Sitting on the train, I try to see what it is like to be autistic. I look ahead, getting a buzz from things flashing by my peripheral vision; I look out of the window and watch the trees in the foreground dash across the ones further away. I let it thrill me and scare me a bit too. I get a rush from the experience of another train whooshing past. I get some satisfaction from watching the tracks go along their parallel lines, converge and part, and feel pleasure from seeing rows of trees in a plantation straighten up into lines as I look.
Then I think about how it must be to feel all the information from all of your senses without any filtering. I become aware not only of those sights but of the sounds: the train clattering and creaking, the murmur of other passengers, mobile phone ringtones, electronic beeps, and the occasional cry of a baby. I feel all the clothes on my body: the seams of my skirt against my legs, the itchy pile of the seat, the label of my blouse irritating the back of my neck. I feel my body moving in space and the effort it takes to keep righting it and the draught blowing across my legs.
I taste the toothpaste from this morning and smell the chemicals from the train toilet and the scent of somebody's orange. I try to feel all these at once.
I look at my fellow passengers; I try to imagine not understanding their faces as they move to talk and stretch and think. How grotesque they might seem. And the chatter; it must seem like an alien language where gestures, tones of voice and words are incomprehensible.
I keep this up for a little while and cling to my handbag as if it will save my life. I stare at a pattern on the seat in front of me and try to imagine how I would feel if I couldn't understand that this journey will end; that, as far as I know, I will never see anyone or anything familiar to me again. But then someone sits down opposite me and I automatically make eye contact, and I smile at the sight of a young mum playing games with her babies. I'm amused at a businesswoman's pompous tone on the telephone and I realise I am focusing on what I want to and engaging with the world around me. My brain can filter out the unnecessary stuff and I can understand what is happening. No, I decide, it's as difficult to step into an autistic world as it must be to step out of one.
Maria Corby is deputy head of a special school for pupils with severe and multiple learning difficulties. She writes under a pseudonym