Three Dimensional Measurement of Spontaneous, Positional, Positioning(Dix-Hallpike) and Post Head Shaking Nystagmus in Cats / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Measuring the eye movements including nystagmus is an essential step in the evaluation of dizzy patients. Therefore, it is necessary to observe and record the eye movements in animal for better understanding of human vestibular function. In this study, we investigated spontaneous, positional, positioning (Dix-Hallpike), post head shaking nystagmus in normal cats. MATERIALS AND METHODS: In ten normal cats, we measured the eye movements in vertical, horizontal and torsional planes using magnetic search coils with eyes open (EO), and eyes open in darkness (EOD). The eye movements were recorded with the head in neutral, tilted, hanging, and Dix-Hallpike positions as well as after head-shaking. RESULTS: 1) Positional nystagmus was present in 3 cats on the head hanging position. 2) Among the three cats which had positional nystagmus, one cat also had positioning nystagmus on Dix-Hallpike maneuver. 3) On repeated positional stimulations, the latency of nystagmus was increased and the duration and the slow phase velocity were decreased. 4) In the follow-up experiment after one month, the positional nystagmus was induced in the two same cats. 5) Spontaneous and post head shaking nystagmus were not present in any of the ten cats.