Helpful supports might include:

• Better seating and quieter spaces where possible
• Visual supports and written or typed backup for spoken information
• Extra processing time and shorter, chunked instructions
• Remote-microphone technology in very noisy environments
• Targeted listening or auditory training activities when suitable