Olivier Le Bon of the Universite Libre de Bruxelles, Hopital Tivoli, Laboratoire de recherches psychiatriques ULB, in La Louviere, Belgium, and Paul Linkowski of the Universite Libre de Bruxelles, Hopital Erasme, Laboratoire de recherches psychiatriques ULB, Bruxelles, said their 35-year-old patient suffered from severe excessive daytime sleepiness.
She suffered sleep attacks up to six times a day and sometimes slept up to 16 hours a day, which limited her use of public transport. She usually fell asleep within a few minutes of sitting down and slept through her station.
Medication had a limited effect, so the patient was put in contact with a charity that provides trained dogs for people with visual or hearing impairment.
The study, published in the British Medical Journal, said a therapy dog was first trained to wake the patient in the morning at the sound of an alarm clock, even if this sometimes required 30 minutes of gentle biting, the researchers said.
The dog then learned to wake the patient at the sound of a cellphone ringing and eventually he learned to wake her up, if necessary, at every metro, tram or bus station.
"This animal companion allowed our patient to move around the city efficiently and carry on a social life," the study author said in a statement.