Jill Hunter MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To test the hypothesis that children with impaired working memory following traumatic brain injury, (TBI), demonstrate a different pattern of activation on fMRI, using an N-back task, when compared to normal controls. Methods and Materials: Four right-handed girls, (mean age 12.7 yrs, S.D= 2.3), who had sustained moderate to severe TBI , (GCS=3-11), 3 to 51 months prior to fMRI were individually matched for age and gender with 4 healthy right-handed controls, (mean age 13.2yrs, S.D =2.3). An N-back letter task was employed using a boxcar design with 12 x 36 second epochs of alternating 0-back, (resting condition), and N-back condition, (Phillips 1.5 T Intera, single shot multislice EPI, 24 x 4 mm, 64x64 matrix, 25.6 cm FOV, TR/TE = 3000/50 ms). The working memory load was increased incrementally from 1- to 2- to 3-back following successful completion, (75% or greater correct responses), of the easier condition. Responses were recorded electronically via a balanced left or right push button control fed back to the laptop computer projecting the paradigm. Task performance was matched within 10% for patient/control pairs. Data were analysed using SPM99. All subjects were trained to reach their level of maximum competence 2 hours prior to entry into the magnet. All children underwent independent neuropsychological testing remote from the time of the fMRI study. Results: Three of the TBI patients, who were able to successfully complete only the 1-back task, demonstrated a different and more focal pattern of frontal activation than the remaining TBI patient and the 4 normal controls, who all showed a more neuro-anatomically distributed pattern of activation, even at the 1-back level. Conclusion: While performing equivalent working memory tasks, the children with poor recovery following TBI had a more focal pattern of brain activation than either normal, age-matched controls or the child who had good recovery after TBI. These findings may have important prognostic and management implications for children sustaining closed head injury.       Questions about this event email: jvhunter@texaschildrenshospital.org

Hunter MD, J, Functional MRI of Working Memory in Brain-injured Children.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3104410.html