Following up from the Hearing Things article I’ve discovered Hyperacusis which is defined as

abnormal acuteness of hearing due to increased irritability of the sensory neural mechanism; characterized by intolerance for ordinary sound levels

Unlike hypersensitivity to low pitched hums this is hypersensitivity to all sounds making day to day life a misery. This report links 40% of autism cases with Hyperacusis. This paper links examines autisim, hyperacusis and Auditory Integration Training (AIT). More information available from the Hyperacusis Network.