Aqua Stim

Aqua Stim delivers warm water or cold water into your patient's left ear or right ear. The temperature is automatically controlled by the Interacoustics videonystagmography (VNG) software if used along with Aqua Stim. Typically, you would perform bithermal irrigations. This consists of one warm water irrigation and one cold water irrigation on the left ear and on the right ear. Vestibular stimulation in this manner enables you to assess your patient's peripheral vestibular system.

By delivering warm or cold water into your patient's ear canal, the temperature changes cause a convection current in the ear being stimulated. Depending on the temperature of the water, this either excites or inhibits the cupula. This initiates the vestibular-ocular reflex (VOR), which causes caloric nystagmus. If you integrate Aqua Stim with Interacoustics' videonystagmography (VNG) software, this nystagmus is quantified during the caloric test.

Caloric testing, or caloric stimulation, be it with air or water, is a good means of stimulating the vestibular end organs. It also does this independently, meaning you can identify how the end organs compare and if the weakness is unilateral or bilateral.

Typically, warm water irrigation will result in nystagmus that beats toward the test ear. On the contrary, cold water irrigation will produce nystagmus that beats away from the test ear. Directional preponderance, or unilateral weakness, are manifested by asymmetrical caloric responses. Asymmetrical caloric responses are reflected by an unequal amount of left-beating nystagmus when compared with right-beating nystagmus. Weak caloric responses from both ears is indicative of a bilateral weakness.