Hypersensitive, Hyposensitive, and Thresholds
These are terms and words that get used frequently when discussing sensory processing, so it seemed like a good idea to break them down. In the previous post I listed eleven senses that I knew of, and made reference to the fact that a person could be hyper or hypo sensitive to any of those senses. The issues with sensory stimuli can occur in the sensory input (receiving the sensory information), sensory processing (where the brain decodes the sensory input), or the output (where the individual reacts to the sensory input).
We all use our senses every day, and they are affected every day by external and internal stimuli. Most people will be near the regular (the green line in the image) threshold for most sensory input – although people without autism or any conditions will still have sensitivities or under-sensitivities to the different senses. Additionally, if there’s a day where you haven’t had enough sleep or you wake up with a bad headache, you’ll find that your threshold for sensory input can be much lower. So changing thresholds and reactions to sensory input are far from just an autistic thing – many non-autistic people will have experienced it. The difference for autistic people or those with sensory processing disorder is often in the frequency of the changes in sensitivity, the extent of the hyper/hyposensitivity, or the way in which the sensitivity presents.
Before I get into that I will quickly go over the image I have used at the top of this post. I’ve already mentioned the regular threshold, but to clarify that is the mean level at which people generally take in an appropriate amount of sensory information. Not too much, not too little.
The hyposensitive threshold is when the individual has a high threshold for sensory input and is not taking in enough sensory information – they need more than the environment is providing for them. Generally, people with high thresholds with either engage in sensory seeking behaviour or conversely they will become lethargic, uninterested and have difficulty attending because they just are not stimulated enough. This is the “give me more” side of sensory processing dysfunction.
Examples of this would be the individual who constantly jumps on their bed, or crashes into walls and people, or who spins objects, or flicks things in front of their eyes. For the second category, examples would be people who just seem to slump into their chairs, want to lie down all the time, and just struggle to show an interest in what’s going on around them.
The hypersensitive threshold is when the individual has a very low tolerance and threshold for sensory input, and the environment that they’re in just provides far too much information for them to process. They are either going to try and remove themselves from the sensory input or – if they don’t know how to remove themselves – they will become very defensive.
Those who remove themselves from sensory input may do so literally by running away, or they might cover their eyes, drop to the floor, cover their ears or hum to themselves. Those who become defensive may seem to go ‘catatonic’ and seem to switch off one of their senses – and there are reports from autistic people of almost switching off their vision to deal with sensory input – or they may become distressed and lash out at sources of sensory information.
From the outset it is important to understand that whilst the aim is to achieve a ‘just right state’ – either by providing more or limiting sensory input – as many times as possible in a day, it’s not likely that anyone can be in that ‘just right state’ all the time.
Sensory Dysfunction and Autism
Responses to hypersensitivity or hyposensitivity in autistic people can be extreme, methods used to regulate the sensory dysfunction may be inappropriate, and communication difficulties can just add to these issues.
Obviously not all autistic people will have extreme responses or inappropriate regulation methods – but they are relatively common, especially in childhood or if autism is co-morbid with learning disabilities. The aim then of providing strategies for sensory dysfunction are:
- To reasonably adapt environments or daily routines for the individual. e.g Change bedroom light bulb to a different colour, take down colourful displays and replace with less visually stimulating ones, consider things like carpet patterns when choosing furniture, include sensory movement breaks, differentiate P.E lessons to include a lot of vestibular input.
- To provide tools or resources to help them manage the sensory dysfunction e.g provide earplugs or ear defenders, provide tinted sun/glasses, provide weighted vests or compression vests.
- To teach or provide appropriate self-regulation strategies e.g if a child has previously lashed out as a response to a build up of sensory over-stimulation teach them to request a break to a sensory tent before they reach the point of lashing out, teach them to use the tools and resources mentioned above appropriately and in time.
- To teach a method of communication so they can request the above strategies e.g the “break” card, requesting a time out in a sensory tent, requesting to leave the room.
I think it is important to clarify the point concerning inappropriate self-regulation. By this I mean strategies currently used by the individual that are in some way damaging to either the individual, other people, or property. Some people may think it is inappropriate for a forty year old woman to chew on a dummy to self-regulate or for an eighteen year old teenage boy to carry around a weighted teddy bear (just as examples); but neither of these hypothetical people are hurting themselves, or anyone or anything else. Appropriate in this context has nothing to do with what anyone else thinks is age or gender appropriate, it is about avoiding self-harm, harming others or damaging property.
Working out sensory needs
To be able to help the individual in your life with their sensory dysfunction (and this will be true of individuals who can communicate as well as those who can’t) you will have to work on detecting what their sensory need is. Once you have detected their sensory need you can then work on providing the above interventions and strategies.
There are sensory profiles you can fill out which will provide you with an idea of someone’s sensory needs, I believe there is one in Olga Bogdashina’s book ‘Sensory Perceptual Issues in Autism and Asperger Syndrome’ (I will be talking about sensory profiles in a future post). These are great if they can be filled out by the individual themselves in conjunction with someone who knows them well, or just by someone who knows the individual well. Occupational Therapists will use tools such as these alongside their observations to set up Sensory Diets (again a future post) for the individual.
Lacking access to a sensory profile, it is still possible to use logic to deduce possible sensory needs just through observation. To give you two examples:
- The individual spends a lot of time jumping on their bed: This can provide vestibular and proprioceptive input from the jumping, visual input from the fact that the eyes are constantly readjusting as they go up and down, and possibly auditory input from the sound of landing on the bed.
- An individual cries and squirms when they are being dressed: it could be to do with visual (the room/person in front of you ‘disappears’ for a short time when you put a top on), it could be tactile from the clothing, it could be vestibular (standing on one leg to dress), or it could be proprioceptive (struggling to move limbs into clothing).
Once you have an idea of an individual’s needs you can then start to provide tools and strategies to meet these sensory needs.
Two last points to leave you with before I finish for this post and they are:
- Always respect the individual. It’s okay to try different strategies and tools, there may be some resistance at first and there will be the need for persistence and encouragement but make sure you do not disrespect the individual or their boundaries when teaching the strategies.
- It may not be sensory. Whilst sensory processing can have a huge impact on day-to-day life it will not explain everything. Alongside sensory needs it is still worth keeping it mind that issues might be communication based, emotional based, or behaviourally based.
Disclaimer: The opinions and information provided in this post are my own, and based on personal, educational, and work-based experience. They do not reflect the opinions of any of the authors of the content referenced in this post. I am not affiliated or supported by any organisation, and this is meant to be an educational series of posts. The information posted here is not a substitute for advice and information provided by your own GP, speech and language therapist, occupational therapist or other professional in the field of autism, and should not be taken as such.