Health conditions in spousal caregivers of people with dementia and their relationships with stress, caregiving experiences, and social networks: longitudinal findings from the IDEAL programme

OBJECTIVES

Longitudinal evidence documenting health conditions in spousal caregivers of people with dementia and whether these influence caregivers' outcomes is scarce. This study explores type and number of health conditions over two years in caregivers of people with dementia and subgroups based on age, sex, education, hours of care, informant-rated functional ability, neuropsychiatric symptoms, cognition of the person with dementia, and length of diagnosis in the person with dementia. It also explores whether over time the number of health conditions is associated with caregivers' stress, positive experiences of caregiving, and social networks METHODS: Longitudinal data from the IDEAL (Improving the experience of Dementia and Enhancing Active Life) cohort were used. Participants comprised spousal caregivers (n = 977) of people with dementia. Self-reported health conditions using the Charlson Comorbidity Index, stress, positive experiences of caregiving, and social network were assessed over two years. Mixed effect models were used RESULTS: On average participants had 1.5 health conditions at baseline; increasing to 2.1 conditions over two years. More health conditions were reported by caregivers who were older, had no formal education, provided 10 + hours of care per day, and/or cared for a person with more neuropsychiatric symptoms at baseline. More baseline health conditions were associated with greater stress at baseline but not with stress over time. Over two years, when caregivers' health conditions increased, their stress increased whereas their social network diminished DISCUSSION: Findings highlight that most caregivers have their own health problems which require management to avoid increased stress and shrinking of social networks.

Comorbid health conditions and their impact on social isolation, loneliness, quality of life, and well-being in people with dementia: longitudinal findings from the IDEAL programme

BACKGROUND

Most people with dementia have multiple health conditions. This study explores (1) number and type of health condition(s) in people with dementia overall and in relation to age, sex, dementia type, and cognition; (2) change in number of health conditions over two years; and (3) whether over time the number of health conditions at baseline is related to social isolation, loneliness, quality of life, and/or well-being.

METHODS

Longitudinal data from the IDEAL (Improving the experience of Dementia and Enhancing Active Life) cohort were used. Participants comprised people with dementia (n = 1490) living in the community (at baseline) in Great Britain. Health conditions using the Charlson Comorbidity Index, cognition, social isolation, loneliness, quality of life, and well-being were assessed over two years. Mixed effects modelling was used.

RESULTS

On average participants had 1.8 health conditions at baseline, excluding dementia; increasing to 2.5 conditions over two years. Those with vascular dementia or mixed (Alzheimer's and vascular) dementia had more health conditions than those with Alzheimer's disease. People aged ≥ 80 had more health conditions than those aged < 65 years. At baseline having more health conditions was associated with increased loneliness, poorer quality of life, and poorer well-being, but was either minimally or not associated with cognition, sex, and social isolation. Number of health conditions had either minimal or no influence on these variables over time.

CONCLUSIONS

People with dementia in IDEAL generally had multiple health conditions and those with more health conditions were lonelier, had poorer quality of life, and poorer well-being.

Trajectories of cognitive and perceived functional decline in people with dementia: Findings from the IDEAL programme

INTRODUCTION

Impaired cognition and instrumental activities of daily living (iADL) are key diagnostic features of dementia; however, few studies have compared trajectories of cognition and iADL.

METHODS

Participants from the IDEAL study comprised 1537, 1183, and 851 people with dementia, and 1277, 977, and 749 caregivers at baseline, 12 and 24 months, respectively. Addenbrooke's Cognitive Examination-III and Functional Activities Questionnaire were used to measure cognition and iADL, respectively. Scores were converted to deciles.

RESULTS

Self-rated iADL declined on average by -0.08 (-0.25, 0.08) decile points per timepoint more than cognition. Informant-rated iADL declined on average by -0.31 (-0.43, -0.18) decile points per timepoint more than cognition.

DISCUSSION

Cognition and self-rated iADL declined at a similar rate. Informant-rated iADL declined at a significantly greater rate than cognition. Therefore, either cognition and perceived iADL decline at different rates or informants overestimate increasing iADL difficulties compared to both cognition and self-ratings.

HIGHLIGHTS

Self-ratings of the degree of functional difficulties were consistent with cognition Decline in self-rated everyday activities was consistent with cognitive decline Informant-ratings of everyday activities declined more than cognition.

Resilience in caregivers of people with mild-to-moderate dementia: findings from the IDEAL cohort

OBJECTIVES

A novel model of resilience was tested in caregivers of people with mild-to-moderate dementia and was extended to explore whether including self-efficacy, optimism, and self-esteem improved its predictive value.

DESIGN

Cross-sectional.

SETTING

Data from the IDEAL cohort were used.

PARTICIPANTS

The study comprised 1222 caregivers of people with dementia.

MEASUREMENTS

A composite resilience score was calculated from five measures. Multivariable regressions were used to investigate factors associated with resilience.

RESULTS

Greater resilience was associated with being older, being male, and caregiving for older people with dementia. Greater resilience was also observed when people with dementia had fewer functional difficulties and/or fewer neuropsychiatric symptoms, there was a stronger dyadic relationship, and the caregiver had fewer social restrictions, less neuroticism, and greater perceived competence. Surprisingly, caregiver self-efficacy, optimism, and self-esteem were unrelated to resilience.

CONCLUSION

Caregivers of people with mild-to-moderate dementia generally scored well for resilience. Resilience was associated with both the personal characteristics of caregivers and level of care need among people with dementia. Future work is needed to determine whether the caregivers in this cohort appeared resilient because the care recipients had relatively low care needs and consequently placed fewer demands on caregiver well-being than would be the case where dementia is more advanced.

Longitudinal Predictors of Informant-Rated Involvement of People with Dementia in Everyday Decision-Making: Findings from the IDEAL Program

The extent to which people with dementia are involved in everyday decision-making is unclear. We explored informant-rated involvement of people with dementia in everyday decision-making over 2 years and whether functional, behavioral, and psychological factors related to the person with dementia and the caregiver explain variability in involvement of people with dementia in everyday decision-making. We used IDEAL data for 1182 people with dementia and their caregivers. Baseline mean score on the decision-making involvement scale was 31/45; it minimally declined over time. People with dementia who were female, single, and/or whose caregiver was younger had greater involvement in everyday decision-making than those without these characteristics. Better cognition, fewer functional difficulties, fewer neuropsychiatric symptoms, less caregiver stress, and better informant-rated relationship quality were associated with higher involvement in everyday decision-making. Cognitive and functional rehabilitation, and educational resources for caregivers, could prolong involvement of people with dementia in everyday decision-making.

Predictors of Awareness of Functional Ability in People with Dementia: The Contribution of Personality, Cognition, and Neuropsychiatric Symptoms - Findings from the IDEAL Program

INTRODUCTION

Discrepancy scores reflecting the difference between parallel ratings made by people living with dementia (PwD) in the mild-to-moderate stages and by their informants provide a way to investigate awareness of functional ability in relation to activities of daily living (ADL).

METHODS

Two measures of ADL (Functional Activities Questionnaire; Dependence Scale) were completed by 1,227 PwD and their informants in the IDEAL cohort study baseline assessment. Self-rated and informant-rated scores were used to calculate discrepancies, which were used as an indicator of awareness of functional ability. Smaller discrepancy scores were considered to reflect greater awareness on the part of PwD. PwD completed questionnaires on depression, personality, comorbidities, neuropsychiatric symptoms, and completed a measure of cognition. Informants provided ratings of stress. Univariable and multiple regressions were used to investigate factors related to ADL discrepancy.

RESULTS

A similar pattern of associations were found for both ADL discrepancy scores. Smaller discrepancy scores were associated with higher levels of depression, higher neuroticism, fewer neuropsychiatric symptoms, higher comorbidity, lower carer stress, and receipt of less than 1 hour of care per day from the informant.

DISCUSSION/CONCLUSION

There was a clear pattern of factors that were associated with greater awareness for both measures of functional ability. These factors associated with smaller discrepancy scores could be used to identify PwD who might benefit from targeted interventions to support their independence.

Attitudes toward own aging and cognition among individuals living with and without dementia: findings from the IDEAL programme and the PROTECT study

Background

It is unclear whether people with dementia (PwD) have more negative attitudes toward own aging (ATOA) than people without dementia and what factors influence ATOA among PwD. We investigated whether PwD have more negative ATOA than individuals without dementia and whether cognition and dementia subtype are associated with ATOA in PwD.

Methods

Data from the IDEAL and PROTECT studies were used to compare ATOA between 1502 PwD (mean (SD) age = 76.3 (8.5)) and 6377 individuals without dementia (mean (SD) age = 66.1 (7.1)). Linear regressions and ANOVA were used.

Results

PwD reported slightly more negative ATOA than people without dementia; this relationship disappeared after controlling for depression and self-rated health. In PwD more positive ATOA showed negligible associations with better general cognition, memory performance, verbal fluency, and visuospatial ability. However, after adjusting for covariates only better visuospatial ability predicted more positive ATOA. Additional analyses showed that before and after controlling for covariates, individuals with poorer self-reported visual acuity have more negative ATOA. Amongst dementia subtypes, people with Parkinson’s disease dementia and dementia with Lewy bodies reported most negative ATOA.

Conclusions

ATOA between PwD and people without dementia do not differ. ATOA in PwD appear to be affected not by cognitive impairment but by other characteristics that vary across dementia subtypes. Among PwD, those with Parkinson’s disease dementia and dementia with Lewy bodies may have higher risk of experiencing negative ATOA due to the motor and visual impairments that they experience.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03336-5.

'Living well' trajectories among family caregivers of people with mild-to-moderate dementia in the IDEAL cohort

Objectives

Understanding whether and how caregivers’ capability to “live well” changes over time, and the factors associated with change, could help target effective caregiver support.

Methods

We analyzed 3 time points (12 months apart) of Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort data from coresident spouse caregivers of community-dwelling individuals who had mild-to-moderate dementia at baseline, using latent growth and growth mixture models. Capability to “live well” was derived from measures of quality of life, well-being, and satisfaction with life.

Results

Data from 995 spouse caregivers at Time 1, 780 at Time 2, and 601 at Time 3 were included. The mean “living well” score decreased slightly over time. We identified 3 classes of caregivers: one with higher baseline scores declining slightly over time (Stable; 66.8%), one with low baseline scores remaining stable (Lower Stable; 26.0%), and one with higher baseline scores showing marked decline (Declining; 7.2%). Scores on baseline measures differentiated the Lower Stable, but not the Declining, from the Stable class. Longitudinally, the Declining class was associated with care recipient cognitive decline and increasing hours providing care, as well as caregiver stress and depression. Findings were similar when caregivers with other kin relationships were included.

Discussion

The findings indicate the importance of prompt identification of, and support for, caregivers at risk of the declining capability to “live well” and may assist in identifying those caregivers who could benefit most from targeted support.

Characteristics of people living with undiagnosed dementia: findings from the CFAS Wales study

Background

Many people living with dementia remain undiagnosed, with diagnosis usually occurring long after signs and symptoms are present. A timely diagnosis is important for the wellbeing of the person living with dementia and the family, allowing them to plan and have access to support services sooner. The aim of this study was to identify demographic characteristics and neuropsychiatric symptoms associated with being undiagnosed, which may help clinicians be more aware of signs that could be indicative of early-stage or undetected dementia.

Methods

This cross-sectional study uses data from waves 1 and 2 (two years apart) of the Cognitive Function and Ageing Studies Wales (CFAS Wales). CFAS Wales participants were included who had a study assessment of dementia, as determined by the Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT) algorithm and by expert assessment, and who had had their primary care records checked for a clinical diagnosis of dementia. We identified 19 people with a diagnosis of dementia and 105 people living with undiagnosed dementia, and explored demographic characteristics and the presence or absence of a range of neuropsychiatric symptoms in the undiagnosed population using logistic regression.

Results

Findings suggest that people living with dementia who have better cognition, have more years of education, or live in more deprived areas are less likely to have a diagnosis. In terms of neuropsychiatric symptoms, depression and sleep problems were associated with being undiagnosed. Apathy was common across all people living with dementia, but those with a diagnosis were more likely to have severe apathy.

Conclusions

This study has clinical practice implications as the findings may help clinicians be more aware of characteristics and symptoms of people who are undiagnosed or who are at greater risk of remaining undiagnosed, enabling them to be more vigilant in picking up signs of dementia at an earlier stage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03086-4.

Longitudinal trajectories of quality of life among people with mild-to-moderate dementia: a latent growth model approach with IDEAL cohort study data

Objectives

We aimed to examine change over time in self-rated quality of life (QoL) in people with mild-to-moderate dementia and identify subgroups with distinct QoL trajectories.

Methods

We used data from people with mild-to-moderate dementia followed up at 12 and 24 months in the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort study (baseline n = 1,537). A latent growth model approach examined mean change over time in QoL, assessed with the QoL-AD scale, and investigated associations of baseline demographic, cognitive, and psychological covariates with the intercept and slope of QoL. We employed growth mixture modeling to identify multiple growth trajectories.

Results

Overall mean QoL scores were stable and no associations with change over time were observed. Four classes of QoL trajectories were identified: 2 with higher baseline QoL scores, labeled Stable (74.9%) and Declining (7.6%), and 2 with lower baseline QoL scores, labeled Stable Lower (13.7%) and Improving (3.8%). The Declining class had higher baseline levels of depression and loneliness, and lower levels of self-esteem and optimism, than the Stable class. The Stable Lower class was characterized by disadvantage related to social structure, poor physical health, functional disability, and low psychological well-being. The Improving class was similar to the Stable Lower class but had lower cognitive test scores.

Discussion

Understanding individual trajectories can contribute to personalized care planning. Efforts to prevent decline in perceived QoL should primarily target psychological well-being. Efforts to improve QoL for those with poorer QoL should additionally address functional impairment, isolation, and disadvantage related to social structure.

Quality of Life and Well-being of Carers of People With Dementia: Are There Differences Between Working and Nonworking Carers? Results From the IDEAL Program

The aim of this study was to identify the differences in quality of life (QoL) and well-being between working and nonworking dementia carers and the relative contribution of psychological characteristics, caregiving experience, and social support. Multiple regressions modeled the contribution of working status, caregiver experiences, and psychological and social resources to carer QoL (EQ-5D) and well-being (WHO-5). After controlling for age, gender, carer-dyad relationship, and severity of dementia, working status contributed significant variance to EQ-5D (2%) but not to WHO-5 scores. Independent of working status, higher self-esteem and reduced stress contributed to variance in both models. Self-efficacy, social support, and positive perceptions of caregiving additionally contributed to higher WHO-5 scores. Working status associated with higher EQ-5D QoL; this may reflect the sustained sense of independence associated with supported work opportunities for carers. Outside of working status, the findings support the importance of psychological and social factors as targets to improved mental health for dementia carers.

Factors associated with self- and informant ratings of quality of life, well-being and life satisfaction in people with mild-to-moderate dementia: results from the Improving the experience of Dementia and Enhancing Active Life programme

BACKGROUND

a large number of studies have explored factors related to self- and informant ratings of quality of life in people with dementia, but many studies have had relatively small sample sizes and mainly focused on health conditions and dementia symptoms. The aim of this study is to compare self- and informant-rated quality of life, life satisfaction and well-being, and investigate the relationships of the two different rating methods with various social, psychological and health factors, using a large cohort study of community-dwelling people with dementia and carers in Great Britain.

METHODS

this study included 1,283 dyads of people with mild-to-moderate dementia and their primary carers in the Improving the experience of Dementia and Enhancing Active Life study. Multivariate modelling was used to investigate associations of self- and informant-rated quality of life, life satisfaction and well-being with factors in five domains: psychological characteristics and health; social location; capitals, assets and resources; physical fitness and health; and managing everyday life with dementia.

RESULTS

people with dementia rated their quality of life, life satisfaction and well-being more highly than did the informants. Despite these differences, the two approaches had similar relationships with social, psychological and physical health factors in the five domains.

CONCLUSION

although self- and informant ratings differ, they display similar results when focusing on factors associated with quality of life, life satisfaction and well-being. Either self- or informant ratings may offer a reasonable source of information about people with dementia in terms of understanding associated factors.

Use and costs of services and unpaid care for people with mild-to-moderate dementia: Baseline results from the IDEAL cohort study

Introduction

We examined 3-month service use and costs of care for people with mild-to-moderate dementia in Great Britain.

Methods

We analyzed Improving the experience of Dementia and Enhancing Active Life cohort study baseline data on paid care, out-of-pocket expenditure, and unpaid care from participants with dementia (N = 1547) and their carers (N = 1283). In regression analyses, we estimated per-group mean costs of diagnostic and sociodemographic subgroups.

Results

Use of services apart from primary and outpatient hospital care was low. Unpaid care accounted for three-quarters of total costs (mean, £4008 [standard error, £130] per participant). Most participants (87%) received unpaid care equating to 36 hours weekly. Estimated costs for people with Parkinson's dementia were £8609, £4359 for participants with mixed dementia, and £3484 for those with Alzheimer's disease. Total costs were lower for participants with dementia living alone than living with others (£2484 vs. £4360); costs were lower for female than for male participants (£3607 vs. £4272).

Discussion

Costs varied by dementia subtype, carer status, and living arrangement. Policy makers should recognize the high costs of unpaid care for people with dementia, who do not always get the support that they need or would like to receive.

The relationship between perceived functional difficulties and the ability to live well with mild-to-moderate dementia: Findings from the IDEAL programme

OBJECTIVES

The objectives of the study are to investigate how different levels of functional ability relate to quality of life, well-being, and satisfaction with life, conceptualised as reflecting capability to "live well" in people with dementia.

METHODS/DESIGN

Participants were 1496 people with mild-to-moderate dementia and 1188 informants who completed baseline assessments in the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort study. Total self-rated and informant-rated scores on the Functional Activities Questionnaire were split into six ability levels to monitor how poorer functioning impacts the ability to live well. We also investigated the potential influence of sociodemographic and diagnostic variables, depression, cognition, and carer stress.

RESULTS

Multivariate multiple regression models found that people with dementia who had the greatest functional impairment according to self-ratings and informant ratings had poorer living well scores than those with the least functional impairment. Sociodemographic and diagnostic factors and cognition had little impact on effect sizes. For self-ratings, depression attenuated the relationship between functional ability and living well, whereas carer stress attenuated informant ratings.

CONCLUSIONS

People with dementia with the least functional impairments had greater capability to live well than those with the most functional impairment. Even subtle perceived difficulties in functional ability had a detrimental effect on the ability of people with dementia to live well. Depression in people with dementia and carer stress in informants influenced these associations, and therefore, these factors should be routinely included in future research studies and clinical assessments.

Protocol for the IDEAL-2 longitudinal study: following the experiences of people with dementia and their primary carers to understand what contributes to living well with dementia and enhances active life

BACKGROUND

There is a major need for longitudinal research examining the experiences of people with dementia and their primary carers, as relatively little is known about how the factors associated with capability to 'live well' vary over time. The main aim of the IDEAL-2 study is to investigate how and why, over time, people with dementia and their primary carers might vary in their capability to live well with dementia, whilst exploring both their use of health and care services and their unmet needs.

METHODS

IDEAL-2 will build on the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort of 1547 people (who, at recruitment between July 2014 and July 2016, had mild-to-moderate dementia), and their 1283 primary carers in Great Britain. The existing cohort will be enriched with additional participants with mild-to-moderate dementia (and their primary carers where available and willing) from the following groups: people with rarer forms of dementia, and/or those who are ≥90 years or < 65 years of age at time of recruitment. We will assess the primary outcome, capability to live well with dementia, and the factors influencing it using questionnaires at yearly intervals for 3 years. Additionally, we will seek to link the cohort data with administrative data to obtain information about health service use. Some participants will be invited for in-depth face-to-face interviews. The cohort study will be supplemented by linked research focusing on: the co-production of new measures of living well; including the perspectives of people with advanced dementia living in residential care settings; including people with dementia from black, Asian, and minority ethnic groups; and understanding the experience of people living with undiagnosed dementia.

DISCUSSION

IDEAL-2 will provide evidence about the key indicators of, and factors associated with, living well over the course of dementia and how these differ for particular subgroups. It will tell us which combinations of services and support are most beneficial and cost-effective. Moreover, the IDEAL-2 study will gather evidence from under-researched groups of people with dementia, who are likely to have their own distinct perceptions of living well.

Protocol for the IDEAL-2 longitudinal study: following the experiences of people with dementia and their primary carers to understand what contributes to living well with dementia and enhances active life

BACKGROUND

There is a major need for longitudinal research examining the experiences of people with dementia and their primary carers, as relatively little is known about how the factors associated with capability to 'live well' vary over time. The main aim of the IDEAL-2 study is to investigate how and why, over time, people with dementia and their primary carers might vary in their capability to live well with dementia, whilst exploring both their use of health and care services and their unmet needs.

METHODS

IDEAL-2 will build on the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort of 1547 people (who, at recruitment between July 2014 and July 2016, had mild-to-moderate dementia), and their 1283 primary carers in Great Britain. The existing cohort will be enriched with additional participants with mild-to-moderate dementia (and their primary carers where available and willing) from the following groups: people with rarer forms of dementia, and/or those who are ≥90 years or < 65 years of age at time of recruitment. We will assess the primary outcome, capability to live well with dementia, and the factors influencing it using questionnaires at yearly intervals for 3 years. Additionally, we will seek to link the cohort data with administrative data to obtain information about health service use. Some participants will be invited for in-depth face-to-face interviews. The cohort study will be supplemented by linked research focusing on: the co-production of new measures of living well; including the perspectives of people with advanced dementia living in residential care settings; including people with dementia from black, Asian, and minority ethnic groups; and understanding the experience of people living with undiagnosed dementia.

DISCUSSION

IDEAL-2 will provide evidence about the key indicators of, and factors associated with, living well over the course of dementia and how these differ for particular subgroups. It will tell us which combinations of services and support are most beneficial and cost-effective. Moreover, the IDEAL-2 study will gather evidence from under-researched groups of people with dementia, who are likely to have their own distinct perceptions of living well.

Living well with dementia: a systematic review and correlational meta-analysis of factors associated with quality of life, well-being and life satisfaction in people with dementia

Current policy emphasises the importance of 'living well' with dementia, but there has been no comprehensive synthesis of the factors related to quality of life (QoL), subjective well-being or life satisfaction in people with dementia. We examined the available evidence in a systematic review and meta-analysis. We searched electronic databases until 7 January 2016 for observational studies investigating factors associated with QoL, well-being and life satisfaction in people with dementia. Articles had to provide quantitative data and include ⩾75% people with dementia of any type or severity. We included 198 QoL studies taken from 272 articles in the meta-analysis. The analysis focused on 43 factors with sufficient data, relating to 37639 people with dementia. Generally, these factors were significantly associated with QoL, but effect sizes were often small (0.1-0.29) or negligible (<0.09). Factors reflecting relationships, social engagement and functional ability were associated with better QoL. Factors indicative of poorer physical and mental health (including depression and other neuropsychiatric symptoms) and poorer carer well-being were associated with poorer QoL. Longitudinal evidence about predictors of QoL was limited. There was a considerable between-study heterogeneity. The pattern of numerous predominantly small associations with QoL suggests a need to reconsider approaches to understanding and assessing living well with dementia.

Using event-related fMRI to examine sustained attention processes and effects of APOE ε4 in young adults

In this study we investigated effects of the APOE ε4 allele (which confers an enhanced risk of poorer cognitive ageing, and Alzheimer’s Disease) on sustained attention (vigilance) performance in young adults using the Rapid Visual Information Processing (RVIP) task and event-related fMRI. Previous fMRI work with this task has used block designs: this study is the first to image an extended (6-minute) RVIP task. Participants were 26 carriers of the APOE ε4 allele, and 26 non carriers (aged 18–28). Pupil diameter was measured throughout, as an index of cognitive effort. We compared activity to RVIP task hits to hits on a control task (with similar visual parameters and response requirements but no working memory load): this contrast showed activity in medial frontal, inferior and superior parietal, temporal and visual cortices, consistent with previous work, demonstrating that meaningful neural data can be extracted from the RVIP task over an extended interval and using an event-related design. Behavioural performance was not affected by genotype; however, a genotype by condition (experimental task/control task) interaction on pupil diameter suggested that ε4 carriers deployed more effort to the experimental compared to the control task. fMRI results showed a condition by genotype interaction in the right hippocampal formation: only ε4 carriers showed downregulation of this region to experimental task hits versus control task hits. Experimental task beta values were correlated against hit rate: parietal correlations were seen in ε4 carriers only, frontal correlations in non-carriers only. The data indicate that, in the absence of behavioural differences, young adult ε4 carriers already show a different linkage between functional brain activity and behaviour, as well as aberrant hippocampal recruitment patterns. This may have relevance for genotype differences in cognitive ageing trajectories.

Disrupted neural activity patterns to novelty and effort in young adult APOE-e4 carriers performing a subsequent memory task

INTRODUCTION

The APOE e4 allele has been linked to poorer cognitive aging and enhanced dementia risk. Previous imaging studies have used subsequent memory paradigms to probe hippocampal function in e4 carriers across the age range, and evidence suggests a pattern of hippocampal overactivation in young adult e4 carriers.

METHODS

In this study, we employed a word-based subsequent memory task under fMRI; pupillometry data were also acquired as an index of cognitive effort. Participants (26 non-e4 carriers and 28 e4 carriers) performed an incidental encoding task (presented as word categorization), followed by a surprise old/new recognition task after a 40 minute delay.

RESULTS

In e4 carriers only, subsequently remembered words were linked to increased hippocampal activity. Across all participants, increased pupil diameter differentiated subsequently remembered from forgotten words, and neural activity covaried with pupil diameter in cuneus and precuneus. These effects were weaker in e4 carriers, and e4 carriers did not show greater pupil diameter to remembered words. In the recognition phase, genotype status also modulated hippocampal activity: here, however, e4 carriers failed to show the conventional pattern of greater hippocampal activity to novel words.

CONCLUSIONS

Overall, neural activity changes were unstable in e4 carriers, failed to respond to novelty, and did not link strongly to cognitive effort, as indexed by pupil diameter. This provides further evidence of abnormal hippocampal recruitment in young adult e4 carriers, manifesting as both up and downregulation of neural activity, in the absence of behavioral performance differences.

Structural and resting-state MRI detects regional brain differences in young and mid-age healthy APOE-e4 carriers compared with non-APOE-e4 carriers

The presence of the e4 allele of the apolipoprotein E (APOE) gene is the best-known genetic risk factor for Alzheimer's disease. In this study, we investigated the link between functional and behavioural differences and regional brain volume and cortical thickness differences in those who carry the e4 allele (e4+) and those who only carry the e3 allele (e3/e3). We studied these genotype populations in two age groups: a young group (average age, 21 years) and a mid-age group (average age, 50 years). High-resolution T1 -weighted MRI scans were analysed with Freesurfer to measure regional white matter brain volume and cortical thickness differences between genotype groups at each age. These data were correlated with behavioural findings in the same cohort. Resting-state MRI was also conducted to identify differences in underlying brain functional connectivity. We found that there was a positive correlation between the thickness of the parahippocampal cortex in young e4+ individuals and performance on an episodic memory task. Young e4+ individuals also showed a positive correlation between white matter volume in the left anterior cingulate and performance on a covert attention task. At mid-age, e4+ individuals had structural differences relative to e3/e3 individuals in these areas: the parahippocampal cortex was thicker and white matter volume in the left anterior cingulate was greater than in e3/e3 individuals. We discuss the possibility that an over-engagement with these regions by e4+ individuals in youth may have a neurogenic effect that is observable later in life. The cuneus appears to be an important region for APOE-driven differences in the brain, with greater functional connectivity among young e3/e3 individuals and greater white matter volume in young e4+ individuals.

Can verbal instruction enhance the recall of an everyday task and promote error-monitoring in people with dementia of the Alzheimer-type?

People with dementia of the Alzheimer-type (DAT) have difficulties with performing everyday tasks, and error awareness is poor. Here we investigate whether recall of actions and error monitoring in everyday task performance improved when they instructed another person on how to make tea. In this situation, both visual and motor cues are present, and attention is sustained by the requirement to keep instructing. The data were drawn from a longitudinal study recording performance in four participants with DAT, filmed regularly for five years in their own homes, completing three tea-making conditions: performed-recall (they made tea themselves); instructed-recall (they instructed the experimenter on how to make tea); and verbal-recall (they described how to make tea). Accomplishment scores (percentage of task they correctly recalled), errors and error-monitoring were coded. Task accomplishment was comparable in the performed-recall and instructed-recall conditions, but both were significantly better than task accomplishment in the verbal-recall condition. Third person instruction did not improve error-monitoring. This study has implications for everyday task rehabilitation for people with DAT.

Improving the experience of dementia and enhancing active life--living well with dementia: study protocol for the IDEAL study

BACKGROUND

Enabling people with dementia and carers to 'live well' with the condition is a key United Kingdom policy objective. The aim of this project is to identify what helps people to live well or makes it difficult to live well in the context of having dementia or caring for a person with dementia, and to understand what 'living well' means from the perspective of people with dementia and carers.

METHODS/DESIGN

Over a two-year period, 1500 people with early-stage dementia throughout Great Britain will be recruited to the study, together with a carer wherever possible. All the participants will be visited at home initially and again 12 months and 24 months later. This will provide information about the way in which well-being, life satisfaction and quality of life are affected by social capitals, assets and resources, the challenges posed by dementia, and the ways in which people adjust to and cope with these challenges. A smaller group will be interviewed in more depth.

DISCUSSION

The findings will lead to recommendations about what can be done by individuals, communities, health and social care practitioners, care providers and policy-makers to improve the likelihood of living well with dementia.

Improving the experience of dementia and enhancing active life--living well with dementia: study protocol for the IDEAL study

BACKGROUND

Enabling people with dementia and carers to 'live well' with the condition is a key United Kingdom policy objective. The aim of this project is to identify what helps people to live well or makes it difficult to live well in the context of having dementia or caring for a person with dementia, and to understand what 'living well' means from the perspective of people with dementia and carers.

METHODS/DESIGN

Over a two-year period, 1500 people with early-stage dementia throughout Great Britain will be recruited to the study, together with a carer wherever possible. All the participants will be visited at home initially and again 12 months and 24 months later. This will provide information about the way in which well-being, life satisfaction and quality of life are affected by social capitals, assets and resources, the challenges posed by dementia, and the ways in which people adjust to and cope with these challenges. A smaller group will be interviewed in more depth.

DISCUSSION

The findings will lead to recommendations about what can be done by individuals, communities, health and social care practitioners, care providers and policy-makers to improve the likelihood of living well with dementia.

Cognitive and neural signatures of the APOE E4 allele in mid-aged adults

The apolipoprotein E (APOE) e4 allele is strongly associated with increased risk of cognitive impairments in older adulthood. There is also a possible link to enhanced cognitive performance in younger adults, and the APOE e4 allele may constitute an example of antagonistic pleiotropy. The aim of this work was to investigate the cognitive and neural (functional) effects of the APOE e4 allele during mid-age (45–55 years), where a transition toward cognitive deficit might be expected. APOE e4 carriers (e4+) were compared with non-e4 carriers (e4−) on tasks of sustained and covert attention and prospective memory, and functional magnetic resonance imaging data acquired. Performance by e4+ was equivalent or better than e4− on all 3 tasks, although performance benefits were less pronounced than in youth. Neurally, e4+ showed less task-related recruitment of extrastriate and parietal areas. This became more evident when neural activation data were compared with that of young adults acquired in a parallel study. As expected, mid-age participants showed more diffuse neural activation. Notable was the fact that e4+ showed a relative inability to recruit parietal regions as they aged. This was coupled with a tendency to show greater recruitment of frontal regions, and underactivation of extrastriate visual regions. Thus, mid-age e4+ show a pattern of neural recruitment usually seen later in life, possibly reflecting the source of an accelerated aging profile that describes the e4 genotype.

Angiotensin and Alzheimer´s disease: therapeutic prospects

This review describes the features of Alzheimer's disease and discusses the evidence that antihypertensive therapies may be beneficial in its treatment and prevention. Drugs acting via the renin-angiotensin system are considered and it is suggested that these drugs may produce their effects via mechanisms other than by their antihypertensive actions. Using evidence from animal studies, the role of angiotensin as a neurotransmitter and its involvement in the control of normal cognitive function is described. Studies of angiotensin and human cognition are reviewed along with studies investigating the possible link between disorders of the system, either inherited or acquired, and the symptoms of Alzheimer's disease. The therapeutic potential of screening for markers of renin-angiotensin abnormality for the prediction of Alzheimer's disease is considered, as is the potential use of agents known to influence the renin-angiotensin system in the treatment or prevention of the disease.

Nicotine effects on attentional reorienting in mid-age adults, and interactions with apolipoprotein E status

Nicotine has been shown to speed attentional reorienting in cued target detection tasks, and work in young adults suggest that individuals carrying the apolipoprotein E (APOE) e4 allele might show greater sensitivity to the cognitive effects of nicotine. The APOE e4 allele is associated with increased risk of Alzheimer's disease (AD), and increased sensitivity to nicotine might reflect early cholinergic differences that relate to an enhanced risk of AD. The aim of this study was to investigate effects of nicotine and APOE on attentional reorienting in mid-age participants. APOE e4 (e4+) were compared to non-APOE e4 (e4-) carriers, and functional magnetic resonance imaging (fMRI) data acquired. Neural data showed that nicotine effects, and the network involved in reorienting, was consistent with studies in young adults. Nicotine improved attentional reorienting at the trend level. Although there were no behavioural effects of genotype, genotype effects were present neurally: e4+ showed decreased extrastriate activation, and enhanced effects of nicotine on reorienting in right middle frontal regions. Drug by genotype interactions were present in hippocampal and anterior cingulate regions. These results are consistent with differential sensitivity to nicotine according to APOE status, possibly reflecting abnormal cholinergic function and accelerated cognitive ageing in mid-age e4+.

MRI of carriers of the apolipoprotein E e4 allele-evidence for structural differences in normal-appearing brain tissue in e4+ relative to e4- young adults

Apolipoprotein E is a protein involved in cholesterol and lipid transport. The gene coding for this protein has three different alleles: e2, e3 and e4. The e4 allele is recognised as a significant risk factor for the development of Alzheimer's disease in later life. Paradoxically, behavioural and functional evidence has demonstrated that the e4 allele may confer a cognitive advantage to the carrier in youth. In this article, a range of sophisticated and novel structural imaging techniques were used to identify subtle differences in the brain tissue of groups of young e4 and homozygous e3 carriers that might support this paradox. Using voxel-based morphometry of high-resolution structural MR images, we identified a higher white matter volume ratio in e4 relative to homozygous e3 carriers. Furthermore, diffusion tensor imaging and tract-based spatial statistics studies identified increases in axial diffusivity and mode of anisotropy in carriers of the e4 allele. In addition, quantitative magnetisation transfer data were analysed using tract-based spatial statistics. Evidence of a trend towards an increased transverse relaxation time of the bound proton pool was detected in e4 carriers, indicative of altered white matter composition. These changes were found to correlate with indices of cognitive performance across the two groups, supporting the notion that such subtle differences in white matter integrity may confer neural advantages that contribute to cognitive outcomes and, potentially, to performance differences, such as observed here in a test of verbal fluency and reported previously by other researchers. Copyright © 2013 John Wiley & Sons, Ltd.

APOE e4 polymorphism in young adults is associated with improved attention and indexed by distinct neural signatures

The APOE e4 allele, which confers an increased risk of developing dementia in older adulthood, has been associated with enhanced cognitive performance in younger adults. An objective of the current study was to compare task-related behavioural and neural signatures for e4 carriers (e4+) and non-e4 carriers (e4-) to help elucidate potential mechanisms behind such cognitive differences. On two measures of attention, we recorded clear behavioural advantages in young adult e4+ relative to e4-, suggesting that e4+ performed these tasks with a wider field of attention. Behavioural advantages were associated with increased task-related brain activations detected by fMRI (BOLD). In addition, behavioural measures correlated with structural measures derived from a former DTI analysis of white matter integrity in our cohort. These data provide clear support for an antagonistic pleiotropy hypothesis--that the e4 allele confers some cognitive advantage in early life despite adverse consequences in old age. The data implicate differences in both structural and functional signatures as complementary mediators of the behavioural advantage.

Positive effects of cholinergic stimulation favor young APOE epsilon4 carriers

The potential of putative cognitive-enhancing compounds to improve mental processing both in healthy and vulnerable populations is an area of growing interest to scientific and clinical communities. The possible influence of individual genetic differences on efficacy of these compounds has yet to be considered. We sought to investigate the profile of young-adult apolipoprotein E (APOE) varepsilon4 carriers across cognitive domains given that possession of this gene variant increases risk of developing dementia in later life. We also explored whether APOE genotype interacts with the cognitive enhancer, nicotine. A total of 1 mg of the cholinergic agonist nicotine was administered through nasal spray to healthy non-smoking young adults (aged 18-30) with either varepsilon3/varepsilon3 (N=29) or varepsilon4 (at least one varepsilon4 allele, N=27) genotype. Participants were matched on age, sex, and IQ in a placebo-controlled, double-blind 2 (drug: placebo, nicotine) x 2 (genotype: varepsilon3, varepsilon4) between subjects design. Here, we show that, paradoxically, possession of the varepsilon4 allele confers a cognitive advantage on tasks mediated by the frontal lobe, and that young carriers of the varepsilon4 allele show larger cognitive benefit from procholinergic nicotinic stimulation. These results are the first to show that genetic differences influence the efficacy of a cognitive enhancer.

Modafinil improves rapid shifts of attention

RATIONALE

The majority of studies investigating the cognitive effects of modafinil, a wake-promoting compound, demonstrate some improvements in attention. The potential of the drug to selectively benefit distinct components of attention has yet to be fully explored in healthy adults.

OBJECTIVE

The present study was conducted to investigate modafinil's effect on specific cognitive tasks that tax components of attention switching. One required the rapid switching of attention between stimuli, and another contained an embedded working memory component on top of the attentional shift requirements. Additionally, prospective memory was examined, which requires the interruption of an ongoing activity to retrieve and act upon a previously formed intention.

MATERIALS AND METHODS

Healthy non-smoking volunteers, matched on age, intelligence, and baseline cognitive ability, received either a capsule that contained 200 mg modafinil or placebo. Subjective measures of mood and physiological response were taken throughout the experimental session, and the tasks were completed between 2 and 3 h post-dosing.

RESULTS

Two hundred milligrams modafinil improved accuracy without a reaction time trade-off, in both conditions of the attention-shifting task, but only when resources were most challenged. In contrast, the drug afforded no improvement in prospective remembering or in the ongoing task that was interrupted.

CONCLUSION

Modafinil appears to promote rapid switching of attention in conditions that are most demanding, whilst it offers no benefits in a task that requires unpredictable and infrequent disengagement of attention from an ongoing task in order to act upon an alternative task.

Positive effects of nicotine on cognition: the deployment of attention for prospective memory

RATIONALE

Human and animal studies over the last two decades report that nicotine can improve cognitive performance. Prospective memory (PM), the retrieval and implementation of a previously encoded intention, is also improved by pre-administration of nicotine. As with other nicotine effects, however, predicting precisely how and when nicotine improves the processes engaged by PM has proved less straightforward.

OBJECTIVE

We present two studies that explore the source of nicotine's enhancement of PM. Experiment 1 tests for effects of nicotine on preparatory attention (PA) for PM target detection. Experiment 2 asks whether nicotine enhances processing of the perceptual attributes of the PM targets.

MATERIALS AND METHODS

Young adult non-smokers matched on baseline performance measures received either 1 mg nicotine or matched placebo via nasal spray. Volunteers completed novel PM tasks at 15 min post-administration.

RESULTS

Experiment 1 confirmed that pre-administration of nicotine to non-smokers improved detection rate for prospective memory targets presented during an attention-demanding ongoing task. There was no relationship between PM performance and measures of preparatory attention. In experiment 2, salient targets were more likely to be detected than non-salient targets, but nicotine did not confer any additional advantage to salient targets.

CONCLUSION

The present study suggests that nicotinic stimulation does not work to enhance perceptual salience of target stimuli (experiment 2), nor does it work through better deployment of preparatory working attention (experiment 1). An alternative explanation that nicotine promotes PM detection by facilitating disengagement from the ongoing task is suggested as a future line of investigation.

Nicotine effects on retrieval-induced forgetting are not attributable to changes in arousal

BACKGROUND

There is emerging evidence from behavioural studies in humans for nicotinic modulation of inhibitory control. Administration of nicotine, however, also increases general arousal, and this may be responsible for the cognitive enhancing effects of nicotine.

DISCUSSION

To test an arousal explanation of nicotine's effects on cognitive inhibition, this study compared the separate and combined effects of an acute dose of nicotine and an arousal manipulation on inhibitory processes associated with the retrieval-induced forgetting (RIF) paradigm.

RESULTS

In a double blind placebo controlled design, 1.0 mg of nicotine delivered via nasal spray to non-smoking healthy young adults significantly increased the retrieval-induced forgetting observed in episodic list learning, relative to the placebo condition. In contrast, negative arousal evoked by an unsolvable anagram task had no effect either separately or in combination with nicotine.

CONCLUSION

This result argues against the attribution of nicotine-induced changes in RIF performance to non-specific arousal effects. It suggests, furthermore, that pharmacological manipulation of the RIF produces effects that are qualitatively distinct from mood-induced effects. We consider these changes to relate to the direct modulation of information processing by nicotine.

Non-cholinergic modulation of antisaccade performance: a modafinil-nicotine comparison

INTRODUCTION

The antisaccade task provides a powerful tool with which to investigate the cognitive and neural systems underlying goal-directed behaviour, particularly in situations when the correct behavioural response requires the suppression of a prepotent response. Antisaccade errors (failures to suppress reflexive prosaccades towards sudden-onset targets) are increased in patients with damage to the dorsolateral prefrontal cortex, and in patients with schizophrenia. Nicotine has been found to improve antisaccade performance in patients with schizophrenia and healthy controls. This performance enhancing effect may be due to direct effects on the cholinergic system, but there has been no test of this hypothesis.

MATERIALS AND METHODS

In a double blind, double dummy, placebo-controlled design, we compared the effect of nicotine and modafinil, a putative indirect noradrenergic agonist, on antisaccade performance in healthy non-smokers.

RESULTS AND DISCUSSION

Both compounds reduced latency for correct antisaccades, although neither reduced antisaccade errors. These findings are discussed with reference to the pharmacological route of performance enhancement on the antisaccade task and current models of antisaccade performance.

The antisaccade task as an index of sustained goal activation in working memory: modulation by nicotine

INTRODUCTION

The antisaccade task provides a laboratory analogue of situations in which execution of the correct behavioural response requires the suppression of a more prepotent or habitual response. Errors (failures to inhibit a reflexive prosaccade towards a sudden onset target) are significantly increased in patients with damage to the dorsolateral prefrontal cortex and patients with schizophrenia. Recent models of antisaccade performance suggest that errors are more likely to occur when the intention to initiate an antisaccade is insufficiently activated within working memory. Nicotine has been shown to enhance specific working memory processes in healthy adults.

MATERIALS AND METHODS

We explored the effect of nicotine on antisaccade performance in a large sample (N = 44) of young adult smokers. Minimally abstinent participants attended two test sessions and were asked to smoke one of their own cigarettes between baseline and retest during one session only.

RESULTS AND CONCLUSION

Nicotine reduced antisaccade errors and correct antisaccade latencies if delivered before optimum performance levels are achieved, suggesting that nicotine supports the activation of intentions in working memory during task performance. The implications of this research for current theoretical accounts of antisaccade performance, and for interpreting the increased rate of antisaccade errors found in some psychiatric patient groups are discussed.

Comparable effects of nicotine in smokers and nonsmokers on a prospective memory task

In a double-blind placebo-controlled study, we examined the effect of nicotine, a cholinergic agonist, on performance of a prospective memory (ProM) task in young adult volunteers. Volunteers were required to complete an ongoing lexical decision task while maintaining the ProM task (responding with a different button press to items containing particular target letters). Half of the volunteers were smokers, half were nonsmokers. Half of each group received a single dose (1 mg) of nicotine nasal spray before completing the task; the remaining volunteers received a matched inactive placebo spray. Nicotine improved performance on the ProM task when volunteers were able to devote resources to that task. Under a variant procedure, where volunteers completed a concurrent auditory monitoring task, ProM performance was impaired under nicotine. Results are discussed in terms of the resource model of ProM, and the arousal model of drug effects. The data suggest that ProM under the conditions tested here is a resource-needy process, and that nicotine can improve performance by increasing available resources. Increased working memory demands that encourage redirection of resources may impair ProM performance, but the conditions under which these deficits emerge depend upon the subjective allocation of resources across tasks, rather than resource availability per se.

Nicotine improves memory for delayed intentions

RATIONALE

The present paper asked first whether the cholinergic agonist nicotine improves memory for delayed intentions (prospective memory, ProM) and second whether pharmacological dissociation would support the psychological distinction that is made between strategic (effortful) and automatic (non-effortful) intention activation in prospective memory.

OBJECTIVES

To use nicotine as a pharmacological tool with which to examine the neurochemical bases of prospective memory and to dissociate strategic from automatic components of ProM retrieval.

METHODS

In three experiments, minimally deprived (2 h) smokers either smoked or abstained prior to completing a standard prospective memory study. This involved participants in the simultaneous processing of a ProM task and a cover task (ongoing between the setting and the recall of the intention). Here, the ongoing task involved lexical decision (LDT), while the ProM task required a response to pre-specified target items occurring within the LDT stimuli. Variations in task instructions were used to manipulate the processing requirements of the ProM task, the attention allocated to the ProM task and the balance of importance assigned to the ongoing and ProM tasks.

RESULTS

In experiment 1, where the ProM processing was automatic, nicotine did not improve ProM accuracy. In experiment 2, where the ProM task involved strategic processing, positive effects of nicotine were observed. In experiment 3, we covaried ProM task instructions, assigned task importance and nicotine conditions. We observed a main effect of nicotine on ProM accuracy, a main effect of task on ProM accuracy and a main effect of assigned task importance on ProM accuracy. There were no interactions between the factors.

CONCLUSIONS

Employing both direct and indirect manipulations of strategic engagement, we demonstrated nicotine-induced enhancement of performance on the ProM task. The results are consistent with the view that relatively small changes in instruction and in task variables engage strategic processing in a ProM task and that when these conditions stretch cognitive resources, nicotine may significantly improve performance.

Acute effects of nicotine on visual search tasks in young adult smokers

RATIONALE

Nicotine is known to improve performance on tests involving sustained attention and recent research suggests that nicotine may also improve performance on tests involving the strategic allocation of attention and working memory.

OBJECTIVES

We used measures of accuracy and response latency combined with eye-tracking techniques to examine the effects of nicotine on visual search tasks.

METHODS

In experiment 1 smokers and non-smokers performed pop-out and serial search tasks. In experiment 2, we used a within-subject design and a more demanding search task for multiple targets. In both studies, 2-h abstinent smokers were asked to smoke one of their own cigarettes between baseline and tests.

RESULTS

In experiment 1, pop-out search times were faster after nicotine, without a loss in accuracy. Similar effects were observed for serial searches, but these were significant only at a trend level. In experiment 2, nicotine facilitated a strategic change in eye movements resulting in a higher proportion of fixations on target letters. If the cigarette was smoked on the first trial (when the task was novel), nicotine additionally reduced the total number of fixations and re-fixations on all letters in the display.

CONCLUSIONS

Nicotine improves visual search performance by speeding up search time and enabling a better focus of attention on task relevant items. This appears to reflect more efficient inhibition of eye movements towards task irrelevant stimuli, and better active maintenance of task goals. When the task is novel, and therefore more difficult, nicotine lessens the need to re-fixate previously seen letters, suggesting an improvement in working memory.

Separate and combined effects of scopolamine and nicotine on retrieval-induced forgetting

RATIONALE

Proficiency of information processing is likely to derive from a combination of effective processing of relevant information and efficient inhibition of unwanted or irrelevant material. Compromised inhibitory processes have been associated with the memory deficits in dementia and the elderly. These deficits in inhibition could be directly related to the reduced cholinergic function evident in dementia of the Alzheimer type (DAT). Scopolamine, a cholinergic antagonist, has been associated with disinhibition. Nicotine, a cholinergic agonist, has been associated with enhanced focus and reduced intrusions in both healthy adults and people with dementia.

OBJECTIVE

This study examines the separate and combined effects of nicotine and scopolamine on inhibitory processes using retrieval induced forgetting (RIF).

METHODS

In two studies, minimally deprived smokers received either nicotine or no nicotine, in the second study combined with placebo, 0.3 or 0.5 mg SC scopolamine. All volunteers completed the RIF procedure providing within-subject measures of inhibition in an episodic recall paradigm.

RESULTS

Nicotine did not modulate recall of practised exemplars but it did increase inhibition of unpractised exemplars. Consistent with an effect on encoding, scopolamine reduced recall for all exemplars. Scopolamine did not differentially affect practised or unpractised exemplars, relative to the control words.

CONCLUSION

Independent of its potential to influence memory at encoding, nicotine can affect task performance by inhibiting unpractised (and by implication, irrelevant) material, thereby reducing interference and benefiting the task in hand. The absence of effects of scopolamine on inhibition in the RIF paradigm argues for a more complex subdivision of "inhibitory" processes, which may be differentially influenced by cholinergic blockade.

Effects of caffeine on performance and mood depend on the level of caffeine abstinence

RATIONALE

Most studies of the effects of caffeine on performance have used regular caffeine consumers who are deprived at test. Thus the reported effects of caffeine could be explained through reversal of caffeine withdrawal.

OBJECTIVES

To test how preloading deprived caffeine consumers with 0, 1 or 2 mg/kg caffeine altered the subsequent ability of caffeine to modify mood and performance.

METHODS

Thirty moderate caffeine consumers were given a drink containing 0, 1 or 2 mg/kg caffeine at breakfast followed 60 min later by a second drink containing either 0 or 1 mg/kg caffeine. Performance on a measure of sustained attention and mood were measured before and after each drink.

RESULTS

Administration of both 1 and 2 mg/kg caffeine at breakfast decreased reaction time and 1 mg/kg caffeine also increased performance accuracy on the sustained attention (RVIP) task relative to placebo. Both breakfast doses of caffeine also improved rated mental alertness. Similarly, 1 mg/kg caffeine administered 60 min after breakfast decreased reaction time and increased rated mental alertness in the group who had not been given caffeine at breakfast. However, this second dose of caffeine had no effect on subsequent performance or mood in the two groups who had received caffeine at breakfast.

CONCLUSIONS

Caffeine reliably improved performance on a sustained attention task, and increased rated mental alertness, in moderate caffeine consumers who were tested when caffeine-deprived. However, caffeine had no such effects when consumers were no longer caffeine deprived. These data are consistent with the view that reversal of caffeine withdrawal is a major component of the effects of caffeine on mood and performance.

Verbal fluency facilitated by the cholinergic blocker, scopolamine

This study was designed to explore putative facilitatory effects of low doses of scopolamine (SP) on phonemic (letter) and semantic (category) verbal fluency. A double-blind, parallel-group design was used with 36 subjects who completed a test battery before and 2 h after 0.6 mg or 1.2 mg of SP or placebo. Fluency measures included total number of words generated, clustering (the production of words within semantic or phonemic subcategories) and switching (the ability to shift efficiently to new subcategories). Low doses of scopolamine increased phonemic fluency, as has been shown previously. Semantic fluency was not increased by SP, although subjects treated with 1.2 mg of SP generated higher-frequency words. SP did not affect clustering or switching. It is suggested that phonemic and semantic fluency reflect distinct cognitive processes.

Moving out of the laboratory: does nicotine improve everyday attention?

The most robust demonstrations of the nicotine-related performance effects on human cognitive processes are seen in tasks that measure attention. If nicotine does have some potential for enhancing attention, the obvious question to ask is whether the effects demonstrated in the laboratory hold any significance for real-life performance. This paper describes three studies that compare the effects in smokers of a single own brand cigarette on laboratory tests of attention and on everyday analogues of these laboratory tasks. In the laboratory measures of sustained attention and in the everyday analogue, performance advantages were registered in the smoking condition. These benefits were observed in smokers who abstained for a self-determined period of not less than 2 h. The studies were unable to replicate previous research reporting positive effects of smoking on a laboratory task of selective attention, the Stroop task. Small but significant improvements in performance were registered in the everyday analogues, which involved sustaining attention in a dual task situation, a telephone directory search task and a map search task. In addition, smokers showed a significant colour-naming decrement for smoking-related stimuli in the Stroop task. This attentional bias towards smoking-related words occurred independent of whether they had abstained or recently smoked an own brand cigarette. The effect is discussed in terms of the two-component model of processing bias for emotionally valenced stimuli.

Nicotinic treatment for degenerative neuropsychiatric disorders such as Alzheimer's disease and Parkinson's disease

Nicotinic systems play an important role in the neural basis of working memory and attention. Recent progress in understanding of the structure, function, and distribution of central nervous system (CNS) nicotinic receptors and their pharmacology has opened up new possibilities for novel CNS therapeutics with nicotinic agents. In this paper, we review the theoretical justification and the experimental evidence supporting these developments. We focus on the applications of nicotinic agonists in CNS disorders that are degenerative in nature, namely Parkinson's disease and Alzheimer's disease. We suggest that there is considerable potential for therapeutic applications in the near future. Clinically, two major issues remain: (a) the selectivity of effects, that is, developing compounds which are selective in producing improvement in cognition, motor function, attention, or pain without significant side-effects; and (b) the realistic likelihood of long-term improvements in everyday functioning in people who have degenerative diseases.