Eye Movement Patterns Can Distinguish Schizophrenia From the Major Affective Disorders and Healthy Control Subjects.

Background and hypothesis: No objective tests are currently available to help diagnosis of major psychiatric disorders. This study evaluates the potential of eye movement behavior patterns to predict schizophrenia subjects compared to those with major affective disorders and control groups. Study design: Eye movements were recorded from a training set of UK subjects with schizophrenia (SCZ; n = 120), bipolar affective disorder (BPAD; n = 141), major depressive disorder (MDD; n = 136), and healthy controls (CON; n = 142), and from a hold-out set of 133 individuals with proportional group sizes. A German cohort of SCZ (n = 60) and a Scottish cohort of CON subjects (n = 184) acted as a second semi-independent test set. All patients met DSMIV and ICD10 criteria for SCZ, BPAD, and MDD. Data from 98 eye movement features were extracted. We employed a gradient boosted (GB) decision tree multiclass classifier to develop a predictive model. We calculated the area under the curve (AUC) as the primary performance metric. Study results: Estimates of AUC in one-versus-all comparisons were: SCZ (0.85), BPAD (0.78), MDD (0.76), and CON (0.85). Estimates on part-external validation were SCZ (0.89) and CON (0.65). In all cases, there was good specificity but only moderate sensitivity. The best individual discriminators included free viewing, fixation duration, and smooth pursuit tasks. The findings appear robust to potential confounders such as age, sex, medication, or mental state at the time of testing. Conclusions: Eye movement patterns can discriminate schizophrenia from major mood disorders and control subjects with around 80% predictive accuracy.

Cognitive Test Scores and Progressive Cognitive Decline in the Aberdeen 1921 and 1936 Birth Cohorts.

The Aberdeen birth cohorts of 1921 and 1936 (ABC21 and ABC36) were subjected to IQ tests in 1932 or 1947 when they were aged about 11y. They were recruited between 1997-2001 among cognitively healthy community residents and comprehensively phenotyped in a long-term study of brain aging and health up to 2017. Here, we report associations between baseline cognitive test scores and long-term cognitive outcomes. On recruitment, significant sex differences within and between the ABC21 and ABC36 cohorts supported advantages in verbal ability and learning among the ABC36 women that were not significant in ABC21. Comorbid physical disorders were self-reported in both ABC21 and ABC36 but did not contribute to differences in terms of performance in cognitive tests. When used alone without other criteria, cognitive tests scores which fell below the -1.5 SD criterion for tests of progressive matrices, namely verbal learning, digit symbol and block design, did not support the concept that Mild Cognitive Impairment (MCI) is a stable class of acquired loss of function with significant links to the later emergence of a clinical dementia syndrome. This is consistent with many previous reports. Furthermore, because childhood IQ-type data were available, we showed that a lower cognitive performance at about 64 or 78 y than that predicted by IQ at 11 ± 0.5 y did not improve the prediction of progress to MCI or greater cognitive loss. We used binary logistic regression to explore how MCI might contribute to the prediction of later progress to a clinical dementia syndrome. In a fully adjusted model using ABC21 data, we found that non-amnestic MCI, along with factors such as female sex and depressive symptoms, contributed to the prediction of later dementia. A comparable model using ABC36 data did not do so. We propose that (1) MCI criteria restricted to cognitive test scores do not improve the temporal stability of MCI classifications; (2) pathways towards dementia may differ according to age at dementia onset and (3) the concept of MCI may require measures (not captured here) that underly self-reported subjective age-related cognitive decline.

Homocysteine, antioxidant micronutrients and late onset dementia.

PURPOSE: To distinguish between contributions to dementia made by homocysteine, folate, B12 and antioxidant micronutrients. METHODS: This is a follow-up study of a sample reported in 2002. Homocysteine was measured at baseline in 201 individuals born in 1921 and without dementia at age 77 years and followed up to age 88 years. Baseline macro- and micronutrient status was estimated from BMI, the MONICA food frequency questionnaire, plasma folate, B12 and, in a subgroup (N = 173), plasma antioxidant micronutrients. Time to dementia onset during follow-up was compared between participants grouped by homocysteine concentration using Cox regression. Model 1 adjusted for age, sex, childhood IQ, education, socioeconomic deprivation, presence of heart disease, hypertension, plasma folate and B12. In model 2 plasma, antioxidants were added to these covariables. RESULTS: During a mean follow-up of about 5 years, there were 39 incident dementia cases among 201 participants. In model 1, being in the highest homocysteine group (>14 µmol/L) was associated with a 234 % increased risk (HR 3.34, 95 % CI 1.16-9.57) of any dementia. After inclusion of plasma antioxidants in model 2, there were 32 incident dementia cases from a subsample (N = 173). Homocysteine >14 µmol was associated with a 272 % increased dementia risk (HR = 3.72, 95 % CI 1.06-13.08). CONCLUSIONS: High homocysteine increases the risk of dementia. The association between tHcy and dementia is independent of plasma folate, B12 and antioxidant micronutrient status.

How the 1932 and 1947 mental surveys of Aberdeen schoolchildren provide a framework to explore the childhood origins of late onset disease and disability.

OBJECTIVES: To describe the discovery and development of the Aberdeen 1921 and 1936 birth cohort studies. STUDY DESIGN: The Aberdeen birth cohort studies were started in 1998 when the Scottish Mental Survey archives of the Scottish Council for Research in Education were re-discovered and permissions granted to follow-up survivors born in 1921 or 1936 and then aged about 77 or 64 years and who had entered (or were about to enter) the age of greatest risk for Alzheimer's disease (AD). MAIN OUTCOME MEASURES: Sources of attrition from the study, exposures to childhood adversity, nutritional, genetic and life style factors of possible relevance to extent of age-related cognitive decline and the timing of onset of dementia. RESULTS: By 2010, the feasibility of following up more than 75% of Scottish Mental Survey survivors living in the Aberdeen area without dementia was well-established, dementia ascertainment to age about 88 years was completed in the 1921 birth cohort and was underway in the 1936 born cohort. CONCLUSION: These databases are available to other bone fide research groups wishing to test specific hypotheses that may either replicate their own findings or make best use of the data collected in the Aberdeen studies.

Brain volume and survival from age 78 to 85: the contribution of Alzheimer-type magnetic resonance imaging findings.

OBJECTIVES: To test the prediction of survival using magnetic resonance imaging (MRI)-derived global and regional brain volumes in subjects aged 78 to 79 without dementia. DESIGN: Observational follow-up study. SETTING: University teaching hospital. PARTICIPANTS: Participants born in 1921, recruited in 1997/98 to a longitudinal study, who underwent brain MRI in 1999/2000. MEASUREMENTS: Vital status on May 12, 2006, global and regional brain volumes. RESULTS: Thirty-seven of 98 (34.9%) participants died during follow-up. After adjustment for cognitive ability at time of MRI examination, childhood intelligence, sex, hypertension, smoking history, obesity, hyperlipidemia, and age at MRI, proportion of intracranial volume occupied by the brain (brain fraction) predicted death before age 85 (P=.04). Participants with brain fraction less than 0.726 had more than twice the relative risk (2.8, 95% confidence interval=1.1-7.3) of death than participants with brain fraction greater 0.726. Lower survival was significantly associated with lower gray matter volumes in bilateral parietal and left frontoparietal areas and with lower white matter volumes in left parietal and right posterior temporal regions. Cox regression analysis showed that parietal white matter volume (P=.003), a subsequent diagnosis of dementia (P<.001), and sex (P=.004) were independent predictors of survival. CONCLUSION: In participants aged 78 to 79, a lower global brain fraction predicted survival to approximately age 85. Smaller regional volumetric brain reductions, seen in Alzheimer's disease (AD), also predicted survival independent of dementia. The presence of prodromal AD probably explain the main findings.

Quality of life and its correlates in octogenarians. Use of the SEIQoL-DW in Wave 5 of the Aberdeen Birth Cohort 1921 Study (ABC1921).

BACKGROUND: The direct-weighted Schedule for the Evaluation of Individual Quality of Life, Direct Weighting (SEIQoL-DW) is an individualised measure of QoL that has been little used in very elderly people. METHODS: We administered SEIQoL-DW during Wave 5 of the Aberdeen Birth Cohort 1921 Study (ABC1921) and sought statistical correlations with other variables in the data set. ABC1921 participants had been IQ-tested in 1932 at age 11. Since 1997, data about cognition, mental/physical function, personality, health, and socioeconomic status have been gathered in five waves of investigations. RESULTS: Ninety-six out of 98 individuals, mean age 82.2, completed the SEIQoL-DW. Health, family, relationships, finances and social pastimes were the commonest cues nominated, but age/gender differences existed. The mean SEIQoL-DW score (74.0) was significantly lower than in an approximately 60% sample from Wave 3, the fall being greater in men. Variables statistically associated with Wave 5 SEIQoL-DW usually reflected current rather than past status [including Short-Form 36 Health Survey (SF-36) components and depression], although there were weaker correlations with years of education, housing in childhood, conscientiousness, and IQ in 1998. CONCLUSIONS: SEIQoL-DW proved feasible and acceptable in community-dwelling octogenarians. Recent (i.e. statelike) rather than early or long-standing (i.e. traitlike) influences appeared to have the greater effect on QoL.

Association study and meta-analysis of low-density lipoprotein receptor related protein in Alzheimer's disease.

Genome scans in sporadic Alzheimer's disease (AD) have revealed a possible susceptibility locus on chromosome 12. The low density lipoprotein receptor related protein (LRP1) gene lies within this area of linkage. Eighteen previous AD case-control studies have investigated the C766T polymorphism in LRP1 with conflicting results, including a protective effect on AD of the T allele, an increased susceptibility towards AD with both the C and T alleles, or no association at all. We have now performed a case-control study based on a large UK cohort of 477 AD patients and 466 matched controls, and have included these data, with those drawn from the 18 previous studies, into in a meta-analysis of 4668 AD patients and 4473 controls. We find no evidence for influence on the risk for AD in either our own present cohort or in the combined data set. Furthermore, we investigated whether the C766T polymorphism might modify the clinical and pathological phenotype in our cohort. We found no association with AD when the cohort was stratified into those with early (<65 years) or late (>65 years) onset, or when split into Apolipoprotein E (APOE) epsilon4 bearers and epsilon4 non-bearers. In addition, the C766T polymorphism was shown not to influence the age onset of AD. In a separate autopsy-confirmed cohort of 130 AD cases, no association with genotype or allele was observed for tissue levels of beta-amyloid 40, beta-amyloid 42, total beta-amyloid, pathological tau proteins, microglial cells or extent of astrocytic activity. Therefore, in this present study, we find no evidence for the involvement of this polymorphism either in increasing the susceptibility to AD, or by acting as a phenotypic modifier.

No association between polymorphisms in the lectin-like oxidised low density lipoprotein receptor (ORL1) gene on chromosome 12 and Alzheimer's disease in a UK cohort.

Genome scans in sporadic Alzheimer's disease (AD) have revealed possible susceptibility loci on chromosome 12. Recently, two studies were published investigating the +1071 and +1073 polymorphisms in the lectin-like oxidised low density lipoprotein receptor (OLR1) gene with AD, a gene that lies within the area of chromosome 12 linkage. OLR1 is a good candidate gene, due to its function in lipid metabolism pathways, other components of which have been previously implicated as risk factors for AD. We undertook an association study in our UK cohort of 356 AD patients and 358 matched controls, using the same polymorphisms and performing the same sub-group and haplotype analysis as previously described. We found no association with AD in our case-control group as a whole, or when stratified into those with early (<65 years) or late (>65 years) onset. When the group was split into APOE 4 bearers and 4 non-bearers, we could not confirm the associations described in the original study. Similarly, no significant differences were observed between AD patients and controls, in terms of their haplotype distributions. Therefore, in this present study, we find no evidence for the involvement of these ORL1 polymorphisms in increasing susceptibility to AD.

Interleukin-6 promoter polymorphism: risk and pathology of Alzheimer's disease.

Inflammatory and immune responses are involved in the pathogenesis of Alzheimer's disease (AD). Interleukin-6 (IL-6), an inflammatory cytokine, is thought to play a role in neurodegeneration of the central nervous system and has been associated with increased amyloid precursor protein expression in vitro and greater cognitive decline. Previously a C-174G polymorphism in the promoter of IL-6, which influences expression in vitro, has been found associated in some studies but not all. We investigated this polymorphism in a large independent UK sample of AD cases (n = 356) and controls (n 434) but found no association. We extended the study to genotype/phenotype correlations but found no correlation with age of onset (n = 338), brain amyloid load (n = 126) or Tau load (n = 101), brain microglial cell load (n = 65) or brain reactive astrocytes (n = 127). Our data do not support a pathogenic role in AD for the C-174G polymorphism in isolation.

Candidate gene association studies of the alpha 4 (CHRNA4) and beta 2 (CHRNB2) neuronal nicotinic acetylcholine receptor subunit genes in Alzheimer's disease.

Consistent deficits in the cholinergic system are evident in Alzheimer's disease (AD) patients, including selective loss of alpha4beta2 nicotinic acetylcholine receptors in the brains of AD patients. Knockout mice for the beta2 subunit have impaired neuronal survival in ageing. Accordingly, we have analysed polymorphisms in the genes that encode the alpha4 and beta2 subunits, CHRNA4 and CHRNB2 respectively, for genetic associations with late-onset AD. A significant association for disease was observed for a non-coding polymorphism in CHRNB2 (odds ratio=0.57, 95% confidence interval=0.35-0.95, P=0.024). Replication analysis was performed in two further sample sets. While these did not individually yield significant results, a significant association remained when all samples were pooled (odds ratio=0.70, 95% confidence interval=0.52-0.95, P=0.019). These data suggest that this variant warrants further examination in large case-control series.

Quality of Life in healthy old age: relationships with childhood IQ, minor psychological symptoms and optimism.

BACKGROUND: The aim of this study was to examine relationships in old age between Quality of Life (QoL), childhood IQ, current cognitive performance and minor psychological symptoms, and to estimate possible contributions to these relationships made by sex, education, socioeconomic deprivation, current living group, sex, and balance and 6m walk time. METHODS: We conducted a follow-up study on 88 community residents without dementia who were survivors of the Aberdeen City 1921 birth cohort. QoL was measured by the Schedule for the Evaluation of Individual QoL-Direct Weighting (SEIQoL-DW), current cognition by MMSE and Raven's Progressive Matrices (RPM), childhood IQ, minor psychological symptoms as assessed by the Hospital Anxiety and Depression Scale (HADS), and optimism by the Life Orientation Test (LOT); we included balance, 6m walk time and demographic data. RESULTS: QoL was better in men than in women. Women reported more anxiety and depression. QoL correlated significantly with current cognition measured by RPM, childhood intelligence, anxiety and depressive symptoms, optimism and balance. The best model to predict QoL relied on childhood intelligence (13.4% of the variance) and was improved by addition of HADS (8.8 %) and LOT (4.8 %). Other variables did not contribute to the prediction of QoL. CONCLUSION: In the absence of dementia, childhood IQ, HADS and LOT explain 26.9% of the variance in QoL as reported by community-resident old people. The direction of association between current anxiety and depressive symptoms and lower QoL is uncertain. Lower childhood IQ may contribute to coping less well with later life. Lower QoL is not an invariable concomitant of mild cognitive decline.