My son has aspergers and as h grew older found the meeting a source of distress. He could not sit still and quiet for 2 hours let alone a full assembly day and was constantly being taken out the back to be disciplined. He was profoundly affected by the illustrations in the literature since they fed his anxieties about unusual events. He was self harming in school and hid under the library table screaming about bad books and meteors falling from the sky.
The problem with autistic conditions is that elders and congregations generally have no training or understanding of it. Since autistic children find field service more difficult and cannot be persuaded to keep quuiet if they are hungry, hot, or cold then they are not contributers and therefore are not valued. I can recall only one article about aspergers in the awake magazine which was such a generalisation as to be worthless to mothers trying to cope. Certainly there were no articles about how to include them in meetings, understand their limitations or approach them in service. The society does not want people who will not work. The attitude of the other children who ignored him or bullied him showed an underlying contempt for those who do not fit the picture book witness image.
When I told elders that the meetings werre harmful to my son and if they could reassure me that there would be no talk of Gods judgement, armageddon, crime, violence, wars, earthquakes, murder, disease, pestilence, starvation angels slaying mankind, the devil or meteors falling from the sky we could attend they told me that they would be unable to guarantee that. I said "I can see no place for my son in this organisation" and they agreed. It was the cruelest thing an elder could say that their organisation which they considered to be the only hope for mankind was not open to a child with aspergers that put the final nail in the coffin for me.
What I will say is that leaving was the best thing we could have done for both our children but there is still a measure of guilt that it took us a while to see the issues and extract them.