How far do lost people with dementia wander, according to Robert Koester on Bear Brook?

Search-and-rescue researcher Robert Koester, who has searched for missing people since 1981, told Jason Moon that for a person with dementia on foot in temperate, mountainous wilderness, 50% are found within half a mile and 75% within 1.2 miles of where they were last seen. Children aged seven to nine typically travel farther. He says a 1.2-mile radius could be searched in a few days with at least 24 trained searchers and some dogs.

• Koester describes two kinds of dementia wandering: heading for a specific place from the past, and, as the disease advances, walking until stuck.
• Thick vegetation, streams, ponds and fences are the obstacles that typically stop such walkers.
• By Koester's data about a quarter of lost people with dementia die within the first 24 hours.

▸In their words

“And for 75% of the subjects, I only have to go out to 1.2 miles.” Robert Koester · at 37:35 — open in the transcript →

Source: our own transcription of the episode. The full conversation is on Bear Brook (2026-11-04). Read the whole episode summary →

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