IBM has been exonerated in a second suit charging that keyboards marketed by the company causecarpel tunnel syndrome. A U. S. District Court held that neither production defects nor design flaws in keyboards marketed by IBM and Atex were responsible for reporter Larry Lewis' carpel tunnel syndrome. Last month IBM won a similar decision from a Minnesota jury. Lewis, who has been a reporter for 30 years, said he wanted to show that "you can get carpal tunnel from a computer." However, hand surgeon Dr. Morton L. Kasdan says that will be a difficult thing to prove. He says that there has never been a study that conclusively proves that carpal tunnel syndrome is caused by the use of a keyboard. U.S. Labor Department figures show that the number of reportedrepetitive stress injurieshas more than doubled from 1989 to 1993. Thousands of lawsuits have been filed against computer manufacturers.