Premorbid history and postinjury environment are also important determinants of recovery after CHI (Satz, Zaucha, McCleary, Light, & Asamow, 1997; Yeates et aI., 1997), although this study did not evaluate these factors. Some of the subjects at the lower end of the distributions of our mild and moderate CHI groups might represent variation in these factors, rather than direct consequences of the CHI. Family distress and burden, for example, can increase the likelihood of poor outcome (Taylor & Alden, 1997; Taylor et aI., 1995). Prospective studies may help to clarify whether or not some of the variability in verbal WM outcome after childhood CHI can be explained by environmental factors.