[Superior canal dehiscence syndrome : Diagnosis with vestibular evoked myogenic potentials and fremitus nystagmus. German version]

BACKGROUND

Superior canal dehiscence syndrome (SCDS) is a relatively rare neurotological disorder that is characterized by a heterogeneous clinical picture. Recently, vestibular evoked myogenic potential (VEMP) measurementwas established for the diagnosis of SCDS. In the present study, a case series of patients with SCDS were analyzed, with a focus on VEMP.

METHODS

Four patients with SCDS were prospectively examined with ocular VEMP (oVEMP) and cervical VEMP (cVEMP). The clinical features and the standard audiovestibular test battery results are summarized and analyzed. The diagnostic accuracy of VEMP testing is evaluated.

RESULTS

The increased oVEMP amplitudes had a specificity of 100% in this patient population. All patients had normal caloric function and head impulse testing. The Tullio sign was observed in two patients. Three patients had autophony. The airbone gap was not greater than 10 dB in any of the patients. Two patients had marked fremitus nystagmus. All patients had a bony dehiscence of the superior semicircular canal on computed tomography imaging.

CONCLUSION

The subjective and clinical features in this case series of SCDS patients were heterogeneous. However, objective oVEMP testing had the highest diagnostic value. Furthermore, we describe a new diagnostic clinical sign: fremitus nystagmus.

Clinical features of delayed endolymphatic hydrops and intralabyrinthine schwannoma : An imaging-confirmed comparative case series. English version

BACKGROUND

The aim of this study was to compare the clinical history and audiovestibular function test results of patients suffering from intralabyrinthine schwannoma or delayed endolymphatic hydrops (DEH).

PATIENTS AND METHODS

Five patients diagnosed with intralabyrinthine schwannoma by magnetic resonance imaging (MRI) and five patients diagnosed with DEH by locally enhanced inner ear MRI (LEIM) were retrospectively studied.

RESULTS

All patients with intralabyrinthine schwannoma or DEH initially presented with hearing loss. Vertigo occurred in two patients with intralabyrinthine schwannoma and in all patients with DEH. While audiometry achieved poorer results for patients with intralabyrinthine schwannomas, vestibular function tests revealed normal results in about half of the patients in both groups.

CONCLUSION

Patients with intralabyrinthine schwannomas may present with clinical symptoms similar to patients suffering from other inner ear disorders such as delayed endolymphatic hydrops and they may obtain similar findings in audiovestibular function tests. High-resolution magnetic resonance imaging with locally applied contrast agent may provide evidence of both underlying pathologies.