I appreciate the opportunity to respond to the concerns raised by Drs Donders, Hanks, Morgan, Ricker and Sweet, hereafter referred to as Donders et al. Given their prominence, leadership roles, and clinical and research acumen in the fields of neuropsychology and rehabilitation psychology, an exchange of letters in the Journal of Head Trauma Rehabilitation (JHTR) offers an excellent forum for public interchange of issues they have raised. I hope my letter elicits more public dialogue on forensic neuropsychology and traumatic brain injury (TBI).

I was the organizer and topical issue editor for the JHTR issue titled "Forensic Neuropsychology" [JHTR, 2009, 24(2)]. The issue had 6 articles on forensic neuropsychology and TBI, the last article being my request of Dr Ron Ruff to summarize the other articles in the form of "guidelines" articulated from a "best practice" perspective. Hence, Ruff's article titled "Best Practice Guidelines for Forensic Neuropsychological Examinations of Patients With Traumatic Brain Injury,"1 hereafter referred to as the "Ruff article," was the concluding article of the topical issue. It was meant as a summary of previous articles, interwoven with threads of experience by a seasoned clinical neuropsychologist who had extensive expertise in TBI. The Ruff article was definitely not intended to be or become a position or "white" paper of a professional organization. To be absolutely clear, the content of Dr Ruff's article was based on his personal, professional, and research experience spanning more than 30 years of clinical practice. Dr Ruff's abstract plainly states that the last section of his article "... provides guidelines based on the introductory article by Bigler and Brooks, as well as a synopsis of the main conclusions offered by the contributors in this journal issue."1^(p131)

Donders et al object to inclusion of the words "Best Practice Guidelines" in the title, considering such wording "presumptuous" or "misleading." In my view, terms such as "best practice" and "guidelines," even when used together, are not restricted terms that are never to be used unless sanctioned by an organization. Similarly, use of such terms by a single author does not presuppose that they signify the official position of a professional society or organization, unless explicitly identified as such. The reader will not find an explicit logo, official statement, declaration, or endorsement of a professional society or organization in Ruff's title or text. At the time this response was written, the National Library of Medicine (http://www.nlm.nih.gov), covering a multitude of specialties, listed thousands of articles that used the term "guidelines" and/or "best practices" as searchable terms. These terms, even when used in titles, generally represent commentary by individuals. In fact, JHTR has published in earlier issues several articles representative of authors' opinions using these terms in their title and/or as key words (see References 2-7). The terms in Dr Ruff's title were used in the spirit of author opinion and commentary and that is unmistakable when the entire article is read.

The opening article by Bigler and Brooks8 clearly states that the "... current issue of JHTR will hopefully offer some general principles that should assist the field in developing standards."^(p77) Bigler and Brooks further state: "The article by Ruff provides a practical commentary and summary regarding a best-practices approach to forensic neuropsychology as the concluding article of this special topical issue of JHTR."^(p85) No professional society sponsorship of Ruff's material is indicated or promised. When an organization does make a position statement, explicit identification is typical. For example, the official policy papers of the 2 neuropsychological organizations that Donders et al mention in their critique-the National Academy of Neuropsychology (NAN) and the American Academy of Clinical Neuropsychology (AACN)-always have a header statement with their guidelines that typically identifies the nature of the document. As an illustration, the recent position of AACN regarding evaluation of mild TBI (mTBI) in military veterans begins as follows: "Official position of the military TBI task force ..." (see Reference 9). Likewise, the recent NAN article on the neuropsychological diagnosis of mTBI (see Reference 10) carries the NAN moniker in its title: "Recommendations for Diagnosing a Mild Traumatic Brain Injury: A National Academy of Neuropsychology Education Paper." I believe it is common knowledge that the presence of a professional imprimatur is expected on any official document promulgating professional standards of a society or organization. Ruff's article, singly authored and lacking official endorsement by a professional society, could not be misconstrued as a consensus-driven position statement of a professional society or organization.

Indeed, I am in complete agreement with Donders et al that practice guidelines should not be dictated by a single individual but rather developed by consensus, based primarily on Class I and II levels of evidence, as discussed in Bigler and Brooks.8 However, there is a major problem regarding forensic practice because comprehensive guidelines have not been formulated by any neuropsychological society or organization. Furthermore, few Class I and II research studies are available on which to base such guidelines involving forensic neuropsychology. Donders et al identify generic guidelines but they provide no specifics for forensic practice, especially with respect to TBI. For many reasons, professional societies within psychology/neuropsychology have not yet published a consensus statement establishing standards. Forensic neuropsychology has functioned in an ad hoc manner, defined, as it were, by individual practitioners viewing and justifying their own forensic practices. The JHTR issue under discussion was motivated, in part, by a desire to bring forensic issues into focus within a public forum so that obvious lacunae within the field could be shown and addressed.

One issue raised by Donders et al is the debate about what defines mTBI. Close to the publication date of "Forensic Neuropsychology," the New England Journal of Medicine published a commentary by Hoge, Goldberg, and Castro11 that criticized definitional statements on mTBI used by the Department of Defense and Veterans Administration for the purpose of developing programs for injured military personnel returning from war. Hoge et al focused on the fact that different professional societies held different positions on what defines mTBI and its association with disorders such as posttraumatic stress disorder (PTSD) and preexisting neuropsychiatric disorders. Their critique represents a major public statement of disagreement that will surely limit progress on program development until consensus is reached on what constitutes mTBI; how it should be diagnosed, evaluated, and treated. Appearing simultaneously with Hoge et al was another mTBI controversy generated by opinions over guidelines in the Archives of Neurology (References 12-14, see also Reference 15) that discussed return to play after "concussion" in amateur and professional sports. Mayers13 offered "guidelines" in the form of return-to-play criteria based on a review of the literature and his own medical practice of sports injuries. Indeed, Mayers (like Ruff) outlined various recommendations based on personal experience and relevant literature. His work, like Ruff's, also elicited much criticism (see References 12 and 14). This merely shows the need for more research, debate, and writing on this topic.

Donders et al make the statement that information within Ruff's1 article is "... fertile grounds for misrepresentation of our best current knowledge in the field of mild traumatic brain injury, which is more adequately summarized elsewhere."1,2,8 They cite 3 studies in support of their position; however, 2 of the studies merely represent the personal opinion of the authors and in no way reflect some consensus opinion. The articles cited by Donders et al certainly cannot be offered as the (italics added) guideline representing "... our best current knowledge." By what standard are Donders et al empowering these 2 articles, and the World Health Organization (WHO) publications as the "... best current knowledge" for the area of forensic neuropsychology? They did not cite a published critique of the WHO conclusions (see Reference 16). As part of the content of these articles on mTBI, WHO did not cover the practice of clinical neuropsychology nor did it include courtroom issues such as how neuropsychologists should handle forensic neuropsychological consultations, write reports, bill for services, or conduct themselves in court. In my view, this series of WHO-funded review articles merely demonstrates how problematic contemporary mTBI research is, how it is confounded by litigation, and how lacking most of the mTBI research paradigms are from a design and methodological standpoint. When Donders et al make the statement that this topic is "... more adequately summarized elsewhere," they are making the same mistake they claim Ruff makes-namely, it is merely their opinion that these 3 studies are representative of the field and better reflective of the state of mTBI. Without professional society endorsement of consensus opinions and independently formed standards, this debate will go on forever.

The solution is large-scale prospective studies, independently conducted. In my opinion, the field should consider the National Institutes of Health (NIH) model of clinical trials for developing evidence-based standards for forensic neuropsychology. The NIH model seeks and selects clinical investigators who can demonstrate independence with respect to study outcomes, but, in clinical trial investigations, NIH also includes a scientific advisory board (SAB) that serves as an oversight panel and advises on a project's science, and a completely separate, external advisory board (EAB) that examines all aspects of the investigation. The model is complemented by a consumer advisory board (CAB) of individuals who may have a vested interest in a study's outcome but who also can advise on its conduct but are kept independent of the investigators. Using such a model, the CAB could be positioned to keep the plaintiff and defense perspectives in balance, while the investigators, the SAB, and the EAB are primed to avoid conflicts of interest that may inadvertently influence study outcomes. When research is conducted in this manner, evidence-based standards can follow. Standards, however, should not be developed by those whose primary role is within forensics because they may be subject to many conflicts of interest that bias the outcome.

Nothing seems to engender controversy within neuropsychology more than forensics and mTBI.17-19 I always find it curious that disciplines such as neuropsychology, rehabilitation psychology, neurology, physiatry, and psychiatry have no difficulty embracing the concept of "mild" in disorders that they treat, until it comes to patients with mTBI, especially when litigation is involved. Donders et al seem to question whether long-term mTBI sequelae can legitimately exist. Specifically, they question Ruff's statement that mTBI "without dispute" can result in a poor outcome. Well-designed, independently performed investigations, including those with a prospective design, have shown that some mTBI patients do have persisting sequelae.20-30 In my opinion, Ruff's statement is supported by the literature.

As discussed in Bigler and Brooks,8 the biomechanics and histopathology of mTBI offer objective methods that can model the physics and neuropathology of the injury, but only infrequently are such factors taken into consideration in neuropsychological research in mTBI. Neuroimaging has become a critical tool in assessing TBI, including mTBI.31-36 Neuroimaging studies of mTBI also specifically address the concern of Donders et al regarding poor outcome in mTBI (mentioned above). Neuroimaging provides an aspect of objectivity that neuropsychological assessments simply cannot. Often, indisputable evidence of brain injury can be documented with neuroimaging studies of the patient with mTBI, by using the timeline and pathological characteristics of imaging findings that are specific to trauma. The presence of positive imaging results is associated with a greater likelihood of poorer outcome following mTBI.31 Although it is beyond the scope of this article to review the field here, more than 30 different studies on mTBI plainly demonstrate abnormalities on high-field magnetic resonance imaging (MRI) and/or diffusion tensor imaging (DTI) in a subgroup of patients. MRI studies sensitive to the detection of microhemorrhages associated with shearing and white matter integrity consistently show abnormalities in a subset of mTBI patients. These studies include individuals with Glasgow Coma Scale scores of 15 and no loss of consciousness-clearly meeting mTBI criteria. Two recent studies of this kind are particularly instructive. Scheid et al37 demonstrated that presence of microhemorrhages relates to neurocognitive sequelae in mTBI. Niogi et al38,39 demonstrated the importance of specifying which white matter tracts are affected in mTBI, in order to relate neuropsychological symptoms to neuroimaging findings.

Another issue raised by Donders et al was Ruff's reliance on "clinical judgment." They apparently confused that issue with the broad latitude of the court's reliance on the "more probable than not" threshold of legal likelihood, pegged at 50.1% (see p 79 of Bigler and Brooks8). Ruff was merely reviewing the legal standard and he was not at all advocating for a simple clinical judgment that tips the scale as justification for a forensic opinion. Ruff's point was that the neuropsychologist in the forensic setting needs to base clinical decisions and interpretations on the best, constantly updated, clinical and scientific information of the day, as outlined by Wood.40 The court simply does not impose a statistical standard because attorneys and judges are not trained in statistics or even required to have background in statistics, psychology, medicine, or differential diagnosis. They rely on the neuropsychological expert. Furthermore, a lay jury comprises diverse individuals without educational prerequisites when selected as jurors. Therefore, final conclusions in the courtroom come down to clinical judgment. What the critique of Donders et al exposes is the absence of guidelines for decision making in forensic cases. Donders et al cannot refer the reader to a "proper" reference for answering questions they raise about clinical judgment in the courtroom because such a document does not exist. The criticisms of Donders et al on this issue do not match what Ruff actually writes or what was contained in the other articles of this JHTR issue. What Ruff writes regarding clinical judgment is not equivalent to "a flip of the coin" as Donders et al imply. To the contrary, Ruff writes about applying the best clinical support for interpreting and deciding issues involved in a forensic case.

One more comment on clinical judgment is offered. Because psychometric scores are just one aspect of a neuropsychological examination, how else does a clinical neuropsychologist comment on the whole patient other than by means of clinical judgment? The sequelae of TBI are multifaceted and extend into many physical, cognitive, psychosocial, and behavioral domains that can be integrated only by using clinical judgment based on history and other available information. This concept was discussed in Wood's article40 and reiterated in Ruff's article. Psychometrically derived scores and their interpretation are but one dimension contributing to a neuropsychologist's opinion; the remainder requires clinical judgment.

Disagreements aside, considerable common ground exists. Donders et al mention the importance of evidence-based research. This very point is also promoted by Bigler and Brooks,8 as well as by Ruff, and both articles provide outlines for what needs to be done. So, here is the starting point. Clinicians and researchers should take the very issues raised by Bigler and Brooks, Ruff, the critique by Donders et al, Ruff's response, and these comments and use these very points to guide future research, discussion, and writing on the topic, with the ultimate goal of professional societies agreeing upon practice standards.

Given the high visibility of mTBI, there is something really important about getting the above issues right. As discussed in Bigler and Brooks,8 it is likely that there are more than 1 million cases of mTBIs annually. A large majority of patients recover and appear to recover fully as discussed by Bailey et al.41 However, if only a small minority of mTBI patients experience genuine behavioral and cognitive sequelae, nevertheless, we owe it to them and to the profession to fully and correctly understand all issues, including forensic ones, related to mTBI and, as a profession, be able to empirically, academically, and dispassionately discuss them. Clinical neuroscience, medicine, and psychology have the tools and technology to provide high-quality, reliable information so that the court can perform its duty. While there is less debate when it comes to moderate-to-severe TBI, here, too, there are no universal standards that can be used to address forensic issues. Hopefully, the articles of the JHTR topical issue on Forensic Neuropsychology, especially Ruff's article and its critique by Donders et al, have helped to bring the issues into greater focus. This special issue, and in particular Ruff's article, puts forth many testable hypotheses. In addition to simply critiquing these positions, I recommend that those interested in advancing the field do so with empirical investigations, proving where we may or may not have accurately summarized the field.

Erin D. Bigler, PhD, ABPP

Department of Psychology and Neuroscience Center, Brigham Young University, Provo, Utah; Department of Psychiatry and The Brain Institute, University of Utah, Salt Lake City.

REFERENCES