Although it's not officially part of the DSM IV (one of the things critics condemn), it is considered to be part of the ASD spectrum diagnosis. It's not just noise sensitivity, but sensitivities to other external stimuli including light, touch, taste/food texture, and smell. I for one have all of these sensitivities, but noise is by far the worst. I startle very easily, much to the amusement of my peers. One of my coworkers even asked if I had sensitive hearing today at work, as I work in a very loud place and am prone to jumping at everything. It is not typically that our senses are more sensitive (i.e we can hear/see things others can't) rather, that the nerve pathway that the stimuli travel along are more sensitive, and so the things that get sent to our brains are interpreted more strongly than in others. There is an official disorder known as Sensory Processing Disorder (not a PDD) that effectively encompasses these sensitivities, as well as several other internal processing difficulties, including trouble with vestibular movement (swinging/being off-balance, etc), kinesthesis (the ability to tell where one's body is in relation to other things), and dyspraxia (lack of physical coordination) to name a few.
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"Survival is insufficient" - Seven of Nine
Diagnosed with ASD level 1 on the 10th of April, 2014
Rediagnosed with ASD level 2 on the 4th of May, 2019
Thanks to Olympiadis for my fantastic avatar!