Erschienen in:
01.02.2016 | Otology
Neutral position of persistent direction-changing positional nystagmus
verfasst von:
Hiroaki Ichijo
Erschienen in:
European Archives of Oto-Rhino-Laryngology
|
Ausgabe 2/2016
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Abstract
The aim of this study was to measure the neutral position of direction-changing apogeotropic positional nystagmus (heavy cupula of the horizontal semicircular canal) and persistent direction-changing geotropic positional nystagmus (light cupula of the horizontal semicircular canal). We conducted a prospective case series study on 31 patients with heavy cupula (12 males, 19 females; mean age, 64.3 years) and 33 patients with light cupula (10 males, 23 females; mean age, 60.9 years). We measured the angle of the neutral position in patients with heavy cupula (θ
1) and that in patients with light cupula (θ
2) using a large protractor. The mean value and standard deviation of θ
1 was 31.6 ± 22.4°, minimum value was 5°, and maximum value was 89°. The mean value and standard deviation of θ
2 was 44.4 ± 20.5°, minimum value was 5°, and maximum value was 85°. θ
2 was significantly greater than θ
1 (p < 0.05). The neutral position varies widely. Some patients exhibit a great angle (more than 40°); therefore, examiners should make patients adopt a completely lateral position in the supine head roll test and should confirm the direction of nystagmus in order to avoid mistaking positional nystagmus for spontaneous nystagmus.