Hemispheric asymmetry reduction in older adults (HAROLD) has been frequently reported in studies of functional brain aging. It is commonly considered to be a plastic brain reorganization that provides compensation for declining unilateral neural efficiency. However, plastic functional alterations may also be associated with neural connectivity changes. Using activation and resting state functional magnetic resonance imaging (fMRI) as well as diffusion tensor imaging (DTI), we examined whether functional and structural connectivity related to prefrontal working memory function is asymmetrically reduced in the two hemispheres of the aging brain; and if yes, whether these asymmetric connectivity declines are correlated with asymmetry reduction in functional activation. With regions of interests defined by verbal working memory activations, it is revealed that although neural connectivity is generally reduced in the aging brain, prefrontal-parietal resting functional connectivity is better preserved in the left hemisphere while prefrontal DTI fiber pathways are better preserved in the right hemisphere. In addition, the laterality change of the functional activation is negatively correlated with that of the resting connectivity and positively correlated with that of the structural connectivity. These results reveal additional aspects of the neuronal alterations of aging and suggest a link between asymmetric connectivity reduction and HAROLD.

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Objective: To develop and calibrate new patient-reported outcome measures of cognitive concerns for individuals with traumatic brain injury (TBI). Setting: Five TBI model systems rehabilitation centers in the United States. Participants: Adults with medically confirmed history of TBI. Design: Cross-sectional survey in interview format. Main Measures: Traumatic Brain Injury-Quality of Life (TBI-QOL) Executive Function and TBI-QOL Cognition-General Concerns item banks. Results: A total of 569 adults with complicated-mild, moderate, or severe TBI completed preliminary item pools, which included 65 Executive Function items and 56 Cognition-General Concerns items. Confirmatory factor analysis supported the retention of 37 Executive Function and 39 Cognition-General Concerns items. Samejima's graded response model was used to estimate item parameters for associated computer adaptive test administrations, and informed the selection of corresponding static short forms. Data from an independent sample of 77 adults with complicated-mild, moderate, or severe TBI supported the test-retest reliability of these newly developed measures. Conclusion: The TBI-QOL Executive Function and Cognition-General Concerns item banks provide researchers and clinicians with reliable tools for assessing patient-reported post-TBI cognitive difficulties as part of the comprehensive TBI-QOL measurement system.