Relationships of Physical Activity and Type 2 Diabetes With Cognition in Mexican Americans and Non-Hispanic Whites.

Problem, Research Strategy, and Findings: Low physical activity (PA) and Type 2 diabetes are associated with cognitive aging and Alzheimer's disease, but the evidence is inconsistent and particularly limited by ethnicity. The purpose of this study was to examine the relationships of PA and Type 2 diabetes with cognition in Mexican Americans and non-Hispanic Whites. The study was a cross-sectional analysis of the Health and Aging Brain Study-Health Disparities (n = 1,982-2,000 after removing outliers). Predictors included Rapid Assessment of Physical Activity and hemoglobin A1c (HbA1c). Episodic memory was assessed by Weschler Memory Scale-Third Edition Logical Memory and Spanish-English Verbal Learning Test, executive function by Weschler Memory Scale-Third Edition Digit Span and Digit Symbol Substitution Test, verbal fluency by FAS and animal naming, and global cognition by the Mini-Mental State Examination. Results show that aerobic PA and HbA1c were not associated with domain-specific, or global cognition, but strength/flexibility PA was associated with FAS (b = 0.404, 95% CI [0.023, 0.761]). Higher aerobic PA was associated with greater verbal fluency for Mexican Americans (b = 0.294, 95% CI [0.96, 0.497]) only. HbA1c was negatively associated with Mini-Mental State Examination (b = 0.838, 95% CI [0.008, 1.656]). For low HbA1c, the association between aerobic PA and Digit Symbol Substitution Test was significant for non-Hispanic Whites (b = 0.838, 95% CI [0.008, 1.656]) in comparison to Mexican Americans. Takeaway for Practice: The relationships between PA, Type 2 diabetes, and cognition vary by cognitive domains and ethnicity. Increasing aerobic activities may be particularly important for Mexican Americans who have elevated HbA1c to potentially improve fluency or executive function.

Slow and Steady Does Not Always Win the Race: Investigating the Effect of Processing Speed across Five Naming Tests.

OBJECTIVE: This retrospective study investigated the effect of processing speed on confrontation naming performance via five naming tests with varying time components. METHOD: The effect of processing speed, as measured by the Wechsler Adult Intelligence Scale-Fourth Edition Processing Speed Index (PSI), and cognitive impairment were examined using Boston Naming Test, Neuropsychological Assessment Battery Naming Test, Visual Naming Test (VNT), Auditory Naming Test (ANT), and Woodcock-Johnson III Rapid Picture Naming (RPN) performance among a mixed clinical sample of 115 outpatient veterans. RESULTS: PSI scores accounted for 5%-26% of the total variance in naming test performances. Comparison of cognitively impaired versus unimpaired participants found significant differences and medium to large effect sizes (η2 = .08-.20) for all naming measures except ANT tip-of-the-tongue responses. After controlling for the effect processing speed, VNT tip-of-the-tongue responses also became non-significant, whereas significant group differences remained present for all other naming test scores, albeit with notably smaller effects sizes (η2 = .06-.10). CONCLUSIONS: Confrontation naming test performance is related to cognitive processing speed, although the magnitude of this effect varies by the demands of each naming test (i.e., largest for RPN; smallest for VNT). Thus, results argue that processing speed is important to consider for accurate clinical interpretation of naming tests, especially in the context of cognitive impairment.