Superior Semicircular Canal Dehiscence Syndrome without Vestibular Symptoms

Teixeira, Emidio; Fonseca, Marconi Teixeira

doi:10.1055/s-0033-1351670

Cited by 4 publications

(3 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reason for a mixed or conductive loss can be explained by the third window effect. Sensorineural hearing loss is not unknown either (16, 17, 24, 25) and in this series it was observed in 2 children. These children did not show any balance symptoms and the reason they were requested for a high resolution CT was because their MRI was normal as suggested in the aetiological diagnosis algorithm.…”

Section: Discussionmentioning

confidence: 49%

Functional and Objective Audiovestibular Evaluation of Children With Apparent Semicircular Canal Dehiscence–A Case Series in a Pediatric Vestibular Center

Dasgupta

Ratnayake

2019

Front. Neurol.

View full text Add to dashboard Cite

Semicircular canal dehiscence is a bony abnormality in the otic capsule especially involving the superior semicircular canal. Since its identification in 1998, there is significant research regarding the pathology in the adult population. This condition generates a third window effect that is well–described in the literature. However, the entity is rare in the pediatric population with limited research. Difficulties encountered in children are obtaining a direct history that is essential for the diagnosis followed by neurovestibular tests that may be difficult to perform. This study presents observations regarding different clinical and diagnostic aspects of semicircular canal dehiscences in children as a retrospective audit in a tertiary pediatric vestibular center. Of 580 children assessed in a 30 months period undergoing comprehensive functional and objective audiovestibular assessment, 13 children (2.2%) were detected to possess radiological semicircular canal dehiscences (high resolution computed tomography scans at 0.625 mm slices reformatted in the axial, coronal and sagittal planes). The right superior semicircular canal was most commonly affected (66.6%). There were 4 bilateral semicircular canal dehiscences. Clinical suspicion of the condition was raised with reliable surrogate history from carers or from older children (100%), a mixed or conductive hearing loss (80% of hearing losses) in the presence of normal impedance audiometry (92.3%), normal transient otoacoustic emissions (84.6%) on the side of the dehiscence and the presence of replicable pathological saccades in the video head impulse test (76.9%). Disequilibrium symptoms and typical third window symptoms were absent or difficult to elicit in children (46.15 and 30.76% respectively). Only 3 (0.5%) fulfilled the adult criteria of a superior semicircular canal dehiscence syndrome. The abnormal video head impulse test characterized by pathological saccades may affect other non-dehisced ipsilateral canals. Semicircular canal dehiscences are rare in children but may be considered as an etiology for hearing losses and imbalance. Children with semicircular canal dehiscence may present differently from the classical superior semicircular canal dehiscence syndrome found in adults.

show abstract

Section: Discussionmentioning

confidence: 49%

Functional and Objective Audiovestibular Evaluation of Children With Apparent Semicircular Canal Dehiscence–A Case Series in a Pediatric Vestibular Center

Dasgupta

Ratnayake

2019

Front. Neurol.

View full text Add to dashboard Cite

show abstract

“…In the current series, three-fourths of the children in the series complained of some features of disequilibrium that is characteristic of a third window abnormality (47). However, balance symptoms may be absent altogether (5,20,47,71). We believe that this could be due to central compensation.…”

Section: Discussionmentioning

confidence: 57%

Audiovestibular Quantification in Rare Third Window Disorders in Children

et al. 2020

View full text Add to dashboard Cite

“…Although the third-window hypothesis is useful for explaining our experimental results and many symptoms observed in patients with SSCD syndrome, it is unclear how it resolves the vast variability in symptoms in SSCD patients mechanistically. Some SSCD patients show debilitating vestibular symptoms, such as a severe sound-induced or pressure-induced vertigo with normal hearing; others have hearing loss, such as conductive, sensorineural, or mixed, with no significant vestibular symptoms; and some patients seem to have a combination of vestibular and auditory symptoms [ 3 , 6 – 8 , 19 , 20 ]. What is the mechanistic basis for these different clinical symptoms?…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Hearing Loss in a Guinea Pig Model of Superior Semicircular Canal Dehiscence

Tong

Ding

et al. 2018

Neural Plasticity

View full text Add to dashboard Cite

Defective acoustic transmission in the cochlea is closely related with various auditory and vestibular symptoms. Among them, semicircular canal dehiscence (SCD) with a defective semicircular bone is typical. Currently, the pathogenesis of SCD is usually explained by the third window hypothesis; however, this hypothesis fails to explain the variability in the symptoms and signs experienced by superior SCD (SSCD) patients. We evaluated the mechanism of hearing loss in a guinea pig model of bony dehiscence with various sizes and locations along the superior semicircular canal. Auditory brainstem responses (ABRs) and laser Doppler velocimetry were used to measure hearing loss and vibration changes before and after fenestration, as well as after restorative patching. ABR thresholds at low frequencies (e.g., 1000 Hz) increased after fenestration and decreased back to the normal range after we repaired the defect. Energy leakage from the surgically introduced third window was detected in the range of 300–1500 Hz, accompanied by increased vibration at the umbo, stapes head, and the dehiscence site, while decreased vibration was observed at the round window membrane in the same frequency range. After the patching procedure, the deviant vibrations were recovered. The degree of postfenestration energy leakage was proportional to the size of fenestration and the proximity of the fenestration site to the oval window. These results suggest that the bony fenestration of the superior semicircular canal mimics the hearing loss pattern of patients with SSCD. The decrease in perilymph wave impedance likely accounts for the auditory changes.

show abstract

Superior Semicircular Canal Dehiscence Syndrome without Vestibular Symptoms

Cited by 4 publications

References 15 publications

Functional and Objective Audiovestibular Evaluation of Children With Apparent Semicircular Canal Dehiscence–A Case Series in a Pediatric Vestibular Center

Functional and Objective Audiovestibular Evaluation of Children With Apparent Semicircular Canal Dehiscence–A Case Series in a Pediatric Vestibular Center

Audiovestibular Quantification in Rare Third Window Disorders in Children

Mechanisms of Hearing Loss in a Guinea Pig Model of Superior Semicircular Canal Dehiscence

Contact Info

Product

Resources

About