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Evaluation of the Skull Base Patient
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Jeyanthi Kulasegarah, Richard M. Irving
Tullio phenomenon is sound-induced episodic vertigo and dysequilibrium and has been associated with a number of conditions, including superior semicircular canal dehiscence (SSCD),30 perilymph fistula31 and middle ear osteoma.32 In a series of 65 patients with SSCD, 60 patients had vestibular manifestations and Tullio phenomenon was noted in 90% of patients.30 Oscillopsia is an unpleasant blurring and jumping of the external world during active and/or passive head movements. If oscillopsia is only present during head movement, the likely underlying cause is bilateral defect in the vestibulo-ocular-reflex (VOR). The more common causes are post-meningitic vestibular failure, gentamicin toxicity or bilateral idiopathic vestibular failure. If oscillopsia comes in brief attacks and is unrelated to head movements, it is usually due to irritative VIIIth nerve and brainstem lesions.33
Video-head impulse test in superior canal dehiscence
Published in Acta Oto-Laryngologica, 2021
Payal Mukherjee, Elodie Chiarovano, Kai Cheng, Leonardo Manzari, Leigh A. McGarvie, Hamish G. MacDougall
This was a retrospective study of 8 patients with 11 SCDs. Data was collected between 2011 and 2019. The sample consisted of 11 ears of 8 patients (3 patients had bilateral unoperated SCD) aged from 34 to 80 years. There were 6 females and 2 males with 5 left and 6 right sided SCD. The size of the defects ranged from 1.5 to 5.7 mm (Table 1). Patients had undergone high resolution petrous temporal bone CT scan including helical CT (0.5 mm) and cone beam CT (125 µm). All subjects also underwent audiogram, cervical and ocular VEMPs and vHIT. Patients presented with a range of symptoms from tullio phenomenon to autophony only. All patients had unambiguous SCD on CT and typical SCD type results on air-conducted VEMP testing: enhanced amplitude and/or decreased threshold of response [6,9]. Patients who had previous ear surgery were excluded.
Cone beam computed tomography imaging of superior semicircular canal morphology: a retrospective comparison of cleft lip/palate patients and normal controls
Published in Acta Odontologica Scandinavica, 2018
Oğuzhan Altun, Suayip Burak Duman, Ibrahim Sevki Bayrakdar, Yasin Yasa, Sacide Duman, Sevcihan Günen Yılmaz
The vestibular system is composed of three semicircular canals (SSCs) and otoliths in the temporal bone. The SSCs run in the posterior, superior and horizontal planes of the bony labyrinth of the inner ear. Each SSC is at a 90° angle to the others. The superior semicircular canal (SSCC) is a component of the vestibular system, regulating rotation of the head around the anteroposterior axis [6,7]. SSCD reflects the absence of bone overlying the SSC and is rare in the absence of lateral canal involvement [6,8–10]. SSCD was first identified by Minör et al. [11] in 1998 as a specific clinical abnormality of the temporal bone [11]. SSCD can cause both vestibular and cochlear symptoms. Auditory symptoms include hyperacusis, tinnitus, aural fullness, and autophony. Vertigo or nystagmus evoked by load noise (the Tullio phenomenon), oscillopsia, changes in middle ear pressure, and disequilibrium caused by sound or changes in intracranial pressure are among the vestibular symptoms of such patients [10,12–15]. Also, SSCD may afford a pathway for the intracranial spread of infection [16].
Bilateral asynchronous sudden sensorineural hearing loss and bilateral superior semicircular canal dehiscence*
Published in Hearing, Balance and Communication, 2018
SSCD syndrome was described by Minor et al. [1] in 1998. The bony labyrinth has two openings, the oval and round windows, to allow for the transmission of sound pressure waves from the middle to the inner ear. The presence of a dehiscence in the bone overlying the membranous SSCC creates a third window, giving rise to: auditory and/or vestibular symptoms, such as hearing loss (most commonly low-frequency conductive or mixed with normal tympanograms and acoustic reflex thresholds), autophony, hyperacusis, aural fullness, tinnitus, imbalance, sound-induced vertigo (Tullio phenomenon), middle ear pressure- or intracranial pressure-induced vertigo (Hennebert sign), and oscillopsia [1–3]. The prevalence of SSCD is estimated to be ∼0.5–0.6%, with an additional 1–2% of the population having a very thin layer of bone overlying the canal. However, not all persons with complete or partial SSCD experience symptoms [3,4].