Autism

Autism is a neurological disorder relative to the brain the spinal cord which effects the nervous system. In other words, it influences the way in which an individual with Autism interprets the environment. Typically their sensory system is tweaked either slightly higher than everyone else's or slightly lower, causing significant difficulty with the way in which they interpret the environment. They may hear sounds higher or lower than the actual presentation, may feel or experience  touch, taste, or  auditory stimuli differently causing them to react rather than respond. They may often cover their ears in the presence of noise that is different from sounds normally occurring on a daily basis as they have a hard time processing what they've just heard. If they are in control of the actual sound then their processing of the sound may differ from if someone else is controlling the sound.

Children with Autism often have Regulatory Disorder of Sensory where they may experience difficulty making sense of their surroundings in an age-appropriate manner. They are very sensitive to sounds in the environment specifically those relative to touch, taste, hearing, tastes, and smells. 

Children with Autism also may experience bouts of anxiety particularly when they are entering a new environment or leaving one that is familiar. It is typically known as Separation Anxiety and overtime tends to improve. Even if they are engaging in a play-based activity and a toy is taken away before introducing another, they may throw a fit, scream, tantrum, and cry. Again this anxiety is due to change and difficulty predicting the change and is  directly relative to their diagnosis of ASD.

Attention Deficit Hyper-Activity Disorder often coexists with Autism, but not always. In 2014, a review of studies looking at the cooccurrence of ADHD and ASD found that 30% to 50% of people with ASD also have symptoms of ADHD.