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Citation
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Niogi SN, Mukherjee P, Ghajar J, Johnson CE, Kolster R, Lee H, Suh M, Zimmerman RD, Manley GT, McCandliss BD. Brain 2008; 131(12): 3209-3221. |
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Abstract
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Memory and attentional control impairments are the two most common forms of dysfunction following mild traumatic brain injury (TBI) and lead to significant morbidity in patients, yet these functions are thought to be supported by different brain networks. This 3 T magnetic resonance diffusion tensor imaging (DTI) study investigates whether microstructural integrity of white matter, as measured by fractional anisotropy (FA) within a small set of individually localized regions of interest (ROIs), is associated with these cognitive domains in normal adults and adults with mild TBI.
RESULTS in a sample of 23 normal controls reveal a significant correlation between attentional control and FA within a ROI in the left hemisphere anterior corona radiata. Furthermore, the controls demonstrate a correlation between memory performance and FA in a ROI placed in the uncinate fasciculus. Next, to examine whether these relationships are found in the pathological ranges of attention, memory and microstructural white matter integrity associated with mild TOBI, these analysis were applied to a group of 43 mild TOBI patients.
RESULTS, which generally demonstrated a wider range of attention, memory and FA scores, replicated the correlation between attentional control and FA in left hemisphere anterior corona radiate, as well as the correlation between memory performance and FA in the insinuate fascicles. These two sets of brain-behavior relationships were highly specific, as shown by a lack of correlation between attention and insinuate fascicles FA and the lack of correlation between memory performance and anterior corona radiate FA. Furthermore, a "correlations double dissociation" was demonstrated to exist between two distinct frontal structures independently associated with attention and memory, respectively, via a series of multiple regression analysis in both normal controls and adults with mild TOBI. The results of the multiple regression analysis provide direct evidence that tract-specific variation in microstructural white matter integrity among normal controls and among mild TBI patients can account for much of the variation in performance in specific cognitive domains. More generally, such findings suggest that diffusion anisotropy measurement can be used as a quantitative biomarker for neurocognitive function and dysfunction.
Language: en |