Claimant has already been found to be permanently and totally disabled. Once this determination has been made, “the employee shall receive an award to continue until his death.” (Emphasis added.) R.C. 4123.58(A). The lifetime nature of the award negates the need for continuing medical proof on claimant’s behalf.

The character of a permanent total disability award does not, however, mean that the award is completely immune from later review. If, for example, the commission learns that the claimant is working or engaging in activity inconsis*568tent with his permanent total disability status, the commission can use its continuing jurisdiction under R.C. 4123.52 to reopen the matter. Similarly, if new medical technology reversed a claimant’s allowed condition, reconsideration of his or her award may be appropriate.

What is common to these examples is the emergence of a new circumstance — a change since the initial award that merits reexamination of the earlier decision. The existence of new and changed circumstances can trigger the commission’s exercise of continuing jurisdiction. State ex rel. Cuyahoga Hts. Local School Dist. Bd. of Edn. v. Johnston (1979), 58 Ohio St.2d 132, 12 O.O.3d 128, 388 N.E.2d 1383.

No allegation of new and changed circumstances has been made here. Moreover, while R.C. 4123.53 does empower the commission to order a medical examination at any time, that provision cannot be applied in this instance unless the commission first had the continuing jurisdiction to reopen the issue of claimant’s permanent total disability. The commission did not have such jurisdiction here.

Roadway contends that because it has not formally asked the commission to reconsider claimant’s permanent total disability award, the commission’s order did not involve a reopening of the permanent total disability issue. We disagree. Claimant was awarded lifetime permanent total disability benefits and, thus, any medical examination going to the question of extent of disability inherently reopens the permanent total disability issue.

Roadway’s assertion that the commission retains continuing jurisdiction so long as the claim has not been barred by R.C. 4123.52’s statute of limitations fails. Under Roadway’s theory, the mere fact that the claim was still active would provide the only justification necessary for commission intervention. This result, however, conflicts with our many decisions imposing substantive prerequisites on the exercise of the commission’s continuing jurisdiction. See, e.g., State ex rel. Kilgore v. Indus. Comm. (1930), 123 Ohio St. 164, 9 Ohio Law Abs. 62, 174 N.E. 345; State ex rel. Griffey v. Indus. Comm. (1932), 125 Ohio St. 27, 11 Ohio Law Abs. 448, 180 N.E. 376; State ex rel. Weimer v. Indus. Comm. (1980), 62 Ohio St.2d 159, 16 O.O.3d 174, 404 N.E.2d 149; State ex rel. Gatlin v. Yellow Freight Sys., Inc. (1985), 18 Ohio St.3d 246, 18 OBR 302, 480 N.E.2d 487; State ex rel. Manns v. Indus. Comm. (1988), 39 Ohio St.3d 188, 529 N.E.2d 1379; State ex rel. Saunders v. Metal Container Corp. (1990), 52 Ohio St.3d 85, 556 N.E.2d 168; State ex rel. B & C Machine Co. v. Indus. Comm. (1992), 65 Ohio St.3d 538, 605 N.E .2d 372.

Absent a showing of any of the substantive prerequisites to R.C. 4123.52’s invocation, we find that the commission had no continuing jurisdiction to order *569further medical examination. Accordingly, the appellate court’s judgment is reversed and the writ is allowed.

Judgment reversed and writ allowed.