Dual Task Performance Is Associated with Amyloidosis in Cognitively Healthy Adults.

BACKGROUND: Preclinical Alzheimer's disease (AD) provides an opportunity for the study and implementation of interventions and strategies aimed at delaying, mitigating, and preventing AD. While this preclinical state is an ideal target, it is difficult to identify efficiently and cost-effectively. Recent findings have suggested that cognitive-motor dual task paradigms may provide additional inference. OBJECTIVES: Investigate the relationship between dual task performance and amyloidosis, suggestive of preclinical Alzheimer's disease and whether dual task performance provides additional information beyond a cognitive composite, to help in the identification of amyloidosis. DESIGN: Cross-sectional. SETTING: Outpatient specialty brain health clinical research institution in the United States. PARTICIPANTS: 52 cognitively healthy adults. MEASUREMENTS: The data included demographics, amyloid standardized uptake value ratio obtained via florbetapir-PET, neuropsychological testing, apolipoprotien E genotype, and dual task performance measures. Data were analyzed via hierarchal multiple linear regression or logistic regression, controlling for age, education, and apolipoprotien E genotype. Receiver operating characteristic curves were plotted, and sensitivity and specificity calculated via 2x2 contingency tables. RESULTS: There was a moderate relationship (rs>.30) between motor and cognitive dual task effects and amyloid standardized uptake value ratio (ps<.042). A strong relationship (r=.58) was found between combined dual task effect, a measure of automaticity derived from dual task performance, and amyloid standardized uptake value ratio (p<.001). Additionally, combined dual task effect showed promise in its unique contributions to amyloid standardized uptake value ratio, accounting for 7.8% of amyloid standardized uptake value ratio variance beyond cognitive composite scores (p=.018). Additionally, when incorporated into the cognitive composite, combined dual task effect resulted in improved diagnostic accuracy for determining elevated amyloid standardized uptake value ratio, and increased the sensitivity and specificity of the cognitive composite. CONCLUSSION: Dual task performance using the combined dual task effect, a measure of automaticity, was a moderate predictor of cerebral amyloidosis, which suggests that it has utility in the screening and diagnosis of individuals for preclinical AD. Additionally, when combined with the cognitive composite, the combined dual task effect improves diagnostic accuracy. Further research is warranted.

Neural dysregulation during a working memory task in human immunodeficiency virus-seropositive and hepatitis C coinfected individuals.

Cognitive and functional neural correlates of human immunodeficiency virus (HIV) are only partially understood at present. Variability in neural response, which has been noted in the literature, may relate to clinical factors associated with HIV, including time since HIV diagnosis, CD4 count and nadir, HIV viral load, and comorbid infectious processes, especially hepatitis C. The present investigation evaluated working memory-related functional neural activation in 26 HIV+ participants, 28 demographically matched HIV-seronegative individuals, and 8 HIV+ individuals with hepatitis C coinfection. Analyses examined impact of HIV infection duration, CD4 count and nadir, HIV viral load, and hepatitis C serostatus. Results showed that HIV-seronegative participants had fastest reaction times, and during the working memory task, HIV+ participants with hepatitis C coinfection showed strongest bias toward commission errors; however, signal detection (i.e., overall task performance) was equivalent across groups. Functional magnetic resonance imaging (fMRI) results showed HIV-related greater activation to an easier vigilance task and HIV-related lower activation to a more difficult working memory task, consistent with reduced cognitive reserve. Hepatitis C coinfection related to diffuse neural dysregulation. Correlational analyses suggested relationships of increasingly severe disease with poorer functioning in brain regions linked to error monitoring and attention regulation.

Special antigens on sperm from autoimmune infertile men.

Sera from three fertile men and four infertile men without sperm antibodies, 17 infertile men with sperm antibodies in serum and seminal plasma (S.P.), and 25 infertile men with sperm antibodies in S.P. were tested by Western Blot analysis against sperm membrane extracts and S.P. from fertile nonautoimmune men and infertile autoimmune men. Sera from fertile men reacted against common antigens with molecular weights (MW) of 28, 38, 48, 60, and 68 kD present on sperm from autoimmune and nonautoimmune men and special antigen of MW 76 kD on the sperm of fertile men. Sera from 15 of 17 (88%) autoimmune infertile men with sperm antibodies in serum and S.P. detected special antigens with MW of 58 kD (sera reactivity in 47% of these men), 43kD (in 29%), 30 kD (in 24%), 35 kD (in 18%), 52 kD (in 12%), 41 kD (in 6%), and 71 kD (in 6%) on the sperm of autoimmune men in addition to the common antigens. Sera from 15 of 25 (60%) men with sperm antibodies in their S.P. showed reactivity to special antigens with MW 52 kD (in 20%), 35 kD (in 16%), 41 kD (in 16%), 58 kD (in 8%), 70/71 kD (in 8%), 30 kD (in 8%), and 56 kD (in 4%). Sera from 18 of 42 (43%) infertile men with sperm antibodies also detected special antigens of MW 26, 46, and 76 kD present only in fertile men's sperm. Sera from only 15 of 42 (36%) autoimmune infertile men reacted against special antigens with MW 17, 20, 23, 30, 43, and 58 kD in the seminal plasma of autoimmune infertile men.(ABSTRACT TRUNCATED AT 250 WORDS)