The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

Abstract

The lifelong acquisition of cognitive skills shapes the biology of the brain. However, there are critical periods for the best use of the brain to process the acquired information.ObjectivesTo discuss the critical period of cognitive acquisition, the concept of cognitive reserve and the HAROLD (Hemispheric Asymmetry Reduction in Older adults) model.MethodsSeven women who learned how to read and to write after the age of 50 (ex-illiterates) and five women with 10 years of regular schooling (controls) were submitted to a language recognition test while brain activity was being recorded using magnetoencephalography. Spoken words were delivered binaurally via two plastic tubs terminating in ear inserts, and recordings were made with a whole head magnetometer consisting of 148 magnetometer coils.ResultsBoth groups performed similarly on the task of identifying target words. Analysis of the number of sources of activity in the left and right hemispheres revealed significant differences between the two groups, showing that ex-illiterate subjects exhibited less brain functional asymmetry during the language task.ConclusionsThese results should be interpreted with caution because the groups were small. However, these findings reinforce the concept that poorly educated subjects tend to use the brain for information processing in a different way to subjects with a high educational level or who were schooled at the regular time. Finally, the recruiting of both hemispheres to tackle the language recognition test occurred to a greater degree in the ex-illiterate group where this can be interpreted as a sign of difficulty performing the task.

Efeito de Idade e Escolaridade no Instrumento de Avaliação Neuropsicológica Breve NEUPSILIN

“…Assim, o clínico deve sempre comparar os resultados do paciente com dados normativos por faixa etária e de escolaridade para evitar um diagnóstico errôneo. Estas são variáveis que mostram influência de acordo com as teorias do envelhecimento cerebral (Cabeza, 2004;Dolcos & Cabeza, 2002, Grady et al, 1994 e da reserva cognitiva proporcionada pela estimulação do ambiente (Nunes et al, 2009). A educação não só protegeria dos efeitos do envelhecimento normal, como também atenuaria a manifestação clínica de alterações neurológicas como as demências (Katzman, 1993).…”

“…Explicações teóricas sobre o efeito da escolaridade nas funções neuropsicológicas sugerem que há diferenças nas conexões cerebrais entre grupos de pessoas alfabetizadas e não alfabetizados (Castro-Caldas, 2004), estando o alto nível educacional relacionado com reserva da capacidade neuronal, maior quantidade de sinapses e vascularização cerebral (Valenzuela & Sachdev, 2006). Ainda, na hipótese da reserva cognitiva, a escolaridade é considerada um dos fatores protetores contra o declínio cognitivo (Nunes, Castro-Caldas, Del Rio, Maestú, & Ortiz, 2009). Assim, sugere-se que pessoas pouco escolarizadas tendem a processar informações de forma diferente de pessoas com alto nível de escolarização, ou que foram escolarizadas na época esperada (Nunes et al, 2009), devido a diferenças em suas conexões cerebrais, desenvolvidas de acordo com a estimulação do ambiente.…”

“…Ainda, na hipótese da reserva cognitiva, a escolaridade é considerada um dos fatores protetores contra o declínio cognitivo (Nunes, Castro-Caldas, Del Rio, Maestú, & Ortiz, 2009). Assim, sugere-se que pessoas pouco escolarizadas tendem a processar informações de forma diferente de pessoas com alto nível de escolarização, ou que foram escolarizadas na época esperada (Nunes et al, 2009), devido a diferenças em suas conexões cerebrais, desenvolvidas de acordo com a estimulação do ambiente.…”

Theoretical, behavioral and neuroimage evidence on discourse processing aging

“…Another model that aims to explain the underlying brain circuitry of cognition and performance in aging, the HAROLD model, posits that brain activity appears to be less lateralized in older adults than in younger ones (Cabeza, Anderson, Locantore, & McIntosh, 2002). A growing concern has been the role of each cerebral hemisphere in the processing of language components in aging, and a combination of imaging and behavioral studies has gradually been designed to investigate this issue (Ansaldo, Monchi, Roy, & Doyon, 2005;Nunes, Castro-Caldas, Del Rio, Maestú, & Ortiz, 2009). The assumption of a hemispheric asymmetry reduction in older adults with high performance when computing cognitive tasks is supported by functional neuroimaging investigations and studies on episodic and semantic memory, working memory capacity, perception, and inhibitory control Cabeza et al, 2004).…”

New approaches to neglected phenomena

“…An intriguing observation was that although no difference between individuals with low or high educational level was seen on cognitive tests, differences were in cerebral processing were evident on magnetoencephalography. 1 This group of researchers led by Alexandre Castro-Caldas, of the University of Lisbon, Portugal, has been investigating the effects of illiteracy and low educational level on the brain by means of more current and sophisticated methods of analysis of the functional organization of the central nervous system.…”