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Hearing in congenital hypothyroidism
Insights
Congenital hypothyroidism in children can lead to significant sensorineural hearing loss. Approximately 20% of affected children experience hearing impairment, with some requiring hearing aids.
Area of Science:
- Pediatrics
- Endocrinology
- Audiology
Background:
- Congenital hypothyroidism (CH) is a condition affecting thyroid hormone production from birth.
- Hearing impairment is a potential complication of CH, necessitating audiological evaluation.
- Understanding the hearing profile in CH patients is crucial for early intervention.
Purpose of the Study:
- To investigate the hearing status of children diagnosed with congenital hypothyroidism.
- To determine the prevalence and type of hearing loss in this pediatric population.
- To assess the need for auditory rehabilitation in CH patients.
Main Methods:
- Studied 45 children with congenital hypothyroidism (thyroid agenesis, hypogenesis, or dyshormogenesis) under substitution therapy.
- Hearing thresholds assessed using pure-tone audiometry or conditioned orientation reflex audiometry.
- Excluded children with temporary secretory otitis media before assessment.
Main Results:
- 80% of patients (36/45) had normal auditory thresholds.
- 20% of patients (9/45) exhibited sensorineural hearing loss.
- 11% of patients (5/45) had significant hearing loss requiring auditory rehabilitation, with 4 using hearing aids.
Conclusions:
- A substantial proportion of children with congenital hypothyroidism experience persistent sensorineural hearing loss.
- The findings align with animal studies showing developmental issues in the auditory system of congenital hypothyroid models.
- Early audiological monitoring is essential for children with congenital hypothyroidism to detect and manage hearing deficits.
Abstract:
The hearing profile of children with congenital hypothyroidism was studied in 45 patients with thyroid gland agenesis, hypogenesis or dyshormogenesis, during adequate substitution therapy. Preliminary, secretory otitis media was found in 6 patients under the age of 6 years; in these children, hearing assessment was performed after cure of the middle ear effusion. Hearing threshold was measured either by conventional pure-tone audiometry or conditioned orientation reflex audiometry according to the patient's age (above and below 4 years). In 36 patients (80%) the auditory thresholds were normal; in the remaining 9 patients (20%) a sensorineural hearing loss of different degree was detected; in 5 cases (11%) the deafness was important and required auditory rehabilitation, with the use of a hearing aid in 4 of them. No relation could be found between hearing acuity and bone age at diagnosis of hypothyroidism or aetiology of thyroid dysfunction. It is concluded that in about one tenth of the children with congenital hypothyroidism a substantial deafness persists. The sensorineural nature of the hearing loss is in agreement with reported histological findings in congenital hypothyroid animals, where an immature development of the organ of Corti including hair cells and tectorial membrane has been observed.