Although she was just 3 years old when she first started sketching, Nadia's pencil drawings of galloping horses have been compared to the works of a young Picasso. "She pumps it full of muscle, turns it around, has it jumping out of the page," according to a London art critic.

"She could not have been taught to draw that way," Walter Cronkite said of her in a television science special, "because no teacher could reach her.

Nadia is autistic.

She is the subject of a famous case study at London's University of Nottingham's Child Research Unit and is the most dramatic example of an autistic child's expression through art. Her case has sparked an interest among parents and experts in the role the arts can play in helping autistic children.

"Autistic children take a tremendous amount of effort and amount of time so there's not much left for cultural activities," says Ruth Page, whose 17-year-old son is autistic. "I guess now we should make time."

The national committee, Arts for the Handicapped, which brought to public attention the need for the arts in the lives of handicapped persons has recently emphasized the role of the arts in treating autistic children. The National Society for Autistic Children, meanwhile, highlighted the role of the arts this year at their annual conference by including sessions on the arts as well as an art exhibit by autistic children and adults.

Some of the pieces in the exhibit, which were on display at the NSAC headquarters at 1234 Massachusetts Ave. NW, are clearly the work of extraordinarily talented artists. The sketches of New York City skyscrapers, trains and streets are as precise as those on an architect's drafting board. Yet they are the work of then 6 1/2-year-old Gilles Trehin. There are the nonrepresentational child's crayon drawings, the work of Jessica Parks, who is now a successful commercial artist.

Other pieces are not as impressive, but it doesn't matter. Even at its simplest, the art is seen as a form of self-expression. And in autistic children, who are characterized by their lack of speech and inability to relate to others, that self-expression is jubilantly welcomed.

"Drawing may be a way of putting on paper an idea that can be shown and therefore communicated to others," says Dr. Karl Feinstein, out-patient psychiatry chief at Children's Hospital National Medical Center. "When dealing with children with severe communication problems such as autism, there is a lot to be said for the visual arts."

Nadia is now 13 and has progressed in verbal skills: She can say a few words, and she relates to people she recognizes. According to Dr. Elizabeth Newson of the Nottingham Research Unit, Nadia's artistic ability has increased. Today her drawings are no longer extraordinary. The same art critic who once praised her work now says she shows no particular artistic talent or inclination. It is as if she traded her phenomenal ability for a few simple words.

As an explanation, Feinstein cites a theory of compensation. "Deprived of any other outlet, or making meaning out of the world around them [children like Nadia] are able to invest a part of their functions with an immensely higher concentration of efforts." Once they acquire language, Feinstein says, they gain other interests and "no longer invest to the same degree."

Autistic children's participation in arts programs is low because of the very nature of autism. Children diagnosed as autistic are characteristically walled into an invisible shell not easily penetrated by those around them.

"The baby is unable to decode language; that is, to make sense of language," explains Newson. There is no cure for autism because the cause -- perhaps a chemical imbalance, or an imbalance of the brain hemispheres, Newson suggests -- is unknown.

One mother who did involve her autistic son in an arts program recounted her frustrations, as she browsed through the sketches, paintings and hand-woven textiles at the NSAC art exhibit.

"He'd sit at the table and draw the same thing over and over," the mother recalls. Her son, now 29, had always loved to draw, so she encouraged him to join an art class.

"His art lasted as long as that class," she laments. "It was as if he thought, 'Here's another one of the world's goddamn systems and I've never been able to deal with any of its systems before.'"

Most of the 100,000 diagnosed autistic children in the United States -- like most children -- are not artistic geniuses like Nadia, Gilles and Jessica.

Ruth Page admits that, artistically speaking, her son, "is not one of the talented ones." No matter. Page stresses the single most important point. . . "He gets pleasure from it."