One of the most commonly reported challenges for people with autism spectrum disorders (ASDs) is hypersensitivity to sound (Stiegler & Davis, 2010). Adults with ASDs have noted in personal accounts that sounds bothered them as children. Individuals with ASDs have been known to cover their ears and flee from situations that might include undesirable sounds. Parents go to great lengths to shield their children on the spectrum from undesirable sounds, often having them use earplugs or curtailing family activities. Teachers and school-based speech-language pathologists also make special adaptations for children with ASDs who cannot tolerate the noise of the gym, cafeteria, class parties, or playground. Many movie theaters offer special, quieter showings for children with autism and their families. Hypersensitivity to sound is commonly believed to be a permanent symptom of autism that must be accommodated.

The Puzzle of Sound Sensitivity 

What is puzzling is that no compelling empirical evidence shows that the hearing of individuals with ASD differs physiologically from their typical peers. There are no known differences in the peripheral or central auditory systems of individuals with ASDs that would result in hypersensitivity to sound. Gravel et al. (2006) found that children with ASDs did not exhibit more sensitive hearing nor did they protest the tone used to stimulate the acoustic reflex more often than typical controls.

In a related study, Tharpe et al. (2006) found no evidence that children with ASDs had more sensitive hearing than typical peers, although in the majority of cases, parents reported that their child experienced pain or distress when exposed to certain sounds. In addition, clinical reports and personal accounts show that many people with ASDs demonstrate strong avoidance reactions to sounds that are neither high-pitched nor extraordinarily loud (e.g., the ticking of a ceiling-fan chain against a glass light fixture or someone saying a non-preferred word).

Moreover, people with ASDs sometimes do not have a negative reaction when they hear the undesired sounds outside of the normal context (e.g., an audiotape of a toilet flushing played in a clinical setting) (Jackson & King, 1982).

So what's going on?

Some researchers view the strong avoidance reactions exhibited by some individuals with ASDs as an emotional regulation issue, possibly as a result of learned responses that are either fear- or annoyance-based (Stiegler & Davis, 2010). Fear of noise is common in typical development but tends to be resolved at a young age. Children with ASDs may feel threatened by certain sounds and may experience uncomfortable sensations related to sound. Their natural reaction may be self-protective (Koegel, Oppendon, & Koegel, 2004).

Compelling Questions 

The issue of self-protection raises compelling questions: In an effort to make individuals with ASDs more comfortable, could clinicians and parents inadvertently reinforce negative reactions to sound and thus decrease opportunities for participation in educational, social, recreational, and vocational activities? Do our beliefs perpetuate and exacerbate the problem? Is it possible for people with ASDs to learn to tolerate and even enjoy a variety of sound stimuli?

Because so many children with ASDs exhibit sound sensitivities, we suggest that audiologists:

• Be proactive and incorporate specific questions about auditory hypersensitivity into case histories.
• Assess loudness discomfort levels (LDLs) as part of the routine audiologic assessment protocol for individuals with ASDs, in children, or when ASDs are suspected (Stiegler & Davis, 2010).

There are no data on assessing LDLs in this specific population, but LDL assessment is considered best practice when assessing otherwise-typical individuals with sound tolerance problems (Henry, Zaugg, & Schechter, 2005). LDLs can provide an important piece of information about whether loudness alone will evoke avoidance responses. If not, the audiologist can recommend positive intervention options to help the individual adjust, habituate, or learn to tolerate particular sounds and perhaps collaborate with an SLP to develop an individualized treatment plan.    

A critical first step may be to work on discontinuing overuse of ear protection (e.g., earplugs, fingers in ears) that may be counterproductive by engaging the individual in tasks that require both hands. Another useful approach may be to enhance the individual's auditory environment by frequently embedding sound stimuli (e.g., music, noise-making toys, or computer programs) into positive, playful activities. Individualized systematic desensitization protocols, consistently implemented, can make a significant difference.

Koegel, Oppendon, and Koegel (2004) demonstrated successful outcomes using systematic desensitization with several young children with ASDs who exhibited extreme reactions to the sounds of household appliances, toilets, and musical toys. Their protocol involves persistently exposing children to their target sounds over time as the distances and obstacles (e.g., closed doors) between the children and sound sources are gradually decreased. Additionally, for some individuals, a simple reward system in which points or tokens are earned for successfully tolerating target sounds may be effective. Each strategy should be accompanied by reassuring messages from caregivers and clinicians, who communicate through words or visuals that target sounds are "safe" or "okay" (Prizant & Meyer, 1993). Ideally, individuals with ASDs would eventually learn to generate their own calming, self-regulating messages.

Clearly, audiologists and SLPs are the appropriate professionals to assist individuals with ASDs and their families as they grapple with sound sensitivity. Early and persistent management characterized by consistency and a good knowledge base may lead to positive outcomes in terms of life participation.