Resting-state functional connectivity abnormalities in subjective cognitive decline: A 7T MRI study.

Resting-state functional connectivity (FC) MRI is sensitive to brain changes in Alzheimer's disease in preclinical stages, however studies in persons with subjective cognitive decline (SCD) have reported conflicting findings, and no study is available at 7T MRI. In this study, we investigated FC alterations in sixty-six participants recruited at the Geneva Memory Center (24 controls, 14 SCD, 28 cognitively impaired [CI]). Participants were classified as SCD if they reported cognitive complaints without objective cognitive deficits, and underwent 7T fMRI to assess FC in canonical brain networks and their association with cognitive/clinical features.

Subjective cognitive decline: Memory complaints, cognitive awareness, and metacognition.

Cognitive complaints are common in elderly subjects and are a frequent reason for referral to memory clinics. If the complaints are not associated with objective cognitive impairment, the condition is labelled subjective cognitive decline (SCD). SCD is often considered as a stage antedating objective impairment, and an at-risk condition for subsequent dementia.

Prognostic value of imaging-based ATN profiles in a memory clinic cohort.

Purpose: The ATN model represents a research framework used to classify subjects based on the presence or absence of Alzheimer's disease (AD) pathology through biomarkers for amyloid (A), tau (T), and neurodegeneration (N). The aim of this study was to assess the relationship between ATN profiles defined through imaging and cognitive decline in a memory clinic cohort.

Methods: One hundred-eight patients from the memory clinic of Geneva University Hospitals underwent complete clinical and neuropsychological evaluation at baseline and 23 ± 5 months after inclusion, magnetic resonance imaging, amyloid and tau PET scans.

The taxonomy of subjective cognitive decline: proposal and first clinical evidence from the Geneva memory clinic cohort.

Background: Subjective Cognitive Decline (SCD) is characterized by subjective cognitive complaints without objective cognitive impairment and is considered a risk factor for cognitive decline and dementia. However, most SCD patients will not develop neurodegenerative disorders, yet they may suffer from minor psychiatric, neurological, or somatic comorbidities. The aim of the present study is to provide a taxonomy of the heterogeneous SCD entity by isolating homogenous SCD subgroups with specific clinical features and cognitive trajectories.

Brain connectivity and metacognition in persons with subjective cognitive decline (COSCODE): rationale and study design.

Background: Subjective cognitive decline (SCD) is the subjective perception of a decline in memory and/or other cognitive functions in the absence of objective evidence. Some SCD individuals however may suffer from very early stages of neurodegenerative diseases (such as Alzheimer's disease, AD), minor psychiatric conditions, neurological, and/or somatic comorbidities. Even if a theoretical framework has been established, the etiology of SCD remains far from elucidated.

Harmonizing neuropsychological assessment for mild neurocognitive disorders in Europe.

Introduction: Harmonized neuropsychological assessment for neurocognitive disorders, an international priority for valid and reliable diagnostic procedures, has been achieved only in specific countries or research contexts.

Methods: To harmonize the assessment of mild cognitive impairment in Europe, a workshop (Geneva, May 2018) convened stakeholders, methodologists, academic, and non-academic clinicians and experts from European, US, and Australian harmonization initiatives.

Results: With formal presentations and thematic working-groups we defined a standard battery consistent with the U.

Diagnostic value of amyloid-PET and tau-PET: a head-to-head comparison.

Purpose: Assess the individual and combined diagnostic value of amyloid-PET and tau-PET in a memory clinic population.

Methods: Clinical reports of 136 patients were randomly assigned to two diagnostic pathways: AMY-TAU, amyloid-PET is presented before tau-PET; and TAU-AMY, tau-PET is presented before amyloid-PET. Two neurologists independently assessed all reports with a balanced randomized design, and expressed etiological diagnosis and diagnostic confidence (50-100%) three times: (i) at baseline based on the routine diagnostic workup, (ii) after the first exam (amyloid-PET for the AMY-TAU pathway, and tau-PET for the TAU-AMY pathway), and (iii) after the remaining exam.

Routine assessment of cognitive function in older patients with hypertension seen by primary care physicians: why and how-a decision-making support from the working group on 'hypertension and the brain' of the European Society of Hypertension and from the European Geriatric Medicine Society.

: The guidelines on hypertension recently published by the European Societies of Hypertension and Cardiology, have acknowledged cognitive function (and its decline) as a hypertension-mediated organ damage. In fact, brain damage can be the only hypertension-mediated organ damage in more than 30% of hypertensive patients, evolving undetected for several years if not appropriately screened; as long as undetected it cannot provide either corrective measures, nor adequate risk stratification of the hypertensive patient.The medical community dealing with older hypertensive patients should have a simple and pragmatic approach to early identify and precisely treat these patients.

The A/T/N model applied through imaging biomarkers in a memory clinic.

Purpose: The A/T/N model is a research framework proposed to investigate Alzheimer's disease (AD) pathological bases (i.e., amyloidosis A, neurofibrillary tangles T, and neurodegeneration N).

Measuring the Impact of Delayed Cerebral Ischemia on Neuropsychological Outcome After Aneurysmal Subarachnoid Hemorrhage-Protocol of a Swiss Nationwide Observational Study (MoCA-DCI Study).

Background: The exact relationship between delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH) and neuropsychological impairment remains unknown, as previous studies lacked a baseline examination after aneurysm occlusion but before the DCI-period. Neuropsychological evaluation of acutely ill patients is often applied in a busy intensive care unit (ICU), where distraction represents a bias to the obtained results.

Objective: To evaluate the relationship between DCI and neuropsychological outcome after aSAH by comparing the Montreal Cognitive Assessment (MoCA) results in aSAH patients with and without DCI at 3 mo with a baseline examination before the DCI-period (part 1).

Interaction between Polymorphism and Physical Activity on Inhibitory Performance in the Elderly without Cognitive Impairment.

In the elderly, physical activity (PA) enhances cognitive performances, increases brain plasticity and improves brain health. The neurotrophic hypothesis is that the release of brain-derived neurotrophic factor (BDNF), which is implicated in brain plasticity and cognition, is triggered by PA because motoneurons secrete BDNF into the bloodstream during exercise. Individual differences in cognitive performance may be explained by individual differences in genetic predisposition.

The impact of physical activity and sex differences on intraindividual variability in inhibitory performance in older adults.

It is well-known that processing speed and executive functions decline with advancing age. However, physical activity (PA) has a positive impact on cognitive performances in aging, specifically for inhibition. Less is known concerning intraindividual variability (iiV) in reaction times.

Associations of educational attainment and cognitive level of job with old age verbal ability and processing speed: The mediating role of chronic diseases.

We investigated whether the relation of educational attainment and cognitive level of job to performance in verbal ability and processing speed in old age was mediated via the number of chronic diseases. A total of 2,812 older adults participated. Psychometric tests on verbal ability and processing speed were administered.

Call for uniform neuropsychological assessment after aneurysmal subarachnoid hemorrhage: Swiss recommendations.

Background: In a high proportion of patients with favorable outcome after aneurysmal subarachnoid hemorrhage (aSAH), neuropsychological deficits, depression, anxiety, and fatigue are responsible for the inability to return to their regular premorbid life and pursue their professional careers. These problems often remain unrecognized, as no recommendations concerning a standardized comprehensive assessment have yet found entry into clinical routines.

Methods: To establish a nationwide standard concerning a comprehensive assessment after aSAH, representatives of all neuropsychological and neurosurgical departments of those eight Swiss centers treating acute aSAH have agreed on a common protocol.

Coordinated within-trial dynamics of low-frequency neural rhythms controls evidence accumulation.

Higher cognitive functions, such as human perceptual decision making, require information processing and transmission across wide-spread cortical networks. Temporally synchronized neural firing patterns are advantageous for efficiently representing and transmitting information within and between assemblies. Computational, empirical, and conceptual considerations all lead to the expectation that the informational redundancy of neural firing rates is positively related to their synchronization.

Individual differences in cognitive plasticity: an investigation of training curves in younger and older adults.

To date, cognitive intervention research has provided mixed but nevertheless promising evidence with respect to the effects of cognitive training on untrained tasks (transfer). However, the mechanisms behind learning, training effects and their predictors are not fully understood. Moreover, individual differences, which may constitute an important factor impacting training outcome, are usually neglected.

Individual alpha peak frequency is related to latent factors of general cognitive abilities.

Some eighty years after the discovery of the human electroencephalogram (EEG) and its dominant rhythm, alpha (~10Hz), the neurophysiological functions and behavioral correlates of alpha oscillations are still under debate. Similarly, the biological mechanisms contributing to the general factor of intelligence, or g, have been under scrutiny for decades. Individual alpha frequency (IAF), a trait-like parameter of the EEG, has been found to correlate with individual differences in cognitive performance and cognitive abilities.

Peak individual alpha frequency qualifies as a stable neurophysiological trait marker in healthy younger and older adults.

The individual alpha frequency (IAF) of the human EEG reflects systemic properties of the brain, is highly heritable, and relates to cognitive functioning. Not much is known about the modifiability of IAF by cognitive interventions. We report analyses of resting EEG from a large-scale training study in which healthy younger (20-31 years, N = 30) and older (65-80 years, N = 28) adults practiced 12 cognitive tasks for ∼100 1-h sessions.

Beyond interference control impairment in ADHD: evidence from increased intraindividual variability in the color-stroop test.

The present study investigates intraindividual variability (IIV) in the Color-Stroop test and in a simple reaction time (SRT) task. Performance level and variability in reaction times (RTs)-quantified with different measures such as individual standard deviation (ISD) and coefficient of variation (ICV), as well as ex-Gaussian parameters (mu, sigma, tau)-were analyzed in 24 children with attention deficit/hyperactivity disorder (ADHD) and 24 typically developing children (TDC). Children with ADHD and TDC presented equivalent Color-Stroop interference effects when mean RTs were considered, and the two groups did not differ in the SRT task.

Increased intraindividual variability is a marker of ADHD but also of dyslexia: a study on handwriting.

It has been suggested that intraindividual variability (IIV) in neuropsychological tasks may be a specific characteristic of Attention-Deficit Hyperactivity Disorder (ADHD), but previous research has not thoroughly examined whether IIV also concerns academic performance or other types of developmental disabilities. The present study investigates the role of IIV in 15 children with ADHD without reading difficulties, 15 children with dyslexia without associated symptoms of ADHD, and 15 typically developing children (TDC) in a simple response time (SRT) task and in a skill more directly related with school learning-handwriting. Results show that children with ADHD and those with dyslexia have a greater IIV than the TDC in both tasks.

Higher intraindividual variability is associated with more forgetting and dedifferentiated memory functions in old age.

Intraindividual trial-to-trial reaction time (RT) variability is commonly found to be higher in clinical populations or life periods that are associated with impaired cognition. In the present study, higher within-person trial-to-trial RT variability in a perceptual speed task is related to more forgetting and dedifferentiation of memory functions in older adults (aged 60-71 years). More specifically, our study showed that individuals in a high-variability group (n=175) forgot more memory scenes over a 1-week retention interval than individuals in the low-variability group (n=174).

Ebbinghaus revisited: influences of the BDNF Val66Met polymorphism on backward serial recall are modulated by human aging.

The brain-derived neurotrophic factor (BDNF) plays an important role in activity-dependent synaptic plasticity, which underlies learning and memory. In a sample of 948 younger and older adults, we investigated whether a common Val66Met missense polymorphism (rs6265) in the BDNF gene affects the serial position curve--a fundamental phenomenon of associative memory identified by Hermann Ebbinghaus more than a century ago. We found a BDNF polymorphism effect for backward recall in older adults only, with Met-allele carriers (i.

Age-related decline in brain resources modulates genetic effects on cognitive functioning.

Individual differences in cognitive performance increase from early to late adulthood, likely reflecting influences of a multitude of factors. We hypothesize that losses in neurochemical and anatomical brain resources in normal aging modulate the effects of common genetic variations on cognitive functioning. Our hypothesis is based on the assumption that the function relating brain resources to cognition is nonlinear, so that genetic differences exert increasingly large effects on cognition as resources recede from high to medium levels in the course of aging.

Human aging magnifies genetic effects on executive functioning and working memory.

We demonstrate that common genetic polymorphisms contribute to the increasing heterogeneity of cognitive functioning in old age. We assess two common Val/Met polymorphisms, one affecting the Catechol-O-Methyltransferase (COMT) enzyme, which degrades dopamine (DA) in prefrontal cortex (PFC), and the other influencing the brain-derived neurotrophic factor (BDNF) protein. In two tasks (Wisconsin Card Sorting and spatial working memory), we find that effects of COMT genotype on cognitive performance are magnified in old age and modulated by BDNF genotype.