Cognitive Processing Speed Is Strongly Related to Driving Skills, Financial Abilities, and Other Instrumental Activities of Daily Living in Persons With Mild Cognitive Impairment and Mild Dementia

Prediction and mediation analysis for treatment responses to combined cognitive and physical training for older adults

Diminished cognitive and physical functions negatively affect the daily functions of individuals. Although combined cognitive and physical training prevents instrumental activities of daily living (IADL) disability in older adults, no predictive model or mediation analysis of IADL after combined training exists. This study aims to employ prediction and mediation analysis to identify the predictors of IADL performance and to elucidate the mediators of the association between baseline global cognition and subsequent IADL performance following combined cognitive and physical training. This study involved 177 participants aged 60 years and older who underwent combined training. Cognitive function was measured with the Montreal Cognitive Assessment (MoCA), Digit Symbol Substitution Test (DSST), Color Trails Test, Word List, and a dual task; physical function with the Timed Up and Go (TUG) test; daily function with the Lawton IADL Scale. We conducted regression analyses to identify the predictors of IADL performance, and mediation analysis to examine whether DSST and TUG mediate the relationship between MoCA and IADL. The pre-intervention DSST and TUG were significant independent predictors of post-intervention IADL. The association between the pre-intervention MoCA and post-intervention IADL was mediated by pre-intervention DSST and TUG. This study highlighted the importance of measuring and improving processing speed and functional mobility before and during interventions to enhance IADL outcomes.Trial registration: NCT03619577, 23/07/2018; NCT04689776, 29/12/2020.

Cardiovascular Health, Race, and Decline in Cognitive Function in Midlife Women: The Study of Women's Health Across the Nation

BACKGROUND

Cognitive decline may progress for decades before dementia onset. Better cardiovascular health (CVH) has been related to less cognitive decline, but it is unclear whether this begins early, for all racial subgroups, and all domains of cognitive function. The purpose of this study was to determine the impact of CVH on decline in the 2 domains of cognition that decline first in White and Black women at midlife.

METHODS AND RESULTS

Subjects were 363 Black and 402 White women, similar in baseline age (mean±SD, 46.6±3.0 years) and education (15.7±2.0 years), from the Chicago site of the Study of Women's Health Across the Nation. Cognition, measured as processing speed and working memory, was assessed annually or biennially over a maximum of 20 years (mean±SD, 9.8±6.7 years). CVH was measured as Life's Essential 8 (blood pressure, body mass index, glucose, non-high-density lipoprotein cholesterol, smoking, physical activity, diet, sleep). Hierarchical linear mixed models identified predictors of cognitive decline with progressive levels of adjustment. There was a decline in processing speed that was explained by race, age, and the 3-way interaction of race, CVH, and time (F1,4308=8.8, P=0.003). CVH was unrelated to decline in White women but in Black women poorer CVH was associated with greater decline. Working memory did not decline in the total cohort, by race, or by CVH.

CONCLUSIONS

In midlife Black women, CVH promotion may be a target for preventing the beginnings of cognitive decline, thereby enhancing independent living with aging.

Cognitive and mental health trajectories of COVID-19: Role of hospitalisation and long-COVID symptoms

BACKGROUND

There is considerable evidence of cognitive impairment post COVID-19, especially in individuals with long-COVID symptoms, but limited research objectively evaluating whether such impairment attenuates or resolves over time, especially in young and middle-aged adults.

METHODS

Follow-up assessments (T2) of cognitive function (processing speed, attention, working memory, executive function, memory) and mental health were conducted in 138 adults (18-69 years) who had been assessed 6 months earlier (T1). Of these, 88 had a confirmed history of COVID-19 at T1 assessment (≥20 days post-diagnosis) and were also followed-up on COVID-19-related symptoms (acute and long-COVID); 50 adults had no known COVID-19 history at any point up to their T2 assessment.

RESULTS

From T1 to T2, a trend-level improvement occurred in intra-individual variability in processing speed in the COVID, relative to the non-COVID group. However, longer response/task completion times persisted in participants with COVID-19-related hospitalisation relative to those without COVID-19-related hospitalisation and non-COVID controls. There was a significant reduction in long-COVID symptom load, which correlated with improved executive function in non-hospitalised COVID-19 participants. The COVID group continued to self-report poorer mental health, irrespective of hospitalisation history, relative to non-COVID group.

CONCLUSIONS

Although some cognitive improvement has occurred over a 6-month period in young and middle-aged COVID-19 survivors, cognitive impairment persists in those with a history of COVID-19-related hospitalisation and/or long-COVID symptoms. Continuous follow-up assessments are required to determine whether cognitive function improves or possibly worsens, over time in hospitalised and long-COVID participants.

Cognitive and emotional predictors of quality of life and functioning after COVID-19

OBJECTIVE

A long-term decline in health-related quality of life (HRQoL) has been reported after coronavirus disease 2019 (COVID-19). Studies with people with persistent symptoms showed inconsistent outcomes. Cognition and emotion are important determinants in HRQoL, but few studies have examined their prognostic significance for HRQoL and functionality in post-COVID patients with persisting symptoms. We aimed to describe QoL, HRQoL, and functioning in individuals post-COVID with varying COVID-19 severities and to investigate the predictive value of cognitive and emotional variables for QoL, HRQoL, and functioning.

METHODS

In total, 492 participants (398 post-COVID and 124 healthy controls) underwent a neurobehavioral examination that included assessments of cognition, mood, QoL/HRQoL (WHOQOL-BREF, EQ-5D), and functioning (WHODAS-II). Analysis of covariance and linear regression models were used to study intergroup differences and the relationship between cognitive and emotional variables and QoL and functioning.

RESULTS

The Physical and Psychological dimensions of WHOQoL, EQ-5D, and WHODAS Cognition, Mobility, Life Activities, and Participation dimensions were significantly lower in post-COVID groups compared with a control group. Regression models explaining 23.9%-53.9% of variance were obtained for the WHOQoL-BREF dimensions and EQ-5D, with depressive symptoms, post-COVID symptoms, employment status, income, and mental speed processing as main predictors. For the WHODAS, models explaining 17%-60.2% of the variance were obtained. Fatigue, depressive symptoms, mental speed processing, and post-COVID symptoms were the main predictors.

INTERPRETATION

QoL/HRQoL and functioning after COVID-19 in individuals with persistent symptoms were lower than in non-affected persons. Depressive symptoms, fatigue, and slower mental processing speed were predictors of lower QoL/HRQoL and functioning.

Processing Speed and Attentional Shift/Mental Flexibility in Patients with Stroke: A Comprehensive Review on the Trail Making Test in Stroke Studies

The Trail Making Test (TMT) is one of the most commonly administered tests in clinical and research neuropsychological settings. The two parts of the test (part A (TMT-A) and part B (TMT-B)) enable the evaluation of visuoperceptual tracking and processing speed (TMT-A), as well as divided attention, set-shifting and cognitive flexibility (TMT-B). The main cognitive processes that are assessed using TMT, i.e., processing speed, divided attention, and cognitive flexibility, are often affected in patients with stroke. Considering the wide use of TMT in research and clinical settings since its introduction in neuropsychological practice, the purpose of our review was to provide a comprehensive overview of the use of TMT in stroke patients. We present the most representative studies assessing processing speed and attentional shift/mental flexibility in stroke settings using TMT and applying scoring methods relying on conventional TMT scores (e.g., time-to-complete part A and part B), as well as derived measures (e.g., TMT-(B-A) difference score, TMT-(B/A) ratio score, errors in part A and part B). We summarize the cognitive processes commonly associated with TMT performance in stroke patients (e.g., executive functions), lesion characteristics and neuroanatomical underpinning of TMT performance post-stroke, the association between TMT performance and patients' instrumental activities of daily living, motor difficulties, speech difficulties, and mood statue, as well as their driving ability. We also highlight how TMT can serve as an objective marker of post-stroke cognitive recovery following the implementation of interventions. Our comprehensive review underscores that the TMT stands as an invaluable asset in the stroke assessment toolkit, contributing nuanced insights into diverse cognitive, functional, and emotional dimensions. As research progresses, continued exploration of the TMT potential across these domains is encouraged, fostering a deeper comprehension of post-stroke dynamics and enhancing patient-centered care across hospitals, rehabilitation centers, research institutions, and community health settings. Its integration into both research and clinical practice reaffirms TMT status as an indispensable instrument in stroke-related evaluations, enabling holistic insights that extend beyond traditional neurological assessments.

Persistent cognitive slowing in post-COVID patients: longitudinal study over 6 months

BACKGROUND

Fatigue is a frequent and one of the most debilitating symptoms in post-COVID syndrome (PCS). Recently, we proposed that fatigue is caused by hypoactivity of the brain's arousal network and reflected by a reduction of cognitive processing speed. However, it is unclear whether cognitive slowing is revealed by standard neuropsychological tests, represents a selective deficit, and how it develops over time.

OBJECTIVES

This prospective study assesses whether PCS patients show deficits particularly in tests relying on processing speed and provides the first longitudinal assessment focusing on processing speed in PCS patients.

METHODS

Eighty-eight PCS patients with cognitive complaints and 50 matched healthy controls underwent neuropsychological assessment. Seventy-seven patients were subsequently assessed at 6-month follow-up. The Test for Attentional Performance measured tonic alertness as primary study outcome and additional attentional functions. The Neuropsychological Assessment Battery evaluated all key cognitive domains.

RESULTS

Patients showed cognitive slowing indicated by longer reaction times compared to control participants (r = 0.51, p < 0.001) in a simple-response tonic alertness task and in all more complex tasks requiring speeded performance. Reduced alertness correlated with higher fatigue (r =  - 0.408, p < 0.001). Alertness dysfunction remained unchanged at 6-month follow-up (p = 0.240) and the same was true for most attention tasks and cognitive domains.

CONCLUSION

Hypoarousal is a core deficit in PCS which becomes evident as a selective decrease of processing speed observed in standard neuropsychological tests. This core deficit persists without any signs of amelioration over a 6-month period of time.

The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment

As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.

Brain Representation of Animal and Non-Animal Images in Patients with Mild Cognitive Impairment and Alzheimer's Disease

Background

In early Alzheimer's disease (AD), high-level visual functions and processing speed are impacted. Few functional magnetic resonance imaging (fMRI) studies have investigated high-level visual deficits in AD, yet none have explored brain activity patterns during rapid animal/non-animal categorization tasks.

Objective

To address this, we utilized the previously known Integrated Cognitive Assessment (ICA) to collect fMRI data and compare healthy controls (HC) to individuals with mild cognitive impairment (MCI) and mild AD.

Methods

The ICA encompasses a rapid visual categorization task that involves distinguishing between animals and non-animals within natural scenes. To comprehensively explore variations in brain activity levels and patterns, we conducted both univariate and multivariate analyses of fMRI data.

Results

The ICA task elicited activation across a range of brain regions, encompassing the temporal, parietal, occipital, and frontal lobes. Univariate analysis, which compared responses to animal versus non-animal stimuli, showed no significant differences in the regions of interest (ROIs) across all groups, with the exception of the left anterior supramarginal gyrus in the HC group. In contrast, multivariate analysis revealed that in both HC and MCI groups, several regions could differentiate between animals and non-animals based on distinct patterns of activity. Notably, such differentiation was absent within the mild AD group.

Conclusions

Our study highlights the ICA task's potential as a valuable cognitive assessment tool designed for MCI and AD. Additionally, our use of fMRI pattern analysis provides valuable insights into the complex changes in brain function associated with AD. This approach holds promise for enhancing our understanding of the disease's progression.

The functional relevance of visuospatial processing speed across the lifespan

Visuospatial processing speed underlies several cognitive functions critical for successful completion of everyday tasks, including driving and walking. While it is widely accepted that visuospatial processing speed peaks in early adulthood, performance across the lifespan remains incompletely characterized. Additionally, there remains a lack of paradigms available to assess visuospatial processing speed in unsupervised web-based testing environments. To address these gaps, we developed a novel visuospatial processing speed (VIPS) task adapted from two tests sensitive to visuospatial processing speed declines in older adults, the Useful Field of View paradigm and the PERformance CEntered Portable Test. The VIPS task requires participants to make a central orientation discrimination and complete a simultaneous peripheral visual search task. Data were collected from 86 in-lab volunteers (18-30 years) to compare performance to traditional neuropsychological measures. Consistent with previous literature, performance on the novel VIPS task significantly correlated with measures of selective attention, executive functioning, visual speed, and working memory. An additional 4395 volunteers (12-62 years) were recruited on TestMyBrain.org to establish lifespan trajectories of visuospatial processing speed and associations with functional disability. VIPS task performance peaked in the early 20's, and steadily decreased such that thresholds doubled in 60-year-olds relative to 20-year-olds (817 ms vs. 412 ms). VIPS task performance significantly correlated with self-reported cognitive functioning deficits broadly across the lifespan but was specifically related to mobility issues in middle-age. These findings have important implications for early detection of cognitive decline and provide insights into potential early intervention targets for younger and middle-aged adults.

CKD Associates with Cognitive Decline in Middle-Aged and Older Adults with Long-Standing Type 1 Diabetes

Key Points

We found that development of both albuminuria and reduced eGFR was associated with clinically significant cognitive decline, particularly in the psychomotor and mental efficiency domain. There was also a significant interaction between worsened albuminuria and eGFR, the combination of which augmented cognitive deficits. A more comprehensive longitudinal phenotype of albuminuria showed that regressed albuminuria did not associate with worsened cognitive decline, as opposed to persistent albuminuria.

Background

Individuals with CKD or type 1 diabetes (T1D) are at risk for cognitive decline, but it is unclear whether these associations are with albuminuria, eGFR, or both.

Methods

We examined the longitudinal relationships between CKD and change in cognition in 1051 participants with T1D in the Diabetes Control and Complications Trial and its follow-up, the Epidemiology of Diabetes Interventions and Complications study. Albumin excretion rate and eGFR were measured every 1–2 years. Three cognitive domains were assessed repeatedly over a 32-year period: immediate memory, delayed memory, and psychomotor and mental efficiency. Associations between cognitive function and CKD were assessed: (1 ) longitudinally and (2 ) in models using eGFR and albuminuria measurements over the first 15–20 years with subsequent change in cognitive function over the ensuing 14 years (when decline in cognition was greatest).

Results

In fully adjusted longitudinal analyses, the magnitude of decline in the psychomotor and mental efficiency domain score was associated with eGFR <60 ml/min per 1.73 m2 (β −0.449; 95% confidence interval [CI], −0.640 to −0.259) and sustained albumin excretion rate 30 to <300 mg/24 hours (β −0.148; 95% CI, −0.270 to −0.026). This was equivalent to a decrease associated with approximately 11 and 4 years of aging, respectively. In analyses focused on changes in cognition between study years 18 and 32, eGFR <60 ml/min per 1.73 m2 was associated with reduced psychomotor and mental efficiency (β −0.915; 95% CI, −1.613 to −0.217).

Conclusions

In T1D, development of CKD was associated with a subsequent reduction on cognitive tasks requiring psychomotor and mental efficiency. These data highlight the need for increased recognition of risk factors for neurologic sequelae in patients with T1D, as well as preventive and treatment strategies to ameliorate cognitive decline.

The Impact of Age, Sex, and Position on Visual-Motor Processing Speed and Reaction Time as Measured by the Vision CoachTM

Occupational therapists are in a unique position to screen and evaluate fitness to drive with both visual-motor processing speed and reaction time being important factors to consider when determining fitness to drive. This study uses the Vision CoachTM to investigate the differences in visual-motor processing speed and reaction time across age and sex of healthy adults. It also explores whether the position of sitting or standing made any difference. The results showed no difference between male/female or standing/sitting positions. However, there was a statistically significant difference between age groups, with older adults demonstrating slower visual-motor processing speed and reaction times. These findings can be used for future studies to explore the impact of injury or disease on visual-motor processing speed and reaction times and its relation to fitness to drive.

Validation of the Norma Latina Neuropsychological Assessment Battery in Patients with Alzheimer's Disease in Mexico

To our knowledge, this is the first study reported in the literature that has validated the Norma Latina Battery in a population of people with Alzheimer's disease (AD) in Mexico. The objective of the study was to determine the discriminant validity of the Norma Latina Battery in a group of Mexican individuals with AD and a group of heathy controls (HC). The Norma Latina Battery was administered to 234 Mexican participants (117 HC and 117 individuals with AD). Results show that: (1) the Norma Latina Battery has high discriminative capacity between groups in all domains; (2) participants with AD presented worse scores in each of the cognitive domains compared to the HC and a greater number of low scores in each of the established thresholds or cut-off points; and finally, (3) the Norma Latina Battery had optimal sensitivity and specificity, especially when a set was observed ≥5 scores below the 10th percentile or ≥4 scores below the 5th percentile. In conclusion, it is recommended that both clinicians and researchers use this battery in the evaluation of Mexican people with AD to better understand the prognosis of the disease and its subsequent treatment.

Long-Term Recreational Cannabis Use Is Associated With Lower Executive Function and Processing Speed in a Pilot Sample of Older Adults

More older adults are using cannabis for recreational and/or medical purposes, but most studies examining cognitive function and cannabis use do not include older adults. The current small pilot study sought to compare cognitive function and emotional functioning among adults age 60 and older who were regular, primarily recreational cannabis users (n = 28) and nonusers (n = 10). A bimodal distribution was observed among cannabis users such that they had either initiated regular use more recently ("short-term" users; ≤7 years, n = 13) or earlier in life ("long-term" users; ≥19 years, n = 15). Nonusers, short-term, and long-term users were not different in depression, anxiety, or emotion regulation, or alcohol use. Nonusers scored significantly higher than long-term users in executive function. Short-term users scored significantly higher than long-term users in executive function, processing speed, and general cognition. Additionally, greater recent cannabis use frequency was negatively associated with working memory. The current findings suggest that short-term recreational cannabis use does not result in differences in cognitive performance compared to nonusers, which may indicate that short-term use is relatively benign in older adults. However, longer duration of use is associated with poorer processing speed and executive functioning, and more recent cannabis use is associated with poorer working memory, which may impact older adults' overall cognitive functioning.

Cognitive training program improves cognitive ability and daily living ability in elderly patients with mild cognitive impairment

BACKGROUND

Mild cognitive impairment (MCI) is a clinical syndrome of mild memory or other cognitive impairment without dementia and is a clinical transition state between normal aging and dementia. Careful and meticulous nursing intervention can improve the clinical symptoms of MCI and delay the progression of the disease.

AIMS

This research aimed to evaluate the efficacy of cognitive function training interventions in elderly patients with MCI.

METHODS

106 patients were randomized into the intervention group or the control group. They received conventional nursing intervention and those in the intervention group received additional cognitive training program for 6 weeks. The Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), activities of daily living (ADL) scales, and Barthel index (BI) were evaluated before and 6 weeks after the intervention, as well as the serum levels of S100β and neuron-specific enolase (NSE) at two time points.

RESULTS

After intervention, the MMSE scores and MoCA scores in both groups were significantly increased and the score in the intervention group was significantly higher. In the intervention group, the performance of conventional nursing intervention and cognitive training program significantly increased the scores of ADL and BI (p < 0.001). The serum levels of NSE and S100β in the intervention group were significantly lower.

DISCUSSION

The performance of cognitive training program alleviated the brain tissue damage in elderly patients with MCI.

CONCLUSIONS

The performance of cognitive training program in elderly patients with MCI improved their cognitive ability and daily living ability.

OUP accepted manuscript

Objective

Attention, inhibition, and processing speed are related to functional decline among older adults. This study attempts to clarify the relationships between these cognitive factors and adaptive functioning.

Method

We examined relationships between attention, inhibition, and processing speed, with scores on the Texas Functional Living Scale (TFLS), a performance-based measure of daily functioning, in a mixed clinical sample of 530 older adults who were referred for an outpatient neuropsychological evaluation.

Results

The current study used a confirmatory factor analysis (CFA) to derive a three-factor cognitive model consisting of attention, inhibition, and processing speed. Results from a hierarchical regression, which included factor scores from the CFA, revealed that processing speed was the only significant predictor of TFLS performance when all three cognitive factors were included within a single model.

Conclusion

These results highlight the influence of processing speed as an important indicator of functional decline among a clinical population of older adults.

Prevalence of Memory-Related Diagnoses Among U.S. Older Adults With Early Symptoms of Cognitive Impairment

BACKGROUND

Early diagnosis of cognitive impairment may confer important advantages. Yet the prevalence of memory-related diagnoses among older adults with early symptoms of cognitive impairment is unknown.

METHODS

A retrospective, longitudinal cohort design using 2000-2014 Health and Retirement Survey-Medicare linked data. We leveraged within-individual variation to examine the relationship between incident cognitive impairment and receipt of diagnosis among 1225 individuals aged 66 or older. Receipt of a memory-related diagnosis was determined by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Incident cognitive impairment was defined as the first assessment wherein the participant's modified Telephone Interview for Cognitive Status score was less than 12.

RESULTS

The unadjusted prevalence of memory-related diagnosis at cognitive impairment was 12.0%. Incident cognitive impairment was associated with a 7.3% (95% confidence interval [CI], 5.6% to 9.0%; p < .001) higher adjusted probability of any memory-related diagnosis overall, yielding 9.8% adjusted prevalence of diagnosis. The increase in likelihood of diagnosis associated with cognitive decline was significantly higher among non-Hispanic Whites than non-Hispanic Blacks (8.2% vs -0.7%), and among those with at least a college degree than those with a high school diploma or less (17.4% vs 6.8% vs 1.6%). Those who were younger, had below-median wealth, or without a partner had lower probability of diagnosis than their counterparts.

CONCLUSIONS

We found overall low prevalence of early diagnosis, or high rate of underdiagnosis, among older adults showing symptoms of cognitive impairment, especially among non-Whites and socioeconomically disadvantaged subgroups. Our findings call for targeted interventions to improve the rate of early diagnosis, especially among vulnerable populations.

Cognitive performance declines in older adults with type 1 diabetes: results from 32 years of follow-up in the DCCT and EDIC Study

BACKGROUND

With improved treatment, individuals with type 1 diabetes are living longer but there is limited information on the effects of type 1 diabetes on cognitive ability as they become older adults. We followed up individuals with type 1 diabetes to identify independent risk factors for cognitive decline as people age.

METHODS

1051 participants with type 1 diabetes enrolled in the Diabetes Control and Complications Trial (DCCT) and its follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. Participants completed cognitive assessments at baseline (median age 27 years) and 2, 5, 18, and 32 years later (median age 59). HbA1c levels, frequency of severe hypoglycaemia, non-glycemic risk factors such as elevated blood pressure, and microvascular and macrovascular complications were assessed repeatedly. We examined the effects of these on measures of memory and psychomotor and mental efficiency. These studies are registered with clinicaltrials.gov, NCT00360815 (DCCT) and NCT00360893 (EDIC).

FINDINGS

Over 32 years of follow-up, we found substantive declines in memory and psychomotor and mental efficiency. Between 18 and 32 years of follow-up, the decline in psychomotor and mental efficiency was five times larger than the change from baseline to year 18. Independent of the other risk factors and comorbidities, exposure to higher HbA1c levels, more episodes of severe hypoglycaemia, and elevated systolic blood pressure were associated with greater decrements in psychomotor and mental efficiency that was most notable by year 32 (p<0·0001). The combined effect of the presence of these three risk factors is the equivalent to an additional 9·4 years of age.

INTERPRETATION

Cognitive function declines with ageing in type 1 diabetes. The association of glycaemia and blood pressure levels with cognitive decline suggests that better management might preserve cognitive function.

FUNDING

United States National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Disease.

The Effect of Prior Knowledge of Color on Behavioral Responses and Event-Related Potentials During Go/No-go Task

In daily life, the meaning of color plays an important role in execution and inhibition of a motor response. For example, the symbolism of traffic light can help pedestrians and drivers to control their behavior, with the color green/blue meaning go and red meaning stop. However, we don't always stop with a red light and sometimes start a movement with it in such a situation as drivers start pressing the brake pedal when a traffic light turns red. In this regard, we investigated how the prior knowledge of traffic light signals impacts reaction times (RTs) and event-related potentials (ERPs) in a Go/No-go task. We set up Blue Go/Red No-go and Red Go/Blue No-go tasks with three different go signal (Go) probabilities (30, 50, and 70%), resulting in six different conditions. The participants were told which color to respond (Blue or Red) just before each condition session but didn't know the Go probability. Neural responses to Go and No-go signals were recorded at Fz, Cz, and Oz (international 10-20 system). We computed RTs for Go signal and N2 and P3 amplitudes from the ERP data. We found that RT was faster when responding to blue than red light signal and also was slower with lower Go probability. Overall, N2 amplitude was larger in Red Go than Blue Go trial and in Red No-go than Blue No-go trial. Furthermore, P3 amplitude was larger in Red No-go than Blue No-go trial. Our findings of RT and N2 amplitude for Go ERPs could indicate the presence of Stroop-like interference, that is a conflict between prior knowledge about traffic light signals and the meaning of presented signal. Meanwhile, the larger N2 and P3 amplitudes in Red No-go trial as compared to Blue No-go trial may be due to years of experience in stopping an action in response to a red signal and/or attention. This study provides the better understanding of the effect of prior knowledge of color on behavioral responses and its underlying neural mechanisms.

Naturalistic Driving Techniques and Association of Visual Risk Factors With At-Fault Crashes and Near Crashes by Older Drivers With Vision Impairment

Importance

Government motor vehicle crash reports used in the study of driver safety can be biased and incomplete. Naturalistic driving methods using in-vehicle instrumentation have been developed in recent years to objectively measure crashes and near crashes as they occur on the road using video and vehicle kinematic data.

Objective

To examine visual risk factors associated with at-fault crashes and near crashes among older drivers, most of whom have age-related eye conditions associated with vision impairment.

Design, Setting, and Participants

This prospective cohort study was conducted at an academic ophthalmology clinic from January 1, 2015, to November 10, 2018, among 154 adults 70 years of age or older who were legally licensed in Alabama and who reported currently driving at least 4 days per week; 137 of 151 participants (90.7%) had an age-related eye condition in at least 1 eye. Drivers participated in a baseline visual function assessment followed by installation of a data acquisition system recording multichannel synchronized video and vehicle kinematics in their personal vehicle. Drivers were instructed to drive for 6 months as they normally would during everyday life. Statistical analysis was performed from June 15 to September 15, 2020.

Main Outcomes and Measures

The rate of combined incident at-fault crashes and near crashes, defined by the number of events and the number of miles driven.

Results

The sample consisted of 154 drivers (85 men [55.2%]; mean [SD] age, 79.3 [5.1] years). Visual functions associated with crash and near-crash involvement included impaired contrast sensitivity (rate ratio [RR], 2.7; 95% CI, 1.3-5.5), moderate (RR, 2.3; 95% CI, 1.1-4.9) and severe (RR, 5.0; 95% CI, 2.2-11.7) slowing in visual processing speed, and elevated motion perception thresholds for a drifting grating (RR, 1.9; 95% CI, 1.1-3.5). Those with impaired peripheral visual field sensitivity had increased rates of crashes and near crashes (RR, 1.8; 95% CI, 1.0-3.3); however, this finding was not statistically significant (P = .07).

Conclusions and Relevance

With the use of naturalistic driving methods in which crashes and near crashes involving older drivers are objectively measured as they occur on the road, associations have been identified between impaired contrast sensitivity, slowed visual processing speed, and impaired motion perception and an increased rate of a combined total of at-fault crashes and near crashes.