This court employs the “some evidence” rule in determining the propriety of mandamus actions which challenge the commission’s factual findings. Where the record contains some evidence to support the commission’s factual conclusions, its decision will stand. Conversely, where the record contains no evidence to support the commission’s order, an abuse of discretion will be found. See State ex rel. Hughes v. Goodyear Tire & Rubber Co. (1986), 26 Ohio St.3d 71, 73, 26 OBR 61, 63, 498 N.E.2d 459, 461; State ex rel. Kokocinski v. Indus. Comm. (1984), 11 Ohio St.3d 186, 188, 11 OBR 499, 500-501, 464 N.E.2d 564, 566.
The final SHO order in the case sub judice found that Dr. Yoder’s “[office] notes plus his reports, taken in totality, show the claimant has reached maximum medical improvement.” Indeed, the only evidence cited by the commission was *653generated by Dr. Yoder. The broad issue, therefore, is whether Dr. Yoder’s office notes and reports, taken in totality, constitute “some evidence” that claimant has reached the maximum medical improvement.
In light of the parties’ arguments, and in light of the opinions rendered in the court of appeals, it is necessary to bifurcate the issue. We must first determine whether Dr. Yoder’s August 27, 1991 report is susceptible of differing interpretations regarding the permanence of claimant’s medical condition. If it is, the matter ends there, and the commission acted within its discretion. If it is not, we must then determine whether Dr. Yoder’s June 6, 1991 report plus his office notes afford the commission some basis upon which to reject the doctor’s August 27 report.
R.C. 4123.56(A) provides that TTD payments “shall not be made for the period * * * when the employee has reached the maximum medical improvement.” Maximum medical improvement is equatable with the concept of permanence. State ex rel. Youghiogheny & Ohio Coal Co. v. Kohler (1990), 55 Ohio St.3d 109, 110, 564 N.E.2d 76, 78. It “relates solely to the perceived longevity of the condition at issue [and not to] the claimant’s ability to perform the tasks involved in his former position of employment * * *. [It is defined] as a condition which will, ‘ * * * with reasonable probability, continue for an indefinite period of time without any present indication of recovery therefrom.’ ” (Citation omitted.) Vulcan Materials Co. v. Indus. Comm. (1986), 25 Ohio St.3d 31, 33, 25 OBR 26, 27, 494 N.E.2d 1125, 1127. Thus, so long as the claimant’s condition has not stabilized, and further medical improvement can be expected, TTD benefits are payable. See 1C Larson, Workmen’s Compensation Law (1992), Sections 57.12(b) and (c).
Accordingly, Ohio Adm.Code 4121-3-32(A)(l) defines “maximum medical improvement” as “a treatment plateau (static or well-stabilized) at which no fundamental functional or physiological change can be expected within reasonable medical probability in spite of continuing medical or rehabilitative procedures. A claimant may need supportive treatment to maintain this level of function.”
Although the syntax of Ohio Adm.Code 4121-3-32(A)(l) is less than ideal in other respects, it clearly recognizes rehabilitative procedures as a viable treatment option for effectuating fundamental change in a claimant’s medical condition. Under this provision, the question of maximum medical improvement turns on whether the proposed rehabilitative procedure is expected to improve or merely maintain the claimant’s level of functionability.
In addition, the nature of the proposed rehabilitative procedure is indicative of whether or not functional improvement is expected. As the court of appeals aptly explained in State ex rel. Matlack, Inc. v. Indus. Comm. (1991), 73 Ohio App.3d 648, 659, 598 N.E.2d 121, 128:
*654“For instance, in State ex rel. Copeland Corp. v. Indus. Comm. (1990), 53 Ohio St.3d 238, 559 N.E.2d 1310, the court found that the claimant had not reached MMI where a doctor opined that claimant ‘ * * * “has likely reached maximal recovery unless he attends a chronic pain and stress center which I feel might be quite helpful in dealing with the multitude of problems of which he still complains. * * * Unless additional improvement is made in a rehabilitation type program, I feel that he has likely reached maximal recovery.” ’ Id. at 239, 559 N.E.2d at 1311. By contrast, in State ex rel. Miller v. Indus. Comm. (1988), 36 Ohio St.3d 58, 521 N.E.2d 775, the court found permanency in a case involving permanent sensitivity and allergy to chemicals where a' doctor opined that the patient ‘ “ * * * should be evaluated for rehabilitation in a field of work involving no exposure to petroleum products or other toxic chemicals. * * * ” ’ Id. at 59, 521 N.E.2d at 777.
“Thus, there is a distinction in the case law between physical rehabilitation and occupational-type therapy related to the condition’s improvement, and vocational rehabilitation or job training related to claimant’s vocational improvement. The former type of rehabilitation can signify continuing possibility of medical improvement while the latter cannot.”
Contrary to appellants’ assertions, the statement on Dr. Yoder’s August 27 report, that “there is little hope in improvement in Carl Eberhardt’s back symptoms unless he is treated through the Workers’ Compensation rehabilitation program,” is not susceptible of differing interpretations. “Unless” means “1: under any other circumstance than that; except on the condition that * * * ; 2: without the accompanying circumstance or condition that; but that; But * * Webster’s Third New International Dictionary (1986) 2503. The stated purpose of the report was precisely to “clear up this matter.” Further, by indicating that it is claimant’s “back symptoms” which can improve if he is “treated through the Workers’ Compensation rehabilitation program,” Dr. Yoder made clear that the rehabilitation program “is the primary treatment modality that I have recommended * * *.” The only meaning that can be ascribed to Dr. Yoder’s August 27 statements, therefore, is that he was recommending physical or therapeutic rehabilitation with the expectation that it would improve the claimant’s medical condition. In order to ascribe a different meaning, it would be necessary to revive the very ambiguity that the report clarified.
We are well aware that in State ex rel. Copeland Corp., supra, 53 Ohio St.3d at 239, 559 N.E.2d at 1311, we considered language in a medical report that bears a striking similarity to the language contained in Dr. Yoder’s August 27 report and remarked that such “comments are susceptible to differing interpretations.” The only issue in Copeland, however, was whether such language constituted some evidence supporting the commission’s finding that claimant’s condition was not *655yet permanent. Thus, it was only necessary to decide in Copeland whether such medical language indicated the potential for improvement in claimant’s medical condition. It was not relevant or necessary to consider and decide whether such language was also susceptible of the contrary interpretation that there was no potential for improvement in claimant’s medical condition. Indeed, there is no indication that we gave any serious consideration in Copeland to the issue of whether the language utilized in the medical report, standing alone, could support a finding that the claimant had reached the maximum medical improvement. Having directly considered this latter issue in this case, we conclude that Dr. Yoder’s August 27 report is not subject to differing interpretations and can only be found to indicate the potential for improvement in claimant’s medical condition.
We hold that where an attending physician certifies a claimant as temporarily and totally disabled but indicates that there is little hope for improvement in claimant’s condition unless treated through rehabilitation, and there is no other medical evidence indicating that claimant has reached the maximum medical improvement, it is an abuse of discretion for the commission to deny TTD benefits on the basis that claimant has reached the maximum medical improvement.
The question remains, however, whether there was some other medical evidence before the commission indicating that claimant had reached the maximum medical improvement. Since the only medical evidence cited by the commission was generated by Dr. Yoder, the question becomes whether Dr. Yoder’s medical statements made prior to his August 27 report afford some basis upon which the commission may reject the doctor’s August 27 report.
“[I]t is the commission which determines the weight and credibility to be given to the medical reports admitted into evidence.”- State ex rel. Burley v. Coil Packing, Inc. (1987), 31 Ohio St.3d 18, 21, 31 OBR 70, 73, 508 N.E.2d 936, 939. Thus, it is within the commission’s discretion to reject these reports as unpersuasive. State ex rel. Pavis v. Gen. Motors Corp., B.O.C. Group (1992), 65 Ohio St.3d 30, 33, 599 N.E.2d 272, 274. Such discretion, however, is not unbounded. The commission is prohibited from arbitrarily rejecting competent medical proof. Id. Thus, there must be some reasonable basis for the commission’s rejection of a physician’s finding, and that basis should be placed in evidence and become part of the record. State ex rel. Hutton v. Indus. Comm. (1972), 29 Ohio St.2d 9, 13, 58 O.O.2d 66, 69, 278 N.E.2d 34, 37.
In this regard, appellants advance the following argument: “Even if one assumes that Dr. Yoder’s August 27, 1991 letter to Mr. Eberhardt’s attorney expresses a different opinion on maximum medical improvement than the June 6, 1991 report that Dr. Yoder had ‘little hope of improvement in this patient in the *656foreseeable future,’ Dr. Yoder’s reports are still nothing better than contradictory on the subject of that opinion. Mr. Eberhardt is the proponent of the award of compensation and bears the burden of proof on entitlement. This court has held that contradictory or equivocal statements by the same physician cannot, as a matter of law, support an award of compensation. State ex rel. Walters v. Indus. Comm. (1985), 20 Ohio St.3d 71 [20 OBR 402, 486 N.E.2d 94]; State ex rel. Paragon v. Indus. Comm. (1983), 5 Ohio St.3d 72 [5 OBR 127, 448 N.E.2d 1372].”
Walters and Paragon do not lead to the conclusion advanced by appellants. A proper analysis must begin with State ex rel. Jennings v. Indus. Comm. (1982), 1 Ohio St.3d 101, 1 OBR 135, 438 N.E.2d 420. In that case, a physician concluded in his deposition that the claimant was not fit for sustained remunerative employment and was permanently and totally disabled, a statement which was in direct conflict with his original report. We rejected the commission’s contention that the physician’s deposition testimony did not detract from the probative value of the original report and held that “where a medical expert has, by deposition testimony, repudiated a conclusion previously made in a medical report, that report cannot constitute evidence to support the order of the commission.” Id. at 102, 1 OBR at 137, 438 N.E.2d at 422.
In Paragon, 5 Ohio St.3d at 75-76, 5 OBR at 130, 448 N.E.2d at 1375-1376, we observed as follows:
“Although Dr. Cullen opines that appellant is totally disabled, he then states that he is uncertain. Dr. Cullen further indicates he does not believe appellant will ever return to work, yet he subsequently indicates that if the patient was ‘motivated,’ he could probably work. However, Dr. Cullen fails to clarify what he meant by the use of the term ‘motivated,’ and furthermore, it is unclear from the report whether the lack of motivation is directly attributable to the depressive neurosis. In short, Dr. Cullen’s report is, at best, equivocal and, accordingly, we conclude that it does not constitute evidence upon which the commission may either grant or deny appellant’s application.” (Emphasis added.)
In Walters, 20 Ohio St.3d at 73-74, 20 OBR at 404, 486 N.E.2d at 96-97, we observed that:
“ * * * Dr. McCloud, subsequent to his medical report, changed his view concerning the effect appellant’s impairment had on his employment prospects. For example, during deposition, Dr. McCloud first agreed with Dr. King’s evaluation as to appellant’s total disability, then stated that appellant was not unfit for some type of gainful employment and then again specifically agreed with Dr. King’s findings as to both appellant’s impairment and total disability. At worst, Dr. McCloud contradicted himself; at best, his conclusion that appellant was not totally disabled was equivocal.
*657“This court faced a strikingly similar situation in [Paragon], * * * We held that such an equivocal report ‘does not constitute evidence upon which the commission may either grant or deny appellant’s application’ for permanent total disability benefits. Id. at 76 [5 OBR at 130, 448 N.E.2d at 1376]. See [Jennings],
“In the instant case * * * [t]he apparent uncertainty in Dr. McCloud’s position gives the commission an insufficient basis to support its order denying appellant permanent total disability benefits.”
The rule that emerges from the foregoing is that equivocal medical opinions are not evidence. See, also, State ex rel. Woodard v. Frigidaire Div., Gen. Motors Corp. (1985), 18 Ohio St.3d 110, 113, 18 OBR 143, 145, 480 N.E.2d 403, 406; Kokocinski, supra, 11 Ohio St.3d at 188-189, 11 OBR at 501, 464 N.E.2d at 566. Such opinions are of no probative value. Further, equivocation occurs when a doctor repudiates an earlier opinion, renders contradictory or uncertain opinions, or fails to clarify an ambiguous statement. Ambiguous statements, however, are considered equivocal only while they are unclarified. Paragon, supra. Thus, once clarified, such statements fall outside the boundaries of Jennings, supra, and its progeny.
Moreover, ambiguous statements are inherently different from those that are repudiated, contradictory or uncertain. Repudiated, contradictory or uncertain statements reveal that the doctor is not sure what he means and, therefore, they are inherently unreliable. Such statements relate to the doctor’s position on a critical issue. Ambiguous statements, however, merely reveal that the doctor did not effectively convey what he meant and, therefore, they are not inherently unreliable. Such statements do not relate to the doctor’s position, but to his communication skills. If we were to hold that clarified statements, because previously ambiguous, are subject to Jennings or to commission rejection, we would effectively allow the commission to put words into a doctor’s mouth or, worse, discount a truly probative opinion. Under such a view, any doctor’s opinion could be disregarded merely because he failed on a single occasion to employ precise terminology. In a word, once an ambiguity, always an ambiguity. This court cannot countenance such an exclusion of probative evidence.
In the present case, Dr. Yoder’s August 27 report does not express a different opinion as to whether claimant had reached the maximum medical improvement than was expressed in his June 6 report or his office notes. Each statement made prior to August 27, 1991 which appellants describe as contradictory indicates that Dr. Yoder had exhausted the treatment procedures at his disposal and recommended outside rehabilitative procedures. Nowhere did the doctor indicate that claimant’s condition was stabilized or static or that he had a poor chance of improvement, nor did the doctor ever use any other language suggest*658ing maximum medical improvement without also recommending rehabilitation. Each time Dr. Yoder stated a prognosis, he did so in conjunction with a recommendation for rehabilitation. What Dr. Yoder failed to do was state whether he expected the rehabilitation to improve the claimant’s condition, or to state whether he was recommending physical or vocational rehabilitation. Such ambiguities were clarified in his August 27 report.
Thus, Dr. Yoder’s statements previous to August 27, 1991 cannot serve as a basis for rejecting his opinion. Where a physician clarifies an ambiguity in stating his opinion, the Industrial Commission may not revive the ambiguity in order to reject that physician’s opinion. There was no evidence, therefore, supporting the commission’s finding that claimant had reached the maximum medical improvement.
For the reasons set forth above, the judgment of the court of appeals is hereby affirmed.
Judgment affirmed.
A.W. Sweeney, Douglas and F.E. Sweeney, JJ., concur. Moyer, C.J., Wright and Pfeifer, JJ., dissent.