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asperger's syndrome information and features


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Sensory Peculiarities / Sensory Integration Dysfunction

Sensory Overload


Scotopic Sensitivity Syndrome


Central Auditory Processing Disorder

Sensory Peculiarities / Sensory Integration Dysfunction

Sensory problems and peculiarities are often reported by people with Asperger syndrome.

S.I.D. is a neurological condition which can occur on it's own, but many people with Asperger syndrome report having at least some of the symptoms, and it can of course occur alongside asperger syndrome too.

The process of receiving and organising sensory information in the brain can be disrupted, sometimes resulting in over or under stimulation. The brain may be receiving sensory information inconsistently, or it may be organising it incorrectly, or it may not even receive it at all in areas where there is a disconnection of the neuron cells. This manifests in some people as being over sensitive to everything, in others as being under sensitive to everything, but it can also be a combination of both, different for each sense, or varying.

An individual may find themselves easily confused and disorientated and may have to put more conscious effort into making sense of their environment than most. Experiences which seem fine to other people may be terrifying or pointless.

The three main consequences of this are inappropriate responses or lack of response, avoidance of distraction or overload by avoiding stimulation, and/or seeking out stimulation or self stimulation. Some examples would be:

  • Bright lights uncomfortable / dim lights or darkness preferable.

  • Disorientated in environments rich with visual stimulation.

  • Plays with lights and shiny, reflective, or brightly coloured items.

  • Staring or fixating on patterns or objects.

  • Repetitive humming or singing or loud outbursts of meaningless noise.

  • Trouble following conversation in groups or noisy environments.

  • Discomfort created by loud or low frequency noise.

  • Delayed or lack of response or over reaction to sudden noises.

  • Over reaction to smells, especially ones no one else is able to detect.

  • Prefers to eat bland food, and fussy about texture.

  • Chews or sucks non food items past age when expected.

  • Fascination with perfumes and / or how people smell.

  • Strong preference for gentle / feather touch or pressure / firm touch.

  • Unusually high or low pain tolerance.

  • Highly sensitive to temperature.

  • Fussy about how clothes or bed sheets feel against skin.

Listed above are just some of the sorts of things people commonly report, but there are many more. One I've heard people say about and have experienced myself is sensitivity to changes in air pressure, but I don't know what 'sense' you would list that under.

Interestingly, we may actually perceive the world using input from at least 21 different senses, if not more. Within vision for example it is suggested that the ability to sense light is different to the ability to sense colour etc. As sensory perception becomes better understood the sheer complexity of how we create our mental model of the world around us is becoming clear. It may be that the sense organs themselves have a much smaller influence than previously thought, and it is what your brain actually does with the information it gets that really counts. It is therefore not surprising that there is such potential for people who have nothing physically wrong with their sense organs to have such different experiences. If this is a subject that interests you there is a very good article on it in the New Scientist from January 29th 2005.

Sensory issues are not evidence of Asperger syndrome on their own. Contrary to what it sounds like, there is not some universal standard of human perception from which only a tiny minority differ and many people have sensory differences without having AS.

When a person has sensory issues on their own that are more severe than most then they might have a diagnosis of Sensory Integration Dysfunction. Sensory Integration Issues themselves are so frequently linked to the learning, behavioural and social difficulties which they can be in part responsible for, that there is a lot of overlap in diagnostic criteria. Some symptoms of Asperger syndrome could be used as evidence of Sensory Integration Dysfunction, and some symptoms of sensory integration dysfunction could be used as evidence of Asperger syndrome.

One thing I am learning is that the way you see the world always seems normal to you. You have no immediate or obvious way of knowing that you experience things differently to others, and if you find something more difficult than other people as a result, you have no way of guessing that is the reason. You often just blame yourself or feel ashamed and confused. Once you are aware of sensory issues though it becomes easier to spot both the enhanced abilities you have as well as the things you find difficult, and you can start to take more control over your environment and things you may have struggled with in the past.

Sensory Overload

When the brain becomes over stimulated some people describe it as 'overload'. The type of sensations that could cause this would be things like bright lights or flashing lights, loud or conflicting noises, strong smells, pressing up against other people in a crowd, being surrounded by moving faces or objects, or any confusing or overwhelming sensory environments where any number of these things could be occurring at the same time.

I find that it can be made much worse when the environment is unfamiliar and also that my emotional state makes a big difference. If I am feeling tired, sad or under stress to begin with then my ability to cope is less than usual and therefore sensory overload is more likely to occur. Sometimes it happens straight away and sometimes it comes on gradually.

The overload can manifest itself as anything from something as mild as a heavy feeling that you can't go on and need to get away to being as severe as becoming almost catatonic. It could be accompanied by headaches and nausea or feelings of panic and disorientation. You may be unresponsive or confused. There is a distinct sensation of slipping away from the world and the brain feels like it is shutting down.


Synaesthesia (also known as cross sensory perception) is when input from one sense is interpreted by another e.g. seeing sound, tasting colour, or hearing light.

Scotopic Sensitivity Syndrome

Scotopic Sensitivity Syndrome (Irlen Syndrome) is thought to be a problem with how the visual cortex processes information, resulting in visual problems, light sensitivity and inaccurate depth perception. This can result in literacy problems, clumsiness and headaches. Treatment involves the use of Irlen lenses, which reduce light sensitivity and perceptual distortions allowing correct interpretation of visual stimuli. Approximately 12% of the population are believed to be affected to some degree.


Agnosia is when you can sense objects and forms but are unable to consciously recognise and interpret their meaning.  Prosopagnosia (face blindness) and Topographical Agnosia are often reported by people with Asperger syndrome.

Prosopagnosia is an inability to recognise peoples faces. You can usually still tell the difference between faces and are still aware that you are actually looking at a face... it is not a problem with vision, it is a problem with interpreting and recognising visual information.

It is not the same as just having trouble remembering names or forgetting people you have only just met or do not know very well. If you are face blind then you may not even recognise people you know well like friends or family, especially if they have changed something about themselves like a new hair cut or outfit, or if they are in an unfamiliar context like in the street instead of at work or home.

Difficulty here may be compensated for by relying on information other than faces to recognise people with such as hair colour/style, sound of voice, body shape, clothing or even just the context of the situation (who you expect it to be). In some cases repeated exposure to a persons face seems to help increase recognition, but this may just be a result of finding other ways to recognise them.

Topographical Agnosia is when people have trouble finding there way around places even if they know them because they are unable to recognise the features around them that tell them where they are and where to go. It is not the same as just forgetting the way to go or getting lost in a new place. There is difficulty finding your way around places that should be familiar.

Facial Recognition Tests

Central Auditory Processing Disorder

Auditory processing is what happens when your brain recognizes and interprets sounds. People with auditory processing difficulty have normal hearing and intelligence, but are observed to have the following difficulties:

  • Trouble discriminating foreground from background noise.

  • Delayed processing of speech.

  • Echolalia.

  • Interrupting or speaking over people.

  • Asking for repetition.

  • Difficulty paying attention.

  • Trouble remembering information presented orally.

  • Problems carrying out multistep directions.

  • Lack of responsiveness.

These symptoms are often reported by people with Asperger syndrome.

Further reading available from Amazon.com or Amazon.co.uk

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