The gadget switches off a device in Rita Carlisle's brain

Rita Carlisle, 53, from Knaphill, Surrey, suffers from a condition called essential tremor.

The stolen remote control gadget sends out pulses to calm the condition and can be switched off so she can rest.

Ms Carlisle, who now struggles to sleep, was carrying the device and £600 cash in a handbag which was stolen in Farnborough, Hants, on 23 December.

Christmas 'ruined'

She said: "I'm extremely tired, I'm getting three to four hours' sleep a night, I can't turn the machine off.

"I had my second operation on 13 December and it was my first outing after leaving hospital.

"I just wish the people who stole the machine would give it back.

"They have totally ruined Christmas and the New Year. There was £600 in my bag as well so they have had a good Christmas out of me."

Ms Carlisle says she is hopeful, but not certain, that the hospital caring for her - the National Hospital for Neurology and Neurosurgery in central London - will be able to replace the device.

Police appeal

It was inside a grey and black canvas pouch, about the size of a pencil case.

The box, made by Medtronic, had four grey buttons and two blue buttons on it and has the serial number 7436.

Hampshire Police appealed for the thief to let them know where it is.

A spokesman said: "It would be of little use to anyone else."

The handbag was stolen at Asda supermarket in Farnborough.