Schools spent an extra $3,555 for each of the 4.4 million handicapped children receiving some form of special education in the 1985-86 academic year, according to a study prepared for the government.

The total cost for special education students was $6,335 on average, or 2.3 times the $2,780 cost for regular classwork, the report said. About 11 percent of the nation's school children receive some form of special education.The new $1.8 million study, done by a private research and analysis firm, Decision Resources Corp., breaks down the special education costs by the different approaches used to teach children with handicaps ranging from physical disabilities to mental disorders.

It examined both "resource programs," or those serving pupils for less than half of the regular 30-hour school week, and "self-contained programs" - defined as those that occupied more than 15 hours per week.

Looking only at what was spent on special education, the resource programs spent $2,463 per pupil versus $5,566 per pupil in the self-contained programs.

But the schools also incurred regular education costs for these pupils - the full regular cost of $2,780 for those in resource programs, and about half as much, $1,347, for those in self-contained programs.

That boosted the total per pupil costs to $5,243 for those in resource programs and to $6,913 for those in self-contained programs, the study said.

"It's an erroneous comparison to say, `If I had all the kids in resource programs, I could save a lot of money,"' said Mary Moore, vice president of Decision Resources Corp. and project director for the study. "The difference is only about $1,700, not $3,000."

The study, based on visits to 60 school districts in 18 states, also found average per-pupil costs of:

-$4,750 for preschool special education programs, plus $973 in regular education costs for a total of $5,723.

-$29,108 for residential programs, plus $389 in regular education costs for a total of $29,497.

Most special education pupils were enrolled in resource programs, and they spent 80 percent of their time in regular education.

Fifteen percent of those in self-contained programs spent no time in regular education. The rest spent an average of 28 percent of their time in regular classes.

The study said special education costs rose 10 percent after inflation between 1977-78 and 1985-86, versus a 4 percent increase for regular education.

Instruction accounted for 63 percent of the special education costs, assessment 13 percent, support services 11 percent, related services 10 percent and transportation 5 percent. Moore said the percentages added to more than 100 percent because of rounding up.

The average caseload for teachers in resource programs was 26 students.

In self-contained programs, there was one teacher for every four hard-of-hearing students; one per five autistic or multihandicapped students; one per seven deaf or visually handicapped students; one per eight mentally retarded or orthopedically impaired students; one per nine speech impaired or seriously emotionally disturbed students, and one per 13 learning disabled students.

Transportation was the most expensive related service provided handicapped students. Thirty percent needed special transportation services, at an average cost of $1,583. Assessment cost an average of $1,206, physical therapy $993, occupational therapy $918, psychological services $867, speech language pathology $648 and guidance and counseling $553.