OBJECTIVEThe macula lagena in birds is located at the apical end of the cochlea and contains many tiny otoliths. The macula lagena is innervated and has neural projections to the brainstem, but its physiological function is still unclear. It remains disputable that it is because otoliths in the lagena are rich in elements Fe and Zn that birds can obtain geomagnetic information for homing. To clarify this issue, we carried out a study to determine whether or not otoliths in the lagena of homing pigeons are richer in magnetic elements than those in the saccule and the utricle.

METHODSThe contents of ferromagnetic elements (Fe, Co, Ni) and other metal elements in lagenal otoliths of adult homing pigeons were precisely analyzed with inductively coupled plasma mass spectrometry (ICP-MS) of high sensitivity, and then they were compared with those in saccular and utricular otoliths (all the contents were normalized to Ca).

RESULTSIn adult homing pigeons, the contents of ferromagnetic elements (Fe, Co, Ni) in lagenal otoliths were less than 0.7% (normalized to Ca element) and were the same order in magnitude as those in saccular and utricular otoliths. The content of Fe in lagenal otoliths was not significantly different from that in utricular otoliths and was even lower than that in saccular otoliths. The content of Co in lagenal otoliths was lower than that in saccular otoliths and higher than that in utricular otoliths. The content of Ni in lagenal otoliths was not significantly different from that in saccular otoliths and was higher than that in utricular otoliths. The contents of other metal elements Na, Mg, K, Al, Mn and Pb in lagenal otoliths were not significantly different from those in utricular and saccular otoliths. The contents of metal elements Zn, Ba and Cu in lagenal otoliths were lower than those in saccular otoliths.

CONCLUSIONThe contents of magnetic elements in lagenal otoliths of homing pigeons are not much higher than those in utricular and saccular otoliths, which does not support the hypothesis that birds depend on high contents of Fe and Zn in lagenal otoliths for sensation of geomagnetic information. Similarities in morphology, element ingredient and element content between lagenal otoliths and utricular otoliths suggest that the two types of otolithic organs may play similar roles in sensing gravitational and acceleration signals.

Acoustic Maculae ; cytology ; Analysis of Variance ; Animals ; Columbidae ; anatomy & histology ; Elements ; Female ; Magnetics ; Male ; Microscopy, Electron, Scanning ; methods ; Otolithic Membrane ; chemistry ; ultrastructure ; Spectrometry, X-Ray Emission ; methods

OBJECTIVETo examine the vesicular glutamate transporters (VGluTs: VGluT1-VGluT3) in the peripheral vestibular system.

METHODSThe vestibular structures, including Scarpa's ganglion (vestibular ganglion, VG), maculae of utricle and saccule, and ampullary cristae, from normal Sprague-Dawley rats were processed immunohistochemically for VGluTs, by avidin-biotinylated peroxidase complex method, with 3-3'-diaminobenzidine (DAB) as chromogen.

RESULTS(1) VGluT1 was localized to partial neurons of VG and to the putative primary afferent fibers innervating vestibular end-organs. (2) Intense VGluT3 immunoreactivity was detected in large number of sensory epithelia cells, and weak labeling of VGluT3-positive afferent fibers was in the maculae and ampullary cristae. (3) No or very weak VGluT2 immunoreactivity was observed in the VG and acoustic maculae.

CONCLUSIONThese results provide the morphological support that glutamate exists in the peripheral vestibular system, and it may play an important role in the centripetal vestibular transmission.

Acoustic Maculae ; metabolism ; Animals ; Neurons ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vesicular Glutamate Transport Proteins ; classification ; metabolism ; Vestibule, Labyrinth ; metabolism ; Vestibulocochlear Nerve ; cytology ; metabolism

Benign paroxysmal positional vertigo (BPPV) is characterized by brief recurrent episodes of vertigo triggered by head position changes. BPPV is one of the most common causes of recurrent vertigo. BPPV results from abnormal stimulation of the cupula within any of the three semicircular canals by free-floating otoliths (canalithiasis) or otoliths adhered to the cupula (cupulolithiasis). Typical symptoms and signs of BPPV are evoked when the head is positioned so that the plane of the affected semicircular canal is spatially vertical and thus aligned with gravity. Paroxysm of vertigo and nystagmus develops after a brief latency during Dix-Hallpike maneuver in posterior canal BPPV and supine roll test in horizontal canal BPPV. Usually positioning the head in the opposite direction reverses the direction of the nystagmus. The duration, frequency, and intensity of symptoms of BPPV vary depending on the involved canals and the nature of otolithic debris. Spontaneous recovery occurs frequently even with conservative treatment, however, canalith repositioning maneuvers are believed to be the best way to treat BPPV by moving the canaliths from the semicircular canal to the vestibule.
Gravitation ; Head ; Otolithic Membrane ; Semicircular Canals ; Vertigo

BACKGROUND AND OBJECTIVES: Aims of the study were to determine if the somatosensory input influences on vertical perception by comparing the results with the head or body tilted (15Degree to the right and to the left, and to examine the influence of tactile sensation in the perception of verticality in head lateral positions. MATERIALS AND METHOD: We tested 34 normal subjects in their ability to set a straight line to the perceived gravitational vertical. Measurements were taken in static conditions, sitting upright, head tilted (15Degree, body tilted (15Degree, and head lateral positions (90Degree on the right/left sides with or without physical support under the head. RESULTS: The normal range of the subjective visual vertical (SVV) was 0.65Degree/-.23Degreein upright position. The normal ranges of SVV in head-tilts 15Degreeto the left/right sides were -0.47Degree/-.76Degreeand 1.88Degree/-.94Degree which were significantly different from those in upright position (E-effect). But the normal ranges of SVV in body-tilts 15Degreeto the left/right were not different from those in upright position. And the normal ranges of SVV in head lateral positions maintained actively and passively were not different each other, but significantly larger than that in upright position (A-effect). CONCLUSION: Our results support that neck somatosensory input plays a part in the perception of verticality. In contrast, tactile sensation of the head had no effect on the settings of a visual line to visual vertical in head lateral positions.
Head ; Neck ; Otolithic Membrane ; Reference Values ; Sensation

Tumarkin's otolithic crisis refers to drop attacks of vestibular origins. It usually occurs without warning in patients with late or end-stage endolymphatic hydrops. However, drop attacks of vestibular origins may occur in patients without otologic deficit. We report a patient with Tumarkin's otolithic crisis from delayed endolymphatic hydrops. The careful delineation of drop attacks in patients with vertigo can provide appropriate therapeutic options for patients with this potentially dangerous condition.
Endolymphatic Hydrops ; Humans ; Otolithic Membrane* ; Syncope ; Vertigo

Benign paroxysmal positional vertigo (BPPV) is characterized by brief recurrent episodes of vertigo triggered by changes in head position. BPPV is the most common etiology of recurrent vertigo and is caused by abnormal stimulation of the cupula by free-floating otoliths (canalolithiasis) or otoliths that have adhered to the cupula (cupulolithiasis) within any of the three semicircular canals. Typical symptoms and signs of BPPV are evoked when the head is positioned so that the plane of the affected semicircular canal is spatially vertical and thus aligned with gravity. Paroxysm of vertigo and nystagmus develops after a brief latency during the Dix-Hallpike maneuver in posterior-canal BPPV, and during the supine roll test in horizontal-canal BPPV. Positioning the head in the opposite direction usually reverses the direction of the nystagmus. The duration, frequency, and symptom intensity of BPPV vary depending on the involved canals and the location of otolithic debris. Spontaneous recovery may be expected even with conservative treatments. However, canalithrepositioning maneuvers usually provide an immediate resolution of symptoms by clearing the canaliths from the semicircular canal into the vestibule.
Gravitation ; Head ; Otolithic Membrane ; Semicircular Canals ; Vertigo

BACKGROUND AND OBJECTIVES: Subjective visual vertical (SVV) and subjective visual horizontal (SVH) are well known otolith function tests. Patients with acute unilateral vestibular weakness have a tendency to set the bar toward the side of the lesion in SVV and SVH tests. The object of this article is to identify the effect of preset angle on SVV and SVH tests in normal subjects and patients with dizziness. MATERIALS AND METHODS: From October 2008 to March 2009, thirty healthy volunteers, twenty eight vestibular neuritis (VN) patients (14-uncompensated, 14-compensated), Twenty five patients who had migrainous vertigo (MV) were enrolled. All subjects performed the test two times in each of the clockwise and counter-clockwise preset angle. RESULTS: In normal subjects, there was significant influence by preset angle on SVV test, not on SVH test. In VN patients with nystagmus, both SVH and SVV were not influenced by preset angle. In VN patients without nystagmus and in MV patients, there were significant influence by preset angle on both SVV and SVH tests. CONCLUSION: SVV and SVH values depend on the direction of the preset angle in MV and uncompensated VN patients. The preset angle should be considered in the interpretation of SVV and SVH values.
Dizziness ; Humans ; Otolithic Membrane ; Vertigo ; Vestibular Neuronitis

Benign paroxysmal positional vertigo (BPPV) is easily diagnosed when the specific pattern of nystagmus is demonstrated by adequate provoking maneuver. Therefore, recognizing the pattern of nystagmus is important to determine the affected ear and whether the otoconia is free-floating in the canal or attached to the cupula. However, the latency and the duration of nystamus can be various depending on the type of otoconia and even the direction of nystagmus is atypical in some cases. In addition, not all the positionally-induced nystamus are ascribed to benign semicircular canal pathology. Atypical pattern and refractory for the canalith repositioning maneuver can raise the possibility for the central positional vertigo or nystagmus. Physicians are often perplexed if the pattern of nystagmus by positioning maneuver is not the expected one. For those account, physicians should be well equipped with the knowledge of the pathophysiology of nystamus in BPPV. The pathophysiology and the various patterns of nystagmus in BPPV are discussed in this review.
Ear ; Otolithic Membrane ; Semicircular Canals ; Vertigo

Benign paroxysmal positional vertigo (BPPV) is characterized by brief recurrent episodes of vertigo triggered by head positional changes. BPPV is one of the most common causes of recurrent vertigo. BPPV results from abnormal stimulation of the cupula within any of the three semicircular canals by free-floating otoliths (canalithiasis) or otoliths adhered to the cupula (cupulolithiasis). Spontaneous recovery occurs frequently even with conservative treatment. However, canalith repositioning maneuvers are believed to be the best way to treat BPPV by moving the canaliths from the semicircular canal to the vestibule. Various treatment methods of posterior, superior, and lateral canal BPPV are discussed in this review.
Head ; Methods ; Otolithic Membrane ; Semicircular Canals ; Vertigo

BACKGROUND AND OBJECTIVES: Benign paroxysmal positional vertigo (BPPV) has been well controlled with otolith reposition therapy. Posterior canal is known as the most common site of BPPV. The purpose of this study was to study the therapeutic result of reposition therapy in posterior canal BPPV, to investigate the unusual cases such as recurred cases and type changed cases during the reposition maneuver, and to figure out the therapeutic strategy. MATERIALS AND METHODS: One hundred and ten patients diagnosed posterior canal BPPV were included in this study. Epley maneuver was performed once a day until nystagmus disappeared. We analyzed the number of treatment, changing type, recurrence and the relationship between recurrence and age or sex of patients. RESULT: All cases except 2 were recovered by Epley maneuver. In 11 cases, the type of disease was changed, and the treatment of these cases were changed according to new type and origin. Overall recurrence rate was 15%, and they were completely treated with reposition therapy. There was no correlation between recurrence and age, sex of patients. CONCLUSION: All most cases were cured with Epley maneuver. The type of the disease was possibly changeable. Recurrence rate was relative high, and close follow up was required.
Follow-Up Studies ; Humans ; Otolithic Membrane* ; Recurrence ; Semicircular Canals* ; Vertigo