Alzheimer’s disease and related dementias were less likely among adults who completed cognitive speed training with booster sessions, according to data published in Alzheimer’s & Dementia: Translational Research & Clinical Interventions.
Memory and reasoning training did not yield similar effects, Marilyn S. Albert, PhD, director of cognitive neuroscience, department of neurology, Johns Hopkins School of Medicine, and colleagues wrote.
Although prior studies indicate that the cognitive function of healthy older adults may improve with training, the researchers said, the effect of these interventions on rates of cognitive decline and risks for Alzheimer’s disease and related dementias remained debatable.
“When the study was started over 20 years ago, the goal was to see whether or not, if you did various kinds of cognitive training, it might generalize to people being more independent in their daily lives,” Albert told Healio. “Subsequently, the investigators decided they would see if this had an impact on dementia.”
Training interventions
The randomized, controlled Advanced Cognitive Training for Independent and Vital Elderly or ACTIVE study followed 2,021 healthy adults (76% women, 70% white) aged 65 to 94 years (average age at enrollment, 73.6 years) for up to 20 years (77% mortality; average age at death, 83.9 years) based on Medicare claims from 1999 to 2019.
Participants were divided into three intervention arms and a control group. Each intervention included up to 10 training sessions of 60 to 75 minutes each, using small groups, scheduled over 5 to 6 weeks. The control group (n = 491) did not have any contact.
The first intervention (n = 512) focused on cognitive processing speed via visual search by tasking participants with switching their attention between two types of visual information on a computer screen that grew more complex, using the Double Decision task in the computerized BrainHQ suite of cognitive exercises from Posit Science.
With a focus on memory, the second intervention (n = 516) provided instruction in mnemonic strategies and allowed participants to practice them by targeting verbal episodic memory.
The third intervention (n = 502) involved reasoning training and aimed to improve participants’ problem-solving abilities by presenting problems with a serial pattern.
“What the participants were asked to do in the memory and the reasoning training was to learn different strategies about how you might improve your memory, or how you might improve your reasoning ability, so that you could manage better on a daily basis in tasks that involved that,” Albert said. “The speed training was quite different.”
Booster training, including up to four sessions of 75 minutes each, followed at 11 months and 35 months after baseline for participants who completed at least eight of the 10 initial sessions, with additional randomization.
Rates of Alzheimer’s disease or a related dementia diagnosis during the follow-up included 48.7% of the control group, 43.6% of the speed group, 44.8% of the memory group and 44.4% of the reasoning group. The researchers did not find that these differences were statistically significant.
Among participants who had cognitive processing speed training, unadjusted hazard ratios for Alzheimer’s disease and related dementias compared with the control group included 0.75 (95% CI, 0.59-0.93) with booster training and 0.97 (95% CI, 0.78-1.21) with no booster training.
Similarly, unadjusted hazard ratios included 0.87 (95% CI, 0.7-1.08) with a booster and 0.85 (95% CI, 0.68-1.07) without a booster for the memory group as well as 0.79 (95% CI, 0.63-0.98) with a booster and 0.97 (95% CI, 0.77-1.23) without a booster for the reasoning group, both compared with the control group.
The researchers did not find these differences between the booster and non-booster groups to be statistically significant, nor did they find that the memory and reasoning interventions had a statistically significant benefit on risks for Alzheimer’s disease or related dementias.
Also, the researchers did not find age to have a significant effect on risks for Alzheimer’s disease or related dementias in any of the intervention groups, although there was a trend for lower risks among younger participants in the memory group.
Specifically, these hazard ratios included 0.69 (95% CI, 0.46-1.02) for those aged 65 to 69 years and 0.73 (95% CI, 0.51 to 1.05) for those aged 70 to 74 years, compared with the control group.
Next steps
Based on these findings, the researchers said that risks for Alzheimer’s disease and related dementias were statistically significantly lower for individuals who completed the intervention for cognitive processing speed including its booster sessions.
The researchers considered the impact of booster training in the speed group may be a dose effect, with better outcomes following more training. They also noted how the difficulty of the tasks increased as the participant’s abilities improved so that the individual was pushed to do as well as possible.
“For the speed training, they were asked to do various tasks on a computer screen,” Albert said. “Nobody was given any instructions about how to do it, so they just tried to do it better. And if they did it well, it actually got harder, and if they had trouble, it got easier.”
Albert called this implicit learning, which involves different parts of the brain, compared with situations where individuals receive explicit instructions, such as the memory and reasoning tasks.
“We do not know what changes in the brain may underlie this lower risk for dementia. One guess is that there was improved brain connectivity from the initial task, and when they had the booster sessions, that was strengthened,” Albert told Healio. “It reinforced what we would call brain reserve, and that served as some sort of buffer to reduce the risk of dementia.”
Albert also said that physicians could encourage patients at risk for poor cognitive outcomes to use Double Decision, which pushes them to do well.
She said the researchers will next explore the mechanisms behind the gains yielded by the cognitive processing speed tests.
“People were randomly assigned to these groups, and all the time they were likely doing what lots of people do. They were doing crossword puzzles. They were being physically active. They were controlling vascular risk,” she said.
“These benefits from the cognitive training were over and above whatever people were doing in their daily lives,” she added. “So, if we could understand the mechanisms better, maybe we could design better tasks.”