Abstract
The horizontal semicircular canal of squirrel monkeys was irradiated unilaterally with either an Arg or CO2 laser. Postoperatively, there was a small but significant reduction in caloric-induced ENG [electronystagmography] responses to 45.degree. C thermal stimulation. The principal morphologic effect of laser irradiation was a plug of fibrous tissue or new bone within the lumen of the lesioned semicircular canal.