Speed of processing training delivers a groundbreaking 25% reduction in dementia risk over 20 years, proving that a modest cognitive intervention can produce remarkable long-term protection against Alzheimer's and other forms of dementia. The adaptive nature of this training — adjusting difficulty to individual performance and building unconscious skills — makes it uniquely effective compared to other cognitive approaches. This represents a major breakthrough in dementia prevention that could dramatically reduce the $600 billion annual cost burden.