Correlations Between Vestibular Function and Imaging of the Semicircular Canals in DFNA9 Patients

Abstract

Background and Purpose: Radiologic abnormalities on computed tomography (CT), including narrowing or sclerosis of the semicircular canals (SCCs), and T2-weighted magnetic resonance imaging (MRI), including signal loss in the SCC, have been reported as potential biomarkers in patients with P51S mutations in the COCH gene (i.e., DFNA9). The aim of our study was to correlate caloric responses through electronystagmography (ENG) data with imaging results in DFNA9 patients. Materials and Methods: A retrospective study was performed in 45 patients; therefore, 90 ears with P51S mutations in the COCH gene were tested. Caloric responses and CT and MRI data were analyzed from June 2003 until May 2014. More than half of patients (54%) were candidates for cochlear implantation. Results: In our population, 91% of tested ears had sclerotic lesions and/or narrowing in one or more SCCs on CT scan. All tested ears had narrowing or signal loss in at least one SCC on T2-weighted MRI. The lateral SCC was affected in 87% on CT scan and 92% on MRI. However, in 83% of tested ears, all three SCCs were affected on MRI. Furthermore, in 77% of tested ears, caloric responses were reduced bilaterally, while 11.5% showed unilateral hypofunction and the other 11.5% had normal caloric responses. CT abnormalities correlated with hypofunction of caloric responses. This statistically significant difference was present if abnormalities were observed in at least one of the SCCs as well as in ipsilateral lateral SCC function loss. MRI abnormalities in at least one of the SCCs correlated with ENG hypofunction, but there was no direct correlation between lateral SCC abnormalities on MRI and caloric responses of the investigated lateral canal. Conclusion: Our retrospective analysis confirms the presence of CT and MRI abnormalities in DFNA9 patients with the P51S mutation in the COCH gene. A correlation between these radiologic features and vestibular function (tested by means of caloric response) was found in this population.

Radiologic Features in Cochlear Implant Candidates: A Prospective Study Comparing Candidates Carrying the p.Pro51Ser Mutation in Coagulation Factor C Homology With Noncarriers

“…Ihtijarevic et al (26) demonstrated a correlation between hypofunction of caloric responses in patients with focal sclerosis on CT and T2-weighted MRI signal loss, but this was not confirmed with the present study. However, a correlation was observed between vHIT VOR gains in all SCC separately and the presence of MRI lesions.…”

“…However, similar lesions were also observed in another cohort consisting of CI candidates who were not carrying the p.P51S COCH -mutation. These radiologic lesions were only observed in case patients had reached similar stages of (advanced) hearing and vestibular deterioration as carriers, and they were far less prevalent compared to DFNA9 patients (26).…”

On the Role of Fibrocytes and the Extracellular Matrix in the Physiology and Pathophysiology of the Spiral Ligament

“…Previous research has demonstrated that mutations in the COCH gene cause DFNA9, an autosomal dominant disorder that causes progressive sensorineural hearing loss associated with vestibular dysfunction (50,(52)(53)(54)(55). Mutations can cause misfolding and progressive accumulation of mutant proteins leading to degeneration of dendrites and loss of vestibular and cochlear neurons.…”

Making the Case for Research on Disease-Modifying Treatments to Tackle Post-lingual Progressive Sensorineural Hearing Loss

“…Progressive vestibular dysfunction starts at a similar age and evolves toward bilateral vestibular function loss (bilateral vestibulopathy, BVP). BVP causes oscillopsia and imbalance while walking (especially in the dark) (75)(76)(77)(78)(79)(80)(81)(82)(83). Currently, no treatment is available to prevent or slow down sensorineural hearing loss or BVP in DFNA9 patients.…”