Abstract for presentation at 6th World Congress on Brain Injury

This study investigates the sensitivity of a test of rate of nonword repetition to the acute effects of mTBI, and whether inclusion of this test improves the diagnostic accuracy of a valid and reliable neuropsychological screen for mTBI, the Rapid Screen of Concussion (RSC) (Comerford, Geffen, May, Medland, & Geffen, 2002). With the aim of facilitating clinical judgement of severity of mTBI and improving diagnostic accuracy of the RSC, both the Nonword Repetition Test (NWRT) and RSC were administered within 24 hours of injury to 37 patients with mTBI, 29 control patients with non-deceleration orthopaedic injuries, and 27 uninjured visitors in a hospital Emergency Department. On average, patients with mTBI repeated fewer nonwords in 10 seconds (M=16.79, SD = 2.82) than patients with orthopaedic injuries (M=17.44, SD = 2.24), who in turn repeated fewer nonwords than uninjured participants (M=18.21, SD = 2.52). However, three paired-comparisons of participant groups were non-significant when age, education and blood alcohol content were controlled for, using analyses of covariance. A positive correlation between mTBI participants’ scores on the NWRT and a composite score derived from performance on RSC subtests was found, r(29) = .49, p < .01, indicating that poorer performance on the NWRT was related to poorer RSC performance. Performance on the NWRT was also a significant predictor of immediate memory performance for mTBI participants, r(37)=.43, p<.01. However, the addition of the NWRT to the RSC did not improve the classification accuracy, sensitivity or specificity of the RSC in mTBI and orthopaedic samples. We conclude that nonword repetition is affected by too many other factors (level of education, blood alcohol level, secondary effects of injury or anxiety associated with injury) to be useful for detecting the specific effects of mTBI.