Contribution of Vestibular-Evoked Myogenic Potential (VEMP) testing in the assessment and the differential diagnosis of otosclerosis

Background: The aim of this prospective clinical study was to evaluate the clinical importance of Vestibular-Evoked Myogenic Potentials (VEMPs) in the assessment and differential diagnosis of otosclerosis and otologic diseases characterized by "pseudo-conductive" components. We also investigated the clinical appearance of balance disorders in patients with otosclerosis by correlating VEMP results with the findings of caloric testing and pure tone audiometry(PTA). Material/Methods: Air-conducted(AC) 4-PTA, bone-conducted(BC) 4-PTA, air-bone Gap(ABG), AC, BC tone burst evoked VEMP, and calorics were measured preoperatively in 126 otosclerotic ears. Results: The response rate of the AC-VEMPs and BC-VEMPs was 29.36% and 44.03%, respectively. Statistical differences were found between the means of ABG, AC 4-PTA, and BC 4-PTA in the otosclerotic ears in relation to ACVEMP elicitability. About one-third of patients presented with disequilibrium. A statistically significant interaction was found between calorics and dizziness in relation to PTA thresholds. No relationship was found between calorics and dizziness with VEMPs responses. Conclusions: AC and BC VEMPs can be elicited in ears with otosclerosis. AC-VEMP is more vulnerable to conductive hearing loss. Evaluation of AC-VEMP thresholds can be added in the diagnostic work-up of otosclerosis in case of doubt, enhancing differential diagnosis in patients with air-bone gaps. Otosclerosis is not a cause of canal paresis or vertigo. © Med Sci Monit

Semicircular canal versus otolithic involvement in idiopathic sudden hearing loss

Objective: To evaluate the results of vestibular evoked myogenic potential testing in patients with idiopathic sudden hearing loss, and to correlate these results with the findings of caloric testing, the clinical appearance of vertigo and the influence of age.Materials and methods: Eighty-six patients with unilateral idiopathic sudden hearing loss and 35 healthy controls underwent a standard protocol of neurotological evaluation. Vestibular evoked myogenic potential responses were measured and compared with caloric responses.Results: On the affected side, 30.2 per cent of patients showed abnormal vestibular evoked myogenic potential responses, while 52.3 per cent had abnormal caloric responses. A statistically significant relationship was found between the results of these two tests. A statistically significant relationship was also found between the type of vestibular lesion and the occurrence of vertigo. Advancing age correlated statistically with more extensive labyrinthic lesions.Conclusions: A combination of vestibular evoked myogenic potential and electronystagmography testing indicated the existence of vestibular involvement in many patients with idiopathic sudden hearing loss. Both tests are necessary in order to obtain a more thorough and in-depth knowledge of the pathophysiology of idiopathic sudden hearing loss. © 2009 JLO (1984) Limited

Maturation of the auditory system: 2. Transient otoacoustic emission suppression as an index of the medial olivocochlear bundle maturation

Contralateral suppression of transient otoacoustic emissions in 42 premature babies (84 ears; post-conceptional age [PCA] 30-36 weeks) was compared to that of 39 full-term babies (78 ears; PCA: 37-45 weeks). Eighteen healthy adults and ten young children (5-14 years old) were studied as controls. Risk factors for hearing loss were registered in both preterm and full-term groups. An ILO-92 otoacoustic emission recording system was used to deliver linear clicks to the ear examined and broadband noise to the contralateral ear in an alternating on and off mode. Suppression in full-term babies was statistically higher than in preterms, whereas no differences existed between children and adults and children and full-terms. Peripheral auditory lateralization was evident in adults but was observed only as a trend in newborns. Only prematurity at the time of examination and aminoglycoside treatment for more than seven days had a negative impact on suppression. The results support the conclusion that maturation of the efferent system takes place from 30 to 45 weeks PCA. The exact age at which this maturation is accomplished has not yet been clearly determined. © 2007 British Society of Audiology, International Society of Audiology, and Nordic Audiological Society

Maturation of the auditory system: 1. Transient otoacoustic emissions as an index of inner ear maturation

The transiently evoked otoacoustic emission amplitude of 42 preterm babies (84 ears; post-conceptional age [PCA] 30-36 weeks) was compared with the TEOAE amplitude of 39 full-term babies (78 ears; PCA 37-45 weeks) in order to trace the inner ear maturation characteristics. An ILO-92 otoacoustic emission recording system was used with linear clicks of 70 dB peak equivalent SPL. The results obtained indicated: (1) There was no statistically significant difference between preterm and full-term ears; (2) There was no significant difference between males and females; (3) There was a significant difference between left and right ear TEOAE amplitude; (4) The interaction of ear with age in relation to TEOAE amplitude was statistically significant; (5) Noise and stimulus parameters did not reveal any significant differences between right and left ears; (6) A positive correlation existed between birthweight and TEOAE amplitude; and (7) A negative correlation existed between aminoglycoside treatment and TEOAE amplitude. The results indicate subtle changes in TEOAE amplitude over time, showing a natural development of the inner ear function during the process of maturation. © 2007 British Society of Audiology, International Society of Audiology, and Nordic Audiological Society

Transient otoacoustic emissions in the detection of olivocochlear bundle maturation

Objective: The medial. olivocochlear bundle, forms a neural pathway connecting the superior olivary complex to the outer hair cells of mainly the contralateral cochlea. Although the biological significance of the bundle remains ambiguous, it is clear that activation of medial. olivocochlear fibers alters cochlear output and this can be experimentally evident through a series of changes on otoacoustic emissions, called otoacoustic emission suppression. The aim of this study is to observe the maturation of the medial olivocochlear bundle by measuring the suppression effects on transient otoacoustic emissions. Methods: The study population consisted of 27 premature babies (53 ears) from the P&A Kyriakou Neonatal Intensive Care Unit (conceptional age: 31-36 weeks) and 43 fullterm babies (61 ears) (conceptional age: 37-42 weeks) from the same unit. The ILO-92 system is used to deliver both the linear clicks to the ear examined (producing the emissions) and the white noise to the contralateral ear. The mode used is based on the alternating on and off presence of the white noise in the contralateral ear. Results: 12/53 (22%) ears of preterm babies presented suppression >= 1 dB. 32/61 (52.4%) ears of fultterm babies presented suppression >= 1 dB. The mean suppression for the ears of premature infants was 0.52 dB, (+/- O.1S.E.M.). The mean suppression for the ears of full term infants was 0.90 dB, (+/- 0.09S.E.M.). At the second half of the time window, suppression of fullterms rises above 1 dB (a pattern similar to that of adults), whereas it remains below 1 dB for preterms. Conclusions: Suppression of otoacoustic emissions helps us to study the function of the medial olivocochlear bundle in different populations. It appears in premature babies but becomes stronger as the postconceptional age advances. (c) 2005 Elsevier Ireland Ltd. All rights reserved

Vestibular evoked myogenic potentials in patients with BPPV

Background: The probable cause of Benign Paroxysmal Positional Vertigo (BPPV) is a degeneration of the oto lithic organs (utricle and saccule). The aim of the study is to find possible alterations in Vestibular Evoked Myogenic Potentials (VEMP) recordings in BPPV patients, because the saccule is part of the VEMP pathway. Material/Methods: 27 BPPV patients (24 unilateral and 3 bilateral) aged 20 to 70 years and 30 healthy age matched controls. BPPV was diagnosed by the upbeating geotropic nystagmus found in the supine position with the head overextended towards one side. The subjects were investigated with pure tone audiometry, bi-thermal caloric test with electronystagmographic (ENG) recording, and VEMP recording. Results: P1 latency and N1 latency did not present any statistical difference between control ears and affected ears of the BPPV population. The percentage of abnormal VEMP in the BPPV population was statistically higher than in the control ears (p<0.005). No significant relationship could be shown between the occurrence of Canal Paresis and abnormal VEMP. No relationship was found between the side (right or left ear) where BPPV appeared clinically and the side where abnormal VEMP was registered. Conclusions: BPPV is a clinical entity associated with increased occurrence of abnormal VEMP recordings, possibly due to degeneration of the saccular macula, which is part of the neural VEMP pathway. © Med Sci Monit