OPINION OF THE COURT
Thompson, J.Defendant’s primary contention on appeal is that he was deprived of a full and fair opportunity to conduct a vigorous and thorough cross-examination of one of the two primary prosecution witnesses. A review of the record leads us to conclude that defendant was not deprived of his right to conduct a vigorous and thorough cross-examination of the witness in issue. Furthermore, in the course of his trial strategy, defendant knowingly and voluntarily waived any possible claim that the cross-examination was curtailed, if such could be deemed to have occurred. The jury received a full and fair presentation of the *159conflicting positions of the parties, and there is no reason for this court to invoke its interest of justice jurisdiction to reverse the judgment of conviction.
On the morning of January 12,1982, Chung Lung Cheng (Mr. Cheng) and Tung Cheng, his son, were leaving their family residence when they were forced back inside the house at gunpoint by two men and a woman. Kam Chai Cheng (Mrs. Cheng) and Belinda Cheng, one of the Cheng daughters, were home at the time. The family safe was opened, and $7,000 and jewelry were taken by the invaders. Tung Cheng was removed from the premises, and he was returned later that day only after Mr. and Mrs. Cheng, accompanied by two of their captors, withdrew $100,000 from a bank and surrendered the money for the safe return of their son. Following a jury trial at which both Mr. Cheng and Mrs. Cheng testified, defendant was convicted of committing the aforementioned acts. On appeal, defendant argues, inter alia, that he was deprived of the right to cross-examine Mrs. Cheng. We do not agree, and, accordingly, we affirm the judgment of conviction for kidnapping in the first degree, robbery in the first degree, burglary in the first degree, and grand larceny in the first degree.
During the course of the trial, prior to Mrs. Cheng testifying, the prosecution sought to call Belinda Cheng as a witness for the purpose of identifying defendant as one of the kidnappers for the jury. The prosecution, however, was not permitted to introduce this testimony. When Mr. and Mrs. Cheng testified at a Wade hearing which preceded the trial, Belinda waited outside the courtroom. She saw defendant come out of the courtroom at one point, and she commented to her sister that he had been one of the people who invaded the Cheng home. The trial court ruled that, as a result of this incident, the prosecution was required to give defendant notice of its intention to offer identification evidence pursuant to CPL 710.30, and that its failure to do so precluded Belinda from giving her identification testimony at the trial. The court refused the prosecution’s request to adjourn the trial so that a Wade hearing could be conducted to determine if Belinda’s identification of the defendant had been tainted by her viewing of defendant on the day of the earlier Wade hearing.
On the first day of Mrs. Cheng’s trial testimony, she began recounting the events of January 12, 1982, and she identified defendant as one of the people who had invaded her home. As her second day of testimony commenced, Mrs. Cheng asked if she was a prisoner and stated that her husband had threatened her in order to compel her to appear. She also asked if she could *160avoid appearing if she felt ill. At this point, the parties retired to the Judge’s chambers.
During the ensuing discussion and questioning, Mrs. Cheng stated that she had been threatened by gangsters from Hong Kong, and she was asked questions about her allegation that her husband was protecting an “illegal person”. She also expressed a reluctance to testify if she was not protected from the people who had threatened her. Defense counsel alleged that Mrs. Cheng had a history of suicide attempts, and that she had previously been diagnosed as schizophrenic. However, Mrs. Cheng stated that she could proceed, that she was not taking medication for a mental condition, and that she had been accused of being mentally disturbed by somebody who wished to take her property from her. The court spoke for approximately 15 minutes with an attorney who represented Mrs. Cheng on a matrimonial matter, and the attorney opined that she could proceed.
Defense counsel then moved for a mistrial based on Mrs. Cheng’s alleged mental condition and her stated desire to avoid his questioning. The court granted the motion pursuant to CPL 280.10. The court also granted the prosecution’s motion to conduct a Wade hearing prior to the retrial with regard to Belinda Cheng’s ability to provide untainted identification testimony of the defendant at the retrial. At this point, defense counsel, obviously believing his client’s chances for acquittal were better with Mrs. Cheng’s testimony, rather than with Belinda Cheng testifying as a prosecution witness at the subsequent retrial, withdrew his mistrial motion, and the trial proceeded.
Prior to the resumption of Mrs. Cheng’s testimony, defense counsel requested that her testimony be stricken or that she be examined by a psychiatrist with regard to her competency. The court stated that it would allow her to testify and would be guided by what followed. The court noted that until she actually testified “it’s an anticipatory situation”. When Mrs. Cheng resumed testifying, her testimony was beneficial to defendant. She stated she did not know if the people who entered her home had permission to do so. She could not state if defendant had accompanied her and Mr. Cheng to the bank. She testified that Fong, one of the people who went to the bank, “said that he wish [sic] to borrow the money and he will return the money including the interest”. On cross-examination, she stated she was “[n]ot so certain” defendant had been in her house. Following her testimony, and not surprisingly in light of Mrs. Cheng’s exculpatory testimony, defense counsel failed to renew his motion to strike her testimony or to have her examined by a psychiatrist. Accord*161ingly, that issue has not been preserved for this court to review as a matter of law (CPL 470.05 [2]).
Under these circumstances, defendant was not deprived of a fair trial because he had an adequate opportunity to conduct a vigorous and thorough cross-examination of Mrs. Cheng, and, in fact, did so. A person who is able to understand an oath and who is able to give a reasonably accurate account of what she has seen and heard with regard to the matters in issue may testify despite a history of mental illness, because mental illness is not, per se, a basis for disqualification from testifying (People v Rensing, 14 NY2d 210; People v Barksdale, 100 AD2d 852). The Trial Judge exercises his discretion in determining whether a person has the mental capacity to testify, and because he has the opportunity to observe the witness’ manner, demeanor, and testimony and to undertake the requisite inquiries to determine the mental capacity of the witness, appellate courts should be hesitant in making their own determination based upon a cold record. As stated in People v Parks (41 NY2d 36, 46), “[impressions that may be validly drawn only from closehand personal observation cannot be ‘photographed into the record’ for later study by appellate courts. (Wheeler v United States, 159 US 523, 525 * * *)”. In this case, there is no reason to find an abuse of discretion in allowing Mrs. Cheng to testify. There is no indication in the record she failed to understand the oath she took prior to testifying. Furthermore, her testimony both at the pretrial Wade hearing and at the trial adequately recounted the events of the day in issue. After an extensive inquiry into Mrs. Cheng’s mental state, during which she asserted she was not mentally ill and denied being on medication, and during which her attorney opined that she was capable of proceeding, the court, observing her demeanor, concluded that she was a competent witness. The record before this court does not provide a basis for disturbing this exercise of discretion.
Despite a generalized stated unwillingness to respond to questions from defense counsel, the record fails to reveal any instance where Mrs. Cheng simply refused to respond to a proper question. The dissent fails to cite a single specific instance in which defense counsel’s questioning was limited in any way, or in which Mrs. Cheng failed to adequately respond during the cross-examination. In fact, her testimony was highly beneficial to defendant, and even the dissent, although at one point characterizing her testimony as “incriminating”, concedes that her testimony cast doubt upon the prosecutor’s entire case. Thus, it is not surprising that defense counsel did not seek to strike her testimony at its conclusion. Having used Mrs. Cheng’s testi*162mony to bolster his defense, defendant may not now come to this court with a belated contention that his alleged inability to properly cross-examine Mrs. Cheng deprived him of a fair trial.
This analysis in no way requires speculation as to whether Mrs. Cheng’s testimony helped defendant more than it hurt him or hurt him more than it helped him. We are in full agreement with the position that such speculation is at odds with the essence of cross-examination. We are simply asserting that the record fails to support a conclusion that Mrs. Cheng, regardless of whether her testimony hurt or helped defendant, was not subject to a full and thorough cross-examination.
The cases cited by the dissent are inapplicable to this case. In People v Cole (43 NY 508) and Diocese of Buffalo v McCarthy (91 AD2d 213), the witnesses gave their direct testimony and then became totally physically unavailable for cross-examination. That is simply not what happened in this case. In People v Carter (86 AD2d 451), the trial court gave instructions which had a chilling effect upon defense counsel’s willingness to conduct a vigorous cross-examination. This, again, is not relevant to the instant appeal.
Furthermore, an affirmance is required because it is clear that defendant waived his rights. The right to confront witnesses may be waived (United States v Armedo-Sarmiento, 524 F2d 591). Defendant had been granted a mistrial in this case, but as a matter of trial strategy, defense counsel decided to forego the mistrial. He evidently concluded that it was to his client’s benefit to permit the testimony of Mrs. Cheng to remain in the case. In stating that the right of cross-examination may be waived, Richardson, Evidence (§ 489, at 475 [Prince 10th ed]) gives as an example a circumstance where a witness becomes ill after his direct testimony and the defendant insists on proceeding with the trial rather than accepting a mistrial. That situation is more egregious than is our situation, since defense counsel did have a full opportunity to cross-examine Mrs. Cheng. As stated in Wigmore, Evidence (vol 5, § 1390, at 136 [Chadbourn rev 1974]) “Where * * * the failure to obtain cross-examination is in any sense attributable to the cross-examiner’s own consent or fault, the lack of cross-examination is of course no objection — according to the general principle * * * that an opportunity, though waived, suffices”.
. The dissent alleges that defendant’s choice was illusory. There is no suggestion by the dissent that it was improper to direct a Wade hearing prior to the commencement of a new trial (see, CPL 710.30 [2]) in the event of a mistrial with regard to Belinda *163Cheng’s potential identification testimony. In the absence of any explanation as to why it would have been improper to permit Belinda Cheng to be the subject of a Wade hearing to determine whether she could testify at a second trial, and in the absence of a motion to have Mrs. Cheng’s testimony stricken or have her examined by a psychiatrist following the completion of her testimony, we simply fail to perceive the basis for the dissent’s conclusion.
The dissent has expressed its concern about the fairness of the verdict. We believe that the verdict of the jury has ample support in the record. Accordingly, and in light of the lack of merit to defendant’s remaining contentions, the judgment of conviction should be affirmed.