Commonly documented symptoms after mild head injury include impaired attention, concentration, information-processing speed, and memory, as well as complaints of headaches, dizziness, nausea, neurasthenia, hyperesthesia, and emotional lability. Most individuals who sustain mild head injury display few symptoms and are reported to recover completely after a brief period, whereas a minority of patients recount numerous complaints and continue to be symptomatic for extended periods.^{*References 3,5,6,10,12,15,16,19,23,24,25,34,36,37 and 46.}

Variability in postconcussive symptom presentation has focused debate on the cause of neuropsychological symptoms after mild cerebral trauma. Several factors, such as undetected parenchymal lesions, history of psychiatric illness or substance abuse, pending litigation, pain, and exaggeration of symptoms or malingering are presumed to be causative, particularly in determining symptom duration.<sup>4Binder L.M. Malingering following mild head trauma Clin Neuropsychol 1990 ;  4 : 25-36 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 13Dikmen S., Levin H.S. Methodological issues in the study of mild head injury Journal of Head Trauma Rehabilitation 1993 ;  3 : 30-47

Cliccare qui per andare alla sezione Riferimenti, 24Levin H.S., Mattis S., Ruff R.N., e al. Neurobehavioral outcome following minor head injury: A three-center study J Neurosurg 1987 ;  66 : 234-243 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Despite these speculations, researchers have failed to find a strong relationship between some of these variables and the presence of extended postconcussive symptoms.<sup>1Alves W.A., Macciocchi S.N., Barth J.T. Postconcussive symptoms after mild head injury Journal of Head Trauma Rehabilitation 1993 ;  3 : 48-59 [cross-ref]

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Controversy regarding the origin of postconcussive symptoms has been exacerbated by methodological limitations. Most studies of mild head injury suffer from various threats to internal and external validity including imprecise injury definition, selection bias, subject attrition, reliance on self-report measures, lack of baseline neuropsychological data, diverse outcome measures, variable test time sequences, and limited documentation or control of potentially influential subject factors.<sup>13Dikmen S., Levin H.S. Methodological issues in the study of mild head injury Journal of Head Trauma Rehabilitation 1993 ;  3 : 30-47

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Much of our knowledge about mild head injury has accumulated through retrospective investigations of selected populations, thus limiting conclusions regarding outcome. Although quasi-experimental retrospective or selected nonequivalent control comparisons have a place in research, using these paradigms to generate population-based predictions of outcome is problematic. Not surprisingly, there are even fewer controlled, prospective studies focused on mild sports-related head injuries.<sup>1Alves W.A., Macciocchi S.N., Barth J.T. Postconcussive symptoms after mild head injury Journal of Head Trauma Rehabilitation 1993 ;  3 : 48-59 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 13Dikmen S., Levin H.S. Methodological issues in the study of mild head injury Journal of Head Trauma Rehabilitation 1993 ;  3 : 30-47

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Despite the limitations of existing research, a number of issues believed to influence outcome following sports-related mild head injury are discussed, including injury mechanism-pathophysiology, severity, frequency, complications (medical, neurologic, and psychological factors), and clinical management. This article attempts to integrate findings in various sports with the exception of boxing, principally because boxing has an inherent objective of rendering an opponent unconscious. Boxing also deviates from other sports in terms of injury biomechanics; the number of injuries sustained; and, presumably, the known morbidity.<sup>35Ross R.J., Casson I.R., Siegel O., e al. Boxing injuries: Neurologic, radiologic, and neuropsychologic evaluation Clin Sports Med 1987 ;  6 : 41-51

Cliccare qui per andare alla sezione Riferimenti, 39Stiller J.W., Weinberger D.R. Boxing and chronic brain damage Psychiatr Clin North Am 1985 ;  8 : 339-356

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In this discussion, we emphasize findings of well-controlled studies. When issues of internal-external validity arise, these concerns are discussed in context. Additionally, most past discussions of sports-related mild head injury rely heavily on research completed in clinical (nonsports) populations. Generalization from nonsports populations may or may not be warranted when discussing outcomes in sports injuries. For example, a recent, large (N = 586) prospective hospital study found only 8% of mild head-injured persons sustained their injuries during sports activity.<sup>1Alves W.A., Macciocchi S.N., Barth J.T. Postconcussive symptoms after mild head injury Journal of Head Trauma Rehabilitation 1993 ;  3 : 48-59 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> As such, findings from general clinical and sports studies are discussed independently.