Gender differences in cognitive abilities: The mediating role of health state and health habits

Digital neuropsychological test performance in a large sample of uninjured collegiate athletes

Digital neuropsychological test batteries are popular in college athletics; however, well-validated digital tests that are short and portable are needed to expand the feasibility of performing cognitive testing quickly, reliably, and outside standard clinical settings. This study assessed performance on digital versions of Trail Making Test (dTMT) and a modified Symbol Digit Modalities Test (dSDMT) in uninjured collegiate athletes (n = 537; 47% female) using the C3Logix baseline assessment module. Time to complete (dTMT) and the number of correct responses (dSDMT) were computed, transformed into z scores, and compared to age-matched normative data from analogous paper-and-pencil tests. Overall sample performance was compared to normative sample performance using Cohen's d. Sample averages on the dTMT, Part A, and dSDMT were similar to published norms; 97 and 92% of z scores fell within 2 standard deviations of normative means, respectively. The sample averaged faster completion times on dTMT, Part B than published norms, although 98% of z scores were within 2 standard deviations of the normative means. Brief, digitized tests may be useful in populations and testing environments when longer cognitive test batteries are impractical. Future studies should assess the ability of these tests to detect clinically relevant changes following a suspected head injury.

Brain MRI disease burden and sex differences in cognitive performance of patients with multiple sclerosis

BACKGROUND

Although there is evidence that shows worse cognitive functioning in male patients with multiple sclerosis (MS), the role of brain pathology in this context is under-investigated.

OBJECTIVE

To investigate sex differences in cognitive performance of MS patients, in the context of brain pathology and disease burden.

METHODS

Brain MRI, neurological examination, neuropsychological assessment (Brief International Cognitive Assessment in MS-BICAMS, and Paced Auditory Verbal Learning Test-PASAT), and patient-reported outcome questionnaires were performed/administered in 1052 MS patients.

RESULTS

Females had higher raw scores in the Symbol Digit Modalities Test (SDMT) (57.0 vs. 54.0; p < 0.001) and Categorical Verbal Learning Test (CVLT) (63.0 vs. 57.0; p < 0.001), but paradoxically, females evaluated their cognitive performance by MS Neuropsychological Questionnaire as being worse (16.6 vs 14.5, p = 0.004). Females had a trend for a weaker negative correlation between T2 lesion volume and SDMT ([Formula: see text] = - 0.37 in females vs. - 0.46 in men; interaction p = 0.038). On the other hand, women had a trend for a stronger correlation between Brain Parenchymal Fraction (BPF) and a visual memory test (Spearman's [Formula: see text] = 0.31 vs. 0.21; interaction p = 0.016). All these trends were not significant after correction for false discovery rate.

CONCLUSIONS

Although, females consider their cognition as worse, males had at a group level slightly worse verbal memory and information processing speed. However, the sex differences in cognitive performance were smaller than the variability of scores within the same sex group. Brain MRI measures did not explain the sex differences in cognitive performance among MS patients.

TEST-RETEST RELIABILITY AND RELIABLE CHANGE INDEX OF MOBILE APPLICATION NEUROCOGNITIVE TEST AMONG MIDDLE AND HIGH SCHOOL ATHLETES

CONTEXT

A mobile application neurocognitive assessment has been used in place of equipment intensive computerized neurocognitive assessment protocol. A previous study reported high to very high test-retest reliability of neurocognitive assessment using the mobile application in healthy adults, but no studies have examined test-retest reliability, reliable change indices (RCIs), and sex effect in middle school and high school populations when conducted 1 year apart.

OBJECTIVE

The purpose of this study was to examine the test-retest reliability and RCIs of baseline data collected at 2-time points approximately 1 year apart using a mobile application neurocognitive rest in middle school and high school athletes. The secondary purpose of the study was to investigate the sex difference in neurocognitive measures.

DESIGN

Cross-sectional study.

SETTING

Institutional.

PATIENTS OR OTHER PARTICIPANTS

172 middle school and high school healthy student-athletes (mean age=13.78±1.59 years old).

MAIN OUTCOME MEASURE(S)

Mobile application neurocognitive rest scores (reaction time, impulse control, inspection, and memory).

RESULTS

The result from the study demonstrated that neurocognitive measures had low test-retest reliability across a 1-year time period in middle and high school settings. Upon retesting, reaction time and inspection time improved significantly in both middle and high school athletes, and impulse control showed significant improvement in middle school athletes. More athletes in middle school showed more RCI improvements compared to high school athletes. While both males and females demonstrated improvements in neurocognitive measures throughout adolescence, males outperformed females on reaction time and impulse control.

CONCLUSIONS

Findings from the study indicate unacceptably low test-retest reliability of a mobile application neurocognitive test most likely due to cognitive development occurring throughout adolescence. Additionally, significant RCIs were noted. These naturally occurring improvements due to cognitive development could mask the post-concussion deficits. The findings warrant consideration of age and sex on the neurocognitive performance of middle and high school athletes.

Computerized Symbol Digit Modalities Test in a Swiss Pediatric Cohort Part 1: Validation

OBJECTIVE

The objective of this study was to validate the computerized Symbol Digit Modalities Test (c-SDMT) in a Swiss pediatric cohort, in comparing the Swiss sample to the Canadian norms. Secondly, we evaluated sex effects, age-effects, and test-retest reliability of the c-SDMT in comparison to values obtained for the paper and pencil version of the Symbol Digit Modalities Test (SDMT).

METHODS

This longitudinal observational study was conducted in a single-center setting at the University Children's Hospital of Bern. Our cohort consisted of 86 children (45 male and 41 female) aged from 8 to 16 years. The cohort included both healthy participants (n = 38) and patients (n = 48) hospitalized for a non-neurological disease. Forty eight participants were assessed during two testing sessions with the SDMT and the c-SDMT.

RESULTS

Test-retest reliability was high in both tests (SDMT: ICC = 0.89, c-SDMT: ICC = 0.90). A reliable change index was calculated for the SDMT (RCIp = -3.18, 14.01) and the c-SDMT (RCIp = -5.45, 1.46) corrected for practice effects. While a significant age effect on information processing speed was observed, no such effect was found for sex. When data on the c-SDMT performance of the Swiss cohort was compared with that from a Canadian cohort, no significant difference was found for the mean time per trial in any age group. Norm values for age groups between 8 and 16 years in the Swiss cohort were established.

CONCLUSION

Norms for the c-SDMT between the Swiss and the Canadian cohort were comparable. The c-SDMT is a valid alternative to the SDMT. It is a feasible and easy to administer bedside tool due to high reliability and the lack of motor demands.

Association of sex differences in dementia risk factors with sex differences in memory decline in a population-based cohort spanning 20-76 years

Sex differences in late-life memory decline may be explained by sex differences in dementia risk factors. Episodic memory and dementia risk factors were assessed in young, middle-aged and older adults over 12 years in a population-based sample (N = 7485). For men in midlife and old age, physical, cognitive and social activities were associated with less memory decline, and financial hardship was associated with more. APOE e4 and vascular risk factors were associated with memory decline for women in midlife. Depression, cognitive and physical activity were associated with memory change in older women. Incident midlife hypertension (β = - 0.48, 95% CI - 0.87, - 0.09, p = 0.02) was associated with greater memory decline in women and incident late-life stroke accounted for greater memory decline in men (β = - 0.56, 95% CI - 1.12, - 0.01), p = 0.05). Women have fewer modifiable risk factors than men. Stroke and hypertension explained sex differences in memory decline for men and women respectively.

Sex-Specific Association of Endogenous PCSK9 With Memory Function in Elderly Subjects at High Cardiovascular Risk

Background: Growing evidence indicates that cognitive decline and cardiovascular diseases (CVDs) share common vascular risk factors. Protease proprotein convertase subtilisin/kexin type 9 (PCSK9) is associated with CV disease risk and has been also involved in neuronal differentiation.

Aim: Evaluate whether in patients at high CV risk cognitive function is related to PCSK9 levels.

Methods. One hundred sixty-six patients (67 female) were enrolled. A detailed neuropsychological (NP) assessment was performed. PCSK9 levels were measured with ELISA.

Results: Men had significantly higher short-term memory, executive function, and praxic and mental representation skills, as reflected by Forward Digit Span (FDS) (p = 0.005), Trail Making Test-A (TMT-A) (p = 0.047), Clock Drawing Test (CDT) (0.016). Endogenous PCSK9 levels were higher in female (p = 0.005). On linear regression analysis PCSK9 predicts short term memory only in females (Beta = 0.408, p = 0.001), with an interaction between PCSK9 and gender (p = 0.004 for interaction PCSK9 by sex). The association of PCSK9 with FDS in female was partially mediated by waist circumference (mediation effect 8.5%).

Conclusions: In patients at high CV risk short term memory was directly related to PCSK9 levels only in women, revealing the relevance of sex in this relationship. The association of PCSK9 with memory function may be mediated, at least in part, by waist circumference.

A Rapid Electronic Cognitive Assessment Measure for Multiple Sclerosis: Validation of Cognitive Reaction, an Electronic Version of the Symbol Digit Modalities Test

Background

Incorporating cognitive testing into routine clinical practice is a challenge in multiple sclerosis (MS), given the wide spectrum of both cognitive and physical impairments people can have and the time that testing requires. Shortened paper and verbal assessments predominate but still are not used routinely. Computer-based tests are becoming more widespread; however, changes in how a paper test is implemented can impact what exactly is being assessed in an individual. The Symbol Digit Modalities Test (SDMT) is one validated test that forms part of the cognitive batteries used in MS and has some computer-based versions. We developed a tablet-based SDMT variant that has the potential to be ultimately deployed to patients’ own devices.

Objective

This paper aims to develop, validate, and deploy a computer-based SDMT variant, the Cognition Reaction (CoRe) test, that can reliably replicate the characteristics of the paper-based SDMT.

Methods

We carried out analysis using Pearson and intraclass correlations, as well as a Bland-Altman comparison, to examine consistency between the SDMT and CoRe tests and for test-retest reliability. The SDMT and CoRe tests were evaluated for sensitivity to disability levels and age. A novel metric in CoRe was found: question answering velocity could be calculated. This was evaluated in relation to disability levels and age for people with MS and compared with a group of healthy control volunteers.

Results

SDMT and CoRe test scores were highly correlated and consistent with 1-month retest values. Lower scores were seen in patients with higher age and some effect was seen with increasing disability. There was no learning effect evident. Question answering velocity demonstrated a small increase in speed over the 90-second duration of the test in people with MS and healthy controls.

Conclusions

This study validates a computer-based alternative to the SDMT that can be used in clinics and beyond. It enables accurate recording of elements of cognition relevant in MS but offers additional metrics that may offer further value to clinicians and people with MS.

Normative Data for the Symbol Digit Modalities Test in Older White Australians and Americans, African-Americans, and Hispanic/Latinos

Background

Processing speed, which can be assessed using the Symbol Digit Modalities Test (SDMT), is central to many brain functions. Processing speed declines with advanced age but substantial impairments are indicative of brain injury or disease.

Objective

The purpose of this study was to provide SDMT normative data for older community-dwelling individuals in the U.S. and Australia.

Methods

The ASPREE trial recruited 19,114 relatively healthy older men and women in Australia and the U.S. from the general community. All participants were without a diagnosis of dementia and with a Modified Mini-Mental State examination score of 78 or more at enrolment. The SDMT was administered at baseline as part of a neuropsychological test battery.

Results

The median age of participants was 74 years (range 65-99), and 56% were women. The median years of education was 12. Ethno-racial differences in SDMT performance were observed and normative data were thus presented separately for 16,289 white Australians, 1,082 white Americans, 891 African-Americans, and 316 Hispanic/Latinos. There were consistent positive associations found between SDMT and education level, and negative associations between SDMT and age. Mean scores for women were consistently higher than men with the exception of Hispanic/Latinos aged ≥70 years.

Conclusion

This study provides comprehensive SDMT normative data for whites (Australian and U.S.), Hispanic/Latinos, and African-Americans, according to gender, age, and education level. These norms can be used clinically as reference standards to screen for cognitive impairments in older individuals.

Normative data of neuropsychological tests of attention and executive functions in Ecuadorian adult population

OBJECTIVE

The purpose of this study was to generate normative data for five tests of attention and executive functions (M-WCST, Stroop test, TMT, BTA, and SDMT), in a group of 322 Ecuadorian adults from Quito between the ages of 18 and 85.

METHOD

Multiple regression analyzes taking into account age, education, and gender were used to generate the normative data.

RESULTS

Age and education were significantly related to test performance such that scores decreased with age and improved as a function of education. An online calculator is provided to generate normative test scores.

CONCLUSIONS

This is the first study that presents normative data for tests of executive functions and attention in an Ecuadorian adult population. This data will improve the clinical practice of neuropsychology and help to develop the field in the country.

Cognitive and Motor Norms for Huntington’s Disease

Background

The progression of Huntington’s disease (HD) for gene-expanded carriers is well-studied. Natural aging effects, however, are not often considered in the evaluation of HD progression.

Objective

To examine the effects of natural aging for healthy controls and to develop normative curves by age, sex, and education from the distribution of observed scores for the Symbol Digit Modalities Test, Stroop Word Reading Test, Stroop Color Naming Test, Stroop Interference Test, Total Motor Score, and Total Functional Capacity (TFC) from the Unified Huntington’s Disease Rating Scale (UHDRS) along with a composite score.

Methods

After combining longitudinal REGISTRY and Enroll-HD data, we used quantile regression and natural cubic splines for age to fit models for healthy controls (N = 3,394; N observations = 8,619). Normative curves were estimated for the 0.05, 0.25, 0.50, 0.75, and 0.95 quantiles. Two types of reference curves were considered: unconditional curves were dependent on age alone, whereas conditional curves were dependent on age and other covariates, namely sex and education.

Results

Conditioning on education was necessary for the Symbol Digit, Stroop Word, Stroop Color, Stroop Interference, and composite UHDRS. Unconditional curves were sufficient for the Total Motor Score. TFC was unique in that the curve was constant over age with its intercept at the maximum score (TFC = 13). For all measures, sex effects were minimal, so conditioning on sex was unwarranted.

Conclusions

Extreme quantile estimates for each measure can be considered as boundaries for natural aging and scores falling beyond these thresholds are likely the result of disease progression. Normative curves and tables are developed and can serve as references for clinical characterization in HD.

A new look at an old test: Normative data of the symbol digit modalities test -Oral version

BACKGROUND

The Symbol Digit Modalities Tests (SDMT) is the most sensitive measure to multiple sclerosis (MS)-related cognitive dysfunction. However, existing normative data has been under scrutiny. Specifically, they are outdated, do not take into account gender, and are poorly stratified by education. More importantly, there exists no oral only version norms, which is typical administration among individuals with MS.

OBJECTIVE

The present investigation aimed to develop updated normative data of the oral version SDMT in which age, gender, and education were taken into consideration.

METHODS

A total of 675 healthy individuals, stratified by age, gender, and education completed the oral version SDMT.

RESULTS

Significant effects were found for age, gender, and education, consistent with previous contentions. Specifically, performance on the SDMT tends to decline with age, with the most noticeable decline beginning in the third decade of life and continuing into the sixth decade. Women, in general perform better than men, with an average of 5.1 more points. Finally, education effects were apparent among those aged 25-54.

CONCLUSION

Based on these findings, updated normative data are provided. Utilization of these updated norms will result in a much needed and more accurate assessment of processing speed for individuals with MS.

Symbol Digit Modalities Test: Regression-Based Normative Data and Clinical Utility

OBJECTIVE

The purpose of this study was to provide regression-based normative data for the written, oral, and incidental recall trials of the Symbol Digit Modalities Test (SDMT).

METHOD

Regression-based normative equations for the written and oral trials were derived from 536 healthy men and women between the ages of 18 and 91. Normative equations for the incidental recall trial are provided for a subset of the normative sample (age range = 60-91). The clinical utility of the newly developed norms was examined by comparing mean performance and rates of impaired scores for participants with traumatic brain injury (TBI), mild cognitive impairment (MCI), and dementia. Within-group analyses were used to compare the new norms to the original published norms.

RESULTS

Age, education, and sex were all significant predictors of written trial performance, age and education were significant predictors of oral trial performance, and only age predicted incidental recall trial performance. As expected, the TBI group demonstrated the highest rates of impaired performance on both written and oral trials. Participants with dementia showed the highest rate of impaired scores on the incidental recall trial, followed by participants with amnestic MCI. Compared to traditional norming methods, the regression-based norms classified more clinical participants as impaired on both the written and oral trials.

CONCLUSIONS

Comprehensive regression-based normative equations with demonstrated clinical utility are provided to improve the detection of cerebral dysfunction using the SDMT. A calculator with the normative equations is provided so that raw scores can be easily converted to demographically-corrected standardized scores.

Sex differences in cognitive functioning of patients at-risk for psychosis and healthy controls: Results from the European Gene-Environment Interactions study

BACKGROUND

Sex differences in cognitive functioning have long been recognized in schizophrenia patients and healthy controls (HC). However, few studies have focused on patients with an at-risk mental state (ARMS) for psychosis. Thus, the aim of the present study was to investigate sex differences in neurocognitive performance in ARMS patients compared with HC.

METHODS

The data analyzed in this study were collected within the multicenter European Gene-Environment Interactions study (11 centers). A total of 343 ARMS patients (158 women) and 67 HC subjects (33 women) were included. All participants completed a comprehensive neurocognitive battery. Linear mixed effects models were used to explore whether sex differences in cognitive functioning were present in the total group (main effect of sex) and whether sex differences were different for HC and ARMS (interaction between sex and group).

RESULTS

Women performed better in social cognition, speed of processing, and verbal learning than men regardless of whether they were ARMS or HC. However, only differences in speed of processing and verbal learning remained significant after correction for multiple testing. Additionally, ARMS patients displayed alterations in attention, current IQ, speed of processing, verbal learning, and working memory compared with HC.

CONCLUSIONS

Findings indicate that sex differences in cognitive functioning in ARMS are similar to those seen between healthy men and women. Thus, it appears that sex differences in cognitive performance may not be specific for ARMS, a finding resembling that in patients with schizophrenic psychoses.

Comparing Traditional and Digitized Cognitive Tests Used in Standard Clinical Evaluation - A Study of the Digital Application Minnemera

The purpose of this study was to compare a new digitized cognitive test battery, Minnemera, with its correspondent traditional paper-based cognitive tests. Eighty-one healthy adults between the ages of 21 and 85 participated in the study. Participants performed the two different test versions (traditional paper-based and digitized) with an interval of four weeks between the tests. Test presentation (the order of the test versions presented) was counterbalanced in order to control for any possible test learning effects. The digitized tests were constructed so that there were only minor differences when compared to the traditional paper-based tests. Test results from the paper-based and digitized versions of the cognitive screening were compared within individuals by means of a correlation analysis and equivalence tests. The effects of demographic variables (age, gender and level of education) and test presentation were explored for each test measure and each test version through linear regression models. For each test measure, a significant correlation between traditional and digitized version was observed ranging between r = 0.34 and r = 0.67 with a median of r = 0.53 (corresponding to a large effect size). Score equivalence was observed for five out of six tests. In line with previous traditional cognitive studies, age was found to be the most prominent predictor of performance in all digitized tests, with younger participants performing better than older adults. Gender was the second strongest predictor, where women outperformed men in tests measuring verbal memory; men performed better than women in tests with a strong visual component. Finally, the educational level of the test subjects had an effect on executive functions, with a higher educational level linked to a better inhibition response and working memory span. This study suggests that the tests in the Minnemera cognitive screening battery are acceptably comparable to the traditional paper-based counterparts.

Normative data for the oldest old: Trail Making Test A, Symbol Digit Modalities Test, Victoria Stroop Test and Parallel Serial Mental Operations

Normative data for evaluating cognitive function in the oldest old, aged 85 years and above, are currently sparse. The normative values used in clinical practice are often derived from younger old persons, from small sample sizes or from broad age spans (e.g. >75 years) resulting in a risk of misjudgment in assessments of cognitive decline. This longitudinal study presents normative values for the Trail Making Test A (TMT-A), the Symbol Digit Modalities Test (SDMT), the Victoria Stroop Test (VST) and the Parallel Serial Mental Operations (PaSMO) from cognitively intact Swedes aged 85 years and above. 207 participants, born in 1922, were tested at 85, 90 (n = 68) and 93 (n = 35) years of age with a cognitive screening test battery. The participants were originally recruited for participation in the Elderly in Linköping Screening Assessment. Normative values are presented as mean values and standard deviations, with and without adjustment for education. There were no clinically important differences between genders, but education had a significant effect on test results for the 85-year-olds. Age effects emerged in analyses of those participants who completed the entire study and were evident for TMT-A, SDMT, VST1 and PaSMO. When comparisons can be made, our results are in accordance with previous data for TMT-A, SDMT and VST, and we present new normative values for PaSMO.

Older women take shorter steps during backwards walking and obstacle crossing

BACKGROUND

Community ambulation requires the ability to adapt walking patterns to task demands. For example, complex walking tasks, such as obstacle crossing (OBS) and backwards walking (BW), require modification of gait kinematics to complete the task, maintain stability and prevent falling. More women than men fall each year, but few studies have investigated gender differences in performance of adaptive walking tasks.

OBJECTIVE

The purpose of this study was to determine gender differences in two common adaptive tasks.

METHODS

Walking performance was assessed from 54 age and gender matched participants (72 ± 5 yrs.) while they completed forward walking (FW), OBS and BW. Gait outcomes and the distance of the lead foot and the trail foot from the obstacle were normalized by leg length and assessed using multivariate analysis of variance. Additionally, performance in a battery of clinical physical and cognitive measures as well as self-reported activity levels were associated with adaptive gait behavior.

RESULTS

Gait speed and step width were not different between genders in any walking task. Compared to FW and OBS, women only decreased step length in BW, resulting in significantly shorter step lengths than men in OBS (p = 0.02) and BW (p = 0.04), a conservative walking strategy. Women crossed the obstacle in a manner that may limit recovery steps in case of a trip: stepping closer to the obstacle during approach without increasing trail toe-clearance. The Timed Up and Go mobility test, Short Physical Performance Battery, and Trail Making Test of processing speed and executive function were associated with gender differences in adaptive gait patterns.

CONCLUSION

The findings revealed that older adult women adapt walking in a way that might predispose them to tripping or falling (i.e. shorter steps and closer obstacle approach). Gender differences in adaptive walking are related to functional test performance and processing speed. Clinicians should consider targeting step length during adaptive walking tasks in women that may be at risk of mobility impairments.

Flemish Normative Data for the Buschke Selective Reminding Test

The purpose of this study was to provide normative data for a Flemish version of the Buschke Selective Reminding Test (SRT). The SRT allows for the simultaneous analysis of several components of verbal memory, such as short and long term retrieval. The Flemish SRT was administered to 3257 neurologically healthy adults (1627 men and 1630 women, age range = 18-94 years). Effects of age, sex and education on SRT performance were assessed. Results indicate that SRT performance decreased with age and that this decline accelerated in men compared to women. Furthermore, an effect of education was found favoring participants who completed a higher education. Normative data quantified through percentile ranks and stratified by age, sex and education level are provided.

Role of Gender in Dual-Tasking Timed Up and Go Tests: A Cross-Sectional Study

Gender plays a role in cognitive performance. Yet the selection of a secondary task, an important paradigm in studies of posture control, has not considered gender as a variable. We explored whether different cognitive tasks differentially influence performance during the Timed Up and Go (TUG) test in men and women. Twenty young adults performed five cognitive tasks while seated and during the TUG test. Men exhibited a slower normalized cadence than women. When seated, women recalled more items than men and men were more accurate in mental calculation task. There were no changes in spatiotemporal measures. We conclude that gender did not play a major role in motor-cognitive interference during dual task TUG test.

Change in Cognitive Performance From Midlife Into Old Age: Findings from the Midlife in the United States (MIDUS) Study

OBJECTIVES

A substantial body of research has documented age-related declines in cognitive abilities among adults over 60, yet there is much less known about changes in cognitive abilities during midlife. The goal was to examine longitudinal changes in multiple cognitive domains from early midlife through old age in a large national sample, the Midlife in the United States (MIDUS) study.

METHODS

The Brief Test of Adult Cognition by Telephone (BTACT) was administered on two occasions (MIDUS 2, MIDUS 3), an average of 9 years apart. At MIDUS 3, those with the cognitive assessment (N=2518) ranged in age from 42 to 92 years (M=64.30; SD=11.20) and had a mean education of 14.68 years (SD=2.63). The BTACT includes assessment of key aging-sensitive cognitive domains: immediate and delayed free recall, number series, category fluency, backward digit span, processing speed, and reaction time for attention switching and inhibitory control, which comprise two factors: episodic memory and executive functioning.

RESULTS

As predicted, all cognitive subtests and factors showed very small but significant declines over 9 years, with differences in the timing and extent of change. Processing speed showed the earliest and steepest decrements. Those with higher educational attainment scored better on all tests except reaction time. Men had better executive functioning and women performed better on episodic memory.

CONCLUSIONS

Examining cognitive changes in midlife provides opportunities for early detection of cognitive impairments and possibilities for preventative interventions. (JINS, 2018, 24, 805-820).

Gender Differences in Cognitive Test Performance in Adults With Heart Failure

BACKGROUND

Cognitive deficits are found in up to 73% of persons with heart failure (HF) and are associated with increased mortality and other poor clinical outcomes. It is known that women have better memory test performance than men do in healthy samples, but gender differences in cognitive performance in the context of HF are not well understood and may have important clinical implications.

OBJECTIVE

The objective of this study was to examine possible gender differences in cognitive function in a sample of individuals with HF (98.9% New York Heart Association class II and III).

METHODS

A total of 183 adults with HF (116 men and 67 women) completed a neuropsychological test battery as part of a larger project. Measures were chosen to assess functioning in attention/executive function and memory.

RESULTS

After controlling for demographic and medical factors, multivariate analysis of covariance revealed that men and women differed on memory test performance (λ = 0.90, F4, 169 = 4.76, P = .001). Post hoc comparisons revealed that women performed better on California Verbal Learning Test Learning, Short Recall, and Delayed Recall. No differences emerged on tests of attention/executive function (λ = 0.97, F5, 168 = 0.96, P = .44).

CONCLUSIONS

In this sample of persons with HF, men exhibited poorer performance on memory measures than women did. Future studies are needed to determine the underlying mechanisms for this pattern and its possible influence on daily function.

Biomarkers, Health, Lifestyle, and Demographic Variables as Correlates of Reaction Time Performance in Early, Middle, and Late Adulthood

We aimed to identify demographic, health, and biomarker correlates of reaction time performance and to determine whether biomarkers explained age differences in reaction time performance. The sample comprised three representative cohorts aged 20–24, 40–44, and 60–64 years, including a total of 7,485 participants. Reaction time measures of intraindividual variability and latency were used. The measure of intraindividual variability used was independent of mean reaction time. Older adults were more variable than younger adults in choice reaction time performance but not simple reaction time performance. The most important correlates of reaction time performance after gender and education were biological markers such as forced expiratory volume at one second, grip strength, and vision. Few measures of physical or mental health or lifestyle were associated with poorer performance on reaction time measures. Biomarkers explained the majority of age-related variance in simple reaction time and a large proportion of variance in choice reaction time. We conclude that for the ages studied, biomarkers are more important than health factors for explaining age differences in reaction time performance.

Sex Differences in Clinical Features of Early, Treated Parkinson's Disease

Introduction

To improve our understanding of sex differences in the clinical characteristics of Parkinson’s Disease, we sought to examine differences in the clinical features and disease severity of men and women with early treated Parkinson’s Disease (PD) enrolled in a large-scale clinical trial.

Methods

Analysis was performed of baseline data from the National Institutes of Health Exploratory Trials in Parkinson’s Disease (NET-PD) Long-term Study-1, a randomized, multi-center, double-blind, placebo-controlled study of 10 grams of oral creatine/day in individuals with early, treated PD. We compared mean age at symptom onset, age at PD diagnosis, and age at randomization between men and women using t-test statistics. Sex differences in clinical features were evaluated, including: symptoms at diagnosis (motor) and symptoms at randomization (motor, non-motor, and daily functioning).

Results

1,741 participants were enrolled (62.5% male). No differences were detected in mean age at PD onset, age at PD diagnosis, age at randomization, motor symptoms, or daily functioning between men and women. Differences in non-motor symptoms were observed, with women demonstrating better performance compared to men on SCOPA-COG (Z = 5.064, p<0.0001) and Symbol Digit Modality measures (Z = 5.221, p<0.0001).

Conclusions

Overall, men and women did not demonstrate differences in clinical motor features early in the course of PD. However, the differences observed in non-motor cognitive symptoms suggests further assessment of the influence of sex on non-motor symptoms in later stages of PD is warranted.

Measuring individual corrective reaction time using the intermittent illumination model

The corrective reaction time (tcr) is an essential motor property when modelling hand control movements. Many studies designed experiments to estimate tcr, but reported only group means with inconsistent definitions. This study proposes an alternative methodology using Drury's (1994) intermittent illumination model. A total of 24 participants performed circular tracking movements under five levels of visual information delay using a modified monitor in a darkened room. Measured movement speeds and the manipulated delays were used with the model to estimate tcr of individuals and test effects of gender and path width. The results showed excellent model fits and demonstrated individual differences of tcr, which was 273 ms on average and ranged from 87 to 441 ms. The wide range of tcr values was due to significant effects of gender and path width. Male participants required shorter tcr compared to female participants, especially for narrow path widths.

PRACTITIONER SUMMARY

This study reports the corrective reaction time (tcr) of individuals using a novel methodology. The estimated tcr ranged from 87 to 441 ms, helping model hand control movements, such as aiming and tracking. The methodology can be continuously applied to study tcr under conditions with various performers and movements.

A test of the Interpersonal Theory of Suicide in a large community-based cohort

BACKGROUND

Joiner's Interpersonal Theory of Suicide (Van Orden et al., 2010; Joiner, 2005) predicts that suicide ideation is strongest in those experiencing both high perceived burdensomeness and thwarted belongingness, and that the combination of suicide ideation and acquired capability for suicide is critical in the development of suicide plans and attempts. However, few datasets exist which allow the examination of these predictions. The present study aimed to test predictions from the model in a population-based cohort.

METHODS

a survey was completed by 6133 participants from the PATH Through Life Project. Scales measuring perceived burdensomeness, thwarted belongingness, hopelessness, capability to self-injure, ideation, plans and attempts were developed using existing items. Regression models were used to predict the outcomes of ideation and of plans/attempts.

RESULTS

consistent with the Interpersonal Theory, interactions were found between perceived burdensomeness and thwarted belongingness predicting ideation, and interactions of capability and ideation for plans/attempts. However, some predictions of the theory were not fulfilled. Nevertheless, the Interpersonal Theory explained more variance than epidemiological models using mental disorders as predictors. Age differences were evident, with models of older cohorts accounting for less variance. Gender models suggested thwarted belongingness was a stronger predictor of ideation in males than females.

LIMITATIONS

while the fit of the factors assessing the Interpersonal Theory was adequate, the findings will need to be confirmed using previously developed scales of these constructs.

CONCLUSIONS

predictive models of suicide need to take into account multiple risk factors, gender differences and changes in associations over the life span.

Cognitive performance in women aged 50 years and older with and without fibromyalgia

OBJECTIVES

Persons with fibromyalgia (FM) report having cognitive dysfunction. Neuropsychological performance was compared across a variety of domains in 43 women with FM (Mage = 63 years) and in 44 women without FM (Mage = 65 years).

METHOD

Measures included explicit memory (Consortium to Establish a Registry for Alzheimer's Disease [CERAD] immediate/delayed recall, delayed recognition), aspects of executive function including interference/inhibition (Stroop Color/Word test), working memory (Digit Span Forward/Backward), set-shifting/complex sequencing (Trails B), monitoring (verbal fluency: naming animals), processing speed (Trails A, Digit Symbol Substitution Coding), and problem solving (Everyday Problems Test).

RESULTS

Women with FM performed more poorly than controls on executive function (Stroop Color/Word) and one processing speed measure (Digit Symbol Substitution Coding).

DISCUSSION

Results partly support altered cognitive function in FM. Mixed findings across cognitive domains among individuals with or without FM is consistent with the literature and suggest that factors beyond those typically controlled for (e.g., heterogeneity in FM) may be influencing findings. Future research is warranted.

Cognitive-behavioural factors that predict sleep disturbance 4 years later

OBJECTIVE

Cognitive models have identified a number of factors that maintain sleep disturbance. It is unknown whether similar factors lead to initial onset. This study tested whether three cognitive-behavioural factors: ruminative style, somatic sensitivity, and behavioural avoidance predicted sleep disturbance onset at four-year follow-up.

METHODS

Participants (n=4,042) were assessed using a) a composite measure of Somatic Sensitivity, b) the Ruminative Style Scale, c) the Behavioural Inhibition Scale of the BISBAS and d) sleep-related items from the Goldberg Depression and Anxiety Scale.

RESULTS

Sleep disturbance at 4 years was significantly predicted by all three cognitive-behavioural factors--somatic sensitivity, ruminative style and behavioural avoidance--and, in the final analysis, was independently predicted by somatic sensitivity (OR=1.427, p<0.001) and ruminative style (OR=1.035, p=0.002).

CONCLUSION

This study tested whether three cognitive-behavioural factors: ruminative style, somatic sensitivity, and behavioural avoidance were predictive of the onset of sleep disturbance after 4 years. Although all three factors were significantly associated with the onset of sleep disturbance, only ruminative style and somatic sensitivity were found to independently predict sleep disturbance, supporting these constructs as predisposing cognitive-behavioural risk factors.

Lifetime cigarette smoking is associated with striatal volume measures

Nicotine, the primary addictive component of tobacco, affects the mammalian brain. Smokers' brains have smaller cortical grey matter volumes and/or lower densities compared with non-smokers'. Differences in subcortical structures like the striatum are however, less clear. A high concentration of nicotinic receptors makes the striatum a potential target for nicotine. In addition, striatal nuclei are essential components of the reward/reinforcement pathway involved in addiction. The aim of this study was to explore the relationship between striatal nuclei (caudate, putamen and nucleus accumbens area) volumes and lifetime smoking in a large community-based sample of 'young-old' individuals. Brain volumes were measured using a semi-automated method in 315 participants aged 64-70 years who were selected from a larger randomly sampled cohort and who consented to a magnetic resonance imaging scan. Multiple regression analysis was used to assess the relationship between striatal volumes and cigarette smoking measures while controlling for age, sex, intracranial and total brain volumes and general physical and mental health measures. Greater lifetime use of cigarettes (measured in pack-years) was associated with smaller left nucleus accumbens area volume (P = 0.018) and larger left putamen volume (P = 0.025). Greater putaminal volume was also associated with a lower age at smoking initiation (P = 0.004). In this generally healthy cohort, lifetime use of cigarettes is significantly associated with striatal volume measures. These changes could indicate predisposing factors for nicotine addiction, or an effect of chronic nicotine exposure or a combination of both.

Sex differences in cognition in healthy elderly individuals

Sex differences in patterns of cognitive test performance have been attributed to factors, such as sex hormones or sexual dimorphisms in brain structure, that change with normal aging. The current study examined sex differences in patterns of cognitive test performance in healthy elderly individuals. Cognitive test scores of 957 men and women (age 67-89), matched for overall level of cognitive test performance, age, education, and depression scale score, were compared. Men and women were indistinguishable on tests of auditory divided attention, category fluency, and executive functioning. In contrast, women performed better than men on tests of psychomotor speed and verbal learning and memory, whereas men outperformed women on tests of visuoconstruction and visual perception. Our finding that the pattern of sex differences in cognition observed in young adults is observed in old age has implications for future studies of both healthy elderly individuals and of those with cognitive disorders.

Prevalence of suicidal behaviours in two Australian general population surveys: methodological considerations when comparing across studies

PURPOSE

To investigate whether methodological differences between two Australian general population surveys have the capacity to affect the apparent prevalence rates of suicidal ideation and suicide attempts.

METHODS

609 Wave 1 of the Personality and Total Health (PATH) Through Life Project participants, and 83 participants derived from the 1997 National Survey of Mental Health and Wellbeing (NSMHWB) met the criteria for inclusion (suicidal ideation/suicide attempt). Analysis involved Chi-square and binary logistic regression.

RESULTS

Twelve-month prevalence rates for suicidal ideation and suicide attempt were 8.2%, (95% CI = 7.6-8.8) and 0.8% (95% CI = 0.6-1.0) for PATH (N = 7,485), and contrast with 2.9% (95% CI = 2.6-3.2) and 0.3% (95% CI = 0.2-0.5) for NSMHWB (N = 10,641) samples, respectively. While notable discrepancies are apparent between the prevalence statistics, both sets of statistics are within the bounds of other Australian and international studies. Parallel rate disparities for suicidal ideation are found across age-by-gender groups. Aside from differences in the basic prevalence rates, surveys have analogous age-by-gender profiles for suicidal ideation.

CONCLUSIONS

While it is possible that samples are representative of the populations from which they are derived, 12-month prevalence rate discrepancies between PATH and NSMHWB surveys are likely to originate from demographic and survey methodology differences. Where investigations employ different methodologies, especially in relation to modes of survey administration and the assessment items utilised, a cautious approach should be taken when comparing findings.

Cannabis use and cognitive function: 8-year trajectory in a young adult cohort

AIM

  To evaluate the relationship between change in cannabis use and changed cognitive performance over 8 years.

DESIGN

  We used survey methodology with a cohort design.

SETTING AND PARTICIPANTS

  An Australian community sample aged 20-24 years at baseline.

MEASURES

  We assessed cognitive performance with the California Verbal Learning Test (CVLT) (immediate and delayed), Spot-the-Word test (STW), Symbol Digit Modality test (SDMT) and Digit Backwards (DB). Groups of cannabis users were defined from self-reports across three waves as: 'never' (n= 420) 'remain light' (n= 71), 'former light' (n= 231), 'remain heavy' (n= 60), 'former heavy' (n= 60) and 'always former' (since start of study) (n= 657). Planned contrasts within mixed model repeated-measures analysis of variance was used for longitudinal analysis with an adjusted alpha of 0.01.

FINDINGS

  Data were obtained from 2404 participants with 1978 (82.3%) completing wave 3. At baseline there were significant differences between cannabis groups on CVLT (immediate and delayed) and SDMT. However, after controlling for education, gender, gender × group and gender × wave, there were no significant between-group differences and only CVLT immediate recall reached adjusted statistically significant longitudinal change associated with changed cannabis use (group × wave P= 0.007). Specifically, former heavy users improved their performance relative to remaining heavy users (estimated marginal means: former heavy 6.1-7.5: remain heavy 6.4-6.6).

CONCLUSIONS

  Cessation of cannabis use appears to be associated with an improvement in capacity for recall of information that has just been learned. No other measures of cognitive performance were related to cannabis after controlling for confounds.

Mixed handedness is associated with greater age-related decline in volumes of the hippocampus and amygdala: the PATH through life study

Handedness has been found to be associated with structural and functional cerebral differences. Left handedness and mixed handedness also appear to be associated with an elevated risk of some developmental and immunological disorders that may contribute to pathological processes developing in ageing. Inconsistent reports show that left handedness may be more prevalent in early-onset as well as late-onset Alzheimer's disease, but might also be associated with slower decline. Such inconsistencies may be due to handedness being usually modeled as a binary construct while substantial evidence suggests it to be a continuous trait. The aim of this study was to investigate the relationship between brain structures known to be implicated in pathological ageing and strength and direction of handedness. The association between handedness and hippocampal and amygdalar atrophy was investigated in 327 cognitively healthy older individuals. Handedness was measured with the Edinburgh Inventory. Two measures were computed from this index, one reflecting the direction (left = 0/right = 1) and the other the degree of handedness (ranging from 0 to 1). Hippocampal and amygdalar volumes were manually traced on scans acquired 4 years apart. Regression analyses were used to assess the relationship between strength and direction of handedness and incident hippocampal and amygdalar atrophy. Analyses showed that strength but not direction of handedness was a significant predictor of hippocampal (Left: beta = 0.118, P = 0.013; Right: beta = 0.116, P = 0.010) and amygdalar (Right: beta = 0.105, P = 0.040) atrophy. The present findings suggest that mixed but not left handedness is associated with greater hippocampal and amygdalar atrophy. This effect may be due to genetic, environmental, or behavioural differences that will need further investigation in future studies.

Sex differences in cognition among persons with schizophrenia and healthy first-degree relatives

Previous research suggests differences between women and men in the clinical features of schizophrenia, but studies examining sex differences in neuropsychological functioning have reached inconsistent results. In the present study, sex differences in cognition and clinical features were investigated in population-based samples of participants with schizophrenia (n=218), their healthy first-degree relatives (n=438) and controls (n=123). Sex differences in illness features were small; nevertheless, women with schizophrenia had less negative symptoms and lived independently more often than men. The schizophrenia group had impairments in all studied neuropsychological domains, and the relatives were impaired in processing speed and set-shifting. In all groups, women performed better than men in processing speed, set-shifting and verbal episodic memory, whereas men outperformed women in visual working memory. The group-by-sex interaction was significant in two variables: women outperformed men in the relatives group in immediate verbal reproduction and in the use of semantic clustering as a learning strategy, while there was no sex difference in the schizophrenia group. In conclusion, sex differences in cognition are mostly similar in schizophrenia to those among controls, despite sex differences in illness features. The preservation of sex differences also in first-degree relatives supports the conclusion.

Gender differences in neuropsychological performance in individuals with atherosclerosis: impact of vascular function

This study was conducted to assess gender differences in cognition in elderly individuals (N = 88; 38 women, 50 men) with atherosclerotic vascular disease (AVD) and to determine whether these were attributable to differences in vascular health. Assessments included neuropsychological testing and measurement of forearm vascular function using venous occlusion plethysmography. There was a significant female advantage on multiple neuropsychological tests. This gender effect was reduced somewhat but remained significant when controlling for education and vascular function. Our study suggests that gender differences in cognition persist into older age and are not primarily due to gender differences in vascular health.

Sex differences in means and variability on the progressive matrices in university students: A meta-analysis

A meta-analysis is presented of 22 studies of sex differences in university students of means and variances on the Progressive Matrices. The results disconfirm the frequent assertion that there is no sex difference in the mean but that males have greater variability. To the contrary, the results showed that males obtained a higher mean than females by between .22d and .33d, the equivalent of 3.3 and 5.0 IQ conventional points, respectively. In the 8 studies of the SPM for which standard deviations were available, females showed significantly greater variability (F(882,656) = 1.20, p < .02), whilst in the 10 studies of the APM there was no significant difference in variability (F(3344,5660) = 1.00, p > .05).