Hello, friends!
This week, I’ve been reading and analyzing a research article on sensory over-responsivity (SOR) written by researchers from multiple institutions in Hong Kong. A comprehensive review on this topic was published in October 2022. The scientists explained the key mechanisms underlying sensory over-responsivity (SOR) and potential effective interventions.
Let’s take a closer look at the article and highlight the most important points.
Individuals with autism often exhibit sensory over-responsivity, characterized by negative reactions to stimuli or avoidance of sensory experiences. Autism spectrum disorder (ASD) includes two primary clusters of symptoms: deficits in social interaction and communication, as well as restricted and repetitive behaviors. In addition to these core criteria, DSM-5 (the Diagnostic and Statistical Manual of Mental Disorders) has added sensory over-responsivity and hyperactivity as key symptoms.
Sensory characteristics can be divided into three patterns:
- Sensory over-responsivity (SOR)
- Sensory under-responsivity
- Sensory seeking
Many individuals with autism exhibit more than one sensory characteristic. Research has shown that unusual sensory traits correlate with the severity of autistic traits, such as repetitive and stereotypical behavior.
Sensory Over-Responsivity (SOR)
Sensory over-responsivity refers to a condition in which an excessive or prolonged response to sensory stimuli interferes with daily life. This phenomenon is not exclusive to individuals with ASD but also occurs in neurotypical individuals (8–28%) and in other conditions, such as ADHD (around 28%).
Studies have also shown a link between SOR and anxiety disorders in preschool children, a connection between SOR and obsessive-compulsive symptoms in children and adolescents, as well as the presence of SOR symptoms in conditions like ADHD and fragile X syndrome.
Does the Severity of SOR Symptoms Change with Age?
According to the article, the intensity of symptoms changes in a nonlinear manner with age. The peak occurs between ages 6–9. In adolescents and adults, symptom severity decreases due to neurohormonal changes and the development of coping strategies.
Mechanisms Underlying Sensory Over-Responsivity in ASD.
Despite ongoing research, several key factors have been identified:
- Prenatal factors
- Genetic factors
- Excitatory/inhibitory neurochemical balance
- Brain connectivity
Prenatal Factors
Medication use, alcohol consumption, and elevated stress-related hormones during pregnancy affect the normal development of the sensory nervous system.
Genetic Factors and Excitatory/Inhibitory Neurochemical Balance
Studies have identified a significant link between mutations in neuroligin-3 and GABRB3 genes and sensory traits in individuals with autism. These mutations disrupt the balance of gamma-aminobutyric acid (GABA) and glutamate. An imbalance between GABA and glutamate leads to either excessive inhibition or, conversely, excessive excitation in response to sensory stimuli in autistic children.
There is also a correlation between GABA concentration in the cerebral cortex and visual perception in children with autism: lower GABA levels are associated with increased visual sensitivity.
Brain Connectivity
Sensory over-responsivity in autism is linked to structural and functional connectivity abnormalities in the brain. These anomalies impair the regulation and integration of sensory input, leading to heightened attention and emotional responses during sensory processing, ultimately resulting in increased reactivity to sensory stimuli.
Potentially Effective Interventions
Based on the identified mechanisms, the authors suggest four approaches that may reduce sensory over-responsivity:
- Physical activity – significantly reduces sensory sensitivity and decreases negative emotions.
- Ayres Sensory Integration Therapy – improves children's ability to process sensory information, enhancing focus and attention.
- Mindfulness-Based Cognitive Therapy (MBCT) – promotes self-regulation, reduces emotional reactivity, and improves attention and concentration.
- Cognitive Behavioral Therapy (CBT) – helps develop social skills and reduces anxiety.
The article is incredibly rich in both content and the number of studies cited by the authors. If you’re interested in any particular aspect, I highly recommend reading it in full.
For myself, I plan to highlight a few particularly interesting smaller studies from the article and review them in detail.
See you soon, and have a great day!
