Although the appropriateness of a new trial is a federal procedural question decided by reference to federal law, Pitts, 607 F.2d at 802, in determining whether a state law claim damage award is excessive, state case law guides our inquiry. England v. Gulf & Western Mfg. Co., 728 F.2d 1026, 1029 (8th Cir.1984). Under Arkansas law, a verdict is excessive if " 'the amount shocks the conscience of the court or demonstrates that the jurors were motivated by passion, prejudice or undue influence.' " White v. Mitchell, 263 Ark. 787, 568 S.W.2d 216, 224 (1978) (quoting Jordan v. Adams, 259 Ark. 407, 533 S.W.2d 210, 213 (1976)).

Here the district court concluded that the $1,000,000 verdict in favor of Jetta's parents was "clearly excessive under the law and the court's instructions to the jury" and that the amount "shock[ed] the judicial conscience." After a review of the record, we cannot say that this conclusion was plainly unjust, the lowest requirement for reversal. The uncontested jury instructions specified that the damage award to Jetta's parents was limited to: 1) the reasonable expense of medical treatment and services received by Jetta; 2) the present value of any future medical care equipment reasonably certain to be required; and 3) the reasonable value of Jetta's services and contributions that the parents have lost and the present value of Jetta's services and contributions that the parents are reasonably certain to lose in the future. The parties stipulated that the parents had incurred $10,892 in medical expenses for Jetta's treatment. Although there was evidence at trial about various equipment available to deaf persons, there was little testimony identifying which of these devices Jetta would need or require or that the likely cost could largely account for the verdict. In light of this, we can not conclude that the district judge abused his discretion in holding that the $1,000,000 verdict in favor of Jetta's parents was excessive.

Counsel for the Sanfords argues, without citation of Arkansas law, that we should fault the district judge for failing to permit nonpecuniary losses " 'in the guise of recovery for loss of services.' "5 We acknowledge that the Arkansas courts appear to allow some "conjecture" by the jury as to what a child's services might have been, in the absence of death or injury, and how they should be valued. Norman v. Gray, 238 Ark. 617, 383 S.W.2d 489, 492-93 (1964). Federal judicial responsibility for reviewing verdicts in such cases may be reflected, however, by the treatment of a New York recovery for $224,000 for loss of a youth's services, which the appellate court ruled must be reduced to $7,000 per year for the remainder of the child's minority. Martell v. Boardwalk Enterprises, Inc., 748 F.2d 740, 755 (2d Cir.1984). We believe the district judge in this case was fully authorized to intervene.

The Sanfords argue that the district court should have ordered a partial new trial on the issue of damages, rather than a new trial on both liability and damages. We disagree. The trial judge stated that in his "view ... the jury was moved by passion and emotion." Where the district court concludes that passion influenced the jurors, a partial new trial on the issue of damages only is generally inappropriate. See, e.g., England, 728 F.2d at 1029 (cautioning against district court use of the words "bias and prejudice" unless the evidence warrants a new trial on both liability and damages). "[P]assion or prejudice may affect the decision of the jury on the issue of liability as well as damages." Everett v. S.H. Parks & Assoc., Inc., 697 F.2d 250, 253 n. 5 (8th Cir.1983). Absent unusual circumstances, where a damage award is motivated by passion or prejudice, a remittitur is not appropriate. See Parsons v. First Investors Corp., 122 F.3d 525, 529 (8th Cir.1997). Accordingly, we find no abuse of discretion in the district court's decision to grant a new trial on both liability and damages.

The Sanfords argue on appeal that even if a new trial on grounds of excessiveness of verdict should have been granted as to the parents, the verdict in favor of Jetta should not have been set aside along with it. This argument was not raised in the district court (see Appendix on Appeal at 230-36), and is not subject to review here.6

In addition, we believe that the district court correctly cited the dramatic mid-trial shift in testimony by Dr. O'Mara--from a failure to diagnose to a failure to prevent--as a reason for granting a new trial. Surprise during trial, by major variance in theory of recovery or defense, undisclosed until after the trial is underway, is a long-established ground for granting a new trial motion. See, e.g., Perez-Perez v. Popular Leasing Rental, Inc., 993 F.2d 281, 286-88 (1st Cir.1993) (undisclosed rebuttal medical testimony that driver, who had testified he could "see without glasses if I want to," suffered from seriously disabling glaucoma); Twigg v. Norton Co., 894 F.2d 672, 674-75 (4th Cir.1990) (midtrial change of position regarding theory of recovery); Conway v. Chemical Leaman Tank Lines, Inc., 687 F.2d 108, 112 (5th Cir.1982) (introduction of new theory by expert witness mid-trial constituted unfair surprise justifying new trial).

In light of the expert's shift of theories, we can not conclude that the district judge abused his discretion in finding that the trial testimony on liability and medical causation was confusingly presented and, at best, inconclusive and that a new trial was in order. In sum, we are very far from concluding that this is one of those rare cases in which a new trial decision should be changed on appeal.

For the reasons indicated, we affirm.