An fMRI Study of Working Memory in Moderate-TBI Patients: Results from Preliminary Data

Introduction: Patients diagnosed with traumatic brain injury (TBI) often report impairments in cognitive functioning that interfere with their daily lives. The present preliminary study looks at brain responses to a working memory task (i.e. n-back task) in healthy participants and participants with moderate TBI using functional Magnetic Resonance Imaging (fMRI). Method: Seven Malay males (5 controls and 2 moderate-TBI participants) underwent the visual n-back task, which consisted of four conditions: 0-, 1-, 2-, and 3-back, during scanning using a 3.0-T scanner (Achieva, Philips, the Netherlands). The functional images were preprocessed and analyzed using MATLAB 8.3 R2014a and Statistical Parametric Mapping 12 (SPM12) software. Two fixed-effects analyses (FFX) were performed for the respective groups, and the activated brain regions were identified using the WFU PickAtlas software at a significant statistical inference FWE of α= .001 for multiple comparisons. Results: The healthy subjects displayed significantly elevated activations in their bilateral middle frontal gyri across all conditions except for 1-back ( P FWE 11.86), with more clusters being significantly activated in the gyri as memory load increased. On the other hand, the moderate-TBI participants exhibited significant activations in their bilateral superior parietal cortex during the 2- and 3-back conditions ( P FWE 11. 81), which were not observed in the healthy subjects. Conclusion: This preliminary study on working memory demonstrates that brain activations differ between healthy and TBI participants. It paves the way for understanding working memory and its underlying brain responses in individuals with moderate-TBI.