Bernard Stoneham signed up for the Mindme GPS locating device after his wife Gill, who has dementia, got disorientated near their home in Fishbourne, Chichester.
He says the device alerted him when his wife got lost while she was walking the couple's dog and without it "I wouldn’t have known where to look for her."
Mr Stoneham said: "If Gill gets into difficulty, she can speak to the staff through the device. They can then contact me or other nominated persons with her position.
"All I can say is how grateful I am to have had the use of this piece of hi-tech wizardry and what a difference it makes at this difficult time in our lives."
More top news
IKEA is recalling almost 36 million chests and dressers in the US and Canada after the deaths of three children.
Toyota is recalling 1.43 million cars for an airbag inflator defect.
Prime Minister insists the UK will maintain a strong relationship with Europe especially on trade and security, even after it leaves the EU.