Repetitive Behaviours in Autistic and Non-Autistic Adults: Associations with Sensory Sensitivity and Impact on Self-Efficacy

PURPOSE

Restricted and repetitive behaviours are a core feature of autism diagnoses but have not been widely studied in adulthood. This study examined the rates of and associations between repetitive behaviours and sensory sensitivity in autistic and non-autistic adults; and whether repetitive behaviours described as "stimming" impacted coping with difficulties (self-efficacy).

METHODS

Diagnosed autistic (n = 182), undiagnosed autistic (n = 163) and non-autistic (n = 146) adults completed online measures of repetitive behaviours, sensory sensitivity, and self-efficacy for when able and not able to stim.

RESULTS

Repetitive behaviours and sensory sensitivity correlated significantly in each group, although ratings were higher in autistic compared to non-autistic groups. When people were able to stim, no differences between the groups were observed on self-efficacy ratings. However when unable to stim, autistic people reported lower self-efficacy than non-autistic people.

CONCLUSIONS

Results suggest that repetitive behaviours are significantly associate with sensory sensitivities. Rather than repetitive behaviours being viewed as negative, stimming was associated with increased self-efficacy. Results suggest that stimming may have beneficial effects. Further work is needed to better understand how repetitive behaviours and stimming manifest in adulthood, how they change over time and their effects for autistic adults.

Self-reported Prospective and Retrospective Memory Among Middle Aged and Older Autistic and Non-autistic People

OBJECTIVE

Self-reported memory difficulties are common among older adults, but few studies have examined memory problems among autistic middle-aged and older people. The current study examines self-rated prospective (PM) and retrospective (RM) memory difficulties and their associations with age in middle-aged and older autistic and non-autistic people.

METHODS

350 autistic people (58% assigned-female-at-birth; age-range: 40-83 years) and 350 non-autistic adults matched on age, birth-sex and education level were included in the analysis. Participants completed the Prospective and Retrospective Memory Questionnaire (PRMQ) which includes questions about PM vs. RM (memory type), environment-cued vs. self-cued (cue), and short vs. long delay (delay).

RESULTS

Autistic people reported significantly more PM and RM difficulties than the comparison group. Both groups reported more difficulties with PM (vs. RM), self-cued (vs. environment-cued), and short (vs. long) delay. No significant interactions were observed. Among autistic people, younger age was associated with reporting more PM and RM difficulties, but this pattern was not observed among non-autistic people.

CONCLUSIONS

Autistic people may be at reduced risk for memory problems as they age, compared to their same-age non-autistic peers. Further studies are required to explore the association between self-reported memory challenges and memory task performance among autistic older people.

A Qualitative Study of Autistic Adults' Quality of Life During the COVID-19 Pandemic and Lockdowns

Background

Autistic people experience higher rates of most mental health conditions and report more difficulties with change than nonautistic people. As such, the periods of national stay-at-home orders (known in the United Kingdom as a "lockdown") endured since the beginning of the COVID-19 (coronavirus disease 2019) pandemic in March 2020 may have been particularly challenging for autistic people.

Aim

This study explored autistic adults' experience of quality of life and well-being during the start of the COVID-19 pandemic (specifically March to August 2020) using open-text responses from an online survey.

Methods

In total, 79 autistic adults from the United Kingdom (aged 21-75 years) took part. Participants completed an online survey, including open-text questions on how various factors influencing quality of life, such as social interactions, general health, well-being, and sensory experiences, were impacted by the COVID-19 pandemic and the first set of national lockdowns that occurred between March and August 2020.

Results

Thematic analysis created four key themes, each illustrated by several subthemes. These four themes explore (1) health, (2) social changes, (3) support provisions, and (4) adopting new routines. Many participants discussed the impact that the COVID-19 pandemic and the first set of national lockdowns had on their health and expressed concerns regarding the transition out of periods of lockdown, including readjusting to new rules, going back to in-person interactions, and reacclimatizing to high-stimulation sensory environments. However, several participants reported positive experiences of the periods of lockdown, such as reduced commuting, more control over sensory environments, and more time to pursue personal interests and self-care.

Conclusions

These findings highlight the importance of giving autistic individuals the support they need to transition back to "normality" as COVID-19 becomes endemic.

Cardiovascular disease risk factors in autistic adults: The impact of sleep quality and antipsychotic medication use

Approximately 40% of American adults are affected by cardiovascular disease (CVD) risk factors (e.g., high blood pressure, high cholesterol, diabetes, and overweight or obesity), and risk among autistic adults may be even higher. Mechanisms underlying the high prevalence of CVD risk factors in autistic people may include known correlates of CVD risk factors in other groups, including high levels of perceived stress, poor sleep quality, and antipsychotic medication use. A sample of 545 autistic adults without intellectual disability aged 18+ were recruited through the Simons Foundation Powering Autism Research, Research Match. Multiple linear regression models examined the association between key independent variables (self-reported perceived stress, sleep quality, and antipsychotic medication use) and CVD risk factors, controlling for demographic variables (age, sex assigned at birth, race, low-income status, autistic traits). Overall, 73.2% of autistic adults in our sample had an overweight/obesity classification, 45.3% had high cholesterol, 39.4% had high blood pressure, and 10.3% had diabetes. Older age, male sex assigned at birth, and poorer sleep quality were associated with a higher number of CVD risk factors. Using antipsychotic medications was associated with an increased likelihood of having diabetes. Poorer sleep quality was associated with an increased likelihood of having an overweight/obesity classification. Self-reported CVD risk factors are highly prevalent among autistic adults. Both improving sleep quality and closely monitoring CVD risk factors among autistic adults who use antipsychotic medications have the potential to reduce risk for CVD.

Self-reported cognitive decline among middle and older age autistic adults

Very little is known about autistic adults as they age. Early evidence suggests a potentially high risk for dementia and atypical cognitive decline in autistic middle and older age adults. Research in the general population indicates that self-reported cognitive decline may predict future dementia earlier than performance-based measures. Nevertheless, self-report dementia screeners have not been used to date in autism research. In a sample of middle and older age autistic adults (N = 210), participants completed a self-rated dementia screener, the AD8, to describe the rate of cognitive decline, examine associations of cognitive decline with age, educational level, sex designated at birth, and autistic traits, and document the psychometrics of a dementia screener in autistic adults. We found high rates of cognitive decline with 30% of the sample screening positive. The most common symptoms were declining interest in leisure activities, and increases in everyday problems with thinking, memory, and judgment. There was evidence that autistic individuals designated female at birth may be more vulnerable to cognitive decline than autistic individuals designated male at birth. Notably, reports of cognitive decline did not vary by age or educational level. Modestly elevated autistic traits were found in those screening positive versus negative for cognitive decline. Finally, the dementia screener showed good psychometrics, including convergent validity with an independent measure of current memory problems. These results could signal an emerging public health crisis in autistic adults as they age, and support the potential utility of self-report measures for early screening for cognitive decline in this population.

The cognitive profile of middle-aged and older adults with high vs. low autistic traits

Cognitive differences in memory, information processing speed (IPS), and executive functions (EF), are common in autistic and high autistic trait populations. Despite memory, IPS and EF being sensitive to age-related change, little is known about the cognitive profile of older adults with high autistic traits. This study explores cross-sectional memory, IPS and EF task performance in a large sample of older adults in the online PROTECT cohort (n = 22,285, aged 50-80 years), grouped by high vs. low autistic traits. Approximately 1% of PROTECT participants (n = 325) endorsed high autistic traits [henceforth Autism Spectrum Trait (AST) group]. Differences between AST and age-, gender-, and education-matched comparison older adults (COA; n = 11,744) were explored on memory, IPS and EF tasks and questionnaires administered online. AST had lower performance than COA on tasks measuring memory, working memory, sustained attention, and information processing. No group differences were observed in simple attention or verbal reasoning. A similar pattern of results was observed when controlling for age, and current depression and anxiety symptoms. In addition, AST self-reported more cognitive decline than COA, but this difference was not significant when controlling for current depression symptoms, or when using informant-report. These findings suggest that autistic traits are associated with cognitive function in middle-aged and later life. Older adults with high autistic traits experienced more performance difficulties in a range of memory, IPS and EF tasks compared with the low autistic traits comparison group. Further longitudinal work is needed to examine age-related change in both older autistic and autistic trait populations.

Predictors of sleep quality for autistic people across adulthood

Poor sleep can have a significant impact on physical health and well-being. Sleep problems are common among autistic children, but less is known about sleep across the autistic adult lifespan. Autistic adults (n = 730, aged 18-78 years) were recruited via Simons Powering Autism Research for Knowledge Research Match. Participants completed online surveys asking about demographics, health problems, social support, symptoms of anxiety and depression, and overall and specific aspects of sleep quality. Regression analyses explored the variables associated with sleep quality. Physical health, assigned female sex at birth and self-reported anxiety symptoms significantly contributed to models for all aspects of sleep. Perceived stress contributed to models of overall and subjective sleep quality, and daytime dysfunction. Depression symptoms did not contribute significantly to any of the models of sleep quality. However, utilizing government support mechanisms (such as social security) contributed to the model of sleep efficiency. Age contributed little to models of sleep quality, whereas perceived stress and psychotropic medication use contributed to some but not all aspects of sleep. Sleep quality is poor for autistic people across the adult lifespan. Given known impacts of poor sleep on health, cognition and quality of life, attention should be paid to sleep and its possible everyday effects for autistic people of all ages.

Social support and links to quality of life among middle-aged and older autistic adults

LAY ABSTRACT

Social support can take many forms, such as practical help, time spent socially with others, or the satisfaction with personal relationships. Social support is known to affect quality of life (QoL) in both non-autistic older and autistic young adults. QoL reflects how satisfied an individual is with their life either overall or in a certain area. We know little about middle-aged and older autistic adults' experiences of social support or QoL. In this study, 388 adults aged 40-83 years old, completed online questionnaires asking about background such as age and sex, depression and anxiety symptoms, QoL (physical, psychological, social, environmental, and autism-specific), and different types of social support. Even after taking into account background, depression, and anxiety, social support was important for individuals' QoL. To our knowledge this is the first paper to examine the relationship between social support and QoL in middle-aged and older autistic adults. Improving social support may have a significant impact on the QoL of older autistic adults. Future studies should examine whether age-related changes in social support (size, content, and arrangement of social networks) that are common in non-autistic aging, also occur among older autistic adults.

Self-harm and Suicidality Experiences of Middle-Age and Older Adults With vs. Without High Autistic Traits

Suicide has been identified as a leading cause of premature death in autistic populations. Elevated autistic traits have also been associated with higher rates of self-harm, suicidal ideation, and suicidal self-harm in the general population, but this has yet to be examined in older age. Using baseline cross-sectional data from the PROTECT study, middle-age and older adults with high autistic traits (n = 276) had significantly higher rates of suicidal ideation, deliberate self-harm, and suicidal self-harm than an age/sex-matched comparison group (n = 10,495). These differences represented a 5- to 6-fold increase in likelihood for self-harming and suicidality. These findings, which remained when controlling for depression symptoms, suggest that middle-age and older adults with high autistic traits may be particularly at risk of self-harm and suicidal behaviours.

Traumatic life experiences and post-traumatic stress symptoms in middle-aged and older adults with and without autistic traits

OBJECTIVES

Research with younger adults has begun to explore associations between autism/autistic traits and vulnerability to Post Traumatic Stress Disorder (PTSD). Large scale studies and/or examination of age-effects have not been conducted.

METHODS

Adults aged 50 years+ from the PROTECT study (n = 20,220) completed items about current and childhood socio-communicative difficulties characteristic of autism. Approximately 1% (n = 251) endorsed high autistic traits, henceforth the Autism Spectrum Traits (AST) group. Differences between the AST and an age-and sex-matched "Comparison Older Adults" (COA; n = 9179) group were explored for lifetime traumatic experiences and current symptoms of PTSD, depression, and anxiety.

RESULTS

Almost 30% of the AST group, compared to less than 8% of the COA, reported severe trauma in childhood/adulthood, including emotional, physical or sexual abuse. Elevated current PTSD symptoms were reported by AST compared to COA. An interaction was observed between autistic traits and trauma severity; the effect of level of trauma on PTSD symptoms was significantly greater for AST versus COA participants. This interaction remained significant when controlling for current depression and anxiety symptoms.

CONCLUSIONS

The findings suggest that high autistic traits may increase the likelihood of experiencing trauma across the lifespan, and the impact of severe trauma on PTSD symptoms. Older adults with high (vs. low) autistic traits may be at greater risk of experiencing PTSD symptoms in latter life. Future research should test whether the pattern of results is similar for diagnosed autistic adults.

The Mental and Physical Health Profiles of Older Adults Who Endorse Elevated Autistic Traits

OBJECTIVES

The mental and physical health profile of autistic people has been studied in adolescence and adulthood, with elevated rates of most conditions being reported. However, this has been little studied taking a dimensional approach to autistic traits and in older age.

METHODS

A total of 20,220 adults aged 50-81 years from the PROTECT study reported whether they experienced persistent sociocommunicative traits characteristic of autism. Approximately 1%, 276 individuals, were identified as endorsing elevated autistic traits in childhood and currently, henceforth the "Autism Spectrum Trait" (AST) group. An age- and gender-matched comparison group was formed of 10,495 individuals who did not endorse any autistic behavioral traits, henceforth the "Control Older Adults" (COA) group. Differences between AST and COA groups were explored in self-reported psychiatric diagnoses, self-reported symptoms of current depression and anxiety, and self-reported physical health diagnoses. Associations were also examined between autistic traits and health across the whole sample.

RESULTS

The AST group reported significantly elevated rates of psychiatric diagnoses compared to the COA group. Additionally, the AST group showed significantly higher self-reported symptoms of current depression and anxiety than the COA group. However, few differences were observed in individual physical health conditions, and no differences in total co-occurring physical diagnoses between groups. Similar associations between autistic traits and health were also found taking a dimensional approach across the whole sample.

DISCUSSION

These findings suggest that older adults with elevated autistic traits may be at greater risk of poorer mental, but not physical, health in later life. Future studies should incorporate polygenic scores to elucidate the possible genetic links between the propensity to autism/high autistic traits and to psychiatric conditions, and to explore whether those with elevated autistic traits experience particular barriers to mental health care.

The Mental and Physical Health of Older Adults With a Genetic Predisposition for Autism

Autism commonly aggregates in families, with twin studies estimating heritability to be around 80%. Subclinical autism-like characteristics have also been found at elevated rates in relatives of autistic probands. Physical and psychiatric conditions have been reported at elevated rates in autistic children and adults, and also in their relatives. However, to date, there has been no exploration of how aging may affect this pattern. This study examined cross-sectional data from the ongoing online PROTECT study. A total of 20,220 adults aged 50 years and older reported whether they have an autistic first-degree relative. In total, 739 older adults reported having an autistic first-degree relative (AFDR group) and 11,666 were identified as having no family history of any neurodevelopmental disorder (NFD group). The AFDR group demonstrated significantly higher frequencies of self-reported psychiatric diagnoses and a greater total number of co-occurring psychiatric diagnoses than the NFD group. Furthermore, the AFDR group reported elevated current self-report symptoms of depression, anxiety, traumatic experience, and post-traumatic stress than the NFD group. By contrast, few differences between AFDR and NFD groups were observed in physical health conditions, and no differences were observed in the total number of co-occurring physical health diagnoses. These findings suggest that adults who have an AFDR may be at greater risk of poor mental, but not physical, health in later life. Older adults with autistic relatives may benefit from close monitoring to mitigate this susceptibility and to provide timely intervention. Autism Res 2020, 13: 641-654. © 2020 The Authors. Autism Research published by International Society for Autism Research published by Wiley Periodicals, Inc. LAY SUMMARY: Children and adults with an autistic relative have been found to experience more psychiatric difficulties than those with no family links to autism. However, a few studies have explored what happens when these individuals get older. Examining over 20,000 adults age 50+, we found that older adults with an autistic relative experienced elevated rates of most psychiatric conditions but not physical conditions. Older adults with autistic relatives may benefit from close monitoring to mitigate this susceptibility and to provide timely intervention.

Theory of mind performance in younger and older adults with elevated autistic traits

Little is known about the impact of aging with Autism Spectrum Disorder on theory of mind (ToM). While ToM difficulties appear to abate with age in older autistic populations, this has yet to be explored in the Broad Autism Phenotype (BAP). The current study examined ToM performance among younger (n = 49, aged 18-46) and older adults (n = 47, aged 60-91) who were classified as on the BAP (younger n = 18; older n = 21) or not (younger n = 31; older n = 26) using the BAP Questionnaire. ToM was assessed using the ecologically valid Strange Stories Film Task (SSFT) and the dynamic Happé-Frith Triangle Animations task (TA). A 2 × 2 analysis of variance examined the effects of autistic traits (BAP vs. non-BAP) and age (young vs. old). For both SSFT and TA, results showed autistic trait main effects on task performance (non-BAP > BAP). Age main effects were observed for some but not all metrics on TA (younger better than older), with no differences in SSFT. An interaction of autistic traits and age was observed in TA Intentionality, with younger non-BAP and younger BAP performing similarly but older non-BAP performing better than older BAP. Results show that younger and older adults with elevated autistic traits show poorer ToM performance. Despite ToM difficulties being common in later life in the general population, this effect was not observed when using a ToM task designed to reflect real-world scenarios. However, results suggest that autistic traits and age could interact to increase risk for poor ToM performance in older adults who endorse elevated autistic traits. Autism Res 2020, 13: 751-762. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The behaviors and characteristics commonly found in autism spectrum disorders have been linked to differences in understanding social situations. Similar difficulties have also been found in older age. We assessed social understanding in younger and older adults from the general population. Both younger and older adults who report more autism-like characteristics experience more difficulties with social understanding. However, few differences were found between younger and older adults.

Predicting Dementia in Cerebral Small Vessel Disease Using an Automatic Diffusion Tensor Image Segmentation Technique

Supplemental Digital Content is available in the text.

Cerebral small vessel disease (SVD) is the most common cause of vascular cognitive impairment, with a significant proportion of cases going on to develop dementia. We explore the extent to which diffusion tensor image segmentation technique (DSEG; which characterizes microstructural damage across the cerebrum) predicts both degree of cognitive decline and conversion to dementia, and hence may provide a useful prognostic procedure.

Exploratory Study of Executive Function Abilities Across the Adult Lifespan in Individuals Receiving an ASD Diagnosis in Adulthood

Little is known about cognition in autism spectrum disorder (ASD) across adulthood. We examined executive function abilities and autism traits in 134 adults receiving a first diagnosis of ASD. Participants aged 18–75 years with abilities in the normal range were assessed on executive function and self-report autism traits. Results suggest that for some abilities relying on speed and sequencing (Trails A and B; Digit Symbol), late-diagnosed individuals with ASD may demonstrate better performance than typical age-norms. On other executive measures (Digit Span, Hayling and Brixton tests) age-related correlations were similar to typical age-norms. Different domains of executive function may demonstrate different trajectories for ageing with ASD, with patterns of slower, accelerated or equivalent age-related change being observed across different measures.

The efficacy of transcranial random noise stimulation (tRNS) on mood may depend on individual differences including age and trait mood

OBJECTIVES

To assess whether changes in brain microstructures associated with ageing and presence of cardiovascular risk factors (CVRF) reduce the efficacy of transcranial electrical stimulation (tES) improving mood in euthymic older adults.

METHODS

Using excitatory high-frequency transcranial random noise stimulation (tRNS) over bilateral dorsolateral prefrontal cortex, the effect on mood was assessed in euthymic young adults (YA), older adults (HOA) and older adults with CVRF (OVR). Active-tRNS or sham was applied over two sessions. Positive and Negative Affect Schedule and Warwick Edinburgh Mental Well-being Scale measured self-reported state mood before and after stimulation. Trait mood was also measured using the Geriatric Depression Scale.

RESULTS

Response to tRNS seemed dependent on individual differences in age and trait mood. In HOA, more negative trait mood was associated with more positive mood change after tRNS. OVR showed a similar but reduced pattern of mood change to HOA. In YA, more positive trait mood was associated with greater positive mood change after tRNS.

CONCLUSIONS

Age and trait mood may be important factors when examining the efficacy of tES as an alternative treatment for depression.

SIGNIFICANCE

Future studies should consider how response to tES is affected by individual differences.

Associations between pro-inflammatory cytokines, learning, and memory in late-life depression and healthy aging

OBJECTIVES

Pro-inflammatory cytokines may play a role in learning and memory difficulties and may be exacerbated in late-life depression (LLD), where pro-inflammatory markers are already elevated because of aging and age-related vascular risk.

METHODS

Learning and memory, and pro-inflammatory cytokines-Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and Interleukin-6 (IL-6) were measured in 24 individuals with LLD and 34 healthy older adults (HOA). Hippocampal volumes were segmented using Freesurfer software.

RESULTS

Pro-inflammatory cytokines were higher in LLD compared with HOA. Regression analyses demonstrated that educational level and right hippocampal volume significantly contributed to explaining the variance in learning. For memory performance, educational level, right hippocampal volume and a group-by-IL-6 interaction significantly contributed to the model.

CONCLUSIONS

High levels of IL-6 impact cognition in LLD but not HOA. Results suggest that high levels of inflammation alone are not sufficient to account for cognitive difficulties, but may interact with other factors in at-risk populations like LLD, to contribute to memory difficulties. Copyright © 2017 John Wiley & Sons, Ltd.

Demographic and Cognitive Profile of Individuals Seeking a Diagnosis of Autism Spectrum Disorder in Adulthood

Little is known about ageing with autism spectrum disorder (ASD). We examined the characteristics of adults referred to a specialist diagnostic centre for assessment of possible ASD, 100 of whom received an ASD diagnosis and 46 did not. Few demographic differences were noted between the groups. Comorbid psychiatric disorders were high in individuals with ASD (58 %) and non-ASD (59 %). Individuals who received an ASD diagnosis had higher self-rated severity of ASD traits than non-ASD individuals. Within the ASD group, older age was associated with higher ratings of ASD traits and better cognitive performance. One interpretation is that general cognitive ability and the development of coping strategies across the lifespan, do not necessarily reduce ASD traits but may mitigate their effects.

Diffusion tensor image segmentation of the cerebrum provides a single measure of cerebral small vessel disease severity related to cognitive change

Cerebral small vessel disease (SVD) is the primary cause of vascular cognitive impairment and is associated with decline in executive function (EF) and information processing speed (IPS). Imaging biomarkers are needed that can monitor and identify individuals at risk of severe cognitive decline. Recently there has been interest in combining several magnetic resonance imaging (MRI) markers of SVD into a unitary score to describe disease severity. Here we apply a diffusion tensor image (DTI) segmentation technique (DSEG) to describe SVD related changes in a single unitary score across the whole cerebrum, to investigate its relationship with cognitive change over a three-year period. 98 patients (aged 43-89) with SVD underwent annual MRI scanning and cognitive testing for up to three years. DSEG provides a vector of 16 discrete segments describing brain microstructure of healthy and/or damaged tissue. By calculating the scalar product of each DSEG vector in reference to that of a healthy ageing control we generate an angular measure (DSEG θ) describing the patients' brain tissue microstructural similarity to a disease free model of a healthy ageing brain. Conventional MRI markers of SVD brain change were also assessed including white matter hyperintensities, cerebral atrophy, incident lacunes, cerebral-microbleeds, and white matter microstructural damage measured by DTI histogram parameters. The impact of brain change on cognition was explored using linear mixed-effects models. Post-hoc sample size analysis was used to assess the viability of DSEG θ as a tool for clinical trials. Changes in brain structure described by DSEG θ were related to change in EF and IPS (p < 0.001) and remained significant in multivariate models including other MRI markers of SVD as well as age, gender and premorbid IQ. Of the conventional markers, presence of new lacunes was the only marker to remain a significant predictor of change in EF and IPS in the multivariate models (p = 0.002). Change in DSEG θ was also related to change in all other MRI markers (p < 0.017), suggesting it may be used as a surrogate marker of SVD damage across the cerebrum. Sample size estimates indicated that fewer patients would be required to detect treatment effects using DSEG θ compared to conventional MRI and DTI markers of SVD severity. DSEG θ is a powerful tool for characterising subtle brain change in SVD that has a negative impact on cognition and remains a significant predictor of cognitive change when other MRI markers of brain change are accounted for. DSEG provides an automatic segmentation of the whole cerebrum that is sensitive to a range of SVD related structural changes and successfully predicts cognitive change. Power analysis shows DSEG θ has potential as a monitoring tool in clinical trials. As such it may provide a marker of SVD severity from a single imaging modality (i.e. DTIs).

Sensitivity of the UK Clinical Practice Research Datalink to Detect Neurodevelopmental Effects of Medicine Exposure in Utero: Comparative Analysis of an Antiepileptic Drug-Exposed Cohort

Introduction

Electronic healthcare data have several advantages over prospective observational studies, but the sensitivity of data on neurodevelopmental outcomes and its comparability with data generated through other methodologies is unknown.

Objectives

The objectives of this study were to determine whether data from the UK Clinical Practice Research Datalink (CPRD) produces similar risk estimates to a prospective cohort study in relation to the risk of neurodevelopmental disorders (NDDs) following prenatal antiepileptic drug (AED) exposure.

Methods

A cohort of mother–child pairs of women with epilepsy (WWE) was identified in the CPRD and matched to a cohort without epilepsy. The study period ran from 1 January 2000 to 31 March 2007 and children were required to be in the CPRD at age 6 years. AED exposure during pregnancy was determined from prescription data and children with an NDD diagnosis by 6 years were identified from Read clinical codes. The prevalence and risk of NDDs was calculated for mother–child pairs in WWE stratified by AED regimen and for those without epilepsy. Comparisons were made with the results of the prospective Liverpool and Manchester Neurodevelopment Group study which completed assessment on 201 WWE and 214 without epilepsy at age 6 years.

Results

In the CPRD, 1018 mother–child pairs to WWE and 6048 to women without epilepsy were identified. The CPRD identified a lower prevalence of NDDs than the prospective study. In both studies, NDDs were more frequently reported in children of WWE than women without epilepsy, although the CPRD risk estimate was lower (2.16 vs. 0.96%, p < 0.001 and 7.46 vs. 1.87%, p = 0.0128). NDD prevalence differed across AED regimens but the CPRD data did not replicate the significantly higher risk of NDDs following in utero monotherapy valproate exposure (adjusted odds ratio [OR_adj] 2.02, 95% confidence interval [CI] 0.52–7.86) observed in the prospective study (OR_adj 6.05, 95% CI 1.65–24.53).

Conclusion

It was possible to identify NDDs in the CPRD; however, the CPRD appears to under-record these outcomes. Larger studies are required to investigate further.

Electronic supplementary material

The online version of this article (doi:10.1007/s40264-017-0506-5) contains supplementary material, which is available to authorized users.

Brain connectivity in late-life depression and aging revealed by network analysis

OBJECTIVE

To use novel methods to examine age associations across an integrated brain network in healthy older adults (HOA) and individuals with late-life depression (LLD). Graph theory metrics describe the organizational configuration of both the global network and specified brain regions.

METHODS

Cross-sectional data were acquired. Graph theory was used to explore diffusion tensor imaging-derived white matter networks. Forty-eight HOA and 28 adults with LLD were recruited from the community. Global and local metrics in prefrontal, cingulate, and temporal regions were calculated. Group differences and associations with age were explored.

RESULTS

Group differences were noted in local metrics of the right prefrontal and temporal regions, but no significant differences were observed on global metrics. Local (not global) metrics were associated with age differently across groups. For HOA, local metrics across all regions correlated with age, whereas in adults with LLD, correlations were only observed within temporal regions. In keeping with hypothesized regions impacted by LLD, stronger hubs in right temporal regions were observed among HOA, whereas LLD individuals were characterized by robust hubs in frontal regions.

CONCLUSION

We demonstrate widespread age-related changes in local network properties among HOA with different and more restricted local changes in LLD. Although a preliminary analysis, different patterns of correlations in local networks coupled with equivalent global metrics may reflect altered local structural brain networks in patients with LLD.

Associations between vascular risk and mood in euthymic older adults: preliminary findings

OBJECTIVES

Vascular risk has been associated with late-life depression, but it is less certain whether it is also associated with the endorsement of depressive symptoms among euthymic older adults. We explore whether vascular risk is associated with endorsement of depressive symptoms among euthymic older adults and examine associations with cognitive function.

METHODS

Fifty-seven adults (50-89 years), were assessed for: 1) vascular risk (Framingham Stroke Risk Profile, FSRP); 2) depressive mood (Center for Epidemiologic Studies Depression, CESD self-rating questionnaire; Hamilton Depression Rating Scale, HDRS clinical interview); and 3) cognitive domains, (Learning and Memory, L-M; Attention and Information Processing, AIP; Executive Function, EF; Semantic Language, SL).

RESULTS

Significant correlations were observed between FSRP and both depression scales, independent of age. No significant correlations were observed between HDRS and any cognitive domain; in contrast, CESD correlated significantly with L-M, AIP and EF but not SL. FSRP correlated significantly with L-M and EF measures only. Regression analyses revealed that 11.5% of the variance in HDRS scores was explained by FSRP, whereas CESD scores were explained by EF (20.8% of variance).

CONCLUSIONS

Vascular risk was associated with endorsement of depressive symptoms in euthymic older adults. However, the patterns of associations with the two depression scales are distinct and may reflect both differences in administration and item characteristics. A limitation of this study was the exclusion of individuals with subclinical depression, leading to a restricted range on depression scales; future studies should include a full population sample to more fully explore low mood in late-life.

In vivo quantification of white matter microstructure for use in aging: a focus on two emerging techniques

Human brain imaging has seen many advances in the quantification of white matter in vivo. For example, these advances have revealed the association between white matter damage and vascular disease as well as their impact on risk for and development of dementia and depression in an aging population. Current neuroimaging methods to quantify white matter damage provide a foundation for understanding such age-related neuropathology; however, these methods are not as adept at determining the underlying microstructural abnormalities signaling at risk tissue or driving white matter damage in the aging brain. This review will begin with a brief overview of the use of diffusion tensor imaging (DTI) in understanding white matter alterations in aging before focusing in more detail on select advances in both diffusion-based methods and multi-component relaxometry techniques for imaging white matter microstructural integrity within myelin sheaths and the axons they encase. Although DTI greatly extended the field of white matter interrogation, these more recent technological advances will add clarity to the underlying microstructural mechanisms that contribute to white matter damage. More specifically, the methods highlighted in this review may prove more sensitive (and specific) for determining the contribution of myelin versus axonal integrity to the aging of white matter in brain.

Preliminary analysis of age of illness onset effects on symptom profiles in major depressive disorder

OBJECTIVE

Major depressive disorder (MDD) is prevalent across the lifespan, but relatively little is known about how age of illness onset impacts the cognitive and affective presentation of MDD.

METHOD

We explore depressive symptoms and cognition in 70 adults (30-89 years old) with MDD. Participants were divided into three groups on the basis of age of MDD onset: early (<30 years), midlife (30-49.9 years), and late (>50 years). Symptoms were assessed using the Hamilton Depression Rating Scale; principal component analysis was used to create symptom component scores. Cognitive functions were measured.

RESULTS

The late-onset group were significantly older than the early-onset and midlife-onset groups. Analysis controlled for age and hemoglobin A1c levels, as some participants had diabetes. The late-onset group demonstrated greater weight loss and gastrointestinal symptoms compared with the early-onset group. Suicidal thoughts and sleep disturbance were higher in both the early-onset and late-onset groups compared with the midlife-onset group. Correlations between symptom components and cognitive domains varied by age-of-onset group.

DISCUSSION

This preliminary analysis demonstrates cognitive and affective profiles that are both unique to age of onset and common across MDD. Symptom profiles may assist in identifying factors influencing depression and enhance the clinical evaluation and care of individuals struggling with the effects of depression across the lifespan.

Cognitive dysfunction in patients hospitalized with acute exacerbation of COPD

BACKGROUND

Cognitive impairment is one of the least well-studied COPD comorbidities. It is known to occur in hypoxemic patients, but its presence during acute exacerbation is not established.

OBJECTIVES

The purpose of this study was to assess neuropsychological performance in patients with COPD who were awaiting discharge from hospital following acute exacerbation and recovery and to compare them with stable outpatients with COPD and with healthy control subjects.

METHODS

We recruited 110 participants to the study: 30 inpatients with COPD who were awaiting discharge following an exacerbation, 50 outpatients with stable COPD, and 30 control subjects. Neuropsychological tests measured episodic memory, executive function, visuospatial function, working memory, processing speed, and an estimate of premorbid abilities. Follow-up cognitive assessments for patients who were stable and those with COPD exacerbation were completed at 3 months.

RESULTS

Patients with COPD exacerbation were significantly worse (P<.05) than stable patients over a range of measures of cognitive function, independent of hypoxemia, disease severity, cerebrovascular risk, or pack-years smoked. Of the patients with COPD exacerbation, up to 57% were in the impaired range and 20% were considered to have suffered a pathologic loss in processing speed. Impaired cognition was associated with worse St. George's Respiratory Questionnaire score (r=-0.40-0.62, P≤.02) and longer length of stay (r=0.42, P=.02). There was no improvement in any aspect of cognition at recovery 3 months later.

CONCLUSIONS

In patients hospitalized with an acute COPD exacerbation, impaired cognitive function is associated with worse health status and longer hospital length of stay. A significant proportion of patients are discharged home with unrecognized mild to severe cognitive impairment, which may not improve with recovery.

Verbal working and long-term episodic memory associations with white matter microstructure in normal aging investigated using tract-based spatial statistics

Reductions in the integrity of white matter microstructure are thought to be a significant cause of age-related decline in mnemonic abilities, including working memory (WM) and long-term episodic memory (LTM). This study uses tract-based spatial statistics (TBSS) applied to diffusion tensor magnetic resonance images to explore correlations between white matter microstructure and verbal WM and LTM in a sample of 98 normal older adults. WM performance was associated with microstructure in left fronto-parietal pathways and LTM was associated with bilateral fronto-temporal pathways. Interhemispheric-frontal pathways (genu of the corpus callosum) were associated with both types of mnemonic function. We hypothesize that in normal aging, damage to certain white matter pathways may reduce the dynamic efficiency of mnemonic abilities by disrupting the connections within multiple distributed networks. By correlating white matter with two mnemonic functions in the same analysis, we have demonstrated that regional white matter networks may share common mnemonic functions but also may be differentiated for memory types.

Prefrontal vulnerabilities and whole brain connectivity in aging and depression

Studies exploring the underpinnings of age-related neurodegeneration suggest fronto-limbic alterations that are increasingly vulnerable in the presence of disease including late life depression. Less work has assessed the impact of this specific vulnerability on widespread brain circuitry. Seventy-nine older adults (healthy controls=45; late life depression=34) completed translational tasks shown in non-human primates to rely on fronto-limbic networks involving dorsolateral (Self-Ordered Pointing Task) or orbitofrontal (Object Alternation Task) cortices. A sub-sample of participants also completed diffusion tensor imaging for white matter tract quantification (uncinate and cingulum bundle; n=58) and whole brain tract-based spatial statistics (n=62). Despite task associations to specific white matter tracts across both groups, only healthy controls demonstrated significant correlations between widespread tract integrity and cognition. Thus, increasing Object Alternation Task errors were associated with decreasing fractional anisotropy in the uncinate in late life depression; however, only in healthy controls was the uncinate incorporated into a larger network of white matter vulnerability associating fractional anisotropy with Object Alternation Task errors using whole brain tract-based spatial statistics. It appears that the whole brain impact of specific fronto-limbic vulnerabilities in aging may be eclipsed in the presence of disease-specific neuropathology like that seen in late life depression.

Brain structure and function in chronic obstructive pulmonary disease: a multimodal cranial magnetic resonance imaging study

RATIONALE

Brain pathology is a poorly understood systemic manifestation of chronic obstructive pulmonary disease (COPD). Imaging techniques using magnetic resonance (MR) diffusion tensor imaging (DTI) and resting state functional MR imaging (rfMRI) provide measures of white matter microstructure and gray functional activation, respectively.

OBJECTIVES

We hypothesized that patients with COPD would have reduced white matter integrity and that functional communication between gray matter resting-state networks would be significantly different to control subjects. In addition, we tested whether observed differences related to disease severity, cerebrovascular comorbidity, and cognitive dysfunction.

METHODS

DTI and rfMRI were acquired in stable nonhypoxemic patients with COPD (n = 25) and compared with age-matched control subjects (n = 25). Demographic, disease severity, stroke risk, and neuropsychologic assessments were made.

MEASUREMENTS AND MAIN RESULTS

Patients with COPD (mean age, 68; FEV(1) 53 ± 21% predicted) had widespread reduction in white matter integrity (46% of white matter tracts; P < 0.01). Six of the seven resting-state networks showed increased functional gray matter activation in COPD (P < 0.01). Differences in DTI, but not rfMRI, remained significant after controlling for stroke risk and smoking (P < 0.05). White matter integrity and gray matter activation seemed to account for difference in cognitive performance between patients with COPD and control subjects.

CONCLUSIONS

In stable nonhypoxemic COPD there is reduced white matter integrity throughout the brain and widespread disturbance in functional activation of gray matter, which may contribute to cognitive dysfunction. White matter microstructural integrity but not gray matter functional activation is independent of smoking and cerebrovascular comorbidity. The mechanisms remain unclear, but may include cerebral small vessel disease caused by COPD.

Aging in autism spectrum disorders: a mini-review

This article addresses an important and barely researched topic: what happens to children with autism spectrum disorders when they grow old. We review the small published literature on aging in autism. We then consider the relevance of research on 'neurotypical' aging in core domains of autistic impairment: social cognition, executive function, cognitive style and memory. Research themes from the study of normal aging, including cognitive reserve, compensation, quality of life, loneliness and physical health are of relevance for future research on autism. Studies of aging in autism will be important not only to plan appropriate services, but also to shed light on the full developmental trajectory of this neurodevelopmental condition, and perhaps provide clues to neuropathology and etiology.

White matter structural decline in normal ageing: a prospective longitudinal study using tract-based spatial statistics

Normal ageing is accompanied by a progressive decline in cognitive function but the mechanisms for this are not fully understood. Nevertheless, the importance of white matter degeneration is supported by diffusion tensor imaging (DTI) studies, although several important questions remain about the pattern and nature of age-related white matter degeneration. Firstly, there is a lack of longitudinal data determining the rate of change in DTI parameters with age, and whether this can be detected over short time periods. Secondly, it is unclear whether observed changes are uniform across the brain or whether accelerated white matter degeneration is localised to particular brain regions, as would support the frontal-ageing hypothesis. This study uses DTI techniques to quantify structural integrity change to determine whether regional differences are apparent in the rate of degeneration during longitudinal follow-up in a sample of healthy middle aged and older adults aged between 50 and 90years. Longitudinal differences in fractional anisotropy, axial and radial diffusivity are investigated using 1D coronal slice profiles, and 2D column maps in standard space, as well as using 3D tract-based spatial statistics (TBSS) to investigate local age-related structural changes on a voxel-by-voxel basis at baseline and two-year follow-up. Results indicate that DTI can detect age-related change in white matter structure over a relatively short follow-up period and that longitudinal analyses reveal significant changes in white matter integrity throughout the brain with no evidence of accelerated decline in the frontal lobe regions during a 2year period. Common changes across different diffusion characteristics are discussed.

Diffusion tensor imaging detects age related white matter change over a 2 year follow-up which is associated with working memory decline

BACKGROUND

Diffusion tensor imaging (DTI) is a sensitive method for detecting white matter damage, and in cross sectional studies DTI measures correlate with age related cognitive decline. However, there are few data on whether DTI can detect age related changes over short time periods and whether such change correlates with cognitive function.

METHODS

In a community sample of 84 middle-aged and elderly adults, MRI and cognitive testing were performed at baseline and after 2 years. Changes in DTI white matter histograms, white matter hyperintensity (WMH) volume and brain volume were determined. Change over time in performance on tests of executive function, working memory and information processing speed were also assessed.

RESULTS

Significant change in all MRI measures was detected. For cognition, change was detected for working memory and this correlated with change in DTI only. In a stepwise regression, with change in working memory as the dependent variable, a DTI histogram measure explained 10.8% of the variance in working memory. Change in WMH or brain volume did not contribute to the model.

CONCLUSIONS

DTI is sensitive to age related change in white matter ultrastructure and appears useful for monitoring age related white matter change even over short time periods.

White matter pathways associated with working memory in normal aging

INTRODUCTION

Previous studies by our group have found that white matter integrity as determined by Diffusion Tensor Imaging (DTI) is associated with working memory decline. It has been proposed that subtle white matter integrity loss may lead to the disruption of working memory in particular because it relies on the dynamic and reiterative activity of cortico-cortical pathways.

METHODS

DTI and working memory measurement were acquired for 99 adults from our GENIE study of healthy middle aged and elderly individuals. Voxel-based statistics were used to identify clusters of voxels in mean diffusivity images specifically associated with variations in working memory performance. Tractography then identified the cortico-cortical white matter pathways passing through these clusters, between the temporal, parietal and frontal cortices.

RESULTS

Significant clusters were identified which were associated with working memory in the white matter of the temporal and frontal lobes, the cingulate gyrus, and in the thalamus. The tracts that passed through these clusters included the superior parietal lobule pathway, the medial temporo-frontal pathway, the uncinate fasciculus, the fronto-parietal fasciculus, and the cingulum.

CONCLUSIONS

Significant clusters were identified in the white matter that were associated with working memory performance. Tractography performed through these clusters identified white matter fiber tracts which pass between grey matter regions known to be activated by working memory tasks and also mirror working memory pathways suggested by previous functional connectivity imaging.

Theory of mind associations with other cognitive functions and brain imaging in normal aging

The study investigated age-related differences in theory of mind and explored the relationship between this ability, other cognitive abilities, and structural brain measures. A cohort of 106 adults (ages 50-90 years) was recruited. Participants completed tests of theory of mind, verbal and performance intelligence, executive function, and information processing speed and underwent structural magnetic resonance imaging (measurement of whole brain volume, volume of white matter hyperintensities, and diffusion tensor imaging of white matter integrity). Theory of mind ability declined with increasing age, and the relationship between theory of mind and age was fully mediated by performance intelligence, executive function, and information processing speed and was partially mediated by verbal intelligence. Theory of mind performance correlated significantly with diffusion tensor imaging measures of white matter integrity but not with volume of white matter hyperintensities or whole-brain volume. Theory of mind age-related decline may not be independent of other cognitive functions; it may also be particularly susceptible to changes in white matter integrity.

Reduced N-acetylaspartate is consistent with axonal dysfunction in cerebral small vessel disease

BACKGROUND

Cerebral small vessel disease (SVD) is an important cause of cognitive impairment, but the pathophysiological mechanisms remain unclear. We used (1)H MRS to investigate brain metabolic differences between patients with SVD and controls and correlated this with cognition.

METHODS

35 patients with SVD (lacunar stroke and radiological evidence of confluent leukoaraiosis) and 35 controls underwent multi-voxel spectroscopic imaging of white matter to obtain absolute metabolite concentrations of N-acetylaspartate (NAA), total creatines, total cholines, myo-inositol, and lactate. A range of cognitive tests was performed on patients with SVD, and composite scores were calculated.

RESULTS

Scans of sufficient quality for data analysis were available in 29 cases and 35 controls. NAA was significantly reduced in patients compared with controls (lower by 7.27%, P = 0.004). However, when lesion load within each individual voxel (mean 22% in SVD vs 5% in controls, P < 0.001) was added as a covariate, these differences were no longer significant, suggesting that the metabolite differences arose primarily from differences in lesioned tissue. In patients with SVD, there was no correlation between cognitive scores and any brain metabolite. No lactate, an indicator of anaerobic metabolism, was detected.

CONCLUSIONS

The most consistent change in SVD is a reduction in NAA, a marker of neuronal integrity. The lack of correlation with cognition does not support the use of MRS as a surrogate disease marker.

Cognitive impairment and white matter damage in hypertension: a pilot study

OBJECTIVES

Hypertension has been associated with impaired cognition. Diffusion tensor imaging (DTI) and magnetic resonance spectroscopy were applied to assess white matter abnormalities in treated vs untreated hypertension and if these correlated with neuropsychological performance.

METHODS

Subjects were 40 patients with medically treated hypertension (mean age 69.3 years), 10 patients with untreated hypertension (mean age 57.6 years) and 30 normotensive controls (mean age 68.2 years). Hypertension was defined as a previous diagnosis and taking hypertensive medication, or a resting blood pressure of >140/90 mmHg on the day of assessment.

RESULTS

Patients with treated hypertension performed worse on immediate (P = 0.037) as well as delayed memory tasks (P = 0.024) compared with normotensive controls. Cognitive performance was worse in untreated compared with treated hypertension on executive functions (P = 0.041) and psychomotor speed (P = 0.003). There was no significant correlation between cognition and any of the imaging parameters in treated hypertension. However, in untreated hypertension the results revealed a positive correlation between an executive functioning and attention composite score and DTI mean diffusivity values (P = 0.016) and between psychomotor speed and spectroscopy NAA/tCr levels (P = 0.015).

CONCLUSIONS

These results suggest there is cognitive impairment in hypertension. Treated hypertension was associated with deficits in memory while untreated hypertension revealed a more 'subcortical' pattern of cognitive impairment.

A structural equation modeling investigation of age-related variance in executive function and DTI measured white matter damage

Cognitive changes in normal aging have been explained by the frontal-executive hypothesis, but the assumptions made by this hypothesis concerning the neurobiological causes are still a matter of debate. Executive functions (EF) may activate neural networks that include disparate grey matter regions, and rely on the integrity of white matter connections. In 118 adults (50-90 years old) from the GENIE study, white matter integrity was measured using diffusion tensor imaging, and information processing speed, fluid intelligence and EF were assessed. A theory-driven structural equation model was developed to test associations between variables. The model was revised, removing non-significant paths. The adjusted model explained well the covariance in our data; and suggested that the reduction in white matter integrity associated with age directly affected only working memory. Fluid intelligence was mediated by all measured cognitive variables. The results suggest that white matter integrity may be particularly important for abilities activating complex neural networks, as occurs in working memory. Integration of the information processing speed and frontal-executive hypotheses may provide important information regarding common, unique, and mediating factors in cognitive aging.

Diffusion tensor imaging and MR spectroscopy in hypertension and presumed cerebral small vessel disease

In patients with cerebral small vessel disease (SVD) diffusion tensor imaging (DTI) is sensitive to white matter damage and correlates better with cognitive function than conventional imaging. It has been proposed as a surrogate marker for treatment trials. However, the pathological changes underlying DTI are not known. The purpose of this study was to use magnetic resonance spectroscopy (MRS) to determine the pathological changes underlying DTI abnormalities in a range of patients from asymptomatic white matter hyperintensities to symptomatic cerebral SVD. 29 SVD patients, 63 hypertensive subjects, and 42 normotensive controls were recruited. The relationship between the DTI and MRS parameters in the centrum semiovale white matter was determined. There was a significant reduction in N-acetylaspartate (NAA; 2.067 +/- 0.042 vs 2.299 +/- 0.029 and 2.315 +/- 0.036, P = 9 x 10(-6)) and increase in mean diffusivity (mm2/s x 10(-3); 0.942 +/- 0.123 vs 0.822 +/- 0.064 and 0.792 +/- 0.057, P = 1 x 10(-8)) in symptomatic SVD patients compared with the other two groups. DTI parameters correlated with NAA in all three groups, in a graded manner depending on severity of disease (r -SVD -0.827, hypertensive subjects -0.457, controls -0.317). NAA is a marker of axonal loss/dysfunction. These findings are consistent with axonal loss/dysfunction being the principal process causing the DTI changes found in cerebral SVD and ageing.

Multimodal MRI in cerebral small vessel disease: its relationship with cognition and sensitivity to change over time

BACKGROUND AND PURPOSE

Cerebral small vessel disease is the most common cause of vascular dementia. Interest in using MRI parameters as surrogate markers of disease to assess therapies is increasing. In patients with symptomatic sporadic small vessel disease, we determined which MRI parameters best correlated with cognitive function on cross-sectional analysis and which changed over a period of 1 year.

METHODS

Thirty-five patients with lacunar stroke and leukoaraiosis were recruited. They underwent multimodal MRI (brain volume, fluid-attenuated inversion recovery lesion load, lacunar infarct number, fractional anisotropy, and mean diffusivity from diffusion tensor imaging) and neuropsychological testing. Twenty-seven agreed to reattend for repeat MRI and neuropsychology at 1 year.

RESULTS

An executive function score correlated most strongly with diffusion tensor imaging (fractional anisotropy histogram, r=-0.640, P=0.004) and brain volume (r=0.501, P=0.034). Associations with diffusion tensor imaging were stronger than with all other MRI parameters. On multiple regression of all imaging parameters, a model that contained brain volume and fractional anisotropy, together with age, gender, and premorbid IQ, explained 74% of the variance of the executive function score (P=0.0001). Changes in mean diffusivity and fractional anisotropy were detectable over the 1-year follow-up; in contrast, no change in other MRI parameters was detectable over this time period.

CONCLUSIONS

A multimodal MRI model explains a large proportion of the variation in executive function in cerebral small vessel disease. In particular, diffusion tensor imaging correlates best with executive function and is the most sensitive to change. This supports the use of MRI, in particular diffusion tensor imaging, as a surrogate marker in treatment trials.

Long and short echo time proton magnetic resonance spectroscopic imaging of the healthy aging brain

PURPOSE

To investigate the relationship between subject age and white matter brain metabolite concentrations and R(2) relaxation rates in a cross-sectional study of human brain.

MATERIALS AND METHODS

Long- and short-echo proton spectroscopic imaging were used to investigate concentrations and R2 relaxation rates of N-acetyl aspartate (NAA) + N-acetyl aspartyl glutamate (NAAG), choline (Cho), creatine (Cr), and myoinositol (mI) in the white matter of the centrum semiovale of 106 healthy volunteers aged 50-90 years; usable data were obtained from 79 subjects. A major aim was to identify which parameters were most sensitive to changes with age. Spectra were analyzed using the LCModel method.

RESULTS

The apparent R2 of NAA and the LCModel concentration of Cr at short echo time were significantly correlated with age after multiplicity correction. Large lipid resonances were observed in the brain midline of some subjects, the incidence increasing significantly with age. We believe this to result from lipid deposits in the falx cerebri.

CONCLUSION

Since only short-echo spectroscopy showed a robust relationship between Cr and subject age, and detects more metabolites than long echo time, we conclude that short-echo is superior to long-echo for future aging studies. Future studies could usefully determine whether the Cr-age relationship is due to changes in concentration, T1, or both.

The relationship between white matter brain metabolites and cognition in normal aging: the GENIE study

Magnetic resonance spectroscopy (MRS) has demonstrated age-related changes in brain metabolites that may underlie micro-structural brain changes, but few studies have examined their relationship with cognitive decline. We performed a cross-sectional study of brain metabolism and cognitive function in 82 healthy adults (aged 50-90) participating in the GENIE (St GEorge's Neuropsychology and Imaging in the Elderly) study. Absolute metabolite concentrations were measured by proton chemical shift imaging within voxels placed in the centrum semiovale white matter. Cognitive abilities assessed were executive function, working memory, information processing speed, long-term memory and fluid intelligence. Correlations showed that all cognitive domains declined with age. Total creatine (tCr) concentration increased with age (r=0.495, p<0.001). Regression analyses were performed for each cognitive variable, including estimated intelligence and the metabolites, with age then added as a final step. A significant relationship was observed between tCr and executive function, long-term memory, and fluid intelligence, although these relationships did not remain significant after age was added as a final step in the regression. The regression analysis also demonstrated a significant relationship between N-acetylaspartate (NAA) and executive function. As there was no age-related decline in NAA, this argues against axonal loss with age; however the relationship between NAA and executive function independent of age and estimated intelligence is consistent with white matter axonal integrity having an important role in executive function in normal individuals.

The cognitive profiles of CADASIL and sporadic small vessel disease

BACKGROUND

Interpretation of treatment trials in vascular dementia is confounded by the presence of coexistent Alzheimer disease (AD) pathology. The younger onset genetic disease cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) offers a model of pure vascular dementia, in which such confounding is unlikely. To validate CADASIL's use as a model it is important to show it results in a similar cognitive impairment.

METHODS

The same neuropsychological assessment was administered to patients with CADASIL (n = 34, 14 of whom had had stroke), sporadic small vessel disease (SVD) presenting with lacunar stroke and having confluent leukoaraiosis (n = 54), and healthy controls (n = 25).

RESULTS

A similar pattern of neuropsychological impairment was seen in the two diseases, with prominent early executive dysfunction. Patients with CADASIL and SVD performed worse than controls on Trails switching test (CADASIL p = 0.006; SVD p < 0.001), and on verbal fluency test (CADASIL p = 0.015; SVD p = 0.004). The SVD group also performed worse on immediate (p = 0.050) and delayed (p = 0.049) memory. When only patients with CADASIL with stroke were included in analysis with SVD subjects, all of whom had had stroke, a very similar cognitive profile was seen. The only difference was on verbal fluency, where CADASIL subjects performed worse (p = 0.044).

CONCLUSION

Patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and small vessel disease show a similar pattern of cognitive deficits. This suggests that CADASIL provides a model of pure vascular dementia relevant for sporadic small vessel disease vascular dementia.

White matter damage on diffusion tensor imaging correlates with age-related cognitive decline

BACKGROUND

Damage to white matter tracts, resulting in "cerebral disconnection," may underlie age-related cognitive decline.

METHODS

Using diffusion tensor MRI (DTI) to investigate white matter damage, and magnetic resonance spectroscopy (MRS) to look at its underlying pathologic basis, the authors investigated the relationship between white matter structure and cognition in 106 healthy middle-aged and elderly adults. Fractional anisotropy (FA) and mean diffusivity (MD) values, whole brain white matter histograms, and regions of interest placed in the white matter of the centrum semiovale were analyzed. Correlations with executive function, working memory, and information-processing speed were performed.

RESULTS

There was a progressive reduction in FA and increase in diffusivity with age in both region of interest (r = 0.551, p < 0.001), and whole brain histograms (r = 0.625, p < 0.001). DTI values correlated with performance in all three cognitive domains. After controlling for age, DTI parameters correlated with working memory but not with the other two cognitive domains. MRS studies found a correlation of N-acetyl aspartate, a neuronal marker, with DTI parameters (r = 0.253, p < 0.05).

CONCLUSION

The results are consistent with white matter damage due to axonal loss, causing age- related cognitive decline. Working memory may be particularly dependent on complex networks dependent on white matter connections.

A combined approach to the assessment of neurological dysphagia

The dysphagia encountered by patients with neurological disorders can be both distressing and life threatening because of the associated problems of aspiration. Decisions regarding management are often difficult because the exact nature of the underlying disorder varies from patient to patient and is frequently complex. A new approach to the assessment and evaluation of acquired neurological dysphagia is presented. Management of the first 50 patients assessed by this method is described. The advantages of a joint dysphagia clinic comprising neurology, speech therapy, ENT and radiology departments are discussed.