Age-Related Difference in Relationships Between Cognitive Processing Speed and General Cognitive Status

Temporal Pattern of Cortical Hypoxia in Multiple Sclerosis and Its Significance on Neuropsychological and Clinical Measures of Disability

OBJECTIVE

Multiple sclerosis (MS) is a degenerative disease of the central nervous system (CNS) characterized by inflammation, demyelination, and axonal damage. It has been hypothesized that hypoxia plays a role in the pathogenesis of MS. This study was undertaken to investigate the reproducibility of non-invasively measured cortical microvascular hemoglobin oxygenation (St O2 ) using frequency domain near-infrared spectroscopy (fdNIRS), investigate its temporal pattern of hypoxia in people with MS (pwMS), and its relationship with neurocognitive function and mood.

METHODS

We investigated the reproducibility of fdNIRS measurements. We measured cortical hypoxia in pwMS, and the relationships between St O2 , neurocognitive function, fatigue, and measures of physical disability. Furthermore, we cataloged the temporal pattern of St O2 measured at 1-week intervals for 4 weeks, and at 8 weeks and ~1 year.

RESULTS

We show that fdNIRS parameters were highly reproducible in 7 healthy control participants measured over 6 days (p > 0.05). There was low variability between and within subjects. In line with our previous findings, we show that 33% of pwMS (n = 88) have cortical microvascular hypoxia. Over 8 weeks and at ~1 year, St O2 values for normoxic and hypoxic groups did not change significantly. There was no significant association between cognitive function and St O2 . This conclusion should be revisited as only a small proportion of the relapsing-remitting MS group (21%) was cognitively impaired.

INTERPRETATION

The fdNIRS parameters have high reproducibility and repeatability, and we have demonstrated that hypoxia in MS is a chronic condition, lasting at least a year. The results show a weak relationship between cognitive functioning and oxygenation, indicating future study is required. ANN NEUROL 2023;94:1067-1079.

Predictors of longitudinal cognitive ageing from age 70 to 82 including APOE e4 status, early-life and lifestyle factors: the Lothian Birth Cohort 1936

Discovering why some people's cognitive abilities decline more than others is a key challenge for cognitive ageing research. The most effective strategy may be to address multiple risk factors from across the life-course simultaneously in relation to robust longitudinal cognitive data. We conducted a 12-year follow-up of 1091 (at age 70) men and women from the longitudinal Lothian Birth Cohort 1936 study. Comprehensive repeated cognitive measures of visuospatial ability, processing speed, memory, verbal ability, and a general cognitive factor were collected over five assessments (age 70, 73, 76, 79, and 82 years) and analysed using multivariate latent growth curve modelling. Fifteen life-course variables were used to predict variation in cognitive ability levels at age 70 and cognitive slopes from age 70 to 82. Only APOE e4 carrier status was found to be reliably informative of general- and domain-specific cognitive decline, despite there being many life-course correlates of cognitive level at age 70. APOE e4 carriers had significantly steeper slopes across all three fluid cognitive domains compared with non-carriers, especially for memory (β = -0.234, p < 0.001) and general cognitive function (β = -0.246, p < 0.001), denoting a widening gap in cognitive functioning with increasing age. Our findings suggest that when many other candidate predictors of cognitive ageing slope are entered en masse, their unique contributions account for relatively small proportions of variance, beyond variation in APOE e4 status. We conclude that APOE e4 status is important for identifying those at greater risk for accelerated cognitive ageing, even among ostensibly healthy individuals.

Does the frequency of reading and writing habits contribute to executive functions, intelligence, and learning in adolescents with healthy development?

The influence of the frequency of reading and writing habits (FRWH) on cognition has been investigated by several studies in the literature. However, the implications of FRWH on executive development, intelligence, and academic achievement are not yet clear in adolescents with healthy development. The aim was to verify whether there are differences in executive functions, intelligence, and academic achievement between adolescents with high and low FRWH. Moreover, we aimed to investigate if there are differences in the parental FRWH between adolescents with high and low FRWH. The sample was composed of 47 healthy adolescents, n = 24 with high FRWH and n = 23 with low FRWH. Adolescents with higher FRWH had better performance on measures of vocabulary, Speech Act analysis, and Oral Narrative Discourse. Therefore, a high FRWH has a positive influence on the cognitive development of healthy adolescents, especially with regard to pragmatic language. However, adolescents with low FRWH performed better than those with a high FRWH on an automatic counting task. The interpretation of cognitive performance and academic achievement scores in neuropsychological assessment should consider the FRWH of parents and adolescents. This factor should be targeted by early stimulation interventions to help adolescents achieve the highest possible levels of global development.

Predictors of functional impairment and awareness in people with dementia, mild cognitive impairment and healthy older adults from a middle-income country

OBJECTIVE

To investigate the demographic, clinical and cognitive correlates of functional capacity and its awareness in people with dementia (PwD; n = 104), mild cognitive impairment (PwMCI; n = 45) and controls (healthy older adults; n = 94) in a sample from a middle-income country.

METHODS

Dementia and MCI were diagnosed, respectively, with DSM-IV and Petersen criteria. Performance in activities of daily living (ADL) at three different levels [basic (The Katz Index of Independence), instrumental (Lawton instrumental ADL scale) and advanced (Reuben's advanced ADL scale)], measured through self- and informant-report, as well as awareness (discrepancy between self- and informant-report), were compared between groups. Stepwise regression models explored predictors of ADL and their awareness.

RESULTS

PwD showed impairment in all ADL levels, particularly when measured through informant-report. No differences were seen between controls and PwMCI regardless of measurement type. PwD differed in awareness of instrumental and basic, but not of advanced ADL, compared to controls. Age, gender, education and fluency were the most consistent predictors for ADL. Diagnosis was a significant predictor only for instrumental ADL. Awareness of basic ADL was predicted by memory, and awareness of instrumental ADL was predicted by general cognitive status, educational level, and diagnosis.

CONCLUSION

Results reinforce the presence of lack of awareness of ADL in PwD. Use of informant-reports and cognitive testing for fluency are suggested for the clinical assessment of ADL performance. Finally, assessment of instrumental ADL may be crucial for diagnostic purposes.

Proportional Changes in Cognitive Subdomains During Normal Brain Aging

Background: Neuroscience lacks a reliable method of screening the early stages of dementia. Objective: To improve the diagnostics of age-related cognitive functions by developing insight into the proportionality of age-related changes in cognitive subdomains. Materials and Methods: We composed a battery of psychophysiological tests and collected an open-access psychophysiological outcomes of brain atrophy (POBA) dataset by testing individuals without dementia. To extend the utility of machine learning (ML) classification in cognitive studies, we proposed estimates of the disproportional changes in cognitive functions: an index of simple reaction time to decision-making time (ISD), ISD with the accuracy performance (ISDA), and an index of performance in simple and complex visual-motor reaction with account for accuracy (ISCA). Studying the distribution of the values of the indices over age allowed us to verify whether diverse cognitive functions decline equally throughout life or there is a divergence in age-related cognitive changes. Results: Unsupervised ML clustering shows that the optimal number of homogeneous age groups is four. The sample is segregated into the following age-groups: Adolescents ∈ [0, 20), Young adults ∈ [20, 40), Midlife adults ∈ [40, 60) and Older adults ≥60 year of age. For ISD, ISDA, and ISCA values, only the median of the Adolescents group is different from that of the other three age-groups sharing a similar distribution pattern (p > 0.01). After neurodevelopment and maturation, the indices preserve almost constant values with a slight trend toward functional decline. The reaction to a moving object (RMO) test results (RMO_mean) follow another tendency. The Midlife adults group's median significantly differs from the remaining three age subsamples (p < 0.01). No general trend in age-related changes of this dependent variable is observed. For all the data (ISD, ISDA, ISCA, and RMO_mean), Levene's test reveals no significant changes of the variances in age-groups (p > 0.05). Homoscedasticity also supports our assumption about a linear dependency between the observed features and age. Conclusion: In healthy brain aging, there are proportional age-related changes in the time estimates of information processing speed and inhibitory control in task switching. Future studies should test patients with dementia to determine whether the changes of the aforementioned indicators follow different patterns.

Resuscitation of the Critically Ill Older Adult

In 30 years, adults 65 and older will represent 20% of the US population, with increased medical comorbidities leading to higher rates of critical illness and mortality. Despite significant acute illness, presenting symptoms and vital sign abnormalities may be subtle. Resuscitative guidelines are a helpful starting point but appropriate diagnostics, bedside ultrasound, and frequent reassessments are needed to avoid procrustean care that may worsen outcomes. Baseline functional status is as important as underlying comorbid conditions when prognosticating, and the patient's personal wishes should be sought early and throughout care with clear communication regarding prospects for immediate survival and overall recovery.

Drug Safety in Geriatric Patients: Current Status and Proposed Way Forward

Elderly patients are the main users of drugs and they differ from younger patients. They are a heterogeneous population that cannot be defined only by age but should rather be stratified based on their frailty. The elderly have distinctive pharmacokinetic and pharmacodynamic characteristics, are frequently polymorbid, and are therefore treated with multiple drugs. They may experience adverse reactions that are difficult to recognize, since some of them present non-specific symptoms easily mistaken for geriatric conditions. Paradoxically, the elderly are underrepresented in clinical trials, especially the frail individuals whose pharmacological response and expected treatment outcome can be different from those of non-frail patients. This means that the benefit-risk balance of drugs used in frail elderly patients is frequently unknown. We present some proposals to overcome the barriers preventing the enrollment of frail elderly patients in clinical trials, and strategies for monitoring their therapy to minimize the risk of adverse reactions. Automated alerts for drug and drug-disease interactions could help appropriate prescribing but should flag only clinically relevant interactions. Pharmaceutical forms should be designed to allow easy dose adjustment and, together with packaging and labeling, should account for the physical and cognitive limitations of frail elderly patients. Aggregate pharmacovigilance reports should summarize the safety profile in the elderly, but rather than presenting the results by age they should focus on patients' frailty, perhaps using the number of comorbidities as a proxy when information on frailty is not available.

Nurse-Led Computerized Cognitive Training for Mild Cognitive Impairment: A Preliminary Study

PURPOSE

This preliminary study aimed to compare the outcomes of an occupational therapist-led and a nurse-led computerized cognitive training (CCT) for mild cognitive impairment (MCI) in older adults.

DESIGN

A single-blind randomized controlled trial was performed.

METHODS

Participants 65 years of age and older with MCI were randomly assigned to a group led by an occupational therapist or by a nurse. Both groups received CCT for 4 weeks.

FINDINGS

Six participants in the occupational therapist-led group and nine in the nurse-led group completed CCT. The nurse-led group showed significant improvement in scores on the Seoul Verbal Learning Test-Elderly's version immediate recall scores (p = .030) and the Korean-Boston Naming Test (p = .012).

CONCLUSIONS

Nurse-led CCT demonstrated improvement in some language and memory areas in older adults with MCI.

CLINICAL RELEVANCE

This study supports the idea of educating nurses to use a CCT program for treating older adults with MCI to improve their cognitive function.

The Role of Sensory Function in Processing Speed and Working Memory Aging

BACKGROUND

Sensory function, processing speed, and working memory are considered to be mechanisms that play important explanatory roles in age-related decline of cognitive abilities. As individuals age, sensory function declines along with other cognitive abilities, including processing speed and working memory. Moreover, the relationship between sensory function, processing speed, and working memory, which represent the most basic mechanism, is one of the important issues in the field of cognitive aging.

METHODS

To explore the role of sensory function, especially visual function, in processing speed and working memory aging, the present study adopted a 2 (age: young and old) × 4 (visual perceptual stress: high, medium, low, and non-stress) mixed design and explored age differences in tasks testing processing speed and working memory. To generate different levels of visual perceptual stress, test materials were masked with Gaussian noise according to each individual's visual function.

RESULTS

The results indicated that age differences in processing speed were not influenced by different levels of visual perceptual stress, while age differences in working memory performance decreased gradually with the increase of visual perceptual stress.

CONCLUSION

Visual function affected age differences in working memory rather than in processing speed. The common-cause hypothesis and information-degradation hypothesis were applied to interpret the relationships between visual function and processing speed and between visual function and working memory, respectively. Moreover, sensory function may not directly affect working memory function, which was also consistent with a resource decrement model of aging.

A study of the influence of cognitive complaints, cognitive performance and symptoms of anxiety and depression on self-efficacy in patients with acquired brain injury

OBJECTIVE:

To examine the relationship between self-efficacy for managing brain injury-specific symptoms and cognitive performance, subjective cognitive complaints and anxiety and depression symptoms in patients with acquired brain injury (ABI).

DESIGN:

Clinical cohort study.

SETTING:

General hospitals, rehabilitation centres.

SUBJECTS:

A total of 122 patients with newly ABI (mean age = 54.4 years (SD, 12.2)) were assessed at discharge home from inpatient neurorehabilitation or at start of outpatient neurorehabilitation after discharge home from acute hospital. Mean time since injury was 14.1 weeks (SD, 8.6).

MAIN MEASURES:

Self-efficacy was measured using the Traumatic Brain Injury (TBI) Self-Efficacy Questionnaire (SEsx), mean score = 82.9 (SD, 21.8). Objective cognitive performance was measured with the Symbol Digit Modalities Test (SDMT), mean z-score = -1.36 (SD, 1.31). Anxiety and depression symptoms were measured with the Hospital Anxiety and Depression Scale (HADS), cognitive complaints with the self-rating form of the Dysexecutive Questionnaire (DEX-P).

RESULTS:

Higher levels of subjective cognitive complaints and higher levels of anxiety and depression symptoms were significantly associated with lower self-efficacy (β = -0.35; P = .001 and β =-0.43; P < .001, respectively). Objective cognitive performance was not significantly associated with self-efficacy (β = 0.04, P = .53). DEX-P scores accounted for 42% and HADS scores for 7% of the total 57% variance explained. Objective cognitive performance did not correlate significantly with subjective cognitive complaints (r = -.13, P = .16).

CONCLUSION:

Control over interfering emotions and mastery over brain injury-associated symptoms seems important in the development of self-efficacy for managing brain injury-specific symptoms.

Cognitive Vulnerability in Aging May Be Modulated by Education and Reserve in Healthy People

Aging is related to a deterioration of cognitive performance and to multiple alterations in the brain. Even before the beginning of a noticeable cognitive decline, the framework which holds cognitive function experiences these alterations. From a system-vulnerability point of view of cognition, the deterioration associated with age would be the collection of repercussions during a life. Brain function and structure are modified in a multidimensional way, which could concern different aspects like structural integrity, functional activity, connectivity, or glucose metabolism. From this point of view, the effects of aging could affect the most brain systems and their functional activity. In this study, we analyze the functional development of three cognitive domains in relation to aging, educational level, and cognitive reserve (CR). A total of 172 healthy subjects were divided into two age groups (young and old), and completed a battery of classic neuropsychological tests. The tests were organized and analyzed according to three cognitive domains: working memory and flexibility, visuoconstructive functions, and declarative memory. Subjects also completed a questionnaire on CR. Results showed that the performance in all cognitive domains decreased with age. In particular, tests related to working memory, flexibility, and visuoconstructive abilities were influenced by age. Nevertheless, this effect was attenuated by effects of education, mainly in visuoconstructive domain. Surprisingly, visual as well as verbal memory tests were not affected either by aging, education, or CR. Brain plasticity plays a prominent role in the aging process, but, as other studies have shown, the plasticity mechanism is quite different in healthy vs. pathological brains. Moreover, this plasticity brain mechanism could be modulated by education and CR. Specially, cognitive domains as working memory, some executive functions and the visuoconstructive abilities seem to be modulated by education. Therefore, it seems to be crucial, to propose mechanisms of maintenance of a healthy and enriched brain, since it promotes auto-regulatory mechanisms of well-aging.

Cognitive Processing Speed across the Lifespan: Beyond the Influence of Motor Speed

Traditional neuropsychological measurement of cognitive processing speed with tasks such as the Symbol Search and Coding subsets of the WAIS-IV, consistently show decline with advancing age. This is potentially problematic with populations where deficits in motor performance are expected, i.e., in aging or stroke populations. Thus, the aim of the current study was to explore the contribution of hand motor speed to traditional paper-and-pencil measures of processing speed and to a simple computer-customized non-motor perception decision task, the Inspection Time (IT) task. Participants were 67 young university students aged between 18 and 29 (59 females), and 40 older adults aged between 40 and 81 (31 females) primarily with a similar education profile. As expected, results indicated that age group differences were highly significant on the motor dexterity, Symbol Search and Coding tasks. However, no significant differences or correlations were seen between age groups and the simple visual perception IT task. Furthermore, controlling for motor dexterity did not remove significant age-group differences on the paper-and-pencil measures. This demonstrates that although much of past research into cognitive decline with age is confounded by use of motor reaction times as the operational measure, significant age differences in cognitive processing also exist on more complex tasks. The implications of the results are crucial in the realm of aging research, and caution against the use of traditional WAIS tasks with a clinical population where motor speed may be compromised, as in stroke.

Cognitive processing speed mediates the effects of cardiovascular disease on executive functioning

OBJECTIVE

The goal of this study was to examine the hypothesized mediating role of cognitive processing speed (CPS) in the relationship between cardiovascular disease (CVD) and executive functioning (EF). We investigated whether the processing-speed hypothesis in aging also explains the unique contribution that CPS may have to EF deficits in CVD patients.

METHOD

A neuropsychological assessment, including multiple measures of CPS and EF, was administered to 21 older adults with a history of CVD and 73 older adults with no history of CVD. Structural equation models were used to measure the indirect associations between CVD and 6 EF task outcomes through a CPS factor. Competing indirect links were assessed using the product-of-coefficients (α*β) approach with bias-corrected bootstrap confidence intervals.

RESULTS

CVD was significantly, negatively related to CPS (β = -.239, 95% CI [-.457, -.021]). CPS was significantly, positively related to an EF composite score (β = .566, 95% CI [.368, .688]). CVD was significantly, negatively related to the EF composite score (β = -.137, 95% CI [-.084, -.211]). The indirect links from CVD to the individual measures of the EF composite score via CPS were all significant. CVD most adversely affected tasks of cognitive flexibility and inhibition indirectly through CPS.

CONCLUSION

With the present study, we have demonstrated that the processing-speed hypothesis in aging extends to older adult patients with CVD. Reduced CPS significantly underlies the link between CVD status and poorer EF. Individuals with CVD demonstrated poorer CPS and EF than those without CVD, and CPS was specifically implicated as a CVD-related mechanism leading to worse EF. (PsycINFO Database Record

Neural Plastic Effects of Cognitive Training on Aging Brain

Increasing research has evidenced that our brain retains a capacity to change in response to experience until late adulthood. This implies that cognitive training can possibly ameliorate age-associated cognitive decline by inducing training-specific neural plastic changes at both neural and behavioral levels. This longitudinal study examined the behavioral effects of a systematic thirteen-week cognitive training program on attention and working memory of older adults who were at risk of cognitive decline. These older adults were randomly assigned to the Cognitive Training Group (n = 109) and the Active Control Group (n = 100). Findings clearly indicated that training induced improvement in auditory and visual-spatial attention and working memory. The training effect was specific to the experience provided because no significant difference in verbal and visual-spatial memory between the two groups was observed. This pattern of findings is consistent with the prediction and the principle of experience-dependent neuroplasticity. Findings of our study provided further support to the notion that the neural plastic potential continues until older age. The baseline cognitive status did not correlate with pre- versus posttraining changes to any cognitive variables studied, suggesting that the initial cognitive status may not limit the neuroplastic potential of the brain at an old age.