Cognitive Activities That Have Evidence Behind Them

Marcus Webb is 73 and sitting in a neurologist’s office in Atlanta for his fourteen-month follow-up. He is a retired school principal. He was diagnosed with mild cognitive impairment fourteen months ago. His neurologist prescribed donepezil, gave him a list of suggestions that included “stay socially engaged, exercise, keep your mind active,” and scheduled this appointment six months out.

In the intervening fourteen months, Marcus has been offered three brain training app subscriptions, two puzzle books, and a daily crossword from the newspaper. He tried all of them. He completed the brain training apps faithfully for four months. He does the crossword every morning with his coffee. He does not know which, if any, is doing anything measurable. His neurologist’s follow-up is the first time anyone has answered the question the brochure never asked: which of these activities has evidence behind it, and which is just satisfying?

The Evidence Hierarchy

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The word “evidence” gets used loosely in cognitive wellness marketing. Brain training apps advertise “clinically proven” benefits. Puzzle books cite “studies show” without naming the studies. The word evidence, used precisely, means something specific: randomized controlled trials comparing the intervention to an active comparator (not just a no-treatment control), measuring outcomes that transfer to real-world function (not just improvement on the trained task), with follow-up periods long enough to detect meaningful change (months or years, not weeks).

Most of what is sold as brain training does not meet these criteria. Improvement on the trained task is common, because practicing a task makes you better at that task. Transfer to real-world function, meaning that the brain training makes you better at something you did not practice, is rare. The distinction between getting better at the game and getting better at living is the distinction that matters, and it is the distinction that marketing consistently blurs.

Exercise: The Most Effective and Least Sold

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The single most robustly evidenced cognitive intervention for adults over 60 is aerobic exercise. One hundred fifty minutes per week of moderate aerobic exercise, walking briskly counts, produces measurable preservation of hippocampal volume in multiple randomized controlled trials. The hippocampus is the brain structure most directly involved in memory formation and most directly affected by Alzheimer’s pathology. Its volume loss is a primary neuroanatomical marker of disease progression.

This is not a wellness recommendation. It is an intervention with a documented mechanism. Aerobic exercise increases brain-derived neurotrophic factor (BDNF), promotes neurogenesis in the hippocampus, improves cerebrovascular function, and reduces neuroinflammation. The effect size is modest but consistent across studies, and the intervention has no significant side effects, costs nothing beyond a pair of shoes, and is available to anyone who can walk.

The exercise evidence is stronger than the evidence for any commercially available brain training product. It is also less marketable, which is why Marcus heard about three apps before anyone told him about the thirty-minute walk.

Learning Something Hard and New

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The crossword puzzle Marcus does every morning is enjoyable, mentally engaging, and builds on knowledge he already has. It is also, after thirty years of daily practice, not doing much for his cognitive reserve. The cognitive benefit of a task depends on whether the task challenges the brain to build new connections, and a practiced task that relies on stored knowledge does not challenge the brain in the way that builds new connections.

What the evidence supports is learning something genuinely new and difficult. Learning a musical instrument in adulthood produces structural brain changes visible on MRI: increased gray matter in auditory and motor cortex, strengthened connections between brain regions involved in coordinated activity. The cognitive transfer effects are documented in multiple studies. Bilingual engagement, actively maintaining and using two languages, produces a cognitive reserve effect that has been replicated across populations. Complex novel skill acquisition, learning to paint, learning to code, learning a new sport, produces transfer effects to other cognitive domains that familiar practiced tasks do not.

The common thread is novelty and difficulty. The brain builds reserve by being required to build new pathways, not by traveling familiar ones more efficiently. For Marcus, who played piano in high school and has not touched one since, relearning the instrument engages preserved procedural memory (his fingers remember patterns his conscious mind has forgotten) while demanding new learning (the pieces he never played, the theory he never studied). For the full account of what cognitive change leaves intact and why it matters, see What Persists on Blue Gray Matters.

Dual-Task Training

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The intervention with the most consistent evidence of cognitive benefit beyond what either component produces alone is dual-task training: performing a physical activity and a cognitive activity simultaneously. Walking while counting backward. Dancing while learning choreography. Swimming while solving mental arithmetic. The simultaneous demand on motor and cognitive systems produces a training effect that neither system produces alone.

Multiple studies have demonstrated that dual-task training in older adults with and without cognitive impairment produces greater improvement in attention, executive function, and gait stability than either cognitive training or physical training in isolation. The most underused intervention in cognitive care is also the one with the strongest integrated evidence, because it requires a structured program or a trainer rather than an app you can download in thirty seconds.

Community dual-task exercise classes designed for older adults are increasingly available through senior centers, YMCAs, and Parkinson’s and dementia wellness programs. Marcus’s senior center in Atlanta offers one. He did not know it existed until his neurologist mentioned it at this appointment.

The Commercial Brain Training Problem

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In 2016, the Federal Trade Commission settled with Lumosity for $2 million over unsubstantiated advertising claims. Lumosity had marketed its brain training games with claims about delaying cognitive decline and reducing Alzheimer’s risk that the evidence did not support. The games made users better at the games. The claimed transfer to real-world cognitive function had not been demonstrated.

The broader peer-reviewed literature on commercial brain training is consistent with the FTC’s assessment. Improvement on trained tasks is reliable. Transfer to untrained tasks is inconsistent. Transfer to real-world function is poorly supported for most products.

One specific exception deserves naming because the audience needs specific guidance, not a blanket dismissal. BrainHQ’s speed-of-processing training has support from the ACTIVE trial, the largest and longest randomized controlled trial of cognitive training in older adults. The ACTIVE trial demonstrated that speed-of-processing training produced real-world transfer effects including reduced automobile accident rates over a ten-year follow-up. This is one program, one type of training, one set of outcomes. It does not validate the brain training category. It validates a specific intervention that has specific evidence.

The Preserved Capacities Insight

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Marcus has mild cognitive impairment. Some of his cognitive capacities are declining. Others are preserved. His procedural memory, the memory system that stores how to do things your body has learned, is intact. His social cognition, the ability to read faces and respond to emotional cues, is strong. His musical memory, stored in brain regions among the last affected by Alzheimer’s pathology, is excellent.

A cognitive engagement plan that targets what is preserved, not only what is declining, is a more effective plan and a more humane one. The dignity test that governs this series applies here: the intervention should serve Marcus, not just the disease. Engaging his preserved strengths produces cognitive benefit, emotional engagement, and the experience of competence, all of which contribute to quality of life in ways that a declining-function-only approach does not.

Marcus’s Plan

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Marcus leaves the appointment with a specific plan. One hundred fifty minutes of walking per week, which he divides into thirty-minute sessions five days a week. A weekly piano lesson, his first in fifty years, using the procedural memory that makes relearning faster than starting from nothing. Twice-weekly dual-task exercise classes at the senior center he has driven past for six years without knowing what was inside. No new app subscriptions. The crossword stays, because he enjoys it, but it is no longer the thing he points to when someone asks what he is doing for his brain.

The plan is not a cure. There is no cognitive engagement plan that reverses mild cognitive impairment. What the plan does is give Marcus the interventions with the strongest evidence for slowing functional decline, engaging preserved capacities, and maintaining quality of life. The difference between a plan built on evidence and a plan built on marketing is the difference between walking thirty minutes a day and completing a brain game that makes you better at the brain game. Marcus has been doing the second for fourteen months. He starts the first tomorrow.