Capability in research on cognition and well-being in ageing and retirement

In this chapter, we outline our thoughts on capability in relation to previous and ongoing research projects conducted by the Adult Development and Ageing (ADA-Gero) Research Group located at the Department of Psychology, University of Gothenburg, Sweden. More specifically, we relate our research on cognitive ageing and subjective well-being to the overarching capability framework implemented as a theoretical platform in the AgeCap research consortium

The reserve concept in patients with Mild Cognitive Impairment - new approaches

The concept of reserve stems from the observation that premorbid factors, e.g. education, result in variation in the response to any kind of brain pathology. As subjects with higher reserve tolerate more neuropathology, symptomatic expression of pathology is delayed. It is thus predicted that neuropathology should be more pronounced in those with higher reserve as compared to those with lower at the same level of clinical severity. Most research within the reserve paradigm has been conducted on patients with established diagnoses, mainly Alzheimer’s disease, but knowledge on the modifying effects of reserve in preclinical, Mild Cognitive Impairment (MCI), and early phases of dementia is limited. The main purpose was to investigate if use of cerebrospinal fluid (CSF) biomarkers, would enable studies of reserve in earlier phases. Specifically, the 42 amino acid form of beta-amyloid (abeta42), mirroring amyloid plaques depositions, and CSF total tau (t-tau), reflecting axonal degeneration, were used as surrogate measures for neuropathology. Another purpose was to explore if patients with higher reserve diverge from patients with intermediate and lower reserve in terms of CSF pathology, and cognitive functioning in various disease phases. As premorbid intelligence Quotient (IQ), cognitive functioning prior to manifest disease, may be a better proxy for reserve than education, the final objective was to construct a test for assessment of premorbid IQ in Swedish. In summary, we found that patients with higher reserve were distinguishable from those with intermediate and lower reserve with regards to abeta42 pathology, but not clinical manifestations. The incongruence between pathology and clinical outcome indicates compensation for neuropathology. We also found that abeta42 may be sensitive to disease progress when taking level of reserve into account. Patients with higher reserve with stable MCI had lower concentrations of CSF t-tau, but comparable abeta42 concentrations. This finding may either indicate a true protective effect for education, or suggests that higher education promotes cognitive stimulation resulting in better axonal integrity. Also, a test for assessment of premorbid IQ, NART-SWE, was successfully constructed and found to have satisfactory psychometric properties. The results of these studies may contribute to earlier identification, and consequentially treatment of patients with higher reserve at risk for dementia

Cognitive performance and cerebrospinal fluid biomarkers of neurodegeneration: a study of patients with bipolar disorder and healthy controls.

The purpose of the present study was to investigate if cerebrospinal fluid (CSF) biomarkers of neurodegeneration are associated with cognition in bipolar disorder and healthy controls, respectively. CSF concentrations of total and phosphorylated tau, amyloid beta (Aβ)1-42, ratios of Aβ42/40 and Aβ42/38, soluble amyloid precursor protein α and β, and neurofilament light chain protein were analyzed in relation to neuropsychological performance in 82 euthymic bipolar disorder patients and 71 healthy controls. Linear regression models were applied to account for performance in five cognitive domains using the CSF biomarkers. In patients, the CSF biomarkers explained a significant proportion of the variance (15-36%, p=.002 - <.0005) in all cognitive domains independently of age, medication, disease status, and bipolar subtype I or II. However, the CSF biomarkers specifically mirroring Alzheimer-type brain changes, i.e., P-tau and Aβ1-42, did not contribute significantly. In healthy controls, CSF biomarkers did not explain the variance in cognitive performance. Selected CSF biomarkers of neurodegenerative processes accounted for cognitive performance in persons with bipolar disorder, but not for healthy controls. Specifically, the ratios of Aβ42/40 and Aβ42/38 were consistently associated with altered cognitive performance

Monte Carlo feature selection and rule-based models to predict Alzheimer's disease in mild cognitive impairment

The objective of the present study was to evaluate a Monte Carlo feature selection (MCFS) and rough set Rosetta pipeline for generating rule-based models as a tool for comprehensive risk estimates for future Alzheimer's disease (AD) in individual patients with mild cognitive impairment (MCI). Risk estimates were generated on the basis of age, gender, Mini-Mental State Examination scores, apolipoprotein E (APOE) genotype and the cerebrospinal fluid (CSF) biomarkers total tau (T-tau), phospho-tau(181) (P-tau) and the 42 amino acid form of amyloid beta (A beta 42) in two sets of longitudinally followed MCI patients (n = 217 in total). The predictive model was created in Rosetta, evaluated with the standard tenfold cross-validation approach and tested on an external set. Features were ranked and selected by the MCFS algorithm. Using the combined pipeline of MCFS and Rosetta, it was possible to predict AD among patients with MCI with an area under the receiver operating characteristics curve of 0.92. Risk estimates were produced for the individual patients and showed good correlation with actual diagnosis in cross validation, and on an external dataset from a new study. Analysis of the importance of attributes showed that the biochemical CSF markers contributed the most to the predictions, and that added value was gained by combining several biochemical markers. Despite a correlation with the biochemical markers, the genetic marker APOE epsilon 4 did not contribute to the predictive power of the model

Cerebrospinal fluid biomarkers associated with cognitive performance in bipolar disorder.

<p>Cerebrospinal fluid biomarkers associated with cognitive performance in bipolar disorder.</p

Variables associated with cognitive performance in healthy controls.

<p>Variables associated with cognitive performance in healthy controls.</p

Cognitive domains and functions assessed in the St Göran bipolar project.

<p>Cognitive domains and functions assessed in the St Göran bipolar project.</p