The way we perceive our environment is driven by our sensory nervous system, and humans have many more than five senses! But, does having ADHD change how we process sensory information?
Each person’s behaviour in response to ‘sensory stimuli’ is determined in part by their brain’s ‘sensitivity threshold’. We can’t react to everything around us, so our brains have a threshold that has to be reached. Sensory stimuli such as light, touch, smell, hearing and temperature tell us about our surroundings, through a variety of spoecialised nerves that detect changes in them.
If someone’s brain has issues in how senses are perceived or responded to, this can lead to a ‘sensory processing disorder’, of which there are broadly three types; sensory modulation disorders, sensory discrimination disorder and sensory-based motor disorder.
Of these three, sensory modulation disorder is probably the most relevant to ADHD, and it can be further subdivided into three different forms; Sensory Over-Responsivity, Sensory Under-Responsivity and Sensory Seeking. Too much, too little or gimme more.
People with a high sensory threshold might be considered as ‘sensory seeking’. In contrast, sensory over-responsivity goes along with having a low sensory threshold. This can lead to sensory avoidance. Sensory over-responsivity means people can respond to sensory stimuli in a way that is faster, longer, or more intense than would normally be expected.
The second of these sensory modulation disorders is sensory under-responsivity where people are unaware or they are slow to respond to sensory input. The third type is ‘sensory-seeking’, where individuals crave or display interest in sensory experiences.
The most common forms of sensory issues are generally auditory, or sound based.
ADHD and Sensory Processing
Abnormalities in sensory processing have been found in many neurodevelopmental disorders, including ASD and dyslexia and there is also evidence that suggests the presence of sensory processing abnormalities in children and adults with ADHD. A number of studies have discovered differences between ADHD and non-ADHD adults in a variety of sensory issues including vision, hearing, touch, smell, balance, and multisensory integration.
Why is this? Well, a number of studies suggest that the areas of the brain associated with sensory processing are different in the brains of people with ADHD. The severity of ADHD symptoms also seems to be linked to sensory processing, with a recent study showing that higher ADHD symptoms were a good indicator of also having sensory processing issues.
What Can Be Done?
Noting which sensory stimuli are issues for you and trying to build coping mechanisms including noise cancelling headphones, self soothing techniques, finding a quiet space and avoidance of triggering situations can help some people. Accepting that there are some sensations that cause you distress, and being able to put your own emotional needs first can be a big step towards living a life with fewer sensory issues.
Authors: James Brown PhD and Alex Conner PhD.