Executive dysfunction, brain aging, and political leadership

Brain network mechanism on cognitive control task in the elderly with brain aging: A functional near infrared spectroscopy study

Objective

To study the brain network mechanism of cognitive control in the elderly with brain aging.

Materials and methods

21 normal young people and 20 elderly people were included in this study. Mini-mental State Examination and functional near-infrared spectroscopy (fNIRS) synchronous judgment test (including forward tests and reverse judgment tests) were performed on all subjects. To observe and compare differences in brain region activation and brain functional connectivity between subjects and forward and reverse trials by recording functional connectivity (FC) in different task paradigms and calculating bilateral prefrontal and primary motor cortical (PMC) areas.

Results

In the forward and reverse judgment tests, the reaction time of the elderly group was significantly longer than the young group (P < 0.05), and there was no significant difference in the correct rate. In the homologous regions of interest (ROI) data, the FC of PMC and prefrontal cortex (PFC) in the elderly group was significantly decreased (P < 0.05). In the heterologous ROI data, except for left primary motor cortex (LPMC)-left prefrontal cortex (LPFC), the other PMC and PFC of the elderly group were significantly lower than the young group (P < 0.05) while processing the forward judgment test. However, the heterologous ROI data of LPMC-right prefrontal cortex (RPFC), LPMC-LPFC and RPFC-LPFC in the elderly group were significantly lower than the young group (P < 0.05) while processing the reverse judgment test.

Conclusion

The results suggest that brain aging affected degeneration of whole brain function, which reduce the speed of information processing and form a brain network functional connection mode different from that of young people.

Cognition and Political Ideology in Aging

OBJECTIVE

The impact of cognitive function and decline on political ideology is unknown. We studied the relationship between cognition and both political orientation and political policy choices in a population of older persons.

DESIGN

Longitudinal investigation.

SETTING

A retirement community and its surroundings in Southern California.

PARTICIPANTS

151 members of a longitudinal investigation of aging and dementia in the oldest-old (the 90+ Study), mean age 95 years.

MEASUREMENTS

Participants self-reported their political ideology (7-point scale from extremely liberal to extremely conservative) and policy preferences for federal spending on public schooling, aid to the poor, and protecting the environment, as well as on preferences on immigration rates, death penalty, and university admission. The same political survey was mailed to participants twice: at time one and 6-months later. Cognitive function based on neurological examination and cognitive testing was classified as normal (55%), cognitive impairment/not dementia (CIND) (33%), or dementia (12%). We calculated rank correlations between ideology and policy choices, stratified by cognitive status, and agreement between Surveys 1 and 2.

RESULTS

Political ideology/orientation was highly consistent over a six-month period (84% agreement) among the 122 who returned the second survey, with no significant relationship to cognitive status. Among cognitively impaired (CIND and dementia), however, there was significant loss of consistency between an individual's political orientation and their policy choices. Level of political engagement was high for participants, with more than 90% voting in the 2016 presidential election.

CONCLUSION

In this population of older persons, political identification on the liberal-conservative spectrum was resilient despite cognitive decline, but its meaning and function were changed. For the cognitively impaired it remained a self-defining label, but no longer operated as a higher order framework for orienting specific policy preferences. There appeared to be loss of coherence between the political orientation and political policy choices of cognitively impaired individuals. Given the high level of political engagement of these individuals, these results have substantial public policy implications.

Effects of sleep-disordered breathing and hypertension on cognitive function in elderly adults

Purpose: The prevalence of sleep-disordered breathing (SDB) increases with aging. SDB is a risk of hypertension, and both might lead to cognitive decline. However, the role of SDB and hypertension on the pathogenesis of age-related cognitive decline remains unclear. We examined the effects of these two diseases on cognitive function in elderly adults.Methods: Fifty-two elderly individuals (mean age, 69.6 ± 4.0 years) free from impairment in daily living activities participated in this study. Apnea/hypopnea index (AHI) and minimum oxygen saturation (SpO₂) were assessed using a portable home monitoring device. We evaluated excessive daytime sleepiness with the Epworth sleepiness scale (ESS). Cognitive performance was assessed using the Wisconsin card sorting test (WCST), continuous performance test-Identical pairs (CPT-IP), and N-back task. Hypertension and diabetes mellitus were evaluated via questionnaire and blood pressure value.Results: The WCST category achievement was significantly lower in participants with minimum SpO₂ <90% than those with minimum SpO₂ ≥90%. The percentage of correct answer on the 0- and 1-back tasks was significantly lower in the hypertensives than normotensives. Minimum SpO₂ was correlated with category achievement on the WCST. Multiple regression analysis including age, sex, body mass index, AHI, minimum SpO₂, ESS, hypertension, and diabetes mellitus revealed that hypertension was the most significant factor for percentage correct answers on the 0- and 1-back tasks. There were no significant correlations between body mass index, ESS or diabetes mellitus and the parameters of WCST, CPT-IP, or N-back tasks.Conclusion: In elderly adults, nocturnal hypoxia and hypertension had a negative effect on cognitive function.