Before we get into this discussion, as it forms part of the next batch of reviews, lets just define Autism. Autism is a spectrum wide neurological disorder. It's NOT a disease and cannot be cured. It encompasses a wide range of symptoms, ranging from how well a person can communicate with others, to how they see the world around them, to how they process information in the world around them. There's a myth that people with Aspergers and Autism don't have feelings. They do, many have a difficulty showing their feelings, or understanding how they should feel in certain situations.
In recent years, as anime has exploded, more and more people on the spectrum have found themselves drawn into Anime and Manga. Many people have asked why this is. One of the biggest reasons I can think of, would be the characters. There are many that are large and bombastic, yet make use of simplistic non-verbal communication and facial expressions, which helps many autistics that aren't that adept in understanding facial expressions, learn and understand better, help them understand how the characters are feeling, which in turn, helps them in real life.
The plots are linear and aren't busy, which really helps autistics understand the flow of the story, without a lot unnecessary background material, that a lot of Austistics would focus on and miss crucial plot points.
Many anime and manga characters help autistics in another way, as many are socially awkward outcasts and seeing these characters on the screen actually overcoming problems and becoming more socially acceptable can help them be more friendly and open. This overall open and clean style, along with realistic plots, allows many austistics to jump in and understand the story and the universe, as well as talk to people who are also fans.
While anime may be the big thing to help autistics now, back in the 80s and 90s, Autistics and people with developmental disabilities turned to 2 series. Thomas the Tank Engine and Tugs. Both of these series were made by the same person, David Mitton. They both shared a very similar style in regards to simplistic plots and plain faces on the characters, this helped many autistic children understand facial expressions better, as they were large,clear and were narrated on screen.
The plots were also very easy to understand, as they were usually condensed between 5 and 20 minutes.