Extent and Burden of Auditory Hypersensitivity Issues in Children with ASD

Background:  

Sensitivity issues are strongly associated with the autism spectrum disorder (ASD) phenotype. Research suggests 30-90% of people with ASD either over or under react to sensory stimuli. Auditory hypersensitivity is reported to be the most common, affecting 30-50% of children with ASD, and is highly concerning due to the often-unpredictable nature of the stimulation, and the potential to lead to avoidant or challenging behaviors.

Objectives:  

• To describe the extent and burden of auditory hypersensitivity issues (AHI) in a sample of children aged 3-17 with at least one AHI in the previous six months.
• To determine whether sound type, emotional response to sound, and physical response to sound load into factors that may help identify subgroups based on response to auditory stimuli.  

Methods:  

The Interactive Autism Network (IAN), a large, well-validated, US-based autism research registry, invited participating families of children with ASD aged 3-17 years to complete a survey about their child’s current and past AHI, and how AHI affects their child behavior and impacts their family.

Results:  

497 children had a completed survey; 400 children (80.5%) had AHI in the six months prior to completing the survey, while 97 did not and were excluded from analysis. The sample was a majority male (83.0%), white (90.3%) and mean age was 11.1 years (standard deviation: 3.5).

Most common frequency for AHI was ‘a few times a week’ (30.0%) and ‘a few times a month’ (21.2%). Common specific sounds were yelling (80.3% react at least sometimes), crying (67.6%), and vacuuming (80.3%). Responses to sound often caused at least a somewhat unsafe situation (41.4%), with 14.4% of children physically injuring themselves and 25.5% hurting others. After AHI, parents noted increased anxiety (89.4%), fear (70.9%), impulsivity (65.6%) and difficulty to control (71.5%). Increased behaviors after AHI included covering ears (86.3%), yelling (58.4%), outbursts (82.6%), and escape (57.2%). AHI often led to frequently (25.4%) or sometimes (38.7%) missing school, family, or community activities. Parents most often indicated that management of AHI was minimally (39.2%) to moderately (39.9%) difficult.  

Exploratory factors were calculated to determine potential subgroups based on sound types that cause issues, and emotional and physical responses to those sounds.  Two-factor solutions were found to explain variance in emotional response (fear and aggression factors), physical response (hyperactive/injury and avoidance factors) and sound type (high pitch and low pitch factors).

Conclusions:

AHI occur frequently among children with ASD. These issues lead to safety concerns, increase in challenging behaviors, and loss of opportunities which impacts schooling and ability to experience public life. Preliminary factor analyses suggest that there are different responses types that may help us understand more about the nature of AHI. Better understanding the manifestation of AHI will help lead to effective therapies and prevent AHI which will reduce their negative impacts.  Results of this study will inform parents and care providers about management of AHI in the community and its potential impact on child behavior and safety.