Hearing alterations following meningitis. 2. Variable hearing

Efficacy of auditory evoked potential follow-up in viral meningitis of infants

PURPOSE

To examine the rate of occurrence of hearing impairments among the infants who had recovered from viral meningitis under 1 year of age through auditory evoked potential (AEP) test and to investigate the efficacy of the follow-up AEP test in viral meningitis infants.

METHODS

Two hundred twenty infants (440 ears) were examined through AEP test once, and 47 (94 ears) of them went back for a second examination and were diagnosed with viral meningitis. The first AEP tests were compared with the second results in 47 infants. I latency, V latency, I-III interpeak latency (IPL), and III-V IPL were checked.

RESULTS

In the first AEP test conducted on 440 ears, the average values of I and V latency and I-III IPL were delayed as compared with normal values. The second AEP results were conducted on 47 infants 92.36 days after the first exam. I latency and V latency of second exam were improved significantly (p < 0.05), but I-III and III-V IPL showed no significant changes. Two hearing impaired patients (4 ears) were confirmed through chart reviews.

CONCLUSION

The AEP test is a helpful study for early detection of hearing problem. However, in this study, AEP test was too sensitive in acute period, and later, the incidence rate of hearing impairment was relatively low. Therefore, age of onset, severity of neurologic symptom, and clinical examination must be considered before the AEP test.

Repeated Audiometry After Bacterial Meningitis: Consequences for Future Management

OBJECTIVE

Sensorineural hearing loss is a common sequela of bacterial meningitis. The objective of this study is to delineate the incidence and course of hearing loss after bacterial meningitis.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Data of 655 patients who suffered from bacterial meningitis between 1985 and 2015 were analyzed.

INTERVENTIONS

None.

MAIN OUTCOME MEASUREMENTS

Availability of audiometric data, incidence of hearing loss, and onset and course of hearing loss.

RESULTS

In this cohort the incidence of hearing loss (>25 dB) was 28% (95% confidence interval 23-34%). The incidence of profound hearing loss (>80 dB) was 13% (95% confidence interval 10-18%). Normal hearing at the first assessment after treatment for meningitis remained stable over time in all these patients. In 19 of the 28 patients with diagnosed hearing loss, the hearing level remained stable over time. Hearing improved in six patients and deteriorated in two patients. One patient showed a fluctuating unilateral hearing loss.

CONCLUSION

Audiological tests in patients with bacterial meningitis, especially children, should be started as soon as possible after the acute phase is over. As we found no deterioration of initial normal hearing after bacterial meningitis, repeated audiometry seems indicated only for those with diagnosed hearing loss at first assessment.

Audiovestibular and neuropsychological outcome of adults who had recovered from childhood bacterial meningitis

A sample of 22 subjects was studied from a population of adults who had suffered from bacterial meningitis in childhood. Audiovestibular, oculomotor and neuropsychological investigations were performed and quality of life was assessed. An age-matched control group of 20 subjects was recruited. In the meningitis group, nine subjects had abnormal pure tone audiograms. One was previously undiagnosed and a progression was found in four. There was an overrepresentation of subclinical vestibular pathology (6 out of 9 (67%)) in this group. Audiovestibular test results showed a peripheral pattern and oculomotor tests were normal. The quality of life scores of those with hearing loss were significantly higher than those in the control group. Neuropsychological tests of brain dysfunction were abnormal in six out of 22 (27%) who had recovered from meningitis. The prevalence of such dysfunctions was not related to audiovestibular disorder. The quality of life scores of those with brain dysfunctions were similar to those of the control group. The findings of reduced auditory memory and tone level perception in four out of 22 (18%), suggest that lesions of central auditory pathways may follow from bacterial meningitis. The results support the idea that inner ear damage is the major cause of hearing loss after bacterial meningitis. Despite the absence of brainstem involvement, central nervous system lesions with disturbed auditory processing and language functions can be of significance. The high frequency of discrete brain dysfunctions indicate that a thorough neuropsychological investigation is required after bacterial meningitis.

Progressive sensorineural hearing loss in childhood

Examination was made of the records of school-aged children with a bilateral sensorineural hearing loss who were seen for audiological assessment in the period 1984 to 1986. These records formed the basis of an investigation, reported in this paper, into the prevalence of progressive sensorineural hearing loss, the causes of hearing impairment in these children, the ages at which deterioriation occurs and the patterns of progression in terms of audiogram shape and symmetry. A figure of 9% was found for prevalence, but arguments are put forward to show that this is probably a minimum figure and that most studies are likely to under-estimate the number of children with progressive sensorineural hearing loss. There is a tendency for the deterioration to be greater in the better ear. The implications of this when assessing the role of hearing aids in causing deterioration is discussed.

Causes of congenital and acquired total sensorineural hearing loss in Ghanaian children

All cases of “deaf and dumb” children of school age seen in a 5-year period between 1979 and 1984 in Komfo Anokye Teaching Hospital, Kumasi are reviewed. The aetiology of 105 cases of congenital and acquired total sensorineural hearing loss is presented. The cause of congenital sensorineural hearing loss is unknown in nearly all cases. Of the 28 congenital cases, 4 mothers had rubella and 2 had icterus in the first trimester of pregnancy. Measles was the commonest cause of acquired sensensorineural hearing loss.

Low-frequency sensorineural hearing loss. Brainstem response, speech and high-frequency audiometry

Four cases of acquired, unilateral sensorineural hearing loss are presented. The low-frequency octave threshold changes are considered compatible with the low-frequency tails of neurons with characteristic frequencies of 2, 4 and 9 kHz. Zero speech discrimination was found in two patients with high-frequency threshold preservation at and above 4 kHz. Normal auditory brainstem responses were obtained in the two patients with low-frequency hearing loss confined to the frequency bands below 2 and 4 kHz respectively. Only wave I could be reliably identified in the two patients with single frequency threshold preservation at 2 and 9 kHz, while both presented a second, low amplitude wave with latency corresponding to our normative values for wave V. The latter may represent a delayed and pathological wave III.

Experiences with the cochlear implant in preschool children

Years of experience with the cochlear implant in profoundly deaf adults led to a decision to attempt to extend the benefits of this device to children. As of March 15, 1983, 43 deaf children ranging in age from 2.7 to 17.5 years have been implanted. Seventeen of these are children under 6 years of age. All had worn hearing aids but demonstrated little or no benefit from them. Auditory thresholds with the implant are significantly better than those obtained unaided and with hearing aids. Although a longer period of experience is required, the preschool-aged children can eventually make the same auditory discriminations as older children and adults. Long-term impact on speech and language development remains to be determined, but there is already evidence for significant improvement in these areas.

A study of the high-risk registry for sensorineural hearing impairment

In the medical evaluation, rehabilitation, and education of the hearing impaired, the first line of defense is the high-risk factor screening for sensorineural damage of all neonates. The most efficacious means of neonatal screening for those factors affecting sensorineural hearing damage is the employment of a high-risk registry. Based on a retrospective study of 109 children with sensorineural loss, high-risk factors and how improved use of the high-risk registry permits earlier detection (and statistically more successful rehabilitation) for such auditory-impaired children are discussed. The importance of pediatric screening of all neonates for hearing loss, in addition to use of the high-risk registry, is evidenced by the fact that only 46% of the children retrospectively identified in our study would have routinely appeared among the high-risk infants were the registry used alone.