A young reader has sent us her senior essay from Westtown School in W. Columbia, S.C. Here is part of it:

"The other night I was sitting under a sparkleberry tree near my house, listening to the crickets, when there was a scream, and then two screams.

"It sounded like someone was being murdered, but I knew better. They were the screams of my twin brothers, who have no speech. They scream out of frustration, but sometimes they hum or chatter cute little noises. At other times they speak to me with their eyes; I can look into them deeply and know exactly what they're thinking.

"My brothers have been diagnosed as 'autistic,' which means they have a mental disorder.

"Scientists have come up with no explanation for autism and have found no cure for it. It isn't that they are not intelligent; in fact, they are brilliant in their own ways.

"They aren't physically handicapped either, but on the contrary, they're beautiful, especially when they are at peace with their world and ours.

"They have bobbing heads and long, lean bodies that stumble when they run, due to their big, careless feet. I almost wish they could run away and live by themselves in the wilderness, where they would be happy.

"I love to watch them on the farm. They find harmony with nature. And when they go to bed Shannon hums along with the crickets and Shawn chatters gibberish--their usual evening routine before they go to sleep.

"They aren't always beautiful. They can be peaceful and loving, but they also can be violent and shamble a whole room, which upsets me. I lose my temper and become violent too; I even may hit one of them trying to get him to stop. Afterwards I'm shocked by my own behavior. I don't know how I could love and hate them so much at the same time.

"The greatest pain is to realize that they will never be normal. I wish they could talk and enjoy life in the same ways that the rest of us do.

"Most people can't understand Shannon and Shawn and I can't always. There is something mysterious about them. Everyone who knows them falls in love with them. They possess some kind of magic. I see them as a blessing, a gift. I feel fortunate to have them as brothers.

"They have made me a more whole person. There has been a lot of pain and joy, but I have grown."

A. Thank you for telling us what it's like to live with your handicapped brothers: a family situation that is probably harder to handle than almost any other. It certainly would be for most teen-agers.

Your essay also gives readers a chance to meet the twins they read about in Style Plus two years ago--children who inspired their parents to start Sparkleberry School in Columbia, S.C., for them and other behaviorally awry children.

You mentioned that autism is a mental disorder, and although it affects the way a child acts, most doctors consider it a neurological one. So far scientists have discovered at least 60 causes for the syndrome -- genetic factors, viruses, a metabolic disease and others--which delay language development so much that half of its victims never learn to talk. That makes these children withdraw emotionally, avert their eyes and behave in ritualistic ways, like flapping their hands or rocking on their haunches.

To some, these signs suggest that autistic children receive every sensory impression at full and equal strength, making the environment so painful they can't deal with any of it, unless they block all of it.

In any case, autistic children need a full neurological workup--EEGs, CAT scans and blood and urine studies -- to see if the cause can be found so it can be treated appropriately.

Some people claim to cure autism, such as Barry Neill Kauffmann. His second book, A Miracle to Believe In (Doubleday, $12.95) is as much of a tear-jerker as his first one, Son-Rise (Warner, $2.25), and just as controversial.

In the first book he chronicles the way he and his wife say they cured the autism of their son; in the second, he reports the successful treatment of another child. In both cases they used a technique of "total acceptance," in which everything the child does in all of his waking hours--unless it is destructive -- is imitated. This technique, the Kauffmanns believe, is a way of showing love. They also advocate a special, natural diet.

The diet is quite like that prescribed by one Washington neurologist for a small sub-group of autistic children who have a metabolic error, keeping them from handling certain foods.

Although you may doubt Kauffmann's conclusions, the book will remind you that there are others who have walked down your road and reacted with love and anger, too, and there should be comfort in that.

A handicapped child stresses a family and twins stress a family --and handicapped twins certainly do. These tensions are added to the natural moments of anger that you would have for normal brothers, but in your case these tensions are much greater, and you have to grow proportionately to meet them.

Obviously, you're doing just that.

You say you wish your brothers could run away and live by themselves in the wilderness, where they would be happy, but that's what they're doing. When they withdraw from reality, they are running away emotionally to a wilderness of their own making.

They also come back to talk to you with their eyes and to be reassured. This helps them know they wouldn't be traded, which must bring them more happiness than anything else.