Methods
A Neurotologist specialist examination revealed no abnormalities. The
auditory evaluation confirmed bilateral conductive hearing loss,
particularly affecting the airway thresholds between 125 to 1000 Hz
frequencies, with ascending curves. Also, the bone conduction study
showed thresholds below 0 dB at 250, 500, and 1000 Hz. Video Oculo
Nystagmography (VNG) was conducted, including analysis of spontaneous
nystagmus with and without ocular fixation and assessment of eye
movements such as slow tracking and saccades. The results were within
normal limits. Additionally, video head impulse test(v-Hit) testing
yielded normal findings. Cervical vestibular myogenic evoked potentials
(c-VEMPs) demonstrated a significant decrease in presentation
thresholds, even occurring at stimuli below 60 dB bilaterally, with
amplitudes well above average values.
Furthermore, spontaneous nystagmus without ocular fixation was observed
during pressure stimuli using the Valsalva Maneuver and sound
stimulation while pronouncing the phoneme ”M.” In particular, the
production of the mentioned phoneme triggered an intense horizontal
rotational nystagmus to the left, defined as “fremitus
nystagmus”4 . Based on the findings, a diagnosis of
bilateral superior semicircular canal dehiscence (B-SCD) is proposed. A
high-resolution ear CT scan with cuts smaller than 0.5 mm is recommended
to confirm the presence of the bone defect (Figure 1 ).
The diagnosis of B-SCD relies on a combination of characteristic
symptoms, audiometric testing, and radiographic findings. Ward et al.
established consensus criteria that include air-bone gaps on audiometry
and visible dehiscence of the superior canal on high-resolution CT
scans. Additional vestibular symptoms may include trigged dizziness or
nystagmus in response to loud noises, as noted in the case report. While
conservative treatment is reasonable in milder cases, surgery aimed at
resurfacing or plugging the dehiscent canal can relieve
symptoms4. The described bilateral B-SCD repair
surgery improves conductive hearing loss, though vestibular disturbances
may persist3-5.