RESUMO
Working memory abilities significantly decrease with advancing age; hence, the search for factors that may increase or mitigate this decline is critical. Several factors have been identified that influence working memory; however, their effects have been mainly assessed separately and rarely together with other factors in the same sample. We examined 120 variables to search for factors that jointly act as mediators of working memory decay across the adult life span. A sample of 1652 healthy adults was assessed in spatial and verbal working memory domains. Structural equation modeling analyses were conducted to search for potential mediators that intervened between age and working memory. Only 14 and 10 variables reliably mediated spatial and verbal working memory, respectively. Factors from several domains remained in the models, such as individual characteristics, physiological traits, consumption habits, and regular activities. These factors are sufficiently powerful to influence working memory decline when they jointly interact, as in everyday living.
Assuntos
Memória de Curto Prazo/fisiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Escolaridade , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Análise de Classes Latentes , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Comportamento Social , Adulto JovemRESUMO
The ability to remember the details of our own experiences declines gradually as we get old. The reason for this decay has been attributed to several factors besides age, such as education, nutrient intake and health status. However, the influence of these factors has mainly been examined individually and rarely together. Here we identify those factors that jointly act as mediators of episodic memory decay across the adult life span. We examined source memory in a lifespan sample of 1557 healthy adults. A total of 70 physical, biological and lifestyle variables were measured and introduced into a structural equation model as potential mediators that intervene between age and source memory. Only 14 mediator variables reliably mediated source memory decay; notably, eight of these variables have an effect on the cardiovascular system. The model unequivocally highlights that the mediators that may impair cardiovascular functioning also impact brain resources involved in episodic memory. We identified the factors that are relevant to episodic memory decline when they interact together as occurs in real life.
Assuntos
Envelhecimento Cognitivo , Estilo de Vida , Transtornos da Memória/fisiopatologia , Memória Episódica , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Rememoração Mental , México , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
Event-related potentials (ERPs) were recorded in young (21-27 years old), middle-aged (50-57 years old) and older adults (70-77 years old) to determine whether the decline in source memory that occurs with advancing age coincides with contemporaneous neurophysiological changes. Source memory for the spatial location (quadrant on the screen) of images presented during encoding was examined. The images were shown in the center of the screen during the retrieval task. Retrieval success for source information was characterized by different scalp topographies at frontal electrode sites in young adults relative to middle-aged and older adults. The right frontal effect during unsuccessful retrieval attempts showed amplitude and latency differences across age groups and was related to the ability to discriminate between old and new images only in young adults. These results suggest that the neural correlates of the retrieval success and attempt were affected by age and these effects were present by middle-age.
Assuntos
Envelhecimento/fisiologia , Potenciais Evocados/fisiologia , Memória/fisiologia , Rememoração Mental/fisiologia , Tempo de Reação/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Fatores Etários , Idoso , Análise de Variância , Mapeamento Encefálico , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
Source memory, the ability to remember contextual information present at the moment an event occurs, declines gradually during normal aging. The present study addressed whether source memory decline is related to changes in neural activity during encoding across age. Event-related potentials (ERPs) were recorded in three groups of 14 subjects each: young (21-26 years), middle-aged (50-55 years) and older adults (70-77 years). ERPs were recorded while the subjects performed a natural/artificial judgment on images of common objects that were presented randomly in one of the quadrants of the screen (encoding phase). At retrieval, old images mixed with new ones were presented at the center of the screen and the subjects judged whether each image was new or old and, if old, were asked to indicate at which position of the screen the image was presented in the encoding session. The neurophysiological activity recorded during encoding was segregated for the study items according to whether their context was correctly retrieved or not, so as to search for subsequent memory effects (SME). These effects, which consisted of larger amplitude for items subsequently attracting a correct source judgment than an incorrect one, were observed in the three groups, but their onset was delayed across the age groups. The amplitude of the SME was similar across age groups at the frontal and central electrode sites, but was manifested more at the posterior sites in middle-aged and older adults, suggesting that source memory decline may be related to less efficient encoding mechanisms.