GREANEY, C.J.

A jury in the Superior Court convicted the defendant on an indictment charging rape of a child and on three indictments charging indecent assault and battery on a child under fourteen. He argues that the judge erred (1) by applying G.L.c. 233, § 20B, the psychotherapist-patient privilege, to deny his counsel the opportunity to examine records of a mental health clinic containing confidential communications between the victim and her therapist, (2) by excluding evidence of prior sexual abuse of the victim by her stepfather, which he suggests should have been admitted under the principles stated in Commonwealth v. Ruffen, 399 Mass. 811 (1987), and (3) by excluding evidence of an allegedly false accusation of rape made by the victim against her stepfather. Additionally, the defendant's counsel, who was also his trial counsel, argues that he furnished the defendant with ineffective assistance at the trial. We affirm the convictions.

The victim testified that on three separate occasions in June, July, and August of 1985 (the exact dates of which she could not remember), she was sexually abused by the defendant, who was he mother's boyfriend. The abuse occurred while the victim's mother was away playing bingo, and she (the victim) was left with the defendant who was babysitting her, her two younger brothers, and her younger sister. According to the victim (who was ten years old when the first two incidents occurred and had turned eleven before the last incident) the abuse consisted of: the defendant rubbing her body against his hard penis, inserting his finger into her "butt," and attempting to insert his penis into her (first incident); lying naked next to her in bed, getting on top of her and rubbing his penis on her leg (second incident); and kissing her, rubbing his penis against her, and making her place her hand on his penis (third incident). About two weeks after the final incident, the defendant left the house permanently.

There was fresh complaint testimony in corroboration of the victim's testimony given by her mother, by two visitors to the home, by the mother's former boyfriend, Dana Duteau, who was also staying at the home when the incidents occurred, and by the State police officer who investigated the allegations.

The defendant testified on his own behalf. He denied abusing the victim and indicated that the accusations had been fabricated by the victim, who disliked him because he had disciplined her. He also indicated that the victim's mother supported her daughter's accusations in order to get the defendant out of the house because she (the mother) had reestablished a relationship with Duteau. The assertion that the mother's estrangement from the defendant, and her resulting dislike for him, led her to back up her daughter's accusations, was corroborated, in some aspects, by three other defense witnesses. The defense was also allowed to put in evidence certain parts of a report made by a social worker for the Department of Social Services (DSS). The report was an investigation of a child abuse complaint pursuant to G.L.c. 119, § 51B, and the defendant used it to show discrepancies between the victim's testimony at trial and her previous statements.

1. Access to privileged information. Prior to trial, defense counsel moved in writing for the production of any and all records of the DSS relating to the victim. A judge of the Superior Court (not the trial judge) allowed the motion, and subsequently permitted defense counsel to examine the DSS records, provided he did so alone in the clerk's office and without making any copies of them. Defense counsel took advantage of the opportunity. The records (which are extensive) are not in issue, but we mention them to provide background for our discussion of the issue under consideration and to show that the defendant had wide access to materials to which he may not have been entitled.

On September 16, 1987, the third day of the trial, in response to a subpoena, additional records, apparently in the custody of DSS, were brought to court. The subpoena, issued by defense counsel, specifically asked for review of the records by the trial judge in camera. These records were from a mental health clinic which is part of the Human Resource Center for Rural Communities located in Athol. The records contain confidential communications between the victim and her primary therapist.

The trial judge made an in camera inspection of the newly produced records in the presence of defense counsel and the prosecutor. The trial judge indicated that the records contained material encompassing a period from 1982, when the victim had been sexually abused by her stepfather, through 1985, when she was allegedly abused by the defendant. Defense counsel told the judge that he specifically wanted to know whether or not the records disclosed that the victim had complained to her therapist about being sexually abused by the defendant. Counsel suggested that it would be important to the defense if the victim had not complained about the defendant because the absence of such complaints, in a setting in which they would be logically expected, would support the defendant's contention that the victim and her mother had fabricated the charges in order to get him out of the house.

In the course of examining the records, the trial judge mentioned to defense counsel that the records described beatings of the victim by the defendant with his belt. When he had completed his review of the records, the trial judge refused to respond to defense counsel's inquiry whether the records were devoid of any mention of sexual abuse by the victim to her therapist in June, July, or August of 1985. The trial judge then specifically found that the records disclosed "nothing . . . that is potentially exculpatory," and he ruled that the conversations contained therein were protected by the psychotherapist-patient privilege provided for in G.L.c. 233, § 20B. Defense counsel's additional motions to examine the records himself, or to question the therapist about them at a voir dire, were denied. A subsequent request by defense counsel to use the records to show that the defendant had beaten the victim with his belt was also denied.

The defendant argues that the trial judge's denial of his motions to inspect the records for evidence of the lack of any complaints of sexual abuse by the victim against the defendant (or to examine the therapist about the subject at a voir dire), and to use the records to show the fact of the defendant's physical beatings, violated his rights to a fair trial, to confront and cross-examine witnesses, and to produce proof favorable to his defense, all as guaranteed by provisions of the United States Constitution and the Massachusetts Declaration of Rights.

The general issues raised by the defendant have been discussed in several recent cases involving the handling by trial judges of different kinds of privileged information in light of motions by defendants to obtain possibly exculpatory facts contained in various records. See Commonwealth v. Two Juveniles, 397 Mass. 261 (1986); Commonwealth v. McDonough, 400 Mass. 639, 643-646 (1987); Commonwealth v. Clancy, 402 Mass. 664, 669-671 (1988); Commonwealth v. Giacalone, 24 Mass. App. Ct. 166, 170-171 (1987); Commonwealth v. Williams, 25 Mass. App. Ct. 210, 216-218 (1988). See also Commonwealth v. Lugo, 23 Mass. App. Ct. 494, 501-505 (1987). These cases deal principally with the fair trial rights guaranteed by the United States Constitution, and they grapple with the vexing problem of protecting confidential communications while permitting a defendant the right to confront accusers and to present relevant proof that might create a reasonable doubt.

There can be no question that the trial judge's examination of the second batch of records in this case in camera, with defense counsel and the prosecutor present met, or exceeded, any requirements imposed by the United States Constitution for a case in which a defendant shows a legitimate need for access to information contained in materials made absolutely privileged by statute. Pennsylvania v. Ritchie, 107 S.Ct. 989 (1987). Commonwealth v. Clancy, 402 Mass. at 664. Commonwealth v. Williams, 25 Mass. App. Ct. at 217. The defendant's arguments to the contrary are groundless.

We take note of the passage set out in the margin from Commonwealth v. Clancy, 402 Mass. at 670, in light of the defendant's further argument that the fair trial rights embodied in the Massachusetts Declaration of Rights supersede any absolute privilege the victim may have with respect to the records and, consequently, that the in camera procedure should have yielded to full examination by defense counsel. We need not address the argument or reach the question reserved in the Clancy decision.

First, the fact that the defendant had been abusive, physically and otherwise, to the victim was more than adequately brought out in the cross-examination of the victim and her mother and in the testimony of the defendant. The testimony included the fact that the defendant had beaten the victim with his belt and fully developed the point that the victim and her mother may have held a grudge against the defendant. The records of the mental health clinic, therefore, would have provided only minor corroboration of the existence of physical abuse. Where information contained in privileged material is already in evidence, or is available to be put in evidence from nonprivileged sources, we have no doubt that State law will maintain the full effect of the privilege. See Commonwealth v. Elder, 389 Mass. 743, 751 (1983).

Second, we have examined the records with attention to the absence of complaints by the victim about sexual abuse by the defendant. They disclose that the clinic had contact with the victim in 1982, in connection with a rape and other sexual crimes that had been committed by her stepfather. Thereafter, active contact between the victim and the clinic did not resume until June, 1984. From that time, there were weekly scheduled therapy sessions with the victim until early June, 1985, when the victim's relationship with the clinic was terminated. It appears that no therapy sessions were held after the three incidents that gave rise to the indictments against the defendant. The trial judge's reference in his discussion with counsel to the records continuing until September, 1985, was apparently based on some scattered materials in the records attempting to follow up on a physical abuse complaint concerning the victim, which ultimately was not substantiated.

The judge's finding that the records contained nothing exculpatory reflects the fact that the victim appears to have had no meetings with her therapist after the incidents in this case occurred and, therefore, had no occasion to mention any sexual abuse by the defendant. This resolves the issue. We add only that there is nothing else in the records which could have helped the defendant in any other way; a conclusion we can state with some assurance now that we have read the transcript of the trial and considered the contentions made there by the defendant. Because the records contain no relevant information, it is not necessary to decide whether State constitutional law would afford the defendant the broad rights he requests. A substantial issue will not be decided simply to ascertain whether a defendant may have a right that cannot benefit him in any event.

2. Evidence of prior sexual abuse. Before trial, the defendant moved for permission to conduct a voir dire of the victim and her mother concerning the sexual abuse of the victim by her stepfather some years before. (The stepfather had entered guilty pleas to indictments charging him with rape and some other sexual crimes; the other crimes, according to counsel, involved either unnatural and lascivious acts or indecent assault and battery on a child.) At the hearing on the motion, defense counsel relied upon Commonwealth v. Ruffen, 399 Mass. 811 (1987). The Ruffen decision holds that the rape shield statute, G.L.c. 233, § 21B, will not preclude, in certain circumstances, admission of evidence of prior sexual abuse of a child when offered to show that the victim's earlier experience, rather than any experience with the defendant, accounts for the victim's knowledge of sexual acts and terminology. 399 Mass. at 814-816 In this manner, a defendant can challenge the reliability of the principal accusing witness by showing that the child's knowledge may have been acquired by prior experience, distinct from the conduct with which the defendant is charged. This may support a claim that the child has lied or fantasized. Ibid.

The trial judge granted the defendant access to the police reports and grand jury minutes regarding the prior sexual abuse and stated that he would hear further argument on the admissibility of the evidence after defense counsel had an opportunity to review the materials. Subsequently, just prior to opening statements, defense counsel again sought permission to introduce evidence of the prior abuse. At the hearing on this motion, defense counsel specifically conceded that the allegations of abuse against the defendant were not similar to those made against the victim's stepfather. Nevertheless, defense counsel argued that the Ruffen principle was applicable because the stepfather's abuse was, as he put it, "far greater" than the abuse with which the defendant was charged. The trial judge denied the request, finding that the abuse alleged against the defendant was different from that alleged against the stepfather, and that G.L.c. 233, § 21B, prevented the inquiry.

While we are doubtful that the defendant has furnished adequate appellate argument on the issue, we will deal with it so that the case can be put to rest.

The Ruffen decision makes clear that, before evidence of the past sexual abuse of a child is admitted, the judge should determine that the past abuse is factually similar to the abuse in the case on trial and that the child victim displays knowledge of sexual matters beyond his or her years. Here, the trial judge found, with a basis in the information furnished to him, that the sexual acts involved in the prior case against the stepfather were not similar to the acts involved in this case. Defense counsel acknowledges this fact. This finding supports the judge's ruling.

Moreover, the testimony of the victim, who was thirteen at the time of trial, did not demonstrate "extraordinary knowledge" of sexual acts or sexual matters in general. See 399 Mass. at 814. The victim's use of such terms in her testimony as "penis," "butt," "hard," and "rubbing" cannot reasonably be viewed as "extraordinary." Further, the victim responded directly to the questions posed by the prosecutor, and her description of the sexual acts committed was simple, concise, and straightforward. Finally, in describing the separate acts of abuse, the complainant continuously interrelated specific details of a nonsexual nature concerning where the incidents took place, particular pieces of clothing, furniture, statements, and other actions. These details tended to demonstrate that she was not drawing upon the previous incidents of abuse which she suffered at the hands of her stepfather years earlier as the source of her testimony. We also place reliance on the trial judge's personal observations of the victim and his ability to assess her maturity based upon her sophistication, exposure to life experiences and mental capacity. The question raised a matter on which the judge had some discretion. Although it would have been preferable for the trial judge to have conducted a voir dire on the matter, there was no error in his exclusion of the evidence.

3. Evidence of an alleged prior false accusation of rape. On the third day of trial, defense counsel filed a further motion seeking, under Commonwealth v. Bohannon, 376 Mass. 90 (1978), to introduce evidence purportedly demonstrating that the victim had made a prior false accusation of sexual misconduct against her stepfather. The motion was made following defense counsel's review of DSS reports made pursuant to G.L.c. 119, §§ 51A and 51B.

The § 51B report was made as a result of an investigation undertaken by the DSS in response to information received from the victim's school nurse. Apparently, in March of 1984, the victim arrived late for school one day and purportedly told a classmate that the reason she was late was because "my [step]father made me do it again." The classmate later told her mother, who, in turn, called the school. A teacher, who received the call, then spoke to the nurse, who ultimately contacted DSS.

Included in the report was a summary of the DSS investigation, including interviews with the victim and her mother. Without divulging the contents of the report, it is fair to say that the victim would not confirm whether her stepfather was abusing her again, but indicated that she would advise her mother if anything improper took place in the future. It is also fair to note that the DSS could not ascertain whether or not sexual abuse was occurring again. After considering the arguments of counsel, the trial judge rejected the defendant's position that the Bohannon decision permitted the elicitation of this evidence for impeachment purposes.

Commonwealth v. Bohannon, 376 Mass. 90 (1978), sets out an exception to the general rule that bars evidence of prior false accusations of sexual misconduct. Specifically, the court in Bohannon held that, in the unusual circumstances there presented, a defendant accused of rape was entitled to put before the jury evidence of prior false accusations of rape by the complaining witness. The specific circumstances identified by the court in Bohannon have been described as follows: "the witness was the victim in the case on trial, her consent was the central issue, she was the only Commonwealth witness on that issue, her testimony was inconsistent and confused, and there was a basis in independent third-party records for concluding that the prior accusations of the same type of crime had been made and were false." Commonwealth v. Sperrazza, 379 Mass. 166, 169 (1979). See Commonwealth v. Blair, 21 Mass. App. Ct. 625, 629 (1986); Commonwealth v. Hicks, 23 Mass. App. Ct. 487, 489 (1987). The Bohannon exception "is a narrow one . . . and is applicable only in `unusual fact situations where justice demands.'" Commonwealth v. Hicks, 23 Mass. App. Ct. at 489, quoting from Commonwealth v. Trenholm, 14 Mass. App. Ct. 1038, 1039 (1982). See Commonwealth v. McDonough, 400 Mass. 639, 650 (1987).

The victim's testimony in this case was neither inconsistent nor confused. The fact that the victim at times had to have her memory refreshed by her statement to the police did not render her testimony contradictory. Her description of the events was otherwise concise, clear, and reasonably detailed, and it did not in any way approach the level of inconsistency apparent in Bohannon. See 376 Mass. at 91 (in addition to many other inconsistencies the complainant testified that she had seen "in a mist" that she had been penetrated). Importantly, unlike Bohannon, consent was not considered as an issue in this case.

There was also no factual basis from any reliable independent third-party record, or any other probative evidence, that a prior allegation of abuse "had, in fact, been made and [was], in fact, untrue." 376 Mass. at 95. "For the Bohannon rule to apply . . . there has to be evidence warranting a finding of falsity. Otherwise, the allegations . . . would be irrelevant to any issue in the case." Commonwealth v. Hicks, 23 Mass. App. Ct. at 490. Here, the purported statement of the victim (which is an extreme example of "totem pole" hearsay), even if construed as an allegation of abuse, was not supported by any concrete evidence that it was false. Further, unlike Bohannon, there is no "pattern of similar [false] allegations." Ibid. See Commonwealth v. Blair, 21 Mass. App. Ct. at 629 n. 8. For all these reasons, the trial judge exercised sound discretion in excluding further inquiry into the matter.

4. Ineffective assistance of counsel. The defendant's final claim is the assertion that he was denied the effective assistance of counsel. The defendant presents a catalogue of purported omissions and shortcomings, the crux of which is that his counsel was forced to proceed to trial inadequately prepared due to the denial of his motions for a continuance. The defendant further asserts that his trial counsel, who is also his appellate counsel, was fatigued, and that this caused significant omissions in his conduct of the case. Upon reviewing the defense counsel's asserted shortcomings, individually and in combination, we are satisfied that counsel's performance was not in any way "measurably below that of an ordinary, fallible lawyer." Commonwealth v. Saferian, 366 Mass. 89, 96 (1974). See Commonwealth v. Reid, 400 Mass. 534, 537 (1987).

Further, there was no abuse of discretion in the judge's denial of defendant's requests for a continuance. See Commonwealth v. Habarek, 402 Mass. 105, 108 (1988). Counsel had been appointed five months before the case was set for trial. The case was an old one, with the indictments dating back to January, 1986, and the underlying incidents of abuse to the summer of 1985. The defendant had already been granted one continuance, apparently representing that he would be prepared to go forward in September, 1987. There is no support in the record for the contention that the denial of defendant's motions prejudiced his case or otherwise "deprived the defendant of an . . . available, substantial ground of defence." Commonwealth v. Saferian, 366 Mass. at 96. The fact that a review of DSS records was involved did not render the case so complex that additional preparation time was necessary. There is nothing to show that defense counsel failed to present or accomplish something material. On the contrary, defense counsel vigorously presented his case by attempting to challenge the credibility and motive of the victim, her mother, and other witnesses. Defense counsel was able to peruse the DSS records and file a number of well argued and well presented motions regarding that material. The resulting defense strategy was logical and consistent. Counsel also preserved the record of alleged errors for appellate review.

Additionally, there was no ineffective assistance of counsel based on any other ground claimed by the defendant. The purported failure of defense counsel to point out to the jury that the victim had not made any statements regarding penetration to the social worker who interviewed her after the incidents was not unreasonable or prejudicial to the defense as there was ample evidence from which the jury could have determined that penetration had occurred. See Commonwealth v. Reid, 400 Mass. at 540-541. Similarly, counsel's failure to elicit one statement from the victim's mother that was indicative of bias did not deprive the defendant of any substantial defense. More than adequate evidence of bias on the part of the victim and her mother was presented. The assertion that excessive fatigue may have marred defense counsel's performance is a weak one. From all that appears, counsel was subject to no greater stress than any other defense lawyer engaged in the trial of a major felony case. An examination of the whole record reveals that the defendant was adequately represented.

Judgments affirmed.