LETTER TO THE EDITOR COMMENTS ON THE TASK FORCE REPORT ON MILD TRAUMATIC BRAIN INJURY: JOURNAL OF REHABILITATION MEDICINE SUPPLEMENT 43 Michelle McKerral, 1,2,3 Fanny Gue ´rin, 1,2 Stephan Kennepohl, 1,4 Aysha Dominique, 1 Wormser Honore ´, 1 Genevie `ve Le ´veille ´ 1 and Nicole Brie `re 1 From the 1 Programme TCC, Centre de Re ´adaptation Lucie-Bruneau, 2 Centre de Recherche Interdisciplinaire en Re ´adaptation, 3 De ´partement de Psychologie, Universite ´ de Montre ´al and 4 Montre ´al Neurological Institute, Montre ´al, Que ´bec, Canada J Rehabil Med 2005; 37: 61–62 Correspondence address: Michelle McKerral, Programme TCC, Centre de Re ´adaptation Lucie-Bruneau, 2275 Avenue Laurier est, Montre ´al, Que ´bec, Canada H2H 2N8. E-mail: michelle.mckerral@montreal.ca Submitted September 18, 2004; accepted October 29, 2004 The results of the Best Evidence Synthesis conducted by the World Health Organization Collaborating Centre Task Force on Mild Traumatic Brain Injury (MTBI), published in this journal in 2004 (suppl. 43), reflect work of exceptional magnitude. The analysis of existing scientific research literature on all aspects of MTBI (diagnosis, prognosis and treatment) was greatly needed. However, the results of such a process merit strong caution as to their possible clinical applications. Thus, the following points should be considered: . As mentioned by the authors themselves, there is variability in the definition of MTBI amongst the different papers reviewed (see ref. 1., p. 114), which render specific inter- study comparisons difficult. . The prognostic factors studied in the articles retained for analysis are mostly medical/neurosurgical in nature (see ref. 2, tables, pp. 90–95), which can limit the conclusions as to global/functional outcome or prognosis. . Some of the authors seem to critique the inclusion of factors such as emotional distress and pain-related symptomatology (amongst others) within the definition of poor outcome following MTBI (i.e. post-concussional disorder), and some- times consider them as possibly confounding the true effects of MTBI (e.g. ref. 2, p. 101). In fact, such elements may be considered an intrinsic part of the complex clinical picture following complicated MTBI (i.e. post-concussive symptoms are not confounding effects, they are factors which need to be considered in order fully to understand outcome variability). Certainly, the criticism that many of the post-concussion symptoms are subjective and subject to recall or selected differences in reporting is a valid one (see ref. 2, p. 89). On the other hand, the use of subjective criteria is far from being an isolated case in the medical literature (e.g. post-traumatic stress disorder) and one cannot dismiss the initial causative nature of the MTBI in bringing about these latter symptoms. Regardless of underlying etiology, from a strictly clinical standpoint (by contrast with a medico-legal viewpoint), it is interesting to note that several studies (retained within this review) emphasize that self-reported symptoms are some of the most consistent predictors of future difficulties (3, 4). . In general, in the studies reviewed, all MTBI patients are confounded and those not recuperating well (e.g. those with significant post-concussive symptoms >3 months post-TBI) are not considered as a separate group, thus masking potentially strong statistical effects. Regarding this point, it is interesting to note that some studies (e.g. ref. 3) have suggested that functional recovery may evolve very differ- ently between these 2 groups over time. . There are no retained articles proposing theories or models to explain the complex multifactorial nature of MTBI. Once again, from a clinical standpoint, this is an important aspect as some models have suggested an evolving etiology for the development of post-concussion symptoms over time. For example, Kay (5) has suggested that although the initial trauma may well be neurological in nature (causing the initial symptoms within the first few weeks), psychological factors may slowly and gradually take over as the primary underlying cause, particularly in cases of poor outcome following MTBI. . The authors state that results indicate no evidence for providing routine intensive treatment in the overall MTBI population (see ref. 6, p. 83), but they do not advance the possibility of identifying and intervening with those individ- uals with potentially negative prognostic indicators (i.e. those who make up the 10–15% or so of MTBI individuals who do not recuperate well). We are in full agreement with Borg et al.’s recommendation (p. 82) that intervention with patients with uncomplicated MTBI (i.e. which constitute the majority) be limited to information regarding symptoms, reassurance and further resource information. However, the difficulty as to what exactly constitutes a “complicated” MTBI remains unresolved, particularly with regards to intervention. . This work was funded primarily by private parties and one of its principal mandates was to evaluate the economic costs related to the treatment of MTBI (6).  2005 Taylor & Francis. ISSN 1650–1977 DOI 10.1080/16501970510026647 J Rehabil Med 37 J Rehabil Med 2005; 37: 61–62