United States District Court, Eastern District of Missouri, Eastern Division
MEMORANDUM AND ORDER
JEAN C. HAMILTON UNITED STATES DISTRICT JUDGE
This matter is before the Court on Defendants’ Joint Motion to Bar Testimony and Opinions of Plaintiff’s Neuropsychologist, Thomas Martin, (ECF No. 69), and Plaintiff Hattie Braxton’s Motion to Exclude Expert Testimony and Opinions of C. Brian Tanner, P.E. (ECF No. 68). The motions have been fully briefed and are ready for disposition.
Braxton initiated this action by filing a Complaint on July 12, 2013. (Complaint, ECF No. 1). She later filed an Amended Complaint, which alleges that Braxton was struck by a tractor-trailer while driving on a Missouri freeway. (Amended Complaint, ECF No. 5, ¶¶ 1, 15). The tractor-trailer was driven by Defendant Kent Bivens, who “was, at all times, acting as an employee and/or agent for Defendant DKMZ and Defendant FedEx.” Id. ¶¶ 16, 18. Both Braxton and Defendants wish to introduce expert testimony at trial to support aspects of their cases. Braxton proffers as an expert witness Dr. Thomas Martin, a neuropsychologist retained by Braxton to “identify her current neuropsychological status” following the crash. (Martin Report, ECF No. 69-1, at 1). Defendants wish to introduce as an expert witness C. Brian Tanner, P.E. (Braxton Motion, ECF No. 68, at 1). Tanner is a biomechanical engineer retained to testify regarding the causation of Braxton’s injuries. (Tanner Aff., ECF No. 72-1, ¶¶ 1-9, 15-17). In their motions, the parties seek to exclude or limit the testimony of each other’s expert witness.
EXPERT ADMISSIBILITY STANDARD
“‘Decisions concerning the admission of expert testimony lie within the broad discretion of the trial court . . . .’” Anderson v. Raymond Corp., 340 F.3d 520, 523 (8th Cir. 2003) (quoting Peitzmeier v. Hennessy Indus., Inc., 97 F.3d 293, 296 (8th Cir. 1996)). “The proponent of the expert testimony must prove its admissibility by a preponderance of the evidence.” Lauzon v. Senco Products, Inc., 270 F.3d 681, 686 (8th Cir. 2001). The starting point for analyzing the admissibility of expert testimony is Federal Rule of Evidence 702, which has been interpreted to require district courts “to perform a ‘gatekeeping’ function and insure that proffered expert testimony is both relevant and reliable.” Dancy v. Hyster Co., 127 F.3d 649, 651-52 (8th Cir. 1997); see also Kumho Tire Co. Ltd. v. Carmichael, 526 U.S. 137, 141 (1999); Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 592-93 (1993).
The Eighth Circuit has identified three prerequisites, based on the language of Rule 702, for the admissibility of expert testimony:
First, evidence based on scientific, technical, or other specialized knowledge must be useful to the finder of fact in deciding the ultimate issue of fact. This is the basic rule of relevancy. Second, the proposed witness must be qualified to assist the finder of fact. Third, the proposed evidence must be reliable or trustworthy in an evidentiary sense, so that, if the finder of fact accepts it as true, it provides the assistance the finder of fact requires . . . .
Lauzon, 270 F.3d at 686 (internal quotation marks and citations omitted). This standard must be applied in light of the fact that “Rule 702 reflects an attempt to liberalize the rules governing the admission of expert testimony[, ]” and “[t]he rule clearly is one of admissibility rather than exclusion.” Lauzon, 270 F.3d at 686 (internal quotation marks omitted).
I. Defendants’ Motion to Exclude Testimony of Dr. Thomas Martin
Defendants seek “to exclude the expert testimony of Thomas Martin, Plaintiff’s expert neuropsychologist, because the testimony and test results fail to meet the reliability requirements set forth in Daubert, and its progeny.” (Defendant Motion, ECF No. 69, at 1). Defendants contend that Dr. Martin could not reliably have made his psychiatric diagnoses of Post-Traumatic Stress Disorder (“PTSD”) and depression not otherwise specified (“DNOS”) because he relied primarily on a “neuropsychological battery of tests” and a brief interview of Braxton, during which Braxton’s boyfriend was present. Id. at 3-5. Because the neuropsychological tests could not have been the basis for these psychiatric conclusions, Dr. Martin’s diagnoses rest primarily on his interview with Braxton, which was insufficient. Id. at 8.
Braxton responds that Defendants’ “arguments do not go to the admissibility of Dr. Martin’s opinions, but to the weight of his opinions and testimony.” (Braxton Response, ECF No. 71, at 1 (emphasis in original)). Braxton contends that neuropsychologists often make diagnoses of a psychiatric nature, and that the line Defendants draw between the two disciplines is unfounded. Id. at 3-5. Braxton also cites Dr. Martin’s report and deposition to show that he relied on the standard methods and diagnoses listed in the Diagnostic and Statistical Manual of Mental Disorders (“DSM”). Id. at 3-4. According to Braxton, the DSM is generally relied on “to diagnose patients’ mental conditions and disorders[, ]” and Dr. Martin’s diagnostic methods are therefore reliable. Id. at 4.
Daubert introduced four non-exclusive factors that district courts may examine to determine the reliability of an expert’s testimony: “(1) whether the theory or technique ‘can be (and has been) tested’; (2) ‘whether the theory or technique has been subjected to peer review and publication’; (3) ‘the known or potential rate of error’; and (4) whether the theory has been generally accepted.” Peitzmeier, 97 F.3d at 297 (quoting Daubert, 509 U.S. at 593-94). “Daubert’s progeny provides additional factors such as: whether the expertise was developed for litigation or naturally flowed from the expert's research; whether the proposed expert ruled out other alternative explanations; and whether the proposed expert sufficiently connected the proposed testimony with the facts of the case.” Lauzon, 270 F.3d ...