  Other intensive studies of the KE family, by Vargha-Khadem and colleagues (e.g., Vargha-Khadem et al 1995, 1998; Watkins et al., 2002) have vigorously disputed the hypothesis that the root cause of the KE's language disorder is a syntactic deficit. Instead, they argue, the KE phenotype is much broader than Gopnik's account suggests, and their ‘feature blindness’ is merely one among the many effects of an underlying articulatory problem. As characterized by Vargha-Khadem's team, the affected KE's speech is effortful, “sometimes agrammatical and often unintelligible” (Watkins et al. 2002:453), and shows impairments not just in morphosyntax (e.g., regular plural and past tense endings) but also in the formation of irregular past tenses (where correct usage is lexically determined, rather than rule-governed) and in sentence-level syntax, particularly word order. Comprehension, too, is impaired at the level of syntax as well as words, and as is their reading of both words and non-words. These results indicate that the KE's problems go beyond morphosyntax, and the fact that affected KE's have significantly lower non-verbal IQs (by 18-19 points; Vargha-Khadem et al. 1995) than unaffected family members indicates that their deficits may be further reaching  still.[28]  Finally, affected KE's have trouble sequencing and executing non-language-related face, mouth and tongue movements and show abnormal activation not just of speech but also of motor areas on fMRI scans (Liegeois, et al. 2003); this deficiency in ‘orofacial praxis’ supports Vargha-Khadem's hypothesis that the root problem for the KE's is articulatory.