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Attention and memory components in every-day cognitive problems in aging

Periodic Reporting for period 2 - MEMORAGE (Attention and memory components in every-day cognitive problems in aging)

Reporting period: 2018-09-01 to 2019-08-31

What is the problem/issue being addressed?
While basic research has revealed essential knowledge on age-related cognitive and neuronal changes, the correlation between laboratory task performance, brain alterations, and experienced difficulties in daily life is imperfect. Presumably, laboratory tasks, while optimized to isolate cognitive processing components, are too simplified to depict the complexity of cognitive facets we find real-world tasks. To achieve a better mechanistic understanding of age-related cognitive changes, we need new paradigms for cognitive research and neuropsychological assessment, which allow measuring the complex dynamics of real-world tasks.


Why is it important for society?
Many older individuals experience age-related cognitive decline in their every-day tasks. Cognitive frailty affects elderly’s independence, quality of life, and need for care. Understanding and counteracting cognitive difficulties in older age is therefore of both societal and economical interest.

What are the overall objectives?
The aim of this project is to develop novel search tasks, which are experimentally well-controlled on the one hand and share important features with real-world tasks on the other. These search tasks permit quantifying cognitive abilities in older age with higher ecological validity. By combining the behavioral search tasks with measures of brain activity, we further identify the neural underpinnings of functional preservation and decline during aging. Our results will be integrated in and extend the current neuro-cognitive aging theories and advance the development of neuropsychological assessment procedures.

Conclusions:
Our newly developed tasks demonstrate that attention and memory functions are largely unaffected by aging in complex experimental tasks. This result stands in contrast to current theories of cognitive aging, which propose specific age deficits in attention and memory functions. However, we show that age differences can arise from differences in learning and strategies applied during search. Our new findings are encouraging, as they suggest that, under task conditions that resemble even complex real-world searches, age deficits can be reduced or even absent.
In course of the project, we developed “extended” hybrid (visual and memory) search and foraging tasks to measure cognitive performance in healthy older adults. In visual search tasks, observers look for a target item among distractor items. For example, where is the coffee maker in the kitchen? In hybrid search, observers search for any of several targets. For example, look for coffee makers, cups, and sugar in this kitchen. Foraging tasks involve collecting multiple instances of targets. For example, collecting the berries from the bush. Finally, hybrid foraging involves collecting multiple instances of several types of target. For example, a child might pick all the raisins, nuts, and seeds out of his muesli. In the final period, paradigms were adapted to allow measuring neural activity during extended search tasks. Other than simplified standard laboratory search paradigms, which are made of brief trial structures and abstract stimulus material, these extended search tasks are more complex, extend over time, and use realistic image material – thus, are more akin to real-world searches. The task structure and eclectic analysis of the collected data allowed us to look at adult age differences in multiple cognitive components (attention, memory, strategic decisions) embedded in these extended search tasks.

Overview of the results and their exploitation and dissemination:
Different from many previous aging studies that used simple, standard experimental tasks, in several experiments, we showed that in hybrid search tasks attention and memory processes in older adults are largely preserved, apart from generalized slowing. Only when the hybrid task embedded learning of sequential information, age differences were observed under high memory load. The hybrid foraging tasks confirmed preserved attention and memory functions in older age. In addition, here, we found that older adults search less efficient than younger adults because they adopt an exploitative, conservative search strategy, that is sub-optimal in terms of maximizing input per time. This result was replicated under conditions with varying prevalence and value of search targets. Our results have been presented on international conferences and are published or are under review in scientific journals.
With our first series of experiments, we succeeded to decompose and measure preserved functions and those affected by aging within complex search tasks. A very interesting and encouraging result was that hybrid search behavior was well-preserved in older observers. Besides some general slowing, older observers did not have problems searching for any of up to 64(!) items that they held in memory. This finding is relevant to advance neuropsychological understanding and assessment of age-related (and potentially other disease- related) changes in cognitive functioning. It suggests that the simplification of task structure and stimulus material used in most conventional tests may overestimate age-related deficits in more natural searches. Extended search tasks may therefore be a more appropriate “baseline” measure of cognitive abilities in healthy aging and could be particularly suited to differentiate between normal aging, subtle/early, and severe, clinically-relevant cognitive decline. Thus, in the future, the clinical relevance could now be tested by assessing individuals who report subjective memory decline and patients diagnosed with mild cognitive impairment, which is associated with memory problems and often proceeds to Alzheimer’s disease.
Another further prospect is to identify neural correlates of age differences in hybrid search by combining experimental tasks with EEG. Several EEG-compatible paradigms have already been developed in the course of the project. In younger adults, using these paradigms, we identified distinct event-related potentials (ERPs) in the EEG that mark the involvement of working memory and long-term memory processes involved in hybrid search. In the future, we will collect data of older sample groups and expect to find a stronger ERPs indicative of compensatory activity in high-performing older adults. This will contribute to the understanding of the neuro-cognitive mechanisms of cognitive reserve and it's relevance for important daily activities.
Together, the projects results advance our understanding of cognitive health in older age and the development of better neuropsychological assessment tools to measure cognitive functions in the elderly. Understanding and measuring cognitive decline and preservation in older adults is relevant, as cognitive frailty in aging reduces older adults’ fitness for work and increases their need for care, thus is both a personal and socio-economic challenge of the aging EU society.
Overview of Task and Results