Three cases with syndrome of crocodile tears: Ipsilateral gusto-lacrimal reflex by study of taste stimulation

We presented 3 cases with syndrome of crocodile tears. Case 1 was a 58 year-old man who noticed bilateral severe facial weakness and decrease in taste sensation and lacrimation in March 1976. Case 2 was a 20 year-old man who noticed right facial weakness and decrease in taste sensation and lacrimation in February 1983. Case 3 was a 52 year-old man who noticed right facial weakness and decrease in lacrimation in January 1984. All 3 cases showed severe peripheral facial nerve palsy. Syndrome of crocodile tears appeared several months later, when facial nerve palsy improved. Taste stimulation test was performed in cases 1 and 2. Taste stimulation on the affected side induced lacrimation on the same side, but no lacrimation on the other side. These findings suggest that syndrome of crocodile tears results from the ipsilateral gusto-lacrimal reflex which is due to an artificial synapse formation between facial nerve sensory fibers and parasympathetic fibers, probably within the geniculate ganglion or at more proximal portion.