The Supreme Court's decision this week to limit school boards' responsibilities for educating handicapped children might discourage future cases, but it will not stop current litigation seeking to expand the rights of disabled students, attorneys for both sides said yesterday.

Hundreds of lawsuits involving the Education for All Handicapped Children Act of 1975 are before federal courts around the nation. According to the National School Boards Association (NSBA), more than 40 percent of all student litigation against school districts concerns the handicapped.

The court's 6-to-3 ruling Monday said that a New York school district didn't have to provide a sign language interpreter for an 11-year-old deaf girl because Congress did not intend that each handicapped child be educated to his full potential.

Kim Swain, an attorney for the Disability Rights and Education Fund Inc. in Berkeley, Calif., said yesterday that many other cases will be unaffected by the ruling because "the law is so complicated and the lower courts have been so split on some issues."

Gwen Gregory, deputy legal counsel at the National School Boards Association, agreed, noting that other areas of law still are unresolved. The Supreme Court, for instance, is considering whether to review a Pennsylvania case on whether the law's requirement to provide a "free appropriate public education," including "related services," means that a school district has to pay for maintaining catheterization of a fourth grader paralyzed from the waist down while he is in school.

The education of the handicapped is probably the most emotional issue facing parents and school officials. Parents with handicapped children have become fierce advocates for expanding the services supplied under the law and courts often have sided with their arguments. School officials counter that the courts have gone far beyond the intent of Congress, leaving them to bear the burden of paying for the additional services.

A recent NSBA survey found that it costs nearly $3,000 per student to educate a handicapped child, double the average for a nonhandicapped student. The federal government appropriates almost $1 billion a year for educating disabled youngsters, but that is only about 6 percent of the total cost, Department of Education officials estimate.

Approximately 4.2 million children are served under the law. Some 1.6 million of those are classified as learning disabled. Another 1.1 million have speech problems and 800,000 are mentally retarded.

NSBA officials say their members complain more about the federal law for handicapped children than any other statute. The organization has urged the Reagan administration to make changes in the law and regulations to lighten the expense and paperwork burden.

Last March, Education Department officials outlined a series of proposed amendments to the law that groups representing the disabled claimed would hinder gains made over the past several years. The bill still has not been introduced. As a fallback, the administration is preparing proposed changes in the regulations. Advocacy groups have also been critical of drafts of these plans.