Vertical Canal Function in Normal Subjects and Patients with Benign Paroxysmal Positional Vertigo

• Published in: Acta oto-laryngologica Vol. 124; no. 9; pp. 1046 - 1052
• Main Authors: Sekine, Kazunori, Imai, Takao, Morita, Masahiro, Nakamae, Koji, Miura, Katsuyoshi, Fujioka, Hiromu, Kubo, Takeshi, Tamura, Koichi, Takeda, Noriaki
• Format: Journal Article
• Language: English
• Published: Stockholm Informa UK Ltd 01.11.2004; Taylor & Francis; Taylor and Francis
• Subjects: Adult; Aged; Aged, 80 and over; benign paroxysmal positional vertigo; Biological and medical sciences; Caloric Tests - methods; Diagnostic Imaging - methods; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Eye Movements; Female; Humans; Lithiasis - complications; Male; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Non tumoral diseases; Nystagmus, Physiologic - physiology; Otorhinolaryngology. Stomatology; Rotation; rotation test; Semicircular Canals - physiology; vertical semicircular canal; Vertigo - physiopathology; Equilibrium disorder; Human; Vertical; rotation test; vertical semicircular canal; Nervous system diseases; Internal ear disease; Semicircular canal; ENT disease; benign paroxysmal positional rertigo; Benign paroxysmal vertigo; Rotation
• ISSN: 0001-6489; 1651-2251
• DOI: 10.1080/00016480410018061

Objectives -To assess the dynamics of the vertical semicircular canal (VSCC)-ocular reflex in normal subjects and then to compare their gain in VSCC-ocular reflex with that of patients with benign paroxysmal positional vertigo (BPPV). Material and Methods -Subjects were sinusoidally rotated around the earth-vertical axis with their head tilted 60° backward and turned 45° to the right or left side from the sagittal plane at frequencies of 0.1, 0.3, 0.5, 0.7 and 1.0 Hz with a maximum angular velocity of 50°/s. Head rotation to the right side on the right anterior semicircular canal (SCC)-left posterior SCC plane or to the left side on the left anterior SCC--right posterior SCC plane stimulated the pair of VSCCs. Eye movements were recorded on a video imaging system with an infrared charge-coupled device camera, using our new technique for analyzing the rotation vector of eye movements in three dimensions. Results -The mean gains in left posterior SCC-ocular reflex in normal subjects ranged from 0.44 at 0.1 Hz to 0.79 at 1.0 Hz, while the mean gains in right anterior SCC-ocular reflex ranged from 0.45 at 0.1 Hz to 0.73 at 1.0 Hz. The mean gains in right posterior SCC-ocular reflex in normal subjects ranged from 0.53 at 0.1 Hz to 0.89 at 1.0 Hz, while the mean gains in left anterior SCC-ocular reflex ranged from 0.53 at 0.1 Hz to 0.88 at 1.0 Hz. Thus, the gains in VSCC-ocular reflex did not differ among the four VSCCs in normal subjects. Similarly, vestibulo-ocular reflex (VOR) gains of the four VSCCs in patients with right- or left-sided BPPV were almost the same at all frequencies compared to those of normal subjects. Conclusion -In patients with BPPV, gains in VOR in the four VSCCs were not changed in comparison with those of normal subjects. It is suggested that the mass of free-floating otoconial debris associated with canalolithiasis was too small compared to that of the endolymph to change the canal dynamics.