Generalized or focal slowing and attenuated posterior alpha may occur in the first several hours after mild TBI among adults (Geets and de Zegher 1985; Nuwer et al. 2005). Among adult patients with loss of consciousness (LOC) of <2 minutes, 17% of 100 subjects recorded within 48 hours demonstrated electroencephalographic abnormalities, and electroencephalograms were abnormal in 56% of 25 subjects with mild TBI (LOC >2 minutes) (Geets and Louette 1985). Similar frequencies (15%–51%) of electroencephalographic abnormalities in the early period after mild TBI are reported elsewhere (Denker and Perry 1954; Geets and de Zegher 1985; Koufen and Dichgans 1978; Torres and Shapiro 1962; von Bierbrauer and Weissenborn 1998). In these cases, slowing, generalized bursts and focal abnormalities were the most common findings. However, such findings are not universal (Levin and Grossman 1978; Voller et al. 1999). Nonetheless, mild slowing is a common finding when EEG is performed within hours to days of a mild TBI. These changes are often subtle, not infrequently still within the range of normal findings in the general population, and may be apparent only when compared with follow-up electroencephalograms in the late postinjury period.