What is Sensory Overload?

By Anthoni Oisin, BScReviewed by Sophia Coveney

Causes and symptoms of sensory overload
Sensory overload and Autism Spectrum Disorder
Sensory overload and attention deficit hyperactivity disorder
How is modern life influencing sensory overload?
The future of research into overstimulation
References
Further reading

Sensory overload occurs when the brain becomes overwhelmed by the volume or nature of the sensory inputs it receives. Sensory inputs can be any stimuli that enter through one of the sensory modalities: sight, sound, gustation, olfaction, and tactile sensations. Tactile sensations include responses to pressure and temperature.

Overstimulation is the product of sensory overload. When one becomes overstimulated, it can feel overwhelming, stressful, and upsetting. Sensory overload is a temporary state, which passes with time and self-regulation, once the extraneous stimuli are removed.

Some conditions and disorders are associated with sensory overload, such as Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD), and Post-Traumatic Stress Disorder (PTSD). However, it is possible for anyone to experience sensory overload, regardless of whether they have such a condition.

Causes and symptoms of sensory overload

There is a gap in the literature regarding the precise cause of sensory overload. However, there is an indication that there may be several etiologies for sensory overload. 

Thalamic connectivity is a neurobiological explanation of sensory overload. The thalamus is an area of the brain that is associated with handling sensory information by relaying it across the brain. Thalamic nuclei and feedback loops are used to move sensory information around the brain through this connectivity.

Sensory gating is thought to be the basis of both cognitive and biological explanations of sensory overload. Sensory gating is a mechanism in the attention system that helps to keep extraneous or unwanted sensory information from being attended to and processed.

When sensory gating is inhibited, sensory stimuli that would normally go unattended are attended to and processed. This can become overloading for the brain’s typical capabilities. 

Symptoms of sensory overload can vary greatly. Some common symptoms include stress reactions, disturbances in thought and perceptive processing, and impaired attentional or concentration abilities, among others.

The literature also suggests that when sensory overload is experienced by someone with another diagnosis, it could also exacerbate the presentation of associated characteristics. For example, an overstimulated person who has a Sensory Processing Disorder (SPD) may experience more difficulties with processing sensory information.

Sensory overload and Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is one of the conditions that sensory overload is associated with. ASD is a developmental disorder with characteristics relating to communication, sensory experiences and more.

Autism differs significantly from one person to another, however sensory overload is a common experience for many autistic people. The exact cause for this has not been pinpointed yet, although one reason may be due to increased levels of thalamic reactivity to sensory inputs.

Sensory overload can affect the way that people experience and access healthcare. Research has indicated that particular characteristics of medical settings may trigger or contribute to sensory overload, which can impact the accessibility of such settings to those who experience sensory overload. For instance, the auditory experience of being in a healthcare setting is stressful for autistic patients.

Sensory overload and attention deficit hyperactivity disorder

Attention Deficit Hyperactivity Disorder (ADHD) is another form of neurodivergence that is associated with experiences of sensory overload. ADHD is a behavioral syndrome with a cognitive and neurobiological basis. 

The mechanism connecting ADHD and sensory overload is not fully understood. However, as ADHD is classified by differences in perceptual and attentional processing, it is thought that the relationship may also have a cognitive foundation. 

Sensory overload may be prevalent among those with ADHD due to a reduced capacity to subconsciously filter irrelevant or unwanted sensory stimuli out of the sensory memory. This can lead to the impaired gating of superfluous sensory stimuli, potentially leading to a large volume of sensory stimuli being processed at once. This can become overstimulating.

How is modern life influencing sensory overload?

Some aspects of the modern experience may be associated with sensory overload, such as relatively higher levels of pollution compared to the past. Both medical and acoustic fields have explored the impact of noise pollution on the brain health of those who live in cities, noting traffic and construction work as both posing a public health risk.

Noise pollution has been a target for sensory research since the 1970s. Concerns have been raised for the brain health of those who live in urbanized areas; particularly with the use of cars and other vehicles in mind. Similarly, poorly sound-insulated buildings and the resonance of particular styles of architecture are thought to have an effect.

Modern inventions can also help to prevent or ease sensory overload. The development and innovation of earplugs, ear defenders, and other noise-reduction technologies can be used as aids to reduce the risk of experiencing overstimulation or sensory overload in certain circumstances.

The future of research into overstimulation

Climate change may affect research into sensory overload. Studies have indicated that increased levels of air pollution could be associated with heightened levels of olfaction-triggered sensory overload. This information could be used to inform climate change or pollution-related policies or to provide a basis for relevant public health programs.

Research into sensory overload and its impact on brain health could also be used to dictate city planning. The Sensory City is an idea explored regarding how to construct cities that are informed by neuro-affective diversity, making them more accessible to a wider range of individuals.

Research into sensory overload and overstimulation is a growing field. Despite this, there is still a lack of consensus regarding many factors of the experience. Because of this, a great deal of further research would help to expand the clinical understanding of sensory overload.

References

• Strömberg M, Liman L, Bang P, & Igelström K (2022). Experiences of sensory overload and communication barriers by autistic adults in health care settings. Autism in Adulthood, 4(1), 66-75. https://doi.org/10.1089/aut.2020.0074
• Holstein DH, Vollenweider FX, Geyer MA, Csomor PA, Belser N & Eich D (2013). Sensory and sensorimotor gating in adult attention-deficit/hyperactivity disorder (ADHD). Psychiatry research, 205(1-2), 117-126. https://doi.org/10.1016/j.psychres.2012.08.013
• Curatolo P, D'Agati E, & Moavero R (2010). The neurobiological basis of ADHD. Italian journal of pediatrics, 36(1), 1-7. https://doi.org/10.1186/1824-7288-36-79
• Scheydt S, Müller Staub M, Frauenfelder F, Nielsen GH, Behrens J & Needham I. (2017). Sensory overload: A concept analysis. International Journal of Mental Health Nursing, 26(2), 110-120.  https://doi.org/10.1111/inm.12303
• Arnold C (2019). Sensory overload? air pollution and impaired olfaction. Environmental Health Perspectives, 127(6). https://doi.org/10.1289/EHP3621
• Vollenweider FX (2022). Brain mechanisms of hallucinogens and entactogens. Dialogues in clinical neuroscience, 3(4): 265-279.  https://doi.org/10.31887/DCNS.2001.3.4/fxvollenweider
• Green SA, Hernandez L, Bookheimer SY & Dapretto M (2017). Reduced modulation of thalamocortical connectivity during exposure to sensory stimuli in ASD. Autism Research, 10(5), 801-809. https://doi.org/10.1002/aur.1726
• Dirks KN, Shepherd D, Welch D & McBride D (2013). Annoyance to traffic noise and annoyance to air pollution: an orthogonal or co-varying relationship in noise-sensitive individuals. Internoise, Innsbruck, Austria.
• Adams M, Cox T, Croxford B, Moore G, Sharples S & Reface M (2009). The sensory city. Designing Sustainable Cities, 75-85.
• Biel L (2017). Students with Sensory Processing Challenges: Classroom Strategies. In Optimizing Learning Outcomes (pp. 74-94). Routledge.
• First MB (2013). DSM-5 handbook of differential diagnosis. American Psychiatric Pub.

Further Reading

• All Autism Content
• What is Autism?
• What is Autistic Burnout?
• Autism Causes
• Autism Mechanism