SALUS II, J.,
SUMMARY
This is a motion in limine filed by the defendants to preclude evidence concerning medical diagnoses rendered by the plaintiffs’ expert, Michael LeWitt M.D. In these suits, the plaintiffs allege that they sustained a number of health problems as a result of their exposure to chemicals used during renovation work at Bryn Mawr College.1 The renovation work took place in the Great Hall in Thomas Library, commencing in December 1991 and concluding in May 1992. Following the alleged exposure, the plaintiffs sought medical attention from Dr. LeWitt, who diagnosed each plaintiff as having toxic chemical encephalopathy. Generally speaking, TCE refers to a pathologic or abnormal condition in the central nervous system that is associated with exposure to chemicals at toxic levels. In the defendants’ motion in limine, the defendants argue that Dr. LeWitt’s diagnoses and his methodology used in rendering his diagnoses are not [4] generally accepted in the medical community.2 As such, the defendants argue that Dr. LeWitt should be precluded from testifying, and any causation evidence that is derived from Dr. LeWitt’s diagnoses should be barred. A hearing on the motion in limine was held before this court, commencing on December 6, 1999 and concluding on December 13, 1999. Based on evidence and testimony introduced at the hearing, this court concludes that Dr. LeWitt’s diagnoses of TCE, and any testimony or evidence based on these diagnoses, are not admissible at trial.
PENNSYLVANIA LAW ON SCIENTIFIC EXPERT TESTIMONY
At the outset, it is important to clarify the defendants’ objections to Dr. LeWitt’s diagnoses of TCE, and the role of the trial court in addressing these objections. As the plaintiffs point out, most of the defendants’ objections go to the credibility of Dr. LeWitt and the weight to be given to his testimony. Ordinarily, questions of credibility of a witness and the weight of his testimony are for the jury to resolve. See Foflygen v. Allegheny General Hospital, 723 A.2d 705, 711 (Pa. Super. 1999). Where evidence involves complex scientific testimony, however, most laypersons lack the required training to assess the validity of the testimony and underlying methodology. In addition, a scientific expert’s credentials can overcome a layperson’s willingness to scrutinize the expert’s testimony. Therefore, the Superior Court has held that scientific methodology and conclusions must be evaluated by the court to ensure that “what might appear ... to be science is not in fact speculation in disguise.” [5] Blum v. Merrell Dow Pharmaceuticals Inc., 705 A.2d 1314, 1325 (Pa. Super. 1997), appeal granted, _ Pa. _,* 735 A.2d 1267 (1999). According to the Superior Court:
“The judge in considering admissibility does not decide whether the proposition or theories are true or false. Rather the judge as gatekeeper decides whether the expert is offering sufficiently reliable, solid, trustworthy science. The question is: is the science good enough to serve as the basis for the jury’s findings of fact, or is it dressed up to look good enough, but basically so untrustworthy that no finding of fact can properly be based upon it.” Blum, 705 A.2d at 1322.
In the instant case, the condition known as TCE, and the methodology involved in making its diagnosis, are subject to debate by allergists, immunologists, toxicologists, neurologists, psychiatrists and occupational physicians. First, many medical professionals disagree as to whether the basis of TCE is immunological, neurological or psychological. Second, medical experts disagree on whether TCE is synonymous with or distinct from other medical conditions and phenomena. Third, medical professionals disagree as to which professionals are qualified to make a diagnosis of TCE. Fourth, medical experts disagree as to the proper method for rendering a diagnosis of TCE. Based on the foregoing, this court cannot agree with the plaintiffs that the credibility and weight of Dr. LeWitt’s diagnoses of TCE should be within the sole province of the jury. Testimony by a qualified expert does not become admissible scientific evidence simply because it is uttered by that expert. See Blum, 705 A.2d at 1323. Since the evidence at issue is complex medical testimony, the admissibility of Dr. LeWitt’s testimony is governed by principles established in Blum. [6] As a result, it is appropriate and necessary for this court to review causation evidence from Dr. LeWitt before it is put in front of the jury.
REVIEW OF DR. LeWITTS DIAGNOSES
In Blum, the Superior Court established a two prong analysis for determining whether scientific evidence of causation is admissible under Pennsylvania law. First, the proponent must show that the causal relationship is generally accepted in the medical community. Blum, 705 A.2d at 1322; see also, Checchio v. Frankford HospitalTorresdale Division, 717 A.2d 1058, 1060 (Pa. Super. 1998). Second, the proponent must show that the methodology used to reach the expert’s conclusions is accepted by the medical community as good science. Blum, 705 A.2d at 1322; see also, Checchio v. Frankford Hospital-Torresdale Division, 717 A.2d 1058, 1060 (Pa. Super. 1998). Following this analysis, this court has concluded that neither criteria is met in this case. Therefore, this court concludes that Dr. LeWitt’s diagnoses of TCE, and any evidence based on or related to his diagnoses, are inadmissible.
a. Causal Relationship Between the Plaintiffs’ Alleged Exposure and Their Symptoms
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SALUS II, J.,
SUMMARY
This is a motion in limine filed by the defendants to preclude evidence concerning medical diagnoses rendered by the plaintiffs’ expert, Michael LeWitt M.D. In these suits, the plaintiffs allege that they sustained a number of health problems as a result of their exposure to chemicals used during renovation work at Bryn Mawr College.1 The renovation work took place in the Great Hall in Thomas Library, commencing in December 1991 and concluding in May 1992. Following the alleged exposure, the plaintiffs sought medical attention from Dr. LeWitt, who diagnosed each plaintiff as having toxic chemical encephalopathy. Generally speaking, TCE refers to a pathologic or abnormal condition in the central nervous system that is associated with exposure to chemicals at toxic levels. In the defendants’ motion in limine, the defendants argue that Dr. LeWitt’s diagnoses and his methodology used in rendering his diagnoses are not [4] generally accepted in the medical community.2 As such, the defendants argue that Dr. LeWitt should be precluded from testifying, and any causation evidence that is derived from Dr. LeWitt’s diagnoses should be barred. A hearing on the motion in limine was held before this court, commencing on December 6, 1999 and concluding on December 13, 1999. Based on evidence and testimony introduced at the hearing, this court concludes that Dr. LeWitt’s diagnoses of TCE, and any testimony or evidence based on these diagnoses, are not admissible at trial.
PENNSYLVANIA LAW ON SCIENTIFIC EXPERT TESTIMONY
At the outset, it is important to clarify the defendants’ objections to Dr. LeWitt’s diagnoses of TCE, and the role of the trial court in addressing these objections. As the plaintiffs point out, most of the defendants’ objections go to the credibility of Dr. LeWitt and the weight to be given to his testimony. Ordinarily, questions of credibility of a witness and the weight of his testimony are for the jury to resolve. See Foflygen v. Allegheny General Hospital, 723 A.2d 705, 711 (Pa. Super. 1999). Where evidence involves complex scientific testimony, however, most laypersons lack the required training to assess the validity of the testimony and underlying methodology. In addition, a scientific expert’s credentials can overcome a layperson’s willingness to scrutinize the expert’s testimony. Therefore, the Superior Court has held that scientific methodology and conclusions must be evaluated by the court to ensure that “what might appear ... to be science is not in fact speculation in disguise.” [5] Blum v. Merrell Dow Pharmaceuticals Inc., 705 A.2d 1314, 1325 (Pa. Super. 1997), appeal granted, _ Pa. _,* 735 A.2d 1267 (1999). According to the Superior Court:
“The judge in considering admissibility does not decide whether the proposition or theories are true or false. Rather the judge as gatekeeper decides whether the expert is offering sufficiently reliable, solid, trustworthy science. The question is: is the science good enough to serve as the basis for the jury’s findings of fact, or is it dressed up to look good enough, but basically so untrustworthy that no finding of fact can properly be based upon it.” Blum, 705 A.2d at 1322.
In the instant case, the condition known as TCE, and the methodology involved in making its diagnosis, are subject to debate by allergists, immunologists, toxicologists, neurologists, psychiatrists and occupational physicians. First, many medical professionals disagree as to whether the basis of TCE is immunological, neurological or psychological. Second, medical experts disagree on whether TCE is synonymous with or distinct from other medical conditions and phenomena. Third, medical professionals disagree as to which professionals are qualified to make a diagnosis of TCE. Fourth, medical experts disagree as to the proper method for rendering a diagnosis of TCE. Based on the foregoing, this court cannot agree with the plaintiffs that the credibility and weight of Dr. LeWitt’s diagnoses of TCE should be within the sole province of the jury. Testimony by a qualified expert does not become admissible scientific evidence simply because it is uttered by that expert. See Blum, 705 A.2d at 1323. Since the evidence at issue is complex medical testimony, the admissibility of Dr. LeWitt’s testimony is governed by principles established in Blum. [6] As a result, it is appropriate and necessary for this court to review causation evidence from Dr. LeWitt before it is put in front of the jury.
REVIEW OF DR. LeWITTS DIAGNOSES
In Blum, the Superior Court established a two prong analysis for determining whether scientific evidence of causation is admissible under Pennsylvania law. First, the proponent must show that the causal relationship is generally accepted in the medical community. Blum, 705 A.2d at 1322; see also, Checchio v. Frankford HospitalTorresdale Division, 717 A.2d 1058, 1060 (Pa. Super. 1998). Second, the proponent must show that the methodology used to reach the expert’s conclusions is accepted by the medical community as good science. Blum, 705 A.2d at 1322; see also, Checchio v. Frankford Hospital-Torresdale Division, 717 A.2d 1058, 1060 (Pa. Super. 1998). Following this analysis, this court has concluded that neither criteria is met in this case. Therefore, this court concludes that Dr. LeWitt’s diagnoses of TCE, and any evidence based on or related to his diagnoses, are inadmissible.
a. Causal Relationship Between the Plaintiffs’ Alleged Exposure and Their Symptoms
The plaintiffs have provided no evidence that the medical community currently accepts the existence of a causal relationship between their symptoms and the type of chemical exposure alleged to have taken place at Bryn Mawr College. First, there is no consensus in the medical community, as to whether TCE is even a disease, or a disease related to chemical exposure.3 Second, even if [7] TCE is generally accepted as a disease related to chemical exposure, existing research on TCE does not support a causal relationship in this case. This court understands that some studies link chemical exposure to a condition known as TCE. Nevertheless, the implications of these studies are limited in scope — they do not imply that TCE may be caused by exposure to every known chemical or combination of chemicals. In this case, there is no literature before this court that shows a generally accepted causal relationship linking exposure to the combination of chemicals used at Bryn Mawr College with the plain[8] tiffs’ symptoms.4 This is the relationship that needs to be established. It is not enough that the plaintiffs cite studies linking adverse health effects with human exposure to chemicals, without any attempt to contrast the conditions in those studies with the facts in the instant case. As a result, this court cannot admit Dr. LeWitt’s testimony or any evidence based on such testimony.
b. Methodology Used in Making Diagnoses of TEC
After a review of expert reports and expert testimony from both sides, this court concludes that the methodology used by Dr. LeWitt in rendering his diagnoses of TCE is not accepted by the medical community as good science. According to the reports and testimony introduced at the hearing, the proper diagnosis of TCE entails the review of: (1) objective evidence of toxic exposure,5 (2) objective physiological evidence of a disability or disease,6 [9] and (3) a differential diagnosis to eliminate possible alternative causes of the symptoms.7 According to his own testimony, Dr. LeWitt rendered his diagnoses of TCE without any of the above elements. First, Dr. LeWitt did not have information on chemical dosage, which would enable him to determine whether the plaintiffs were exposed to chemicals at toxic levels.8 Second, Dr. LeWitt observed no physiological evidence of a disability or disease.9 Third, Dr. LeWitt did not complete a differential diagnosis that ruled out alternative causes of the plaintiffs’ symptoms.10Dr. LeWitt’s failure to complete a differential diagnosis is of particular concern, since many [10] facts were available to him that suggest alternative causes for the plaintiffs’ symptoms.11
Dr. LeWitt’s diagnoses of TCE were based on two criteria: (1) “temporality,” which is the relationship between the time of the alleged exposure and the time when the symptoms occurred; and (2) “biological plausibility,” which is a reasonable theory or hypothesis that an expo[11] sure to something might cause a particular effect.12 In addition, Dr. LeWitt testified that he .used results from neuropsychological testing (NPT) to make his diagnoses of encephalopathy.13 This court is persuaded by the defendants’ experts that Dr. LeWitt’s methodology is not generally accepted as good science. According to Dr. Snyder, temporality and biological plausibility, without more, cannot serve as the basis for concluding causation.14 In addition, Dr. LeWitt has not properly established biological plausilbility.15 As stated earlier, Dr. LeWitt had no objective evidence of a toxic exposure and no objective physiological evidence of a neurologic disorder. Therefore, the only way Dr. LeWitt could hypothesize any causal relationship would be through complete speculation. Lastly, NPT is not generally accepted in the scientific community as a rehable method for diagnosing an encephalopathy when there is no other objective evidence [12] of an encephalopathy.16 As a result, Dr. LeWitt’s diagnoses of TCE were based on a methodology that is not generally accepted by the scientific community as good science.
CONCLUSION
The trial judge must be careful not to trespass over the domain which our judicial system reserves exclusively for the fact-finder. Nevertheless, the trial judge must balance this caution with his or her duties as the gatekeeper of evidence. When the court is confronted with scientific or medical evidence, that evidence may stand firmly on good science, or it may be strung together by controversial principles and sketchy methodology. This court concludes that Dr. LeWitt’s diagnoses of TCE fall into the latter category. The condition known as TCE is subject to debate by medical experts who question whether it is even a bona fide disease. They debate whether the basis of TCE is neurological or psychological. Furthermore, the causal relationship specifically alleged in this case has not been supported by medical literature or any objective evidence of toxic exposure or neurologic dam[13] age. This court cannot allow the jury’s findings of fact to be supported by such evidence. Therefore, any evidence of Dr. LeWitt’s diagnoses of TCE, and any causation evidence that is based on his diagnoses, must be precluded.
ORDER
And now, January 13, 2000, based on the findings in this court’s opinion sur motion in limine, it is hereby ordered and decreed that the defendants’ motion in limine is granted. The plaintiffs and plaintiffs’ witnesses are precluded from arguing, making reference to, or testifying about any diagnosis of toxic chemical encephalopathy, toxic exposure, multiple chemical sensitivity, or any causal relationship that attributes one or more of the plaintiffs’ symptoms to chemical exposure.
“We don’t know what to call it.
[7] “It can’t be defined.
“It can’t be diagnosed.
“Responsible scientific disciplines tells [sic] us it does not qualify as a disease or as a syndrome.
“It has no consistently identified biologic mechanism of action.
“It is based on toxicological and physiological rationale that is implausible.
“It is inconsistent with the laws of chemistry and physics.
“For these reasons, it is best to think of ‘environmental illness,’ ‘multiple chemical sensitivity’ or ‘toxic chemical encephalopathy’ as a phenomenon rather than a disease.” Report of Herman Staudenmayer Ph.D. 8/31/98, at 5.
In addition, Dr. Abba I. Terr, an allergist and immunologist, states in his report:
“The term ‘toxic chemical encephalopathy’ used in this case is a synonym for ‘multiple chemical sensitivities....”
“The MCS phenomenon has been extensively studied and critiqued by a number of clinical and scientific investigators in recent years. These investigations show that patients diagnosed with MCS do not suffer an organic illness, but in many, if not most, cases, the symptomatology is consistent with underlying psychiatric disease unrelated to chemical exposure. Several national medical specialty societies have published reviews and position statements to the effect that MCS is not a recognized disease and that the methods used in diagnosis are unscientific.” Report of Abba Terr M.D. 8/24/98, discussion paragraphs 7-8. (references omitted)