BACKGROUND: Bohmer and Straumann have proposed that downbeat nystagmus is due to an asymmetry of the geometry of the vertical semicircular canals of the vestibular labyrinth. This hypothesis does not predict any sustained change in vertical nystagmus when subjects are placed in a head-upside-down position. METHODS: Using the magnetic search coil technique, I measured vertical eye movements in darkness in three normal human subjects while they maintained head-erect or head-upside-down positions. RESULTS: Two subjects had upbeat nystagmus and one downbeat nystagmus with their heads erect (slow-phase velocity < 1 deg/sec). All developed sustained nystagmus with quick phases directed towards their chins while in the head-upside-down position. CONCLUSIONS: These findings suggest that factors other than canal imbalance - otolithic or ocular - may also cause downbeat nystagmus.
Cerebellum ; Chin ; Darkness* ; Eye Movements ; Head ; Humans ; Nystagmus, Pathologic ; Otolithic Membrane ; Semicircular Canals ; Vestibule, Labyrinth

This review focuses on our effort in addressing the development and lesion-induced plasticity of the gravity sensing system. After severance of sensory input from one inner ear, there is a bilateral imbalance in response dynamics and spatial coding behavior between neuronal subpopulations on the two sides. These data provide the basis for deranged spatial coding and motor deficits accompanying unilateral labyrinthectomy. Recent studies have also confirmed that both glutamate receptors and neurotrophin receptors within the bilateral vestibular nuclei are implicated in the plasticity during vestibular compensation and development. Changes in plasticity not only provide insight into the formation of a spatial map and recovery of vestibular function but also on the design of drugs for therapeutic strategies applicable to infants or vestibular disorders such as vertigo and dizziness.
Animals ; Humans ; Neuronal Plasticity ; Neurons ; physiology ; Otolithic Membrane ; innervation ; physiology ; Vestibule, Labyrinth ; innervation ; physiology

Isolated otolith dysfunction(iOD) involves a group of unexplained vestibular syndromes that manifest clinically as a sense of translation, tilting or floating, and blurred vision with head movement, with normal semicircular canal function but abnormal otolith function on laboratory vestibular testing. As vestibular medicine has gained widespread popularity in recent years, increasing attention has also been paid to iOD and case reports, clinical studies and diagnostic criteria have been published. However, there is no consensus document to guide the diagnosis of this disease in China. In this context, the Special Committee on Vertigo of China Medical Education Association organized a group of domestic experts in vestibular medicine and formulated this diagnostic consensus after thorough discussion based on the latest evidence in China and abroad, in order to promote the best clinical practice for iOD.
Humans ; Otolithic Membrane ; Vestibular Diseases/diagnosis* ; Vertigo/diagnosis* ; Vestibule, Labyrinth ; Semicircular Canals

OBJECTIVETo discuss the characteristics of subjective visual gravity (subjective visual vertical/horizontal, SVV/SVH) and assess its clinical application for peripheral unilateral vestibular compensation.

METHODS69 cases of acute peripheral unilateral vestibular dysfunction patients (case group) accepted SVV/SVH, spontaneous nystagmus (SN), caloric test (CT) and other vestibular function tests. 49 healthy people (control group) accepted SVV/SVH only. SVV/SVH, SN and unilateral weakness (UW) were selected as for the observation indicators. The correlations between SVV/SVH, SN, UW and courses were investigated respectively, as well as the characteristic of SVV/SVH, SN in period of vestibular compensation.

RESULTSAmong case group SVV, SVH positive in 42 patients(60.9%) and 44 patients(63.8%), the absolute values of the skew angle were in the range between 2.1°-20.0°, 2.1°-22.2°. Skew angles of SVV/SVH in control were in the range between -1.5°-2.0° and -2.0°-1.6°, and had no statistical significance with case group(t=5.336 and 5.864, P<0.05). SN-positive 28 cases (40.6%), the range of intensities at 2.4°-17.1°; UW-positive 50 cases (72.5%). In case group, positive correlation between SVV and SVH(r=0.948, P=0.00), negatively correlated between SVV/SVH and SN respectively(r values were -0.720, -0.733, P values were 0.00), no correlation between the skew angle of SVV/SVH, strength of SN and UW value(r values were 0.191, 0.189, and 0.179, P>0.05), there was no correlation between the absolute value of SVV, SVH, SN, UW with the duration (rs values were -0.075, -0.065, -0.212, and 0.126, P>0.05).

CONCLUSIONSubjective visual gravity can be used not only to assess the range of unilateral peripheral vestibular dysfunction, but also help assess the static compensatory of otolithic, guidance and assessment of vestibular rehabilitation.

Caloric Tests ; Gravitation ; Humans ; Otolithic Membrane ; Pilot Projects ; Vestibular Diseases ; physiopathology ; Vestibular Function Tests ; Vestibule, Labyrinth ; physiopathology ; Visual Perception

OBJECTIVETo identify the aging effects on air-conducted sound (ACS) elicited ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) in normal Chinese population.

METHODSNighty-seven normal subjects (194 ears) were recruited for conventional ACS-oVEMP and ACS-cVEMP examinations. The candidates'age were 4-83 years old (Ave. ± SD, 45.7 ± 19.3), 41 male and 56 female, divided into 5 groups according to age. 500 Hz short tone burst was employed for examinations. Thresholds were identified and the parameters of the responses to 100dB nHL were calculated and compared among groups. SPSS 13.0 software was used to analyze the date.

RESULTSAs the age growing, the response rate for oVEMP decreased. It was recorded 100% in both ≤ 10-year-old and 11-30-year-old groups, 84.00% in the 31-50-year-old group, 48.15% in the 51-70-year-old group and 15.00% in the > 70-year-old group; while that for cVEMP were 100% in both ≤ 10-year-old group and 11-30-year-old group, 82.00% in the 31-50-year-old group, 77.78% in the 51-70-year-old group and 45.00% in the > 70-year-old group. The thresholds elevated and the amplitudes decreased in both examinations with the age growing. However, latencies and latency-intervals of both oVEMP and cVEMP examinations displayed minor difference among groups except that nI latency of oVEMP prolonged with age growing.

CONCLUSIONSWith the age growing, the otolithic end organ input pathways degenerate in normal subjects, as shown that ACS elicited oVEMP and cVEMP responsed less with higher threshold and smaller amplitude. The extremely low response rates of both VEMPs in the > 70-year-old group in this study indicates that VEMPs can only provide limited diagnostic information among very old people in clinical practice.

Aging ; Evoked Potentials ; Eye ; Female ; Head ; Humans ; Male ; Neck ; Otolithic Membrane ; Sound ; Vestibular Evoked Myogenic Potentials ; Vestibule, Labyrinth

OBJECTIVETo observe the function of the otolithic end organs and their input pathways in sudden sensorineural hearing loss (SSHL) patients.

METHODSForty cases of unilateral SSHL were enrolled as the observing group from May, 2011 to May, 2012. Thirty age- and gender-matched normal subjects were recruited as the control group. Both patients and normal subjects underwent conventional air-conducted ocular vestibular evoked myogenic potential (oVEMP) and cervical vestibular evoked myogenic potential (cVEMP) in bilateral ears. The results were compared between the affected ears, the contralateral ears and the normal controls.

RESULTSOverall, oVEMP was elicited in 16 affected ears (40.0%), 23 contralateral ears (57.5%) and 43 normal ears (71.7%). cVEMP could be elicited in 25 affected ears (62.5%), 30 contralateral ears (75.0%) and 49 normal ears (81.7%) respectively. Significant statistical significance could be found in the oVEMP response rate between the affected ears and the normal ears (χ(2) = 9.949, P = 0.002) and in the cVEMP response rate between the affected ears and the normal ears (χ(2) = 4.582, P = 0.032). Significant statistical difference could not be found in all oVEMP and cVEMP parameters (threshold, N1 latency, P1 latency, latency interval and amplitude) among groups (P > 0.05).

CONCLUSIONSThe otolithic vestibular end organs and their input pathways could be damaged in SSHL patients. Such damages could be monitored objectively by cVEMP and oVEMP examinations.

Evoked Potentials ; Hearing Loss, Sensorineural ; diagnosis ; pathology ; Humans ; Otolithic Membrane ; Vestibular Evoked Myogenic Potentials ; Vestibule, Labyrinth ; pathology

OBJECTIVE: The purpose of this study is to assess the effects of aging on air-conducted sound elicited cervical vestibular evoked myogenic potential (cVEMP) and ocular vestibular evoked myogenic potential(oVEMP) in normal people. METHOD: Sixty normal subjects were recruited for the vestibular evoked myogenic potential examination. Among them, 20-40 year-old group was setted as the first group, 41-60 year-old group was setted as the second group, > 60-year-old group was setted as the third group. Each group included 20 normal subjects. SPSS 16.0 software was used to analyze the data. RESULT: As the age growing, P1 latency prolonged, N1-P1 amplitude decreased, and amplitude asymmetric ratio increased in cVEMP; N1 latency prolonged, P1-N1 amplitude decreased, and amplitude asymmetric ratio increased in oVEMP. CONCLUSION With the age growing, the time of otolithic organ input pathways prolonged, the function of otolithic organ decreased and the decrease level may be asymeetrical on both sides.
Adult ; Aging ; Eye ; Head ; Hearing ; Humans ; Middle Aged ; Otolithic Membrane ; Vestibular Evoked Myogenic Potentials ; Vestibule, Labyrinth ; Young Adult

Cochlear Implantation ; Humans ; Vestibule, Labyrinth ; physiology

Cognition ; Humans ; Vestibular Diseases ; Vestibule, Labyrinth

OBJECTIVE: Analyze the data of the patients with sensorineural hearing loss in China and study the classification and incidence of inner ear malformationsby the high-resolution computed tomography. METHOD: The investigation took a retrospective review of CT findings relating to the 2,747 cases of outpatients. The inner ear malformations diagnosed by CT were classified according to the methods proposed by Sennaroglu. RESULT: (1)843 cases of inner ear malformations were found in 2747 cases of patients with sensorineural hearing loss by CT examination. The incidence of inner ear malformation was 30.69%(843/2747). (2) The epidemiological information of 843 cases of inner ear malformation according to Sennaroglu's classification was as follows: cochlea was 52. 31%(441/843), simple vestibular aqueduct was 40.33%(340/843), simple vestibular/ semicircular canal/internal auditory canal were 7. 35%(62/843) of the group. (3) 441 cases of cochlea malformation were consisted of these types of malformation: Michel deformity was 1.13% (5/441), cochlear aplasia was 1. 81% (8/441), common cavity deformity was 3. 17% (14/441), incomplete partition type I was 8. 62% (38/441), cochlea hypoplasia was 9. 07% (40/441) and incomplete partition type II was 76. 19% (336/441) of the group. CONCLUSION The results suggested that 30. 69% cases of inner ear malformation can be found in patients with sensorineural hearing loss, which is more higher than reported by the high-resolution computed tomography. Sennaroglu's classification is instructively significant in investigating the status of inner ear malformations.
China ; Cochlea ; Ear, Inner ; abnormalities ; Hearing Loss, Sensorineural ; etiology ; Humans ; Outpatients ; Retrospective Studies ; Semicircular Canals ; Temporal Bone ; Tomography, X-Ray Computed ; Vestibular Aqueduct ; Vestibule, Labyrinth