But this is believed to be the first time such a device has been suggested to monitor patients with cognitive impairments such as dementia.
The activPAL tracker, which is strapped to the bottom of the leg, measures all movement from side to side, up and down, and backwards and forwards.
It sends the information back to a computer which analyses it to provide details about how long a patient spends sitting, how active they are, when they eat, whether they are going to bed at the right time and how many times they get up in the night.
Speaking at the Dementia Congress 2016 in Brighton, Dr Pickford said he was inspired to research the subject after caring for his grandmother who had dementia.
"We didn't really understand at the time what was going on," he added. "If we had little bits of data and could gather all that together to help explain, it would have made it so much easier for us."
But other experts raised questions over whether the practice was ethical. Dementia specialist consultant Hilary Woodhead said: "There are so many issues around consent and permission. What concerns me is things can be shared so freely."