Extending the phenotypic spectrum assessed by the CDR plus NACC FTLD in genetic frontotemporal dementia.

Introduction: We aimed to expand the range of the frontotemporal dementia (FTD) phenotypes assessed by the Clinical Dementia Rating Dementia Staging Instrument plus National Alzheimer's Coordinating Center Behavior and Language Domains (CDR plus NACC FTLD).

Methods: Neuropsychiatric and motor domains were added to the standard CDR plus NACC FTLD generating a new CDR plus NACC FTLD-NM scale. This was assessed in 522 mutation carriers and 310 mutation-negative controls from the Genetic Frontotemporal dementia Initiative (GENFI).

On the use of the reproduction number for SARS-CoV-2: Estimation, misinterpretations and relationships with other ecological measures.

The basic reproduction number, , and its real-time analogue, , are summary measures that reflect the ability of an infectious disease to spread through a population. Estimation methods for  have a long history, have been widely developed and are now enhanced by application to the COVID-19 pandemic. While retrospective analyses of have provided insight into epidemic dynamics and the effects of control strategies in prior outbreaks, misconceptions around the interpretation of have arisen with broader recognition and near real-time monitoring of this parameter alongside reported case data during the COVID-19 pandemic.

Power and sample-size calculations for trials that compare slopes over time: Introducing the slopepower command.

Trials of interventions that aim to slow disease progression may analyze a continuous outcome by comparing its change over time-its slope-between the treated and the untreated group using a linear mixed model. To perform a sample-size calculation for such a trial, one must have estimates of the parameters that govern the between- and within-subject variability in the outcome, which are often unknown. The algebra needed for the sample-size calculation can also be complex for such trial designs.

Increased variability in reaction time is associated with amyloid beta pathology at age 70.

Introduction: We investigated whether life-course factors and neuroimaging biomarkers of Alzheimer's disease pathology predict reaction time (RT) performance in older adults.

Methods: Insight 46 study participants, all born in the same week in 1946 (n = 501; ages at assessment = 69 to 71 years), completed a 2-choice RT task and amyloid beta (Aβ) positron emission tomography and MR imaging. We tested for associations between task outcomes (RT; error rate; intra-individual variability in RT) and life-course predictors including childhood cognitive ability and education.

Amyloid β influences the relationship between cortical thickness and vascular load.

Introduction: Cortical thickness has been proposed as a biomarker of Alzheimer's disease (AD)- related neurodegeneration, but the nature of its relationship with amyloid beta (Aβ) deposition and white matter hyperintensity volume (WMHV) in cognitively normal adults is unclear.

Methods: We investigated the influences of Aβ status (negative/positive) and WMHV on cortical thickness in 408 cognitively normal adults aged 69.2 to 71.

CSF neurogranin or tau distinguish typical and atypical Alzheimer disease.

Objective: To assess whether high levels of cerebrospinal fluid neurogranin are found in atypical as well as typical Alzheimer's disease.

Methods: Immunoassays were used to measure cerebrospinal fluid neurogranin in 114 participants including healthy controls ( = 27), biomarker-proven amnestic Alzheimer's disease ( = 68), and the atypical visual variant of Alzheimer's ( = 19) according to international criteria. CSF total-tau, Aβ42, and neurofilament light concentrations were investigated using commercially available assays.