Of the states that have considered this issue, the vast majority have held that if the jury cannot apportion damages between a preexisting and an aggravating injury, the defendant is liable for the total injury. LaMoureaux v. Totem Ocean Trailer Express, Inc., 632 P.2d 539, 545 (Alaska 1981); Newbury v. Vogel, 151 Colo. 520, 379 P.2d 811, 813 (1963); Maser v. Fioretti, 498 So.2d 568, 570 (Fla.Dist.Ct.App. 1986); Bushong v. Kamiah Grain, Inc., 96 Idaho 659, 534 P.2d 1099, 1101 (1975); Lovely v. Allstate Ins. Co., 658 A.2d 1091, 1092 (Me. 1995); McNabb v. Green Real Estate Co., 62 Mich.App. 500, 233 N.W.2d 811, 819-20 (1975), superseded by statute on other grounds, Mich. R. Evid. 404; Brake v. Speed, 605 So.2d 28, 33 (Miss. 1992); David v. DeLeon, 250 Neb. 109, 547 N.W.2d 726, 730 (1996); Kleitz v. Raskin, 103 Nev. 325, 738 P.2d 508, 509 (1987); Pang v. Minch, 53 Ohio St.3d 186, 559 N.E.2d 1313, 1324-25 (1990) (relying on Restatement (Second) of Torts § 433B cmt. d); Haws v. Bullock, 592 S.W.2d 588, 591 (Tenn.Ct.App. 1979); Tingey v. Christensen, 987 P.2d 588, 592 (Utah 1999); Phennah v. Whalen, 28 Wash.App. 19, 621 P.2d 1304, 1309 (1980); Bigley v. Craven, 769 P.2d 892, 898 (Wyo. 1989). Only two states considering the issue of indivisible injury have rejected this approach.

In Kawamoto, doctors had treated the plaintiff for an arthritic neck at least eight years before the defendant aggravated the plaintiff's pre-existing condition in an automobile accident. See, e.g., Bigley v. Craven, 769 P.2d 892, 898 (Wyo. 1989) (cervical degenerative disc disease); McNabb v. Green Real Estate Co., 62 Mich. App. 500, 516, 233 N.W.2d 811, 818-20 (1975) ("brittle diabetic"); Lamoureaux v. Totem Ocean Trailer Exp., Inc., 632 P.2d 539, 542 (Alaska 1981) ("thoracic outlet syndrome"); Haws v. Bullock, 592 S.W.2d 588, 591 (Tenn.App. 1979) (degenerative arthritis and degenerative disc disease in neck and back); see also Damages in Tort Actions § 15.34[1][b] ("[s]hould apportionment of damages prove impossible in a pre-existing condition case, the tortfeasor may be liable for the whole of the plaintiff's injuries.").

A defendant is not "responsible for plaintiff's previous condition, except to the extent of aggravation or enhancement by defendants' acts." Haws v. Bullock, 592 S.W 2d 588, 591 (Tenn. Ct. App. 1979). Thus, a plaintiff may recover for an increase in disability, but not for the total disability which resulted from the pre-existing condition plus aggravation of the pre-existing condition caused by the accident.

Plaintiff would be able to recover in this case for the increase of her disability, but not for her total disability resulting from the pre-existing condition plus the aggravation of the condition caused by the accident. See Haws v. Bullock, 592 S.W.2d 588 (Tenn. App. 1979). As noted the jury returned a verdict for $129,681.46 after hearing arguments of counsel wherein the plaintiff's attorney argued the future effect of the injury and the future medical expenses premised upon the speculative testimony.