To the Editor Nelson et al¹ state that the term mild in mild traumatic brain injury misrepresents the burden of traumatic brain injury. Seminal prospective controlled studies by 3 of Nelson’s own coauthors, who are neuropsychologists, that date back to the 1980s contradict the findings of this article.¹ To my knowledge, Levin et al² were the first to conclusively show that a single uncomplicated mild head injury produces no permanent neurobehavioral impairment. A Glasgow Coma Scale score of 13 to 15 and a coma not to exceed 20 minutes was introduced earlier as a definition of mild head injury.³ Levin et al² added normal imaging as the third defining feature to separate those with complicated mild head injury, namely acute imaging abnormalities. An earlier study³ that included patients with mild complicated injury showed cognitive and functional impairment. Dikmen et al⁴ published the second important article. One year post–head injury, patients who took up to an hour to follow commands did not differ cognitively from the controls. Curiously, neither of these 2 articles are cited by Nelson et al.¹ The benign outcome of mild head injury seen in the civilian literature was established by McCrea et al⁵ in the best-characterized sports concussion sample published at that time. The cognitive effects of concussion resolve in 7 days.⁵

编者纳尔逊（Nelson）等人¹指出，轻度轻度颅脑外伤一词代表了轻度颅脑外伤的负担。纳尔逊自己的三位作者（神经心理学家）的开创性前瞻性对照研究可追溯至1980年代，与本文的发现相矛盾。¹据我所知，Levin等人²是第一个得出结论的人，它表明一个简单的轻度颅脑损伤不会产生永久的神经行为损害。格拉斯哥昏迷量表评分为13到15，昏迷不超过20分钟，是轻度颅脑损伤的定义。³ Levin等人²添加了正常成像作为第三个定义特征，以将那些患有复杂的轻度颅脑损伤（即急性成像异常）的患者分开。较早的一项研究³包括轻度复杂性损伤患者，显示其认知和功能受损。Dikmen等人⁴发表了第二篇重要文章。头部受伤后一年，遵循命令长达一个小时的患者在认知上与对照组没有差异。奇怪的是，Nelson等人均未引用这两篇文章。¹ McCrea等人[ ^5]在当时发表的最典型的脑震荡样本中确定了在平民文献中看到的轻度颅脑损伤的良性结局。脑震荡的认知作用在7天内消失。⁵