VIsualEyes 515/525 - Additional Information Page 109
9.2 Nystagmus tests
The average slow phase velocity (a.SPV) bar graph displays the a.SPV of 3 or more beats found within the
peak response time period defined in the test properties. The Max Slowphase Velocity value of 6 degrees
per second is treated as within threshold limits and will be displayed as a white bar. Values exceeding this
threshold will have the threshold value portion in white and the remaining displayed in gray.
Figure 9.2.1 Average Slow Phase Velocity bar graph with 6 dps threshold
Figure 9.2.2 Nystagmus threshold levels
9.3 Caloric tests
Unilateral Weakness and Directional Preponderance are calculated using Jongkees formula. Unilateral
weakness is 25%. Directional Preponderance is 30%. Monothermal Warm Screening Test weakness is
defined as 30%. When cool tests are performed, the software will use the Unilateral weakness value.
Bilateral Weakness is defined if the total slow phase velocity is less than 11 degrees per second. The
Fixation Index threshold is considered 50%. Patients with a Fixation Index less than 50% is said to have a
failure to suppress nystagmus with fixation.
Figure 9.3.1 Caloric threshold levels
To Next Page
Loading...
