A new roll test to diagnose posterior semicircular canal benign paroxysmal positional vertigo.

BACKGROUND: The Dix-Hallpike (DH) test is a gold standard for diagnosing benign paroxysmal positional vertigo (BPPV). However, lateral semicircular canal BPPV is not rare. We have been performing the new roll test that begins from the sitting position and contains a head-hanging position, in order not to overlook lateral canal BPPV. We noticed that transient vertical/torsional nystagmus sometimes occurs during the new roll test. OBJECTIVE: To clarify the value of the new roll test in diagnosing posterior canal BPPV and elucidate the position that elicits nystagmus. MATERIALS AND METHODS: The subjects were 100 consecutive patients (79 were female, 21 were male) with posterior canal BPPV. We classified the patients into four types based on a position that induced nystagmus. RESULTS: The patient's position that elicited nystagmus varied. The supine type accounted for 24 %, the lateral type accounted for 62 %, the head-hanging type accounted for 9 %, and the DH type accounted for 5 %. CONCLUSION: The new roll test is valuable for diagnosing posterior canalolithiasis cases. Most patients reveal vertical/torsional nystagmus in the supine or lateral position. Therefore, performing the new roll test first is efficient at the initial visit.

Three-dimensional analysis of per-rotational nystagmus.

BACKGROUND: Head rotation produces a vestibulo-ocular reflex (VOR). In horizontal rotation, not only lateral semicircular canals but also posterior semicircular canals are stimulated, because posterior canals cupulae are not horizontal in the sitting position. Therefore, theoretical nystagmus is horizontal and torsional. Convection of endolymph does not occur, because the centre of head rotation is a dens of the second cervical vertebra, not the center of lateral canal. Although per-rotational nystagmus is a result of VOR, whether it could be explained by the movement of cupula remains undetermined. To answer this question, we analysed per-rotational nystagmus using three-dimensional video-oculography. OBJECTIVE: To clarify whether per-rotational nystagmus is the same as the physical movement of cupula (theoretical nystagmus). MATERIALS AND METHODS: Five healthy human were evaluated. The participant's head was rotated (sinusoidal yaw rotation) manually (frequency, 0.33 Hz; amplitude, 60°). The experiment was performed in a dark, with the participant's eyes open. Nystagmus was recorded and converted into digital data. RESULTS: In all participants, the direction of nystagmus was rightward on rightward rotation and leftward on leftward rotation. In all participants, nystagmus was purely horizontal. CONCLUSIONS: Practical per-rotational nystagmus differs completely from the theoretical nystagmus. Therefore, VOR is strongly influenced by the central nervous system.

Analysis of 30 patients with cupulolithiasis of the posterior semicircular canal.

BACKGROUND: The diagnostic characteristics of patients with cupulolithiasis of the posterior semicircular canal are persistent torsional nystagmus in the supine position and persistent torsional nystagmus (opposite direction) in the nose-down position, which are caused by the affected canal becoming gravity sensitive. OBJECTIVE: To investigate the clinical features of posterior cupulolithiasis. MATERIALS AND METHODS: We interviewed 30 consecutive patients with cupulolithiasis of the posterior canal and categorized them by onset time into the following four groups: (1) during sleep; (2) at the time of awakening; (3) morning; and (4) afternoon. We defined disease duration as the period from onset to the day when we detected remission of positional nystagmus. RESULTS: Time of awakening was the most common onset time. The mean disease duration was 18.2 days, and 90% of patients achieved cure within 1 month. CONCLUSIONS: Physicians should take into account the duration of nystagmus, because cupulolithiasis of posterior canal exists. The etiology of posterior cupulolithiasis is closely related to sleep, because time of awakening is the most common onset time of vertigo. Most patients with posterior cupulolithiasis cure within 1 month.

Recurrence in patients with benign paroxysmal positional vertigo of the lateral semicircular canal.

OBJECTIVES: There are 3 subtypes of lateral canal benign paroxysmal positional vertigo. Persistent geotropic positional nystagmus is due to a light cupula, heavy cupula produces apogeotropic positional nystagmus, and canalolithiasis accounts for transient geotropic positional nystagmus. The aims of this study were to determine the recurrence rate and to examine the number of times of recurrence in each of the 3 subtypes. METHODS: Subjects were patients with light cupula (n = 47), heavy cupula (n = 48), and canalolithiasis (n = 45). We investigated the number of times of recurrence and determined the subtypes of a recurrent vertigo attack over the period of 5 years. RESULTS: The subtype of a recurrent vertigo attack was not always the same as the subtype at the first visit. The recurrence rate of light cupula group was 72.3%, that of heavy cupula group was 20.8%, and that of canalolithiasis group was 28.9%. Some patients experienced recurrence more than once. The mean value and standard deviation of the number of times of recurrence in light cupula group was 2.5 ±â€¯1.3 times, that in heavy cupula group was 1.5 ±â€¯0.7 times, and that in canalolithiasis group was 1.5 ±â€¯0.7 times. CONCLUSIONS: The recurrence rate in patients with light cupula is much higher than that in patients with heavy cupula or canalolithiasis. The number of times of recurrence in patients with light cupula is greater than that in patients with heavy cupula or canalolithiasis.

A new treatment (the affected-ear-up 90° maneuver) for benign paroxysmal positional vertigo of the lateral semicircular canal.

Background: Although several researchers have tried various kinds of canalith repositioning procedures for lateral canalolithiasis, a standard treatment has not been established. We have adopted 90° rotation, which is anatomically appropriate. Objective: To clarify the efficacy of the affected-ear-up 90° maneuver. Materials and methods: The subjects were 23 consecutive patients (15 females, 8 males) who revealed transient direction-changing geotropic positional nystagmus. After determining the affected side, we immediately performed the canalith repositioning procedure. To perform this maneuver: (1) Place the patient in the supine position. (2) Rotate the head toward the healthy side until 90° from the supine. (3) Sit up. (4) Ask the patient to remain upright with the chin down until going to bed. Results: Nineteen patients (83%) became symptom-free by only one maneuver. However, three patients converted to ipsilateral cupulolithiasis of the lateral canal, and one patient required a second maneuver. Conclusion: The affected-ear-up 90° maneuver is effective against lateral canalolithiasis.

Gender difference and laterality of sleep position.

OBJECTIVE: A higher incidence in women (approximately 7:3) and a predominant involvement of the right ear (approximately 7:5) are interesting features of BPPV (benign paroxysmal positional vertigo). It is speculated that these features are related to sleep position. The first aim of this study was to compare the frequency of position shifts during sleep between men and women. The second aim was to elucidate any differences in sleep position between men and women. The third aim was to clarify the laterality of sleep position. METHODS: We retrospectively selected the data of 30 males (mean, 53.1 years) and 22 females (mean, 50.6 years) diagnosed as mild or moderate obstructive sleep apnea. A position sensor was attached to the patient's anterior chest. Supine position was defined as less than 45° tilt, and lateral position was defined as more than 45° tilt. A single overnight laboratory polysomnography provided the number of position shifts, total sleep time, sleep time spent in the supine position (S), sleep time spent in the right-side-down lateral position (R), and sleep time spent in the left-side-down lateral position (L). RESULTS: The mean value and standard deviation of the number of position shifts per hour was 2.4±1.3 in males, and 2.3±1.1 in females. There was no significant difference between males and females. Twelve cases (40%) were lateral type (SR+L) in males. Ten cases (45%) were lateral type, and 12 (55%) were supine type in females. There was no significant difference between males and females. Seventeen cases (56.6%) were right-dominant type (R-L>0), and 13 (43.3%) were left-dominant type (R-L<0) in males. Thirteen cases (59%) were right-dominant type, and 9 (41%) were left-dominant type in females. CONCLUSION: Body position and the number of position shifts during sleep differ substantially between individuals. There is no gender difference in the frequency of position shifts. Although the supine type is more common than the lateral type, there is no gender difference in sleep position. Therefore, the reason of higher incidence in women is not related to sleep. The right-dominant type occurs more than the left-dominant type in both genders. It is possible that this behavior is the reason for the predominant involvement of the right ear in BPPV.

Affected-ear-up 120° maneuver for treatment of lateral semicircular canal benign paroxysmal positional vertigo.

Although several researchers have tried various canalith repositioning procedures for lateral canalolithiasis, a standard treatment has not been established. We adopt 120° rotation, which is anatomically appropriate because the principle of cure may be the fixing of pathological debris to the dark cells of the utricle. The aims of this study were to clarify the efficacy rate of the affected-ear-up 120° maneuver and to elucidate the appearance rate of lying-down nystagmus in patients with lateral canalolithiasis. The subjects were 31 patients (26 females, 5 males) who revealed transient direction-changing geotropic positional nystagmus. After determining the involved side, we performed the canalith repositioning procedure immediately. To perform this maneuver: (1) Place the patient in the supine position. (2) Rotate the head toward the healthy side until facing downward 120° from supine. (3) Sit up. (4) Ask the patient to remain upright with the chin down until going to bed. Twenty-nine patients (94%) became symptom free by only one maneuver. However, one patient converted to ipsilateral posterior cupulolithiasis, and another required a second maneuver. Lying-down nystagmus was found in 29 patients (94%), the transient type in 23 (74%), and the persistent type in 6 (19%). The direction of transient (not persistent) lying-down nystagmus was mostly toward the healthy side. These results suggest that the affected-ear-up 120° maneuver is effective and that lying-down nystagmus appears at a high rate.

Onset time of benign paroxysmal positional vertigo.

CONCLUSION: Benign paroxysmal positional vertigo (BPPV) is strongly related to sleep. This study proposes a micro-otoconia accumulation theory in which the pathological debris is an aggregate of micro-otoconia over a long time period, and which begins to slide by its own weight during sleep. OBJECTIVES: To examine the onset time of idiopathic BPPV and to investigate its etiology. METHOD: Patients (n = 351) were classified as posterior canalolithiasis (PC), horizontal canalolithiasis (HC), and horizontal heavy cupula (HHC) according to nystagmus findings. This study examined the medical records, and categorized the onset times into the following four groups; (1) during sleep, (2) at the time of rising, (3) morning, and (4) afternoon. RESULTS: PC (n = 135): In 33 patients, vertigo occurred during sleep, in 69 patients at rising, in 10 patients in the morning, and in 23 patients in the afternoon. HC (n = 87): In 38 patients, vertigo occurred during sleep, in 30 patients at rising, in eight patients in the morning, and in 11 patients in the afternoon. HHC (n = 129): In 27 patients, vertigo occurred during sleep, in 59 patients at rising, in 15 patients in the morning, and in 28 patients in the afternoon.

Neutral position of persistent direction-changing positional nystagmus.

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.

Caloric testing in patients with heavy or light cupula of the lateral semicircular canal.

OBJECTIVE: To clarify whether the dysfunction of the lateral semicircular canal remain or not in patients with heavy or light cupula. STUDY DESIGN: Prospective case series. METHODS: The subjects were 19 patients with heavy cupula (3 males, 16 females; mean age, 62.8 years) and 14 patients with light cupula (5 males, 9 females; mean age, 63 years). Caloric testing (iced water) was carried out after complete disappearance of positional nystagmus. We measured maximum slow-phase velocity and calculated asymmetry. RESULTS: In heavy cupula group, no one revealed canal paresis (CP) and 4 patients (21%) showed inverse CP (affected ear response is greater than healthy ear response). In light cupula group, 3 patients (21%) revealed CP. CONCLUSIONS: Dysfunction of the lateral semicircular canal does not always remain in either heavy cupula or light cupula. The caloric response increases in some cases with heavy cupula. We can explain this phenomenon based on the hydrostatic pressure theory involved in ossicles. LEVEL OF EVIDENCE: 4.

The second and third phases of caloric nystagmus.

CONCLUSION: The second and third phases of caloric nystagmus occur at a high rate. We can explain this phenomenon based on the hydrostatic pressure theory involved in perilymph. OBJECTIVES: To clarify the incidence of the second and third phases of caloric nystagmus, and to measure their intensity. METHODS: The subjects were 12 healthy humans. The right ear was stimulated using iced water. The first phase of caloric nystagmus was recorded in a supine position. Immediately after the cessation of the first phase, each subject was repositioned to a prone position, and the second phase was recorded. Immediately after the halt of the second phase, each subject was repositioned to a supine position, and the third phase was recorded. Nystagmus was analyzed using three-dimensional video-oculography. RESULTS: The mean value of maximum slow-phase velocity (MSV) of the first phase was 27.2°/s. All subjects revealed the second phase, and the direction was toward the right. The mean value of MSV was 7.2°/s. Nine subjects (75%) showed the third phase, and the direction was toward the left. The mean value of MSV was 2.7°/s.

Cupulolithiasis of the posterior semicircular canal.

BACKGROUND: We sometimes experience patients with persistent torsional/vertical (upbeating) positional nystagmus in the head-hanging position. We have been convinced of the existence of cupulolithiasis of the posterior semicircular canal because such cases reveal persistent torsional/vertical (downbeating) positional nystagmus in the nose-down position. PURPOSE: In order to confirm the validity of Ewald's third law, we quantified the difference between positional nystagmus in the head-hanging position and that in the nose-down position. METHODS: The subjects were 10 patients with posterior cupulolithiasis, 9 female and 1 male, with a mean age of 58.9years. Nystagmus was recorded using an infrared camera and the findings were converted to digital data. Using ImageJ, we performed three-dimensional video-oculography and measured the maximum slow-phase velocity (MSV) of three components. RESULTS: In the horizontal component, the mean value of MSV in the head-hanging position was 3°/s, and that in the nose-down position was 2.7°/s. There was no significant difference between the two positions. In the vertical component, the mean value of MSV in the head-hanging position was 4.3°/s, and that in the nose-down position was 6°/s. There was no significant difference between the two positions. In the torsional component, the mean value of MSV in the head-hanging position was 4.4°/s, and that in the nose-down position was 1.4°/s. The former was significantly greater than the latter (p<0.01). CONCLUSIONS: Although we could not confirm the validity of Ewald's third law, the torsional component in the head-hanging position was significantly greater than that in the nose-down position.

Asymmetry of positioning nystagmus in posterior canalolithiasis.

CONCLUSIONS: Ewald's third law is correct in the posterior semicircular canal and the intensity of stimulatory nystagmus is 2.7 times as strong as that of inhibitory nystagmus. OBJECTIVES: Ewald's third law states that a flow of endolymph away from the ampulla causes more stimulation than a flow toward the ampulla in the posterior canal. The aims of this study were to quantify the asymmetry of positioning nystagmus in posterior canalolithiasis and to confirm the validity of Ewald's third law. METHODS: Subjects were 20 patients who revealed typical vertical/torsional positioning nystagmus in the Dix-Hallpike test, 14 females and 6 males, with a mean age of 55.2 years. Nystagmus was recorded using an infrared camera and the findings were converted to digital data. Using ImageJ, we performed three-dimensional video-oculography and measured maximum slow-phase velocity of three components (horizontal, vertical, and torsional). RESULTS: The mean value of maximum slow-phase velocity (sum of three components) in the head-hanging position was 42.3°/s and that in the sitting position was 15.6°/s. The former was significantly greater than the latter (p < 0.01).

Does the superior semicircular canal receive caloric stimulation?

BACKGROUND: Caloric nystagmus contains not only a horizontal component but also vertical and torsional components. Several researchers considered that their origins are the posterior and superior semicircular canals. If the right superior canal receives caloric stimulation in the left-ear-down 40° position, an endolymphatic flow occurs in the direction of gravity in the long arm and induces ampullofugal cupular deflection. As a result, the direction of the vertical component of nystagmus should be downward (toward the lower eyelid), and the direction of the torsional component should be rightward. PURPOSE: The purpose of this study is to confirm the hypothesis that the superior semicircular canal receives caloric stimulation. METHODS: The subjects were 10 healthy humans. The right ear was stimulated using iced water. Each subject was kept in a left-ear-down 40° position for 60 seconds and then repositioned to a supine position. Nystagmus was analyzed by 3-dimensional video-oculography. RESULTS: In the left-ear-down 40° position, the direction of quick phase of the horizontal component was leftward in all subjects. Eight subjects exhibited a vertical component, and the direction was upward (toward the upper eyelid). Six subjects showed a torsional component, and the direction was leftward (the superior pole of the eyeball moved toward the left ear of the subject in a quick phase). These findings contradict the hypothesis. CONCLUSION: Caloric stimulation does not reach the superior canal; therefore, caloric testing cannot be used to evaluate the function of superior canal.

Is horizontal semicircular canal ocular reflex influenced by otolith organs input?

CONCLUSION: Otolith organs input influences the axis of horizontal semicircular canal ocular reflex; therefore, the plane of compensatory eye movements induced by the horizontal canal stimulation is not always parallel to the canal. OBJECTIVE: To clarify whether horizontal canal ocular reflex is influenced by otolith organs input. METHODS: The subjects were seven healthy humans. The right ear was stimulated using ice-water. Each subject was kept in a left-ear-down position for 20 s and then repositioned to a prone position, a right-ear-down position and a supine position with 20 s intervals. Nystagmus was analysed using three-dimensional video-oculography. RESULTS: Eye movements in the supine position and the prone position were not in a symmetric fashion. Nystagmus in the left-ear-down position and the right-ear-down position were not symmetric either. These phenomena indicate that the axis of the eyeball rotation was affected by the shift of the direction of gravity exerted on the head.

Cupulolithiasis of the horizontal semicircular canal.

To clarify whether positional nystagmus of horizontal cupulolithiasis contains vertical and torsional components, and to quantify the asymmetry, we analyzed nystagmus in four positions (healthy-ear-down, affected-ear-down, supine, nose-down), using 3-dimensional video-oculography. Subjects were 20 patients with direction-changing apogeotropic positional nystagmus, 11 females and 9 males, with a mean age of 58.1 years. Nystagmus was recorded using an infrared camera and the findings were converted to digital data. Using ImageJ, we performed 3-dimensional video-oculography and measured maximum slow-phase velocity (MSV) of three components. Positional nystagmus was not purely horizontal. Eleven (55%) patients revealed a vertical component, and 14 (70%) patients had a torsional component in the healthy-ear-down position. The mean value of MSV of the horizontal component in the healthy-ear-down position was 18°/s and that in the affected-ear-down position was 7.8°/s. For the horizontal component, MSV in the healthy-ear-down position was significantly greater than that in the affected-ear-down position (p < 0.01). These results suggest that vertical and torsional components occur from the horizontal semicircular canal, and the response to ampullopetal bending is more than two times as strong as that to ampullofugal bending.

Persistent direction-changing geotropic positional nystagmus.

The aims of the study were to clarify whether persistent direction-changing geotropic positional nystagmus contains vertical and torsional components, and to quantify the asymmetry. We analyzed nystagmus in four positions (healthy-ear-down, affected-ear-down, supine, nose-down) using three-dimensional video-oculography. Subjects were 18 patients with persistent direction-changing geotropic positional nystagmus, 16 females and 2 males, with a mean age of 55 years. Nystagmus was recorded using an infrared camera and the findings were converted to digital data. Using ImageJ, we performed three-dimensional video-oculography and measured maximum slow-phase velocity (MSV) of three components. Positional nystagmus was not purely horizontal. Eight (44%) patients revealed a vertical component (upward) and 15 (83%) patients had a torsional component in the healthy-ear-down position. Seven (39%) patients revealed a vertical component (downward) and 10 (56%) patients showed a torsional component in the nose-down position. The mean value of MSV of the horizontal component in the supine position was 9.3°/s and that in the nose-down position was 15.7°/s. The latter was significantly greater than the former (p < 0.05). Eye movements in the supine position and the nose-down position were not mirror images. These results suggest that vertical and torsional components occur from the horizontal semicircular canal, and that horizontal canal ocular reflex is influenced by input from the otolithic organs.

Can caloric testing evaluate the function of vertical semicircular canals?

CONCLUSION: Neither posterior nor superior semicircular canal receives a caloric effect; therefore, caloric testing cannot evaluate the function of vertical semicircular canals. OBJECTIVE: To clarify whether caloric stimulation reaches the posterior and superior semicircular canals. METHODS: The subjects were 10 healthy humans. The right ear was stimulated using ice-water. Each subject was kept in a supine position for 40 s and then repositioned to a sitting position until horizontal nystagmus stopped; afterwards, a nose-down position was adopted. Nystagmus was analyzed by three-dimensional video-oculography. RESULTS: In the supine position, four subjects revealed a vertical component and five subjects showed a torsional component. In the sitting position, neither a vertical nor a torsional component occurred when the horizontal component stopped. Three subjects revealed a vertical component and four subjects showed a torsional component in the nose-down position.

Positional nystagmus of horizontal canalolithiasis.

CONCLUSION: Vertical and torsional components occur from the horizontal semicircular canal, and the response to ampullopetal flow is greater than that to ampullofugal flow in every component. OBJECTIVES: To clarify whether positional nystagmus of horizontal canalolithiasis contains vertical and torsional components, and to quantify the asymmetry of nystagmus. METHODS: Twenty patients with transient direction-changing geotropic positional nystagmus were examined, and we performed three-dimensional video-oculography and measured the maximum slow-phase velocity (MSV) of three components. RESULTS: Positional nystagmus was not purely horizontal. Fifteen (75%) patients revealed a vertical component and 19 (95%) patients had a torsional component. The mean value of MSV of the horizontal component in the affected-ear-down position was 51.5°/s and that in the healthy-ear-down position was 19.1°/s. The mean value of MSV of the vertical component in the affected-ear-down position was 8.7°/s and that in the healthy-ear-down position was 3.0°/s. The mean value of MSV of the torsional component in the affected-ear-down position was 12.8°/s and that in the healthy-ear-down position was 6.5°/s. For every component, MSV in the affected-ear-down position was significantly greater than that in the healthy-ear-down position (p < 0.01).