Cognitive Training in the Elderly: Bottlenecks and New Avenues Nahid Zokaei, Christopher MacKellar, GiedrėČepukaitytė, Eva Zita Patai, and Anna Christina Nobre Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/29/9/1473/1786573/jocn_a_01080.pdf by MIT Libraries user on 17 May 2021 Abstract ■ Development of measures to preserve cognitive function or lack of consensus on a comprehensive assessment protocol. We even reverse cognitive decline in the ever-growing elderly pop- propose that the success of training-based therapeutics will rely Downloaded from http://direct.mit.edu/jocn/article-pdf/29/9/1473/1952866/jocn_a_01080.pdf by guest on 01 October 2021 ulation is the focus of many research and commercial efforts. on targeting specific cognitive functions, informed by compre- One such measure gaining in popularity is the development hensive and sensitive batteries that can provide a “fingerprint” of computer-based interventions that “exercise” cognitive func- of an individual’s abilities. Instead of expecting a panacea from tions. Computer-based cognitive training has the potential to be training regimens, focused and personalized training interven- specific and flexible, accommodates feedback, and is highly ac- tions that accommodate individual differences should be cessible. As in most budding fields, there are still considerable developed to redress specific patterns of deficits in cognitive inconsistencies across methodologies and results, as well as a rehabilitation, both in healthy aging and in disease. ■ INTRODUCTION population is therefore a primary focus of research Over the last century, the fields of medicine and health efforts. care have had tremendous success, increasing life expec- In the last decade, interest has been growing for devel- tancy to an average age of approximately 80 years (www. oping computer-based cognitive training interventions cdc.gov/nchs/fastats/life-expectancy.htm). Although phys- that can preserve or even improve cognition both in ical health has resulted in prolonged lifespan, preserva- the medical sector and the technology industry. These tion of cognitive health has remained a fundamental provide an alternative to pharmacological treatments challenge. Normal aging, as well as disorders associated and could be used independently or in combination with with the old age (e.g., dementias), have been associated medication. Cognitive training is characterized by several with considerable decline in fundamental cognitive abili- features, which make it a highly promising lifestyle-based ties, such as attention, working memory, long-term mem- intervention that could dramatically improve the mental ory, decision-making, and task switching, to name just a life in older adults and in patients. Numerous enterprises few (e.g., Stark, Stevenson, Wu, Rutledge, & Stark, 2015; are sprouting to develop brain training tasks that exercise Brockmole & Logie, 2013; Chowdhury et al., 2013; Peich, cognitive abilities in an analogous fashion to using phys- Husain, & Bays, 2013; Stark, Yassa, Lacy, & Stark, 2013; ical exercises for improving physical fitness and health. Zanto, Sekuler, Dube, & Gazzaley, 2013; Chowdhury, This review will take stock of the state of play on the em- Guitart-Masip, Bunzeck, Dolan, & Düzel, 2012; Smyth & pirical research that supports the development of cogni- Shanks, 2011; Zanto et al., 2011; Brockmole, Parra, Della tive training in the elderly population. We will comment Sala, & Logie, 2008; Gazzaley, Cooney, Rissman, & on success and limitations and propose key factors that D’Esposito, 2005). Importantly, cognitive decline impacts need to be considered for the field to advance. the quality of life by adversely affecting activities of daily living such as driving, shopping, or taking medication (Maki et al., 2014; Bárrios et al., 2013; Teng, Tassniyom, ADVANTAGES OF COMPUTER- & Lu, 2012; Wadley, Okonkwo, Crowe, & Ross-Meadows, BASED TRAINING 2008) as well as compromising social interactions and relations (e.g., Davies et al., 2010; Frank et al., 2006). De- There are a number of key aspects that, if well imple- veloping approaches to preserve healthy cognitive func- mented, can set computer-based cognitive training apart tion and improve the quality of life of the elderly from other medical interventions. Should they prove effective, they have the potential to transform our approach to preservation of cognitive health during normal University of Oxford aging and in disease. © 2017 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 29:9, pp. 1473–1482 doi:10.1162/jocn_a_01080 First, computer-based training can be directed to a spe- tive data. Peretz and colleagues (2011) successfully imple- cific cognitive function and thereby selectively trigger mented personalized cognitive training using the plasticity or changes in efficiency in the specific neural “CogFit” personal coach. The time spent playing the systems that support the trained cognitive function. Al- training tasks for each participant was determined by per- though arguably not to the same extent as in younger in- formance in a battery of baseline cognitive tests. Com- dividuals, the aging brain retains the capacity for plasticity pared with a group of individuals playing conventional (Li et al., 2008; Craik & Bialystok, 2006; Li, Brehmer, video games (e.g., Tetris, Puzzled, or Snake), personal- Shing, Werkle-Bergner, & Lindenberger, 2006), and thus, ized cognitive training yielded superior training benefits. Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/29/9/1473/1786573/jocn_a_01080.pdf by MIT Libraries user on 17 May 2021 it is possible to drive plasticity and improvements in effi- Similarly, one can incorporate immediate quantitative ciency in selective neural systems. The natural and inher- feedback, modifying the task demands as the training ent ability of cognitive training to target specific neural evolves to optimize the regimen for each individual. Al- systems is in contrast to pharmacological medications, though in principle it is possible to regulate dosage in which tend to act in a diffuse manner in the brain to in- pharmacological treatments, obtaining accurate and fluence chemicals involved in widespread neurotransmit- quantitative feedback to guide dosing can be highly chal- ter or neuromodulator systems linked to a deficit or lenging. In other words, cognitive training tasks can Downloaded from http://direct.mit.edu/jocn/article-pdf/29/9/1473/1952866/jocn_a_01080.pdf by guest on 01 October 2021 disorder. Typically, any given neurotransmitter or neuro- change flexibly based on the participant’s performance modulator is involved in many neural systems and cogni- to ensure maximum gain. This homeostatic dynamic ad- tive functions. As a consequence, treatment effects often justment based on continual feedback is referred to as a entail other, unplanned and potentially undesirable side closed-loop system (Mishra & Gazzaley, 2015). A few effects. Cognitive interventions therefore naturally pro- studies have indeed shown benefits of closed-loop train- vide a superior level of specificity and neural targeting, ing tasks that adjust parameters adaptively according to which pharmacological treatments struggle to achieve. participants’ performance (e.g., Mishra, de Villers-Sidani, An example of the neural specific cognitive training Merzenich, & Gazzaley, 2014; Anguera et al., 2013; Smith comes from a recent study that trained the ability to sup- et al., 2009; Mahncke et al., 2006). For example, Anguera press distraction in older human participants and rats, a and colleagues (2013) trained older participants on a function often reported to be impaired in the elderly custom-designed adaptive multitasking video game, (Mishra, de Villers-Sidani, Merzenich, & Gazzaley, 2014). NeuroRacer, designed to enhance the ability of individ- The task involved identifying target tones presented in- uals to multitask effectively in the context of driving while frequently among other distracting tones. In the main having to respond appropriately to attention-grabbing distractor suppression training task, distractors became transient events. The difficulty of the task in the adaptive progressively more similar to the target tone in frequency. group was modified after each run according to partici- The task required increasingly refined perceptual dis- pant’s performance and ensured continuous challenge crimination and specifically focused adaptive training in and high level of engagement and motivation. The results the ability to recognize and ignore distractors. With task showed a reduction in multitasking costs, as well as en- progression, the distractor became increasingly more hanced performance in tasks that measured attention similar to the target stimuli. As a stringent control, a dif- and working memory following training. Training bene- ferent group of participants was also required to discrimi- fits were observed only in the multitasking adaptive nate targets amidst distracting tones in a similar training group compared with a group of individuals performing environment. In contrast to the previous group, the adap- each of the tasks in isolation. However, it is important to tive aspect of the task focused on recognizing and selec- note that, because of the nature of the control task, ting the target stimuli. Over the task, the target became participants who performed the multitasking procedure progressively more similar to the distractors. Of these had twice as many trials