He tried the same with the hiccupping patient and it worked. He then published his paper in 1988 “Termination of intractable hiccups with digital rectal massage” for which he won an IgNobel prize.
The variety in causes means that for persistent and intractable hiccups, you're better off ... One scientist who led a review on hiccup treatment swears by holding your breath on the exhale.
Intractable hiccups, which last for longer than one ... it would be worth talking with your doctor who may consider further testing or treatment for your hiccups," says Madsen.