A per se rule barring a criminal defendant from testifying about a matter about which he or she was previously hypnotized is unconstitutional.

United States v. Green, 305 F.3d 422, 428-429 (6th Cir. 2002) (upholding trial court's ruling which allowed the government's questions to witnesses on cross-examination about their knowledge on a specific airport incident involving the accused after the witnesses testified on direct examination as to...Although a character witness who testifies to the reputation of another person or gives an opinion of the character of another person cannot testify to specific instances of that person's conduct to bolster the character witness's testimony, an opposing party may question the character witness about specific instances of the person's conduct to show that the character witness' testimony about the character of the person was not well-founded.

David v. Pueblo Supermarket of St. Thomas, 740 F.2d 230, 235 (3d Cir. 1984) (holding, in plaintiff pregnant shopper's negligence action against defendant supermarket chain owner/operator for damages, that the trial court properly....A statement falls within the hearsay exception provided by Federal Rule of Evidence 803(2) only if the statement is related to a startling event or condition.

Mosser v. Freuhauf Corp., 940 F.2d 77, 81 (4th Cir. 1991) (upholding the trial court's exclusion of decedent's trafffic or speeding citations where such evidence was unrelated to the incident in question ).The prohibition against circumstantial use of character -- the use of character or disposition to show conduct on a particular occasion -- applies in trials of civil actions.