Neuropsychological and neurobiological markers of the preclinical stage of Alzheimer’s disease.

Abstract

Dementia, especially Alzheimer's disease, has a high prevalence in the elderly population. Therefore, identifying individuals who are at a high risk for early diagnosis is crucial to allow both pharmacological and behavioral therapeutic interventions, which in some cases can delay the progression of dementia. This paper describes neuropsychological and neurobiological markers for the early diagnosis of Alzheimer's disease and presents the main risk factors, including neuropathological, neuroanatomical, neurofunctional, genetic, and neuropsychological. The literature shows that the combination of these markers is the best method for predicting Alzheimer's disease, years before its clinical manifestation. The most prevalent neurobiological and neuropsychological risk factors include (1) senile plaques and neurofibrillary tangles in the medial temporal lobe and cortical regions, (2) low concentrations of Aβ1-42 peptide and high concentrations of total tau protein and phosphorylated tau protein in cerebrospinal fluid, (3) reduced global cerebral volume, increased ventricular volume, and atrophy in the hippocampal formation and entorhinal cortex, (4) global reductions in cerebral metabolism and perfusion in the temporoparietal junction, temporal, parietal, and frontal lobes, hippocampal formation, and posterior cingulate cortex, (5) the presence of the apolipoprotein E ε4 allele, and (6) verbal anterograde episodic long-term memory impairment and executive dysfunction. The present review discusses the evidence for markers that identify individuals who are at a high risk of developing Alzheimer's disease and the importance of longitudinal studies in this context.

Event-based prospective memory and everyday forgetting in healthy older adults and individuals with mild cognitive impairment

“…The significant relationship between PM accuracy and tests thought to be predominately supported by medial temporal lobe structures suggests a possible link between the deficient PM memory performance of the MCI participants and impaired spontaneous retrieval processes for this non-focal PM task. This is based on data which suggests that medial temporal structures both support spontaneous associative retrieval (Moscovitch, 1992; 1994) and are prominent areas for plaques and tangles in early AD (Fichman, Oliver, & Fernandes, 2011). In addition, McDaniel et al (2011) recently suggested that deficits observed on a focal PM task in very early Alzheimer’s disease (AD) were linked to impaired spontaneous retrieval.…”

The neuropsychology and neurobiology of late-onset schizophrenia and very-late-onset schizophrenia-like psychosis: A critical review

“…Some researchers have disputed the diagnostic validity of LOS or VLOSLP [12,13]. They suggest that particularly VLOSLP encompasses a prodromal phase of a neurodegenerative disease such as Alzheimer's disease (AD) with predominantly memory (and language) dysfunction [14,15], frontotemporal degeneration (FTD) with important executive dysfunction and impaired social cognition in the behavioral variant [16], or dementia with Lewy bodies (LBD) which is initially primarily characterized by perceptual and executive deficits [17] according to systematic review and/or meta-analysis. Neurodegenerative illnesses are certainly more prevalent in late life and are often accompanied by behavioral and psychological symptoms, such as depression or psychosis [18].…”

Identificação automática de unidades de informação em testes de reconto de narrativas usando métodos de similaridade semântica

“…O envelhecimento da populaçãoé uma tendência social conhecida em países desenvolvidos e que tem se tornado cada vez mais pronunciada também nos países em desenvolvimento (Fichman et al, 2011). O Brasil, por exemplo, está mudando sua pirâmide etária, segundo os censos do Instituto Brasileiro de Geografia e Estatística (IBGE) de 2000 e 2010 1 .…”