  Finally, not even very young children are guaranteed to recover  language after serious insults, whether to the left or right  hemisphere. As Bates and Roe (2001) argue in their survey of the  childhood aphasia literature, outcomes differ wildly from case to  case, and the reported studies exhibit numerous methodological  confounds (e.g., inability to localize the lesion or to know its  cause, different measures of linguistic competence, different time  frames for testing, statistical irregularities, and failure to  control for other factors known to affect language such as seizure  history) that cast doubt on the degree of empirical support possessed by Lenneberg's claim in this instance.