My mother started an app after reading that bilingualism delays dementia by several years, and now treats a fifteen minute streak as medical insurance. I want her to keep going because she enjoys it, but I do not want to keep repeating something that turns out to rest on one contested study. Has anyone actually read past the headlines on this, and what does the evidence look like underneath?
Whether or not it delays anything, a weekly conversation class gets her out of the house, talking to people she would not otherwise meet, and doing something hard in front of others. That part is not contested by anyone. If you want to steer her, steer her from the app towards a class.
I will defend the idea slightly. The cognitive reserve framing is not exotic - the argument is that varied, effortful mental activity builds redundancy, and language learning is unusually effortful across memory, attention and hearing all at once. That is plausible without being proven, and it is a long way from the claim on the app's front page. I would tell your mother it might help, nobody knows, and it is a good use of an hour either way.
No argument with that version. Might help, plausible mechanism, unproven at the level of any individual person is exactly where I would put it too. My objection is only to the number of years being quoted as if it were a dosage.
I repeated the several years figure at work once and got taken apart by someone who had read the follow-ups, which was embarrassing and educational. What I learned: whenever a health claim comes with a clean round number attached, the number is usually the part that did not survive replication.
My grandmother did evening Italian classes for eleven years and what visibly changed was her social life, not her memory. She had four people to ring on a Sunday who she met in that room. I would not sell the health angle to your mother at all - sell the room full of people.
@bobbin_bind · 4mo ago · 2 replies
The claim you are thinking of comes from retrospective clinic studies of people who had been bilingual for their entire lives, comparing the age at which symptoms were first reported. That is a very different population from someone starting an app at 65, and the finding has been argued about hard - some prospective cohorts have not reproduced it, and the confounds are ugly, because lifelong bilingualism in many samples correlates with migration, education and social network size, all of which independently affect when people present at a clinic. My honest reading is that it is a live scientific question rather than a settled fact, and that nothing in it supports a claim about starting late. Also, and not as a downer: if she has an actual memory worry, that is a GP conversation, not a study one.
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@proof_pilar · 4mo ago
The age-at-presentation detail matters more than people realise. If one group brings a relative to a clinic later for social reasons, you measure a delay that has nothing to do with the brain.
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