Is there any case law where a witness refused to testify at trial for medical reasons?

In State v. Thomas (1973) 110 Ariz. 120, 515 P.2d 865, the witness was apparently hospitalized at the time of the trial. The court examined him and concluded that "it is obvious that the man is incapable of testifying" which finding was amply supported by excerpts from the witness' testimony. (Id., 515 P.2d at p. 870.)

In United States v. Brasco (S.D.N.Y. 1974) 385 F.Supp. 964, a witness refused to testify for reasons which appeared on the record in camera but not divulged in the written opinion. He was adjudged in civil contempt on Thursday, June 27, 1974, and given until Monday, July 1 to either purge himself of contempt or to show cause why he should not be found guilty of criminal

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