Working memory and metacognition in sentence comprehension by severely head-injured children: A preliminary study

We studied the effects of working memory (WM) load on a sentence anomaly task in 12 children (mean age at study = 10.3 years) who had sustained a severe closed-head injury (CHI) at least 10 months previously and 12 healthy children (mean age = 8.92 years). Children were asked to judge whether each sentence (32 anomalous and 32 correct under high and low WM load conditions) was "good" or "not good," and to identify and repair the anomaly. Group and age effects were significant, and both variables interacted with sentence type, reflecting greater sensitivity of anomalous than sensible sentences to CHI and age. A Group x WM load interaction was found. WM deficit contributes to impaired language processing after severe CHI and a metacognitive problem is dissociable from generalized cognitive dysfunction. Traumatic brain injury is one of the leading causes of morbidity in children, with an estimated incidence of 200/100,000 (17,000) children annually (Kraus, 1995). Among the most disabling sequelae of pediatric traumatic brain injury is cognitive impairment, including disabilities in executive functioning (e.g., planning, flexibility in problem solving allocation of resources, inhibitory control), attention, and working memory (WM; Mateer, Kerns, & Eso, 1996). Children who sustain severe closed-head injuries (CHIs) are likely to display impairments in both verbal and nonverbal WM Levin et al. 1988) as well as in semantic memory (Levin, Fletcher, Kufera, et al., 1996; (Levin, Fletcher, Kusnerik, et al., 1996). Recent research has also linked deficits in executive control functions as a consequence of head injury to impairment in metacognitive abilities (Dennis, Barnes, Donnelley, Wilkinson, & Humphreys, 1996).