Differential Caloric Reactions In Deaf Children

Electronystagmography findings in child unilateral sensorineural hearing loss of probable viral origin

We studied the labyrinthine function in a group of 72 children aged between 4 and 14 years affected by unilateral sensorineural hearing loss of probable viral origin. From the analysis of the results obtained we confirm the concomitance of cochlear and vestibular damage. However, there were no statistically significant differences between type of audiogram at onset of hearing loss and type of electronystagmography (ENG), while we found a direct correlation between the presence of vertigo or dizziness and type of ENG. Finally hearing recovery was influenced by the presence of vertigo or labyrinthine function alterations. The results of statistical analysis confirmed a significant statistical difference between patients with vertigo or dizziness (V(+)) and those without vertigo (V(-)) and also between patients with ENG 3 (subjects with spontaneous nystagmus or positional nystagmus and canal paresis ipsilateral to the cochlear lesion) and those with ENG 1 (subjects without spontaneous nystagmus or positional nystagmus and with normal vestibular reflex). In fact, hearing recovery was worse in V(+) group and in ENG 3 group.

The vestibulo-ocular reflex in pupils at a Dutch school for the hearing impaired; findings relating to acquired causes

The vestibulo-ocular reflex was evaluated with caloric tests and velocity step (VS) tests in 121 pupils at a school for the hearing-impaired. Vestibular impairment was found in a total of 50 pupils (41%). It was found in 17 out of the 33 (52%) pupils with acquired causes of hearing impairment and significantly more often in pupils with a pure tone hearing threshold of more than 90 dB than in those with a lower threshold. In the group with prenatal causes, 5 out of 8 rubella cases showed vestibular impairment. Four of these cases had impaired VS responses and normal caloric responses. The high proportion of vestibular impairment in the group with postnatal causes was due to 5 cases with meningitis, all of whom showed caloric weakness. Kernicterus was significantly associated with vestibular hyperreactivity (5 cases out of 7), presumably due to a central dysfunction.

Waardenburg's syndrome: a case report with CT scanning and cochleovestibular evaluation

The Waardenburg's syndrome, a congenital ectodermal germ layer defect of autosomal dominant inheritance with variable phenotypic expressivity consists of 6 major characteristics: dystopia canthorum, broad nasal root, hypoplasia of the medial eyebrow, heterochromia irides, white forelock, and congenital deafness. Twelve additional characteristics have been reported including meningocele, atresia of the esophagus, and Hirshsprung's disease supporting an early hypothesis that the neural crest is the embryonic site linking defects of the cervical sympathic system with pigmentary abnormalities and inner ear anomalies. Congenital deafness reported in 20% of Waardenburg patients, and the most disabling characteristic, has been associated with ENG abnormalities in 30% of these deaf patients. A congenitally deaf young person with Waardenburg's syndrome is examined for basic cause of episodic vertiginous symptoms. Diagnostic assistance from previous investigations is lacking because they have not involved state-of-the-art functional evaluations or correlations of behavioral and radiographic findings. In this patient, high-resolution computerized tomography failed to demonstrate bony labyrinthine anomalies. Functional cochleovestibular analysis revealed a bilateral profound sensorineural hearing loss and a unilateral weakness in oculomotor responses to caloric stimulations. Repeated measurements of ocular counterroll show variations compatible with intermittent otolithic dysfunctioning. These findings are consistent with a diagnosis of an acquired active unilateral peripheral vestibular disorder. Some of the technical issues underlying the derivation of this conclusion are discussed.