BACKGROUND AND OBJECTIVES: At the beginning of the Dix-Hallpike maneuver, one of the two functional pair planes of the vertical canals is presumed to lie in the sagittal plane. However, this presumption is not correct. This paper aims to describe this problem more clearly and speculate on clinical implications. Mathematical and theoretical reasoning will be discussed. MATERIALS AND METHODS: Two sets, each composed of three perpendicular planes, were modeled for simplified semicircular canals in the anatomical position with a 3D modeler. After a yaw rotation of 45 degrees, the surface normal of the vertical canal plane is compared with that of the true sagittal plane. RESULTS: The angle between the two normals was approximately 21.1 degrees. The theoretical vertical canal plane did not lie in the sagittal plane at the beginning position of Dix-Hallpike maneuver. CONCLUSIONS: More exact Dix-Hallpike maneuvers may require a roll tilting about 20 degrees toward the affected side.
Semicircular Canals ; Vertigo

Humans ; Semicircular Canals ; abnormalities

A 31-year-old woman presented with the very unusual symptom of being able to hear the movement of her eyeballs in her left ear: “I can hear my eyeballs move!” She initially described hearing a recurrent “swishing” sound that would occur intermittently. She eventually realized that its occurrence coincided with eyeball movement. In the eight months’ duration of her symptom, she had been unable to obtain a diagnosis from physicians whom she consulted and had even been referred for psychiatric evaluation and treatment. An otolaryngologist whom she consulted had a standard pure tone audiometric examination done, and this showed normal hearing acuity in both ears. A Magnetic Resonance Imaging (MRI) of the inner ear and brain likewise showed no abnormalities. Due to the peculiarity of the patient’s complaint, the otolaryngologist consulted with a neurotologist who suspected the presence of a semicircular canal dehiscence. A computerized tomographic imaging study of the temporal bone confirmed the presence of a left superior semicircular canal dehiscence syndrome.
Semicircular Canal Dehiscence ; Semicircular Canals ; Eye Movements

Even though benign paroxysmal positional vertigo (BPPV) mostly affects a single semicircular canal (SCC), BPPV simultaneously involving more than one SCC is not rare. This multi-canal BPPV may either involve the same canals on both sides or simultaneously affect different canals on the same or on both sides. Since the SCCs can be involved in various combinations in one or both ears, multi-canal BPPVs pose diagnostic and therapeutic challenges. The different patterns of nystagmus induced during each positional maneuver should be differentiated from positional vertigo and nystagmus due to central lesions. It remains unknown which canal should be treated first and which maneuver should be adopted for multi-canal BPPVs. Furthermore, the optimal interval from treatment of a canal to another should be determined. The response to canalith repositioning maneuvers and recurrences do not differ between multi- and single canal BPPVs in spite of more frequent involvement of multiple canals in traumatic cases.
Ear ; Recurrence ; Semicircular Canals ; Vertigo

Benign paroxysmal positional vertigo (BPPV) is a commonly presenting problem at the emergency department. Three types have been recognized based on the pathogenesis of BPPV. The first is posterior-canal canalolithiasis, the second is horizontal-canal canalolithiasis, and the last is horizontal-canal cupulolithiasis. With the first two types of BPPV, an otolith-repositioning manuever can be performed quickly at the bedside with rapid results, often providing much satisfaction to both patient and physician. However, in the case of horizontal-canal cupulolithiasis, no established repositioning maneuver existed until recently. In 2000, Jo et al. developed a new repositioning maneuver and reported excellent results. We report a case of BPPV horizontal-canal cupulolithiasis that immediately responded to the maneuver of Jo et al. and strongly recommend use of this repositioning maneuver at the emergency department.
Emergency Service, Hospital ; Humans ; Semicircular Canals* ; Vertigo

The authors report jerky seesaw nystagmus, extorsional downbeating in the right eye and intorsional upbeating in the left eye, in a patient with right internuclear ophthalmoplegia (INO). This pattern of nystagmus may occur by disrupting pathways from contralateral posterior and anterior semicircular canals by a lesion in the medial longitudinal fasciculus. Depending on damage to the pathways from contralateral vertical canals, various patterns of dissociated torsional-vertical nystagmus may accompany INO.
Humans ; Ocular Motility Disorders* ; Semicircular Canals

BACKGROUND AND OBJECTIVES: The purpose of the study was to compare the mastoid air-cell volume of the patients with superior semicircular canal dehiscence syndrome (SCDS) and that of the control patients with otosclerosis and temporal bone (TB) fracture. SUBJECTS AND METHODS: Ten patients with SCDS were enrolled and 10 patients with bilateral otosclerosis and TB fracture were selected as control groups by age and sex matching. To measure the mastoid air-cell volume, 3D reconstruction software was used. RESULTS: In 10 patients with SCDS, the mean age was 44.5 years, ranging from 16 to 79 years (M : F=4 : 6). Mean mastoid air-cell volume in the SCDS side was 3319.9 mm3, whereas 4177.2 mm3 in the normal side (p=0.022). Mean mastoid air-cell volume in the right side of otosclerosis patients was 6594.3 mm3 and it was not different from 6380.5 mm3 in the left side (p=0.445). Mean mastoid air-cell volume in normal side of TB fracture was 6477.2 mm3. The mastoid air-cell volume in the SCDS side was significantly smaller than that of otosclerosis and TB fracture patients (p=0.009, p=0.002, respectively). The mastoid air-cell volume in the normal side of SCDS was significantly smaller than that of TB fracture (p=0.019), but not significant with that of otosclerosis (p=0.063). CONCLUSIONS: Our findings revealed that the mastoid air-cell volume in the SCDS side was significantly smaller than control group, which suggest that the decreased mastoid pneumatization is closely related to the generation of SCDS.
Humans ; Mastoid ; Otosclerosis ; Semicircular Canals ; Temporal Bone

BACKGROUND AND OBJECTIVES: The purpose of the study was to compare the mastoid air-cell volume of the patients with superior semicircular canal dehiscence syndrome (SCDS) and that of the control patients with otosclerosis and temporal bone (TB) fracture. SUBJECTS AND METHODS: Ten patients with SCDS were enrolled and 10 patients with bilateral otosclerosis and TB fracture were selected as control groups by age and sex matching. To measure the mastoid air-cell volume, 3D reconstruction software was used. RESULTS: In 10 patients with SCDS, the mean age was 44.5 years, ranging from 16 to 79 years (M : F=4 : 6). Mean mastoid air-cell volume in the SCDS side was 3319.9 mm3, whereas 4177.2 mm3 in the normal side (p=0.022). Mean mastoid air-cell volume in the right side of otosclerosis patients was 6594.3 mm3 and it was not different from 6380.5 mm3 in the left side (p=0.445). Mean mastoid air-cell volume in normal side of TB fracture was 6477.2 mm3. The mastoid air-cell volume in the SCDS side was significantly smaller than that of otosclerosis and TB fracture patients (p=0.009, p=0.002, respectively). The mastoid air-cell volume in the normal side of SCDS was significantly smaller than that of TB fracture (p=0.019), but not significant with that of otosclerosis (p=0.063). CONCLUSIONS: Our findings revealed that the mastoid air-cell volume in the SCDS side was significantly smaller than control group, which suggest that the decreased mastoid pneumatization is closely related to the generation of SCDS.
Humans ; Mastoid ; Otosclerosis ; Semicircular Canals ; Temporal Bone

Paroxysmal positional nystagmus is a common finding in patients with vertigo and can occur in typical and atypical forms. Atypical forms of paroxismal positional nystagmus are thought to represent conditions which are in fact not "benign". This patient was diagnosed as right posterior semicircular canal BPPV at first. After modified Epley maneuver, the type of nystagmus was changed to atypical forms. After left cupulolith reposition maneuver (CRmM), the nystagmus and dizziness were disappeared finally.
Dizziness ; Humans ; Nystagmus, Physiologic ; Semicircular Canals ; Vertigo*

The authors report jerky seesaw nystagmus, extorsional downbeating in the ipsilesional eye and intorsional upbeating in the contralesional eye, in a patient with internuclear ophthalmoplegia (INO) from focal pontine lesion. This pattern of nystagmus may occur by disrupting pathways from contralateral posterior and anterior semicircular canals by a lesion in the medial longitudinal fasciculus. Depending on the pathways involved, various patterns of dissociated torsional-vertical nystagmus may accompany INO.
Humans ; Ocular Motility Disorders* ; Semicircular Canals