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A Van der Stappen

Publications and source records attributed to A Van der Stappen.

5 recordsLinked to original sources
PubMed2001

Rate influences on tone burst summating potential amplitude in electrocochleography: clinical(a) and experimental(b) data.

Electrocochleographic recordings of action and summating potentials are widely used in the electrophysiological assessment of endolymphatic hydrops (ELH). Increased amplitudes of the summating potential (SP) in response to tone burst stimuli are indicative of positive ELH. This study reports the effect of repetition rate of tone burst stimulation on the SP amplitude. Using transtympanic electrocochleography (ECochG), the SP in response to 1 kHz tone bursts was recorded in both a Ménière and a non-Ménière population. Absolute values of the SP were systematically higher in the Ménière group. Moreover, in the Ménière and non-Ménière groups, the response amplitudes of the SP at a repetition rate of 8.4 tone bursts/s were only 66 and 32%, respectively, of the maximal response amplitude which was obtained at the rate of 37.4 tone bursts/s. Additionally, in normal guinea pigs chronically implanted with a round window electrode, the SP was recorded to 0.5-16 kHz tone burst stimulations presented at 100 dB SPL with the same different repetition rates. Similar enhancement of the SP amplitude was observed from 8.4 to 37.4 stimuli/s, whatever the frequency. This effect is interpreted as an increased asymmetry of vibration of the cochlear partition, whose mechanical operating point would not return to the normal resting position at high repetition rates, since it is permanently shifted in ELH.

Acoustic Stimulation↗
PubMed2001

Otolith function after acoustic neuroma surgery.

The response of the vestibular system after acoustic neuroma surgery was investigated in nine patients. The otolith system was studied by means of ocular counterrolling, assessed by video oculography. Horizontal vestibulo-ocular reflex (VOR) function was tested by the sinusoidal harmonic acceleration test using electronystagmography. The results were compared with those obtained from a normal control population. The response to slow rotation tests was symmetric, but the gain was significantly reduced when compared to the normal population. Phase lag was significantly increased. No difference in ocular torsion was observed with lateroflexion of the head to the ipsilateral side in comparison with lateroflexion to the contralateral side. Moreover, the overall ocular counterrolling was well within normal limits. We conclude that the semicircular canal response differs from the otolith response. The component of the torsional VOR mediated by otolith stimulation appears to be more robust than the horizontal VOR mediated mainly by the horizontal semicircular canal system. Ocular counterrolling induced by lateroflexion does not reveal abnormalities in patients with surgically produced unilateral peripheral loss.

Adult↗
PubMed2001

Hereditary otovestibular dysfunction and Ménière's disease in a large Belgian family is caused by a missense mutation in the COCH gene.

OBJECTIVE: To report the clinical, auditory, and vestibular characteristics of a nonsyndromic otovestibular dysfunction in a large Belgian family caused by a missense mutation of the DFNA9 gene: COCH. STUDY DESIGN: Retrospective study of the clinical, audiologic, and vestibular data of 60 genetically affected cases. SETTING: Tertiary referral center. PATIENTS: All members of a Belgian kindred who carry the genetic (P51S) defect linked to the inherited hearing and vestibular impairment. INTERVENTIONS: Diagnostic otologic, audiometric, and vestibular analysis and imaging. MAIN OUTCOME MEASURES: Pure tone audiometry, supraliminary audiometry. and vestibular investigation. RESULTS: The autosomal dominant inherited impairment was characterized by peripheral degeneration of the inner ear, leading to total deafness and bilateral vestibular areflexia. CONCLUSIONS: The genetically affected persons of a Belgian family shared a progressive sensorineural hearing loss starting between the third and sixth decade. Vestibular symptoms started at about the same age as the hearing loss. The vestibular symptoms consisted of instability in darkness, a tendency to fall sideways, light-headiness, a drunken feeling, and attacks of vertigo. Most of the patients reported tinnitus, and half of them reported pressure in the ears. Clinically, 9 of the 60 patients met the criteria for definite Ménière's disease, and another 13 and 17 patients met the criteria for probable or possible Ménière's disease, respectively. All 9 were older than the age of 35, but only 1 was older than 55 years, so more than 30% of the patients were between 35 and 55 years old. A specific pattern could be recognized in the evolution of the otovestibular impairment. Under the age of 35 years, almost all the affected family members had normal hearing, whereas above the age of 55 years, the hearing loss was at least moderate, and vestibular hypofunction occurred. In between, there was a transition period of two to three decades, when deterioration of the cochleovestibular function occurred, with a temporary audiometric and vestibular asymmetry.

Adult↗
PubMed1999

Influence of head position on the vestibulo-ocular reflex during rotational testing.

The influence of two static head positions on the horizontal nystagmus induced by sinusoidal rotational stimulation in a group of 24 healthy subjects was investigated. The rotation test was performed with the subject's head in the primary position (upright) and with the head 30 degree pitched down. Computerized electronystagmography was used to measure the maximum slow component velocity of the horizontal nystagmus and to calculate gain, phase and asymmetry. The vestibulo-ocular reflex (VOR) gain obtained during rotation with the head in the primary position was significantly higher than with the head bent 30 degree forward. No other significant differences were found.

Adult↗