Across a human life span, changes in cognition are expected to occur as individuals grow older. Most of the changes experienced in aging are related to a decline in fluid intelligence, defined as the capacity to solve problems and articulate ideas, to navigate new situations, and to acquire knowledge. On the other hand, crystallized intelligence, defined as acquired general knowledge (e.g., vocabulary and procedures), is preserved for longer periods [1]. Moreover, during aging, other neuropsychological abilities are known to decline, such as attention, working memory, and episodic memory [2].
Some faculties related to crystalized intelligence might increase over time, such as general knowledge and wisdom [2]. And this amount of additional information, when integrated to crystalized intelligence, can become an advantage. On the other hand, the attentional and working memory decline, related to fluid intelligence, makes it more challenging to solve problems and articulate ideas.
Image studies have shown atrophy in white matter and gray matter, synaptic degeneration, blood flow reduction, and neurochemical alterations [3]. Those changes are more prominent at the prefrontal cortex; however, older adults that maintain their performance on pair with young adults tend to increase activation in order to keep performance, and this increased activation creates more hemispheric asymmetry in elderly than in youth. Consequently, Cabeza et al. [3] proposed a model called hemispheric asymmetry reduction in older adults (HAROLD), in which an older adult tends to compensate the neuropsychological decline with higher activation at the frontal cortex.
Cognitive training with the intent of increasing abilities and enriching neural networks has been a tendency since the 1960s, when the first behavior protocols sought to train memory using strategies of “chunking” (grouping information bits to be stored as single concepts) and using metacognitive strategies for dealing with complex information. Those strategies to enhance memory capacity were based in conscious and external mechanisms [4].
In the late 1980s, Baltes et al. [1] have demonstrated that older adults may benefit from cognitive training by creating reserve and increasing their performance in cognitive tasks. Afterward, many studies and protocols have been developed to provide cognitive training for the aging population. Some of them are related to strategy making, where the individual has to identify a difficulty level and naturally self-adjust. Reasoning, problem-solving, and goal management also have been used to enhance cognition. Multimodal approaches have also been tried, in which an unrelated task is trained in order to provide skill transfer (e.g., video games or cardiovascular exercise). Lastly, there is the process training, which includes a set of cognitive tasks to be trained heavily and specifically [5].
Recent technological developments have supported new forms of training, nowadays using tools such as computer games to enhance cognitive capacity [6] or neurofeedback brain training. Therefore, cognitive training has increasingly become a potential tool to aid healthy individuals with cognitive aging as well as patients with cognitive decline.
Training working memory—a component of the executive function—is one of the tendencies to enhance cognition and enrich neural networks [7], especially to form cognitive and neuronal reserve in aging people.
Working memory is a neuropsychological function that allow us to deal with daily information, such as keeping in mind a telephone number while dialing, organizing the mental operations to accomplish a task in hands, or listening and remembering a sequence of facts in a story in order to understand it.
Working memory can be described as a multimodal system, and Baddeley [11] defines it as a system of temporary storage under attentional control, encompassing our ability for complex thought and comprising diverse neuropsychological constructs. The abilities which working memory allows, although natural to most humans, require a complex cognitive model and several brain areas.
For about 50 years, working memory has been studied to define its main properties. The model adopted in this chapter is based on a construct of Baddeley and Hitch [12], in which working memory orchestrates information received through four components, one attentional and three mnemonic (Figure 1).
According to the Baddeley and Hitch model [12], the first component of the working memory is the central executive: an attentional control system that is connected to other three storage systems—the phonological loop, visuospatial sketchpad, and the episodic buffer. The episodic buffer component was included posteriorly [13] and all the components work interconnectedly.
Studies have demonstrated positive neurophysiological and cognitive effects related to working memory and attention. Therefore, these results suggest that neurofeedback might be an important tool to increase cognitive reserve at aging.
Since i) neurofeedback is an accessible technique that provides operant conditioning and cognitive self-perception. and ii) aging individuals experience decline in their neuropsychological abilities, therefore techniques and tools that favor the formation of cognitive reserve have become of fundamental importance to society as the increase in life expectancy leads to a longer period in this later stage of life.
This blog is edited from “Neurofeedback Training on Aging: Prospects on Maintaining Cognitive Reserve” by Valeska Kouzak Campos da Paz and Carlos Tomaz
Oksana Pueschel 