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The brain changes of Alzheimer's disease and other degenerative dementias begin long before cognitive dysfunction develops, and in people with subtle cognitive complaints, clinicians often struggle to predict who will develop dementia. The public increasingly sees benefits to accessing dementia risk evidence (DRE) such as biomarkers, predictive algorithms, and genetic information, particularly as this information moves from research to demonstrated usefulness in guiding diagnosis and clinical management. For example, the knowledge that one has high levels of amyloid in the brain may lead one to seek amyloid reducing medications, plan for disability, or engage in health promoting behaviors to fight cognitive decline. Researchers often hesitate to share DRE data, either because they are insufficiently validated or reliable for use in individuals, or there are concerns about assuring responsible use and ensuring adequate understanding of potential problems when one's biomarker status is known. Concerns include warning people receiving DRE about situations in which they might be compelled to disclose their risk status potentially leading to discrimination or stigma. The Advisory Group on Risk Evidence Education for Dementia (AGREEDementia) welcomes all concerned with how best to share and use DRE. Supporting understanding in clinicians, stakeholders, and people with or at risk for dementia and clearly delineating risks, benefits, and gaps in knowledge is vital. This brief overview describes elements that made this group effective as a model for other health conditions where there is interest in unfettered collaboration to discuss diagnostic uncertainty and the appropriate use and communication of health-related risk information.

The study of cognition in Parkinson's disease (PD) traditionally requires exhaustive recruitment strategies. The current study examines data collected by the Brain Health Registry (BHR) to determine whether ongoing efforts to improve the recruitment base for therapeutic trials in Alzheimer's disease may be similarly effective for PD research, and whether online cognitive measurements can discriminate between participants who do and do not report a PD diagnosis. Participants enrolled in the BHR (age ≥50) with self-reported PD data and online cognitive testing available were included (n = 11,813). Associations between baseline cognitive variables and diagnostic group were analyzed using logistic regression. Linear mixed effects models were used to analyze longitudinal data. A total of 634 participants reported PD diagnosis at baseline with no self-reported cognitive impairment and completed cognitive testing. Measures of visual learning and memory, processing speed, attention, and working memory discriminated between self-reported PD and non-PD participants after correcting for multiple comparisons (p values < 0.006). Scores on all cognitive tests improved over time in PD and controls with the exception of processing speed, which remained stable in participants with PD while improving in those without. We demonstrate that a novel online approach to recruitment and longitudinal follow-up of study participants is effective for those with self-reported PD, and that significant differences exist between those with and without a reported diagnosis of PD on computerized cognitive measures. These results have important implications for recruitment of participants with PD into targeted therapeutic trials or large-scale genetic and cognitive studies.

The authors present a case demonstrating that a blast injury was associated with both conduction aphasia and an abnormality in the left Arcuate Fasciculus (AF) on MR DTI (Diffusion Tensor Imaging). In addition, this study showed the presence of conduction aprosodia in the setting of damage to the homologous area in the right hemisphere (hereafter referred to as the right homologue of the AF). In prior research, diffusion tensor images have revealed injuries invisible to standard structural imaging. Our finding is consistent with a previous diffusion tensor study demonstrating that damage to the AF is associated with conduction aphasia. Based on the patient's length of posttraumatic amnesia this patient's second TBI would be classified as mild and unlikely to be associated with enduring cognitive deficits, and yet we have observed evidence from both DTI and behavior that there is enduring dysfunction. This case report suggests that further study of patients with complaints following blast injuries is warranted, particularly with advanced imaging techniques such as DTI. Of particular interest, change over time in white matter tracts, observed using sequential DTI, could show improvement of connectivity., Published in Military Medicine, v174 n9, Nov 2009. Note: This is the full text version of the radiology corner question published in the October 2009 issue, with the abbreviated answer in the November 2009 issue. The original document contains color images. All DTIC reproductions will be in black and white.