Mrs. A said she would have involuntary orgasms that suddenly started in her left foot and weren't connected to sexual arousal.
The sensation would travel up her leg to her vagina and spark what felt like the kind of orgasm achieved during sex, the report said.
Much to her embarrassment, this would happen five or six times a day.
The phenomenon started after Mrs. A spent weeks in intensive care, during which she fell into a coma, for a sepsis infection.
When she came out of the coma, the woman complained of tingling and burning feelings in her left foot.
The nerves that register sensory information from the foot and the vagina both enter the spinal cord at the same level, and study author Dr. Marcel D. Waldinger and his team believe that Mrs. A's brain could no longer differentiate which sensations started in her left foot and which came from her genitals.
As a result, her brain "decided that every stimulus coming from the foot was actually coming from the vagina," he said.
The study is published in the Journal of Sexual Medicine.