[Introduction] The presence of neuron projection of the peripheral vestibula and the cerebrum was demonstrated by neuroanatomical studies and imaging findings of brain function. I conducted this experiment to examine whether imaginary fixation and deep sensation can suppress nystagmus.
[Subjects] Twelve healthy adult volunteers (total 24 ears).
[Method] The experiment was conducted as follows:
1. Subjects fitted with infrared Fresnel lenses glass for nystagmus measurement underwent a caloric test (20°C, 5 mL, 20-second stimulation), and nystagmus was recorded.
2. When the slow-phase velocity of nystagmus reached the maximum value, subjects were instructed to raise their arms anteriorly, interlock fingers of both hands tightly, and keep looking in the general direction of their thumbs (as they were fitted with Fresnel lenses, they were unable actually to see their thumbs).
3. After 10 seconds, they were instructed to stop “looking” (could not see in reality) and lower their arms.
4. I compared the slow phase velocity of nystagmus during the 10 seconds before instruction with that during 10 seconds of instruction.
[Results] The mean slow phase velocity of caloric nystagmus during loading (stimulation) significantly decreased (p<0.01). The mean slow phase velocity during the 10 seconds before loading (stimulation) was 13.7±4.7°/s, and that during loading (stimulation) was 9.7±3.7°/s. The rate of nystagmus suppression was 28.5±15.7%.
[Summary] The study suggested that when imaginary fixation was added to deep sensation, peripheral nystagmus was suppressed.
