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1.
Strahlenther Onkol ; 194(12): 1132-1143, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30203112

ABSTRACT

PURPOSE: Stereotactic radiosurgery (SRS) is an effective treatment for vestibular schwannoma (VS). Three-dimensional (3D) constructive interference in steady state (CISS) is the preferred magnetic resonance imaging (MRI) sequence for evaluating signal changes in the inner ear endolymph. Previous studies demonstrated a correlation between pretreatment cochlear signal intensity in 3D-CISS and posttherapeutic hearing outcomes. The purpose of our study was to compare 3D-CISS sequences before and after primary SRS of unilateral VSs to evaluate the effect of radiosurgery on the 3D-CISS signal intensities of cochlea and sacculus/utriculus. METHODS: We retrospectively reviewed 47 patients with unilateral VS treated with SRS. The neuroradiological MRI datasets were analysed to evaluate the signal intensity of the inner ear structure, tumour size, Koos grade, tumour volume, and infiltration of the cochlear aperture before therapy and at follow-up. The differences in these signal intensities before SRS and at follow-up were correlated with clinical symptoms, cochlear radiation dose, tumour volume and infiltration of the cochlear aperture. RESULTS: No differences were found between signal intensities in cochlea and utriculus/sacculus before and after SRS and no correlation with clinical symptoms, cochlear radiation dose, tumour volume, Koos grade or infiltration of the cochlear aperture (all p > 0.05). CONCLUSION: Our study supports the theory of a complex interaction causing alteration of the endolymph protein concentration and not a direct dependency on the SRS. Use of modern dosing schemes will have a positive impact on clinical outcome with preservation of hearing in patients with VS.


Subject(s)
Hearing/radiation effects , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Neuroma, Acoustic/radiotherapy , Radiosurgery/methods , Radiotherapy Planning, Computer-Assisted/methods , Adult , Aged , Audiometry, Pure-Tone , Cochlea/diagnostic imaging , Cochlea/radiation effects , Female , Humans , Male , Middle Aged , Neuroma, Acoustic/diagnostic imaging , Predictive Value of Tests , Prognosis , Retrospective Studies , Saccule and Utricle/diagnostic imaging , Saccule and Utricle/radiation effects , Treatment Outcome
2.
J Neurophysiol ; 119(2): 662-667, 2018 02 01.
Article in English | MEDLINE | ID: mdl-29118200

ABSTRACT

The vestibular system plays a critical role in detection of head movements and is essential for normal postural control. Because of their anatomical proximity to the cochlea, the otolith organs are selectively exposed to sound pressure and are at risk for noise overstimulation. Clinical reports suggest a link between noise exposure and balance problems, but the structural and physiological basis for this linkage is not well understood. The goal of this study was to determine the effects of low-frequency noise (LFN) on the otolith organs by correlating changes in vestibular short-latency evoked potentials (VsEPs) with changes in saccular afferent endings following noise exposure. LFN exposure transiently abolished the VsEP and reduced the number of stained calyces within the sacculus. Although some recovery of the VsEP waveform could be observed within 3 days after noise, at 3 wk recovery was only partial in most animals, consistent with a reduced number of afferents with calyceal endings. These data show that a single intense noise exposure is capable of causing a vestibular deficit that appears to mirror the synaptic deficit associated with hidden hearing loss after noise-induced cochlear injury. NEW & NOTEWORTHY This is the first study to explore the effects of low-frequency high-intensity noise on vestibular short-latency evoked potential (VsEP) responses, which shows a linkage between attenuated noise-induced VsEPs and pathological changes to otolith organ afferents. This finding suggests a potential limitation of the VsEP for evaluation of vestibular dysfunction, since the VsEP measurement may assess the activity of a specific class rather than all afferents.


Subject(s)
Noise/adverse effects , Saccule and Utricle/radiation effects , Vestibular Evoked Myogenic Potentials , Animals , Male , Rats , Rats, Sprague-Dawley , Reaction Time , Saccule and Utricle/physiology
3.
Laryngoscope ; 119(8): 1594-605, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19479742

ABSTRACT

OBJECTIVES/HYPOTHESIS: To assess the potential carbon dioxide (CO(2)) and potassium-titanyl-phosphate (KTP) laser-related trauma to the saccule and utricle in a cat model. STUDY DESIGN: Basic science experiment utilizing cat model. METHODS: Twelve adult male cats were divided into two groups-CO(2) and KTP-to assess the potential saccule and/or utricle trauma with direct discharge of laser energy into the vestibule after the stapes was removed. Both groups were subdivided to assess the effects with acute sacrifice and three-month survival. Bone conduction auditory brain-stem response thresholds were used to monitor auditory function. Clinical observation was used to monitor vestibular function. The temporal bones were harvested, processed, and stained with hematoxylin and eosin (H&E) in all animals with the uninvolved side serving as the control. RESULTS: None of the animals demonstrated changes in bone conduction auditory brain-stem responses. None of the animals in the survival group demonstrated clinical vestibular dysfunction. Saccular and utricular wall rupture was observed in all animals sacrificed acutely. None of the saccular and utricular wall ruptures were of a size and location that could be attributed to laser trauma, and none of the saccular and utricular wall ruptures were associated with neuroepithelial trauma. CONCLUSIONS: There is no evidence of a difference between the CO(2) and KTP laser in potential laser-related trauma. Using bone-conducting auditory brain-stem response threshold and clinical monitoring of vestibular function, there was no evidence of clinical auditory or vestibular dysfunction. The histologic evidence of saccular and utricular wall rupture is more consistent with stapes extraction trauma than laser-related trauma.


Subject(s)
Evoked Potentials, Auditory, Brain Stem/radiation effects , Lasers, Gas/therapeutic use , Lasers, Solid-State/therapeutic use , Low-Level Light Therapy/methods , Saccule and Utricle/injuries , Animals , Auditory Threshold/radiation effects , Biopsy, Needle , Bone Conduction/radiation effects , Cats , Disease Models, Animal , Evoked Potentials, Auditory, Brain Stem/physiology , Immunohistochemistry , Lasers, Gas/adverse effects , Lasers, Solid-State/adverse effects , Low-Level Light Therapy/adverse effects , Male , Random Allocation , Reference Values , Risk Assessment , Saccule and Utricle/radiation effects , Sensitivity and Specificity , Stapes Surgery , Vestibule, Labyrinth/pathology , Vestibule, Labyrinth/radiation effects
4.
J Comp Physiol A ; 172(6): 653-62, 1993.
Article in English | MEDLINE | ID: mdl-8350283

ABSTRACT

1. Responses of 73 fibers to dorso-ventral vibration were recorded in the saccular and utricular branchlets of Rana pipiens pipiens using a ventral approach. The saccular branchlet contained nearly exclusively vibration-sensitive fibers (33 out of 36) with best frequencies (BFs) between 10 and 70 Hz, whereas none of the 37 fibers encountered in the utricular branchlet responded to dorso-ventral vibrations. 2. Using a dorsal approach we recorded from the VIIIth nerve near its entry in the brainstem and analyzed responses to both sound and vibration stimuli for 65 fibers in R. pipiens pipiens and 25 fibers in Leptodactylus albilabris. The fibers were classified as amphibian papilla (AP), basilar papilla (BP), saccular or vestibular fibers based on their location in the nerve. Only AP and saccular fibers responded to vibrations. The AP-fibers responded to vibrations from 0.01 cm/s2 and to sound from 40 dB SPL by increasing their spike rate. Best frequencies (BFs) ranged from 60 to 900 Hz, and only fibers with BFs below 500 Hz responded to vibrations. The fibers had identical BF's for sound and vibration. The saccular fibers had BFs ranging from 10 to 80 Hz with 22 fibers having BFs at 40-50 Hz. The fibers responded to sound from 70 dB SPL and to vibrations from 0.01 cm/s2. 3. No differences in sensitivity, tuning or phase-locking were found between the two species, except that most BP-fibers in R. pipiens pipiens had BFs from 1.2 to 1.4 kHz, whereas those in L. albilabris had BFs from 2.0 to 2.2 kHz (matching the energy peak of L. albilabris' mating call). 4. The finding that the low-frequency amphibian papilla fibers are extremely sensitive to vibrations raises questions regarding their function in the behaving animal. They may be substrate vibration receptors, respond to sound-induced vibrations or bone-conducted sound.


Subject(s)
Anura/physiology , Rana pipiens/physiology , Sound , Vestibulocochlear Nerve/physiology , Vibration , Animals , Nerve Fibers/physiology , Nerve Fibers/radiation effects , Saccule and Utricle/physiology , Saccule and Utricle/radiation effects , Vestibulocochlear Nerve/radiation effects
5.
Otolaryngol Head Neck Surg ; 103(6): 926-30, 1990 Dec.
Article in English | MEDLINE | ID: mdl-1980533

ABSTRACT

An argon laser was used to irradiate the otolithic organs of guinea pigs and cynomolgus monkeys. After stapedectomy, the argon laser (1.5 W x 0.5 sec/shot) irradiated the utricle or saccule without touching the sensory organs. The stapes was replaced over the oval window after irradiation. The animals used for acute observation were killed immediately for morphologic studies; those used for long-term observation were kept alive for 2, 4, or 10 weeks. Acute observation revealed that sensory and supporting cells were elevated from the basement membrane only in the irradiated area. No rupture of the membranous labyrinth was observed. Long-term observation revealed that the otolith of the macula utriculi had disappeared in 2-week specimens. The entire macula utricili had disappeared in 10-week specimens. No morphologic changes were observed in cochlea, semicircular canals, or membranous labyrinth. The saccule showed similar changes.


Subject(s)
Laser Therapy , Otolithic Membrane/radiation effects , Acoustic Maculae/pathology , Acoustic Maculae/radiation effects , Acoustic Maculae/ultrastructure , Animals , Argon , Basement Membrane/radiation effects , Basement Membrane/ultrastructure , Cytoplasm/radiation effects , Cytoplasm/ultrastructure , Guinea Pigs , Labyrinth Supporting Cells/pathology , Labyrinth Supporting Cells/radiation effects , Labyrinth Supporting Cells/ultrastructure , Macaca fascicularis , Microscopy, Electron , Otolithic Membrane/ultrastructure , Saccule and Utricle/pathology , Saccule and Utricle/radiation effects , Saccule and Utricle/ultrastructure , Stapes Surgery , Time Factors , Wound Healing
6.
Nihon Jibiinkoka Gakkai Kaiho ; 93(2): 199-206, 1990 Feb.
Article in Japanese | MEDLINE | ID: mdl-2348279

ABSTRACT

Experimental positional nystagmus (EPN) similar to benign paroxysmal positional nystagmus (BPPN) was induced in 8 of 20 rabbits by argon laser irradiation to the footplate. The power of the argon beam used was 2.0 watts and irradiation time was 1 or 2 sec. EPN and BPPN showed the following similarities maintained (1) When the head was maintained in the affected ear down position and the head positioned from the sitting to the supine position nystagmus directed to the affected ear or vertical nystagmus corresponding to rotatory nystagmus in man were provoked. (2) Delayed onset for provocation of nystagmus. (3) Limited duration. (4) Fatigability. (5) The direction of nystagmus was reversed when the head returned to the initial position (in two rabbits). Histological examination of the temporal bones showed separation of otoconia from the otolithic membrane of the saccule and bleeding in the saccule in both conditions. No lesions in the utricle and semicircular canals were evident. It was assumed that ablation of otoconia of the saccule causes this experimental positional nystagmus.


Subject(s)
Lasers , Nystagmus, Pathologic/etiology , Oval Window, Ear/radiation effects , Vestibule, Labyrinth/radiation effects , Animals , Disease Models, Animal , Head , Posture , Rabbits , Saccule and Utricle/pathology , Saccule and Utricle/radiation effects
7.
Acta Otolaryngol ; 100(5-6): 365-78, 1985.
Article in English | MEDLINE | ID: mdl-4082975

ABSTRACT

The 13th and 16th gestational day inner ear anlagen, respectively, were exposed after explantation to an organ culture system to low-dose gamma irradiation with a 2 Gy single dose. The explants were thereafter cultured in vitro for 8 vs. 5 days to an age corresponding to birth in vivo. The explants were analysed with regard to gross morphology and at the light and electron microscopic levels. The 13th gestational day inner ear anlage showed malformations of the gross shape. The gross morphology of the 16th gestational day inner ear explant was unaffected. Irradiated specimens showed a delayed development in general as compared with controls. A defective cytodifferentiation of hair cells was observed at the ultrastructural level. Sensory hair fusion occurred, the sensory hair rootlets were poorly developed as also was the cuticle. Nerve terminals were not identified. The observations in the present in vitro study are in agreement with corresponding earlier published in vivo investigations. The organ culture model can thus be used for irradiation induced selective effects on labyrinthine development.


Subject(s)
Ear, Inner/embryology , Gamma Rays/adverse effects , Radiation, Ionizing/adverse effects , Animals , Cochlea/radiation effects , Ear, Inner/radiation effects , Hair Cells, Auditory/radiation effects , Hair Cells, Auditory/ultrastructure , In Vitro Techniques , Mice , Mice, Inbred CBA , Saccule and Utricle/radiation effects , Semicircular Canals/radiation effects , Time Factors
8.
Am J Otolaryngol ; 6(2): 79-91, 1985.
Article in English | MEDLINE | ID: mdl-3993862

ABSTRACT

Thirty-two CBA/CBA mice were irradiated in utero on the 12th, 13th, or 16th gestational day with doses of 0.5, 1, and 2 Gy, respectively (1 Gy = 100 rads). One month after birth, the inner ears were examined by light microscopy and transmission and scanning electron microscopy. Otoconia with defective shapes was identified frequently. The strict hexagonal shape of normal otoconia seldom developed and, in exposed animals, had often been replaced with rounded, oval, or elongated shapes. The otoconial substructure was disarrayed, and fusion of two or three otoconia occurred. Degenerating otoconia appeared in the intercellular space of the dark-cell epithelium. Fetal gross structures of otoconia persisted into maturity.


Subject(s)
Otolithic Membrane/radiation effects , Saccule and Utricle/radiation effects , Animals , Female , Gamma Rays , Mice , Mice, Inbred CBA , Microscopy, Electron , Microscopy, Electron, Scanning , Otolithic Membrane/ultrastructure , Pregnancy , Prenatal Exposure Delayed Effects
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