Tracking devices for people suffering from dementia could benefit both them and their carers, an expert has argued.
Dr Rupert McShane, an NHS trust psychiatrist, said the technology could provide patients with more freedom because they would be able to go out safely.
Dr McShane told BBC Radio Five Live: "About 30% of people with dementia get lost at some point, and about 25% of them are locked into their houses by worried relatives.
"With the development of GPS technology, we think people with dementia might have more freedom to go out and they might be safer if they do go out, if it's possible to know where they are if they get lost."
He has fitted 20 patients with pocket GPS devices as part of a two-year trial at the Oxfordshire and Buckinghamshire Mental Health Trust. The movements of the patients can be monitored on a map via a secure website. A carer can also be alerted by a phone call or text if the wearer goes outside a specific area.
In April 2007, the then Science Minister Malcolm Wicks was criticised for suggesting dementia patients could be monitored with GPS devices, but the Alzheimer's Society backed the idea later that year.
Its chief executive Neil Hunt said it "could offer benefits to people with dementia and their carers".