TY - JOUR
T1 - Frontal hypoactivation on functional magnetic resonance imaging in working memory after severe diffuse traumatic brain injury
AU - Sánchez-Carrión, Rocío
AU - Gómez, Pere Vendrell
AU - Junqué, Carme
AU - Fernández-Espejo, Davinia
AU - Falcon, Carles
AU - Bargalló, Nuria
AU - Roig-Rovira, Teresa
AU - Enseñat-Cantallops, Antònia
AU - Bernabeu, Montserrat
PY - 2008/5
Y1 - 2008/5
N2 - Working memory is frequently impaired after traumatic brain injury (TBI). The present study aimed to investigate working memory deficits in patients with diffuse axonal injury and to determine the contribution of cerebral activation dysfunctions to them. Eighteen patients with severe TBI and 14 healthy controls matched for age and gender were included in the study. TBI patients were selected according to signs of diffuse axonal injury on computed tomography (CT) and without any evidence of focal lesions on MRI clinical examination. Functional magnetic resonance (fMRI) was used to assess brain activation during n-back tasks (0-, 2-, and 3-back). Compared to controls, the TBI group showed significant working memory impairment on the Digits Backwards (p=0.022) and Letter-Number Sequencing subtests from the WAIS-III (p<0.001) under the 2-back (p=0.008) and 3-back (p=0.017) conditions. Both groups engaged bilateral fronto-parietal regions known to be involved in working memory, although patients showed less cerebral activation than did controls. Decreased activation in TBI patients compared to controls was observed mainly in the right superior and middle frontal cortex. The correlation patterns differed between patients and controls: while the control group showed a negative correlation between performance and activation in prefrontal cortex (PFC), TBI patients presented a positive correlation in right parietal and left parahippocampus for the low and high working memory load, respectively. In conclusion, severe TBI patients with diffuse brain damage show a pattern of cerebral hypoactivation in the right middle and superior frontal regions during working memory tasks, and also present an impaired pattern of performance correlations.
AB - Working memory is frequently impaired after traumatic brain injury (TBI). The present study aimed to investigate working memory deficits in patients with diffuse axonal injury and to determine the contribution of cerebral activation dysfunctions to them. Eighteen patients with severe TBI and 14 healthy controls matched for age and gender were included in the study. TBI patients were selected according to signs of diffuse axonal injury on computed tomography (CT) and without any evidence of focal lesions on MRI clinical examination. Functional magnetic resonance (fMRI) was used to assess brain activation during n-back tasks (0-, 2-, and 3-back). Compared to controls, the TBI group showed significant working memory impairment on the Digits Backwards (p=0.022) and Letter-Number Sequencing subtests from the WAIS-III (p<0.001) under the 2-back (p=0.008) and 3-back (p=0.017) conditions. Both groups engaged bilateral fronto-parietal regions known to be involved in working memory, although patients showed less cerebral activation than did controls. Decreased activation in TBI patients compared to controls was observed mainly in the right superior and middle frontal cortex. The correlation patterns differed between patients and controls: while the control group showed a negative correlation between performance and activation in prefrontal cortex (PFC), TBI patients presented a positive correlation in right parietal and left parahippocampus for the low and high working memory load, respectively. In conclusion, severe TBI patients with diffuse brain damage show a pattern of cerebral hypoactivation in the right middle and superior frontal regions during working memory tasks, and also present an impaired pattern of performance correlations.
KW - Brain Mapping
KW - Diffuse Axonal Injury
KW - Female
KW - Humans
KW - Image Processing, Computer-Assisted
KW - Magnetic Resonance Imaging
KW - Male
KW - Memory
KW - Neuropsychological Tests
U2 - 10.1089/neu.2007.0417
DO - 10.1089/neu.2007.0417
M3 - Article
C2 - 18363509
SN - 0897-7151
VL - 25
SP - 479
EP - 494
JO - Journal of Neurotrauma
JF - Journal of Neurotrauma
IS - 5
ER -