Fig. 5.

Right lateral cupulolithiasis. The otoconia adhere to the cupula of the right lateral canal. There was no spontaneous nystagmus in this subject. During the right roll test, the cupula is deflected away from the ampulla creating an inhibitory left-beating nystagmus. During the left roll test, the cupula is deflected towards the ampulla generating an excitatory right-beating nystagmus. The slow phase velocity (SPV) profiles during both roll tests reveal persistent nystagmus, with a higher peak velocity reached during the left roll test.