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Concept: Semicircular canal


Spontaneous nystagmus, which has been considered a typical sign of acute vestibulopathy, has recently been reported in benign paroxysmal positional vertigo involving the lateral semicircular canals (LC-BPPV) without unilateral vestibulopathy (pseudo-spontaneous nystagmus, PSN), but research about its clinical application is still limited. Here we investigate the frequency and characteristics of PSN in LC-BPPV patients, and estimate its prognostic value.

Concepts: Medical terms, Semicircular canal, Prognosis, Ear, Canal, Pathologic nystagmus, Benign paroxysmal positional vertigo, Horizontal semicircular canal


We report on a 61-year-old woman with cupulolithiasis of the right horizontal semicircular canal, which is usually difficult to treat. The patient reported that several years ago, similar symptoms relieved completely after having performed several somersaults together with her granddaughter. This time, repetitive somersaults were again effective to treat her benign paroxysmal positional vertigo. Acceleration during a somersault may induce an intracanalicular force strong enough to detach otoconia debris from the cupula. Rolling may then promote their reentrance into the utricle. This case suggests that repetitive somersaults may be an alternative treatment of cupulolithiasis of the horizontal semicircular canal.

Concepts: Report, Semicircular canal, Alternative medicine, Classical mechanics, Ear, Benign paroxysmal positional vertigo, Treats, Somersault


INTRODUCTION: Benign paroxysmal positional vertigo (BPPV) is the most common vestibular disorder. However, BPPV in children has been studied less extensively than in the adult population. This is because the observation of benign paroxysmal positional nystagmus (BPPN) in children is technically very difficult and BPPV is rare in children. In this study, we present the only two cases of BPPV in children in which we successfully recorded and analyzed the BPPN. METHODS: One case was an 11-year-old boy and the other was a 3-year-old girl. We analyzed their BPPN three-dimensionally. RESULTS: Apogeotropic positional nystagmus was observed in the first case. We analyzed it to verify the presence of cupulolithiasis in the horizontal semicircular canal (HSCC). Geotropic positional nystagmus was observed in the second case, and the analyzed data indicated the presence of canalolithiasis in HSCC. Over the last decade, we have examined 3341 patients complaining of vertigo or dizziness. Among them, there were 63 children with the same complaint, so that the proportion of cases of BPPV in children was only 3% (2/63). DISCUSSION: Among patients complaining of vertigo or dizziness, children with BPPV are rare (3%). However, we have recorded their BPPN to confirm that BPPV does occur in children and that their characteristics of positional nystagmus are generally identical to those in adults. We emphasize that this is the first report of a child as young as 3 years old being diagnosed with BPPV.

Concepts: Scientific method, Observation, Semicircular canal, Ear, Case, Pathologic nystagmus, Complaint, Benign paroxysmal positional vertigo


To investigate whether reported vertigo during the Epley maneuver predicts therapeutic success in patients with benign paroxysmal positioning vertigo of the posterior semicircular canal (pc-BPPV). Fifty consecutive adult patients with pc-BPPV, based on a positive Dix-Hallpike test (DHT), were treated with the Epley maneuver and retested after 2 days. Patients were asked to report the presence of vertigo upon assuming each of the four positions of the maneuver. Thirty seven patients (74 %) were treated successfully in one session. Twenty out of 23 patients who reported vertigo at turning the head to the opposite side (2nd position) had a negative DHT on follow-up. These patients had a higher chance of a successful outcome compared to patients who did not report vertigo in the 2nd position (Odds ratio 5.3, 95 % CI: 1.3-22.2, p = 0.022). Report of vertigo at the other positions was not associated with the outcome. Report of vertigo at the second position of a single modified Epley maneuver is associated with therapeutic success.

Concepts: Report, Semicircular canal, Success, Odds, Benign paroxysmal positional vertigo, Epley maneuver, Positioning, Posterior semicircular canal


OBJECTIVE: The relatively low success rate of the treatment maneuver for horizontal semicircular canal (HSC) benign paroxysmal positional vertigo (BPPV) may be caused by the difficulty determining the affected side. We developed a 180-degree supine roll test (SRT) by modifying the 90-degree SRT to increase diagnostic accuracy and evaluated its significance. STUDY DESIGN: A prospective study. SETTING: Tertiary referral center. PATIENTS: A total of 122 patients with HSC-BPPV performed both the 90- and 180-degree SRTs. INTERVENTIONS: The affected side was determined by the 90- and 180-degree SRTs. The bow and lean (BL) test was also performed in cases with ambiguous or opposite results on both SRTs. MAIN OUTCOME MEASURE: A comparison of the difference in slow phase velocity (SPV) of nystagmus among the 90- and 180-degree SRTs and BL test. RESULTS: The maximum SPV of nystagmus during the 180-degree SRT was significantly greater than that during the 90-degree SRT. The SPV difference was less in the 180-degree SRT than that in the 90-degree SRT. Although the 180-degree SRT showed fewer meaningful results (n = 65) than the 90-degree SRT (n = 71), the affected side was determined by the 180-degree SRT in 15 cases with ambiguous results on the 90-degree SRT. Among 10 cases showing opposite results, 7 were identified by the BL test. Five (71.4%) of 7 cases had consistent affected sides with the 180-degree SRT. CONCLUSION: The 180-degree SRT can be an additional method when it is difficult to determine the affected side from the 90-degree SRT.

Concepts: Measurement, Semicircular canal, Arithmetic, Ear, Determinacy, Pathologic nystagmus, Benign paroxysmal positional vertigo, Horizontal semicircular canal


Abstract Conclusion: In the present study, about one-third of patients with Meniere’s disease developed benign paroxysmal positional vertigo (BPPV)-like attacks. Additionally, more than one-third of all vertigo attacks were BPPV-like attacks. Thus, vertigo attacks in patients with Meniere’s disease must be carefully treated because the therapy for such vertigo attacks is totally different from the therapy for BPPV. Objective: Physicians sometimes encounter patients with previously diagnosed Meniere’s disease who develop BPPV attacks during the course of clinical follow-up. In this study, we explored the frequency with which BPPV was involved in all vertiginous episodes among patients with Meniere’s disease. Methods: This retrospective study involved 296 patients with Meniere’s disease who visited Kyoto University Hospital. The diagnosis of Meniere’s disease was based on the guidelines for the diagnosis of Meniere’s disease proposed by the Committee on Hearing and Equilibrium. We judged the cause of vertigo as one of the following five types: (1) definite Meniere’s disease attack, (2) suspicious Meniere’s disease attack, (3) definite BPPV attack, (4) suspicious BPPV attack, or (5) unknown. Results: In all, 96 patients (32.8%) developed BPPV-like attacks, and 187 vertiginous episodes (37.9%) were caused by BPPV. The lateral semicircular canal was the most frequently involved canal.

Concepts: Hospital, Physician, Semicircular canal, Ear, Ménière's disease, Pathologic nystagmus, Benign paroxysmal positional vertigo, Diseases of inner ear


Objective: To investigate the clinical features and evaluate the efficacy of manual reduction in treatment of age patients with secondary benign paroxysmal positional vertigo (s-BPPV). Methods: Thirty-two cases of aged patients ( the s-BPPV group: including 19 cases of female and 13 males, age from 60 to 86 years old)with secondary benign paroxysmal positional vertigo from Jul. 2013 to Sep. 2015 in our hospital were retrospectively analyzed. The results were compared with 121 patients( the primary group: including 82 cases of female and 39males, aged from 60 to 86 years old)with aged primary benign paroxysmal positional vertigo(p -BPPV). All the patients were followed up for 12 months. Statistical data analysis was carried out with SPSS 19.0. Results: 20.92%(32/153)of all the observed elderly patients with BPPV was the aged s-BPPV. The sex ratio and onset age had no significant difference between the two groups(χ(2)=0.79, P>0.05; t=0.37, P>0.05). The rate of two or more semicircular canal involvement in the secondary group(21.88%) was higher than that in primary group(6.61%)(χ(2)=6.67, P<0.05). Bilateral semicircular canals were involved in 5 of the 32 cases in secondary group(15.63%) and 4 of the 121 cases in aged primary group(3.31%), The difference was significant(χ(2)=6.94, P<0.05). The effective rate after first manual reduction was 57.50%(23/40)in secondary group and 82.31%(107/130)in primary group, the difference was significant(χ(2)=10.46, P<0.05). The total effective rate were 87.50%(35/40) after more than once manual reduction in secondary group and 91.54%(119/130) in primary group, the difference was not significant(χ(2)= 0.59, P>0.05). The numbers of circulation of the first successful manual reduction management were (3.9±1.3)times in secondary group and (2.1±1.1)times in primary group, the difference was significant(t=3.15, P<0.05). The recurrence rate was 37.50%(15/40) in the secondary group and 16.15%(21/130)in primary group after during follow-up for 12 months, the difference was statistically significant(χ(2)=8.35, P<0.05). Conclusions: It's shown that the aged patients with secondary BPPV is not rare in clinical practice, sudden deafness and head trauma are frequent more than other reasons. The aged patients with secondary BPPV are prone to injury in multi-semicircular and bilateral canal compared with the primary BPPV. The effective rate after first manual reduction of secondary BPPV is lower than primary BPPV, it's needed more circulation of first success in manual reduction management. The total effective rates are not significant in two groups and recurrence rate is relatively high in secondary group.

Concepts: Clinical trial, Statistics, Statistical significance, Sex, Semicircular canal, Ageing, Ear, Benign paroxysmal positional vertigo


The vestibular system of the inner ear houses three semicircular canals-oriented on three nearly-orthogonal planes-that respond to angular acceleration stimuli. In recent years, the orientation of the lateral semicircular canal (LSC) has been regularly used to determine skull orientations for comparative purposes in studies of non-avian dinosaurs. Such orientations have been inferred based on fixing the LSC to a common set of coordinates (parallel to the Earth’s horizon), given that the orientation to gravity of this sensory system is assumed constant among taxa. Under this assumption, the LSC is used as a baseline (a reference system) both to estimate how the animals held their heads and to describe craniofacial variation among dinosaurs. However, the available data in living birds (extant saurischian dinosaurs) suggests that the orientation of the LSC in non-avian saurischian dinosaurs could have been very variable and taxon-specific. If such were the case, using the LSC as a comparative reference system would cause inappropriate visual perceptions of craniofacial organization, leading to significant descriptive inconsistencies among taxa. Here, we used Procrustes methods (Geometric Morphometrics), a suite of analytical tools that compares morphology on the basis of shared landmark homology, to show that the variability of LSC relative to skull landmarks is large (ca. 50°) and likely unpredictable, thus making it an inconsistent reference system for comparing and describing the skulls of saurischian (sauropodomorph and theropod) dinosaurs. In light of our results, the lateral semicircular canal is an inconsistent baseline for comparative studies of craniofacial morphology in dinosaurs.

Concepts: Bird, Vestibular system, Semicircular canal, Ear, Inner ear, Dinosaur, Saurischia, Comparative anatomy


Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature to body mass. However, this method fails to discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range of relative head sizes, we use dinosaurs to test the hypothesis that semicircular ducts scale more closely with head size. Comparing the area enclosed by each semicircular canal to estimated body mass and to two different measures of head size, skull length and estimated head mass, reveals significant patterns that corroborate a connection between physical parameters of the head and semicircular canal morphology. Head mass more strongly correlates with anterior semicircular canal size than does body mass and statistically separates bipedal from quadrupedal taxa, with bipeds exhibiting relatively larger canals. This morphologic dichotomy likely reflects adaptations of the vestibular system to stability demands associated with terrestrial locomotion on two, versus four, feet. This new method has implications for reinterpreting previous studies and informing future studies on the connection between locomotion type and vestibular function.

Concepts: Head and neck, Vestibular system, Semicircular canal, Superior semicircular canal, Locomotion, Posterior semicircular canal, Dinosaur, Bipedalism


Despite its high incidence and severe morbidity, the physiopathogenesis of adolescent idiopathic scoliosis (AIS) is still unknown. Here, we looked for early anomalies in AIS which are likely to be the cause of spinal deformity and could also be targeted by early treatments. We focused on the vestibular system, which is suspected of acting in AIS pathogenesis and which exhibits an end organ with size and shape fixed before birth. We hypothesize that, in adolescents with idiopathic scoliosis, vestibular morphological anomalies were already present at birth and could possibly have caused other abnormalities.

Concepts: Vertebral column, Greek loanwords, Vestibular system, Experiment, Semicircular canal