Case Studies Illustrating Focal Alzheimer's, Fluent Aphasia, Late-Onset Memory Loss, and Rapid Dementia

The neuropathological diagnosis of Alzheimer's disease

Alzheimer's disease is a progressive neurodegenerative disease most often associated with memory deficits and cognitive decline, although less common clinical presentations are increasingly recognized. The cardinal pathological features of the disease have been known for more than one hundred years, and today the presence of these amyloid plaques and neurofibrillary tangles are still required for a pathological diagnosis. Alzheimer's disease is the most common cause of dementia globally. There remain no effective treatment options for the great majority of patients, and the primary causes of the disease are unknown except in a small number of familial cases driven by genetic mutations. Confounding efforts to develop effective diagnostic tools and disease-modifying therapies is the realization that Alzheimer's disease is a mixed proteinopathy (amyloid and tau) frequently associated with other age-related processes such as cerebrovascular disease and Lewy body disease. Defining the relationships between and interdependence of various co-pathologies remains an active area of investigation. This review outlines etiologically-linked pathologic features of Alzheimer's disease, as well as those that are inevitable findings of uncertain significance, such as granulovacuolar degeneration and Hirano bodies. Other disease processes that are frequent, but not inevitable, are also discussed, including pathologic processes that can clinically mimic Alzheimer's disease. These include cerebrovascular disease, Lewy body disease, TDP-43 proteinopathies and argyrophilic grain disease. The purpose of this review is to provide an overview of Alzheimer's disease pathology, its defining pathologic substrates and the related pathologies that can affect diagnosis and treatment.

Continuity and Stability in Development

Developmental science is centrally concerned with both consistency and change in characteristics through time. Consistency and change in development are tracked by group mean level continuity and individual order stability. Group mean level and individual order consistency and change are both developmentally informative and can co-exist conceptually and empirically as the two are partially orthogonal perspectives on development. Continuity and stability are broadly applicable to characteristics of the individual, dyad, and environment. Significantly, absent the distinctions we draw between mean level continuity and individual order stability, researchers who use the terms willy-nilly leave their readers in the dark as to which key feature of development is meant. In this article, we distinguish the two types of consistency and change, their measurement, importance, moderation, and implications.