ABSTRACT
OBJECTIVES: Assesses whether preoperative functional testing can distinguish vestibular schwannomas from facial nerve schwannomas medial to the labyrinthine segment. STUDY DESIGN: Retrospective cohort. METHODS: Retrospectively review surgically managed intracranial facial and vestibular schwannomas between January 2015 and December 2019 at two tertiary care centers. Patients with neurofibromatosis 2 and surgery for recurrence were excluded. Preoperative functional testing to include House-Brackmann scores, electroneuronography (ENoG), cervical vestibular evoked myogenic potentials (cVEMP), caloric testing, acoustic brainstem responses (ABRs), acoustic reflexes, and audiograms was compared between the two groups of schwannomas. RESULTS: Twelve facial and 128 vestibular schwannomas met inclusion criteria. In only one case was a facial schwannoma diagnosed preoperatively from imaging. No statistically significant difference was found in preoperative House-Brackmann scores, ENoG, cVEMP, caloric testing, ABRs, or acoustic reflexes. Pure tone average was worse in the vestibular schwannoma group (63 dB [95% CI: 58-68 dB] vs. 46 dB [95% CI: 34-58 dB], P = .01), and the difference was more apparent in the lower frequencies. Word recognition score was better in the facial schwannoma group (66% [95% CI: 45-86%] vs. 41% [95% CI: 34-47%], P = .02). CONCLUSION: Specialized preoperative functional evaluation of the nerves of the internal auditory canal cannot reliably predict the presence of an intracranial facial schwannoma. Hearing is better in facial schwannomas, particularly in the lower frequencies. This should raise the index of suspicion for an intracranial facial schwannoma, especially in candidates for hearing preservation vestibular schwannoma surgery. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2098-2105, 2021.
Subject(s)
Cranial Nerve Neoplasms/pathology , Ear, Inner/innervation , Facial Nerve/pathology , Neurilemmoma/diagnosis , Neuroma, Acoustic/diagnosis , Adult , Aged , Audiometry, Pure-Tone/methods , Caloric Tests/methods , Case-Control Studies , Diagnosis, Differential , Ear, Inner/physiology , Electrophysiology/methods , Facial Nerve/physiopathology , Female , Hearing/physiology , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Neurilemmoma/surgery , Neuroma, Acoustic/surgery , Preoperative Care/statistics & numerical data , Retrospective Studies , Vestibular Evoked Myogenic Potentials/physiologyABSTRACT
OBJECTIVE: To compare subjective and objective findings between patients with true dehiscence versus thin bone over the superior semicircular canal (SSC). STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: All patients from our institution with true dehiscence or thin bone over the SSC on computed tomography temporal bone (oblique view) from 2007 to 2013. MAIN OUTCOME MEASURES: Subjective test: Dizziness Handicap Inventory (DHI). Objective tests: Infrared video eye recording with varying stimuli (Tulio, Fistula, and Vibration); vestibular evoked myogenic potential (VEMP); electrocochleography; videonystagmography; pure-tone audiometry (i.e., air-bone gap). RESULTS: Fifty-four patients (64 ears) were reviewed. Thirty-nine patients (47 ears) had true dehiscence of the SSC on temporal bone computed tomography. Fifteen patients (17 ears) had thin bone over the SSC. There was no statistical difference in DHI scores for patients with true dehiscence versus those with thin bone over the SSC. Only cervical VEMP and air-bone gap via pure-tone audiometry revealed a significant difference between the two groups. The remaining vestibular assessments did not demonstrate any difference. No significant correlations were revealed between DHI and objective test findings across and within the two groups. CONCLUSION: Among the objective tests, cervical VEMP and pure-tone audiometry are the only tools to distinguish between true dehiscence and thin bone over the SSC. DHI does not differentiate between these two groups. Furthermore, no correlation exists between DHI and any objective finding. Further investigation is necessary to develop a validated subjective symptom index of patients with SSC syndrome.
Subject(s)
Dizziness/diagnosis , Ear Diseases/diagnosis , Semicircular Canals/diagnostic imaging , Temporal Bone/diagnostic imaging , Vertigo/diagnosis , Adult , Aged , Audiometry, Evoked Response , Audiometry, Pure-Tone , Dizziness/diagnostic imaging , Dizziness/physiopathology , Ear Diseases/diagnostic imaging , Ear Diseases/physiopathology , Electronystagmography , Evoked Potentials/physiology , Female , Humans , Male , Middle Aged , Retrospective Studies , Tomography, X-Ray Computed , Vertigo/diagnostic imaging , Vertigo/physiopathology , Vestibular Evoked Myogenic Potentials/physiologyABSTRACT
The purpose of the present study was to evaluate communication ability in noise at two signal presentation levels when using acoustic and electronic hearing protection devices (HPDs). Fourteen normal hearing subjects were fitted binaurally with custom acoustic HPDs (ER-15) and custom electronic HPDs (Starkey SA T9). Probe microphone measurements were obtained on 28 ears for three experimental conditions (open ear, acoustic HPD, electronic HPD) at four input signal levels (60, 70, 80, 90 dB SPL). Also, communication in noise was evaluated for three conditions (open ear, acoustic HPD, electronic HPD) at two input signal levels (75 and 90 dB SPL) using the Hearing In Noise Test. Results indicated significantly greater attenuation as well as significantly better communication in noise for the acoustic HPD. Results also indicated that the electronic HPD failed to attenuate any input signal utilized. Although results of behavioral testing indicated that communication ability in noise was not significantly impacted by varying the signal presentation level when utilizing either HPD, a more salient finding may be that utilization of the electronic HPD may place listeners at risk for temporary or permanent sensorineural hearing loss.
