To the casual onlooker, Eddie the Affenpinscher may look like any other lap dog, but to his owner Eileen Reed he is literally a lifesaver.

The pocket-sized pet ranks among a select band of Medical Detection Dogs in the South West by helping to alert his diabetic owner to a sudden drop in blood sugar levels.

Now the crucial but little-known role played by dogs which are trained to warn their owners to potentially life-threatening medical crises is being highlighted in the Westcountry by volunteers trying to raise the profile of the charity.

Mrs Reed, who lives in Exmouth, said Eddie had made a "huge difference" to the way in which she manages her condition, alerting her to the onset of a hypoglycaemic attack.

She said: "I use an electric scooter and having Eddie has made me much more confident to go out without being worried about having a 'hypo'.

"It's like he's got a sixth sense. If something is wrong he picks up on it so quickly and will start to pull at my leg or jump up and lick my face."

It is thought the dogs detect subtle changes in smell when an attack is imminent and have been used to help not just diabetics but those with the sleep disorder narcolepsy and Addison's disease, a chronic hormonal problem which can lead to seizures.

Mrs Reed, 58, who has been diabetic since childhood, said her medical condition nosedived after losing her husband Terry in 2009.

She said: "He was excellent at picking up my low sugars but after he died, I had to call the paramedics out because I'd have sudden attacks.

"We've all heard of Guide Dogs for the Blind but I didn't know there were dogs that could help with my situation.

"Eddie came with basic training and it did take him a while to really identify the scent I was giving off when I was becoming unwell, but then something just clicked.

"Sometimes I know when my blood sugars are dropping but it can happen quite suddenly and then he starts jumping up at me to let me know. It's lovely when I go out now because people want to stop and talk to me about him. He really has made such a difference."

Volunteer Tim Sutton-Woodhouse, from Lifton, who raises awareness of the charity Medical Detection Dogs, said: "The simple use of a dog's wonderful sense of smell has and is saving lives by alerting to changes in body smells.

"We train dogs to assist people with life-threatening health conditions such as diabetes, Addison's disease, narcolepsy, and some allergies. The dogs alert to give them greater independence and save lives on a daily basis."

It costs several hundred pounds to train each dog, but they can reduce the cost of NHS care and hospital admissions. Research is being carried out at Cardiff and Vale NHS Trust and Bristol University to try and establish exactly how the dogs detect the onset of an attack and promising early work has also been done to see whether dogs can be used in the detection of some cancers.

A talk and video on the role of Medical Detection Dogs and how to volunteer will be held at the Lifton Hall Hotel, at Lifton, West Devon, on January 26, at 7.30pm.