Secular Improvements in Cognitive Aging: Contribution of Education, Health, and Routine Activities

Objectives Limited evidence exists regarding the reasons for secular changes in cognitive functioning over historical time. Thus, we examined potential explanatory factors for changes in cognitive speed, a central dimension of cognitive functioning. Methods Population-based data of middle-aged and older adults from Germany ( N = 5443) was used with baseline participants from 2002 to 2014, comparing the time periods 2002–2014. Results Cognitive speed improved in middle-aged adults (40–65) and older adults (66+). In both age groups, increases were partly explained by education, employment status, volunteering status, routine activities, and physical functioning. Changes in education were more important in explaining increases in older than in middle-aged adults, whereas changes in health were more important for explaining increases in middle-aged adults. Conclusions Cognitive speed increased in both age groups over historical time. Education, employment, volunteering, routine activities, and health were all important in explaining these changes, but their importance differed between age groups.

Cerebrovascular Reserve Capacity as a Predictor of Postoperative Delirium: A Pilot Study

Introduction: Postoperative delirium is a common complication after cardiac surgery with cardiopulmonary bypass (CPB). Compromised regulation of the cerebral circulation may be a predisposing factor for delirium. However, the potential relationship between cerebrovascular reserve capacity and delirium is unknown. The aim of this study was to investigate if impaired cerebrovascular reserve capacity was associated with postoperative delirium.Methods: Forty-two patients scheduled for cardiac surgery with CPB were recruited consecutively. All patients underwent preoperative transcranial Doppler (TCD) ultrasound with calculation of breath-hold index (BHI). BHI < 0.69 indicated impaired cerebrovascular reserve capacity. In addition, patients were examined with preoperative neuropsychological tests such as MMSE (Mini Mental State Examination) and AQT (A Quick Test of cognitive speed). Postoperative delirium was assessed using Nursing Delirium Screening Scale (Nu-DESC) in which a score of ≥2 was considered as delirium.Results: Six patients (14%) scored high for postoperative delirium and all demonstrated impaired preoperative cerebrovascular reserve capacity. Median (25th−75th percentile) BHI in patients with postoperative delirium was significantly lower compared to the non-delirium group [0.26 (−0.08–0.44) vs. 0.83 (0.57–1.08), p = 0.002]. Preoperative MMSE score was lower in patients who developed postoperative delirium (median, 25th−75th percentile; 26.5, 24–28 vs. 28.5, 27–29, p = 0.024). Similarly, patients with postoperative delirium also displayed a slower performance during the preoperative cognitive speed test AQT color and form (mean ± SD; 85.8 s ± 19.3 vs. 69.6 s ± 15.8, p = 0.043).Conclusion: The present findings suggest that an extended preoperative ultrasound protocol with TCD evaluation of cerebrovascular reserve capacity and neuropsychological tests may be valuable in identifying patients with increased risk of developing delirium after cardiac surgery.

Reliability and validity of a quick test of cognitive speed (AQT) in screening for mild cognitive impairment and dementia

Background Cognitive disorders are one of the important issues in old age. There are many cognitive tests, but some variables affect their results (e.g., age and education). This study aimed to evaluate the reliability and validity of A Quick Test of Cognitive Speed (AQT) in screening for mild cognitive impairment (MCI) and dementia. Methods This is a psychometric properties study. 115 older adults participated in the study and were divided into three groups (46 with MCI, 24 with dementia, and 45 control) based on the diagnosis of two geriatric psychiatrists. Participants were assessed by AQT and Mini-Mental State Examination (MMSE). Data were analyzed using Pearson correlation, independent t-test, and ROC curve by SPSS v.23. Results There was no significant correlation between AQT subscales and age and no significant difference between the AQT subscales in sex, educational levels. The test-retest correlations ranges were 0.84 from 097. Concurrent validity was significant between MMSE and AQT. Its correlation was with Color − 0.78, Form − 0.71, and Color-Form − 0.72. The cut-off point for Color was 43.50 s, Form 52 s, and Color-Form 89 s were based on sensitivity and specificity for differentiating older patients with MCI with controls. The cut-off point for Color was 62.50 s, for Form 111 s, and Color-Form 197.50 s based on sensitivity and specificity measures for differentiating older patients with dementia and MCI. Conclusion The findings showed that AQT is a suitable tool for screening cognitive function in older adults.

Tbx1, a gene encoded in 22q11.2 copy number variant, is a link between alterations in fimbria myelination and cognitive speed in mice

Copy number variants (CNVs) have provided a reliable entry point to identify the structural correlates of atypical cognitive development. Hemizygous deletion of human chromosome 22q11.2 is associated with impaired cognitive function; however, the mechanisms by which the CNVs contribute to cognitive deficits via diverse structural alterations in the brain remain unclear. This study aimed to determine the cellular basis of the link between alterations in brain structure and cognitive functions in mice with a heterozygous deletion of Tbx1, one of the 22q11.2-encoded genes. Ex vivo whole-brain diffusion-tensor imaging (DTI)–magnetic resonance imaging (MRI) in Tbx1 heterozygous mice indicated that the fimbria was the only region with significant myelin alteration. Electron microscopic and histological analyses showed that Tbx1 heterozygous mice exhibited an apparent absence of large myelinated axons and thicker myelin in medium axons in the fimbria, resulting in an overall decrease in myelin. The fimbria of Tbx1 heterozygous mice showed reduced mRNA levels of Ng2, a gene required to produce oligodendrocyte precursor cells. Moreover, postnatal progenitor cells derived from the subventricular zone, a source of oligodendrocytes in the fimbria, produced fewer oligodendrocytes in vitro. Behavioral analyses of these mice showed selectively slower acquisition of spatial memory and cognitive flexibility with no effects on their accuracy or sensory or motor capacities. Our findings provide a genetic and cellular basis for the compromised cognitive speed in patients with 22q11.2 hemizygous deletion.

Are cognition and personality related in budgerigars?

In recent years, researchers have been attempting to relate differences in personality (e.g., boldness, aggressiveness, exploration tendency) to variation in cognition (performances in tasks that require learning, reasoning, attention, or memory, etc.) both theoretically and empirically. However, it is unclear on what basis personality and cognition might be associated with each other. Previous theory suggests a connection between fast–slow personality types and cognitive speed–accuracy tradeoffs. In this study, we tested this hypothesis in budgerigars and found that, in their 1st associative learning, birds with fast personality (less fearful of handling stress) were fast learners in the beginning, while slow personality individuals improved faster, but both types of birds did not differ in accuracy. However, these relationships were context-dependent. No significant relationship was found in subsequent learning tasks (reversal learning and a 2nd associative learning) in the familiar context (task setup and apparatus similar to the 1st associative learning). We then conducted a problem-solving experiment with novel setup and apparatus to test 1 possible explanation that the association between personality and cognition in the 1st associative learning might be caused by noncognitive constraint, such as fearfulness when facing novel task setup and apparatus. We found that fast individuals interacted more with the problem box and solved it, whereas the slow birds were not. We suggest that personalities can influence cognitive performances and trigger a cognitive speed-improvement tradeoff under the novel context. However, there are no consistent cognitive styles that co-varied with different personalities.

A-125 The Impact of Bilingualism on Symbol Digit Modalities Test Performance Following Traumatic Brain Injury

Objective Traumatic brain injury (TBI) survivors exhibit cognitive deficits. Research suggests that multilingualism can influence neurocognitive performance. We examined the effects of TBI and bilingualism/monolingualism on a test of attention and cognitive speed (i.e., Symbol Digit Modalities Test; SDMT). Method The sample consisted of 55 healthy comparison (27 Spanish-English bilinguals; 28 English-monolinguals), 34 acute TBI (14 Spanish-English bilinguals; 23 English-monolinguals), and 27 chronic TBI (13 Spanish-English bilinguals; 12 English-monolinguals) participants. Acute TBI participants were tested 6 months post-injury; chronic TBI participants were tested 12 months or more post-injury. A series of 3X2 ANOVAs were conducted to determine the effect of TBI and language on SDMT written and oral performance. Results ANOVAs revealed the healthy comparison group outperformed both TBI groups on SDMT written, p = 0.000, ηp2 = 0.21. Also, the healthy comparison and chronic TBI groups outperformed the acute TBI group on SDMT oral, p = 0.000, ηp2 = 0.13. Interaction effects emerged between TBI and bilingualism/monolingualism. On SDMT written and oral, acute TBI English-monolinguals outperformed acute TBI Spanish-English bilinguals; meanwhile, chronic TBI Spanish-English bilinguals outperformed chronic TBI English-monolinguals, p < 0.05, ηp2 = 0.09–0.10. Conclusion The acute TBI group performed worse than healthy comparison adults on both SDMT tasks. Furthermore, the chronic TBI group demonstrated better SDMT oral abilities compared to the acute TBI group. Relative to monolinguals with TBI, our findings suggest better cognitive recovery of attention and cognitive speed in bilingual TBI participants. Future studies with larger sample sizes should examine if learning English first or second impacts Spanish-English bilingual TBI survivors’ SDMT performance compared to English-monolingual TBI survivors.

Modulation of Working Memory and Resting-State fMRI by tDCS of the Right Frontoparietal Network

Many cognitive functions, including working memory, are processed within large-scale brain networks. We targeted the right frontoparietal network (FPN) with one session of transcranial direct current stimulation (tDCS) in an attempt to modulate the cognitive speed of a visual working memory task (WMT) in 27 young healthy subjects using a double-blind crossover design. We further explored the neural underpinnings of induced changes by performing resting-state fMRI prior to and immediately after each stimulation session with the main focus on the interaction between a task-positive FPN and a task-negative default mode network (DMN). Twenty minutes of 2 mA anodal tDCS was superior to sham stimulation in terms of cognitive speed manipulation of a subtask with processing of objects and tools in unconventional views (i.e., the higher cognitive load subtask of the offline WMT). This result was linked to the magnitude of resting-state functional connectivity decreases between the stimulated FPN seed and DMN seeds. We provide the first evidence for the action reappraisal mechanism of object and tool processing. Modulation of cognitive speed of the task by tDCS was reflected by FPN-DMN cross-talk changes.

Effects of head-down tilt bed rest plus elevated CO2 on cognitive performance

NEW AND NOTEWORTHY This study investigated the effects of prolonged head-down tilt bed rest with and without elevated (3.73 mmHg) levels of ambient CO2 on cognitive performance across a range of cognitive domains and is one of the few studies investigating combined effects of environmental stressors prevalent in spaceflight. The study showed moderate declines in cognitive speed induced by head-down tilt bed rest and suggests that exposure to elevated levels of ambient CO2 did not modify this effect.