Click-evoked otoacoustic emissions recorded from untreated congenital hypothyroid newborns

• Published in: Hearing research Vol. 166; no. 1; pp. 136 - 142
• Main Authors: Parazzini, Marta, Ravazzani, Paolo, Medaglini, Stefania, Weber, Giovanna, Fornara, Carla, Tognola, Gabriella, Vigone, Maria Cristina, Bianchi, Carlo, Comi, Giancarlo, Chiumello, Giuseppe, Grandori, Ferdinando
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2002; Elsevier
• Subjects: Acoustic Stimulation; Biological and medical sciences; Case-Control Studies; Congenital Hypothyroidism; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Evoked Potentials, Auditory, Brain Stem; Hair Cells, Auditory, Outer - physiopathology; Hearing Loss - congenital; Hearing Loss - etiology; Hearing Loss - physiopathology; Humans; Hypothyroidism; Hypothyroidism - etiology; Hypothyroidism - physiopathology; Infant, Newborn; Medical sciences; Newborn; Non tumoral diseases; Otoacoustic Emissions, Spontaneous; Otorhinolaryngology. Stomatology; Thyroid Hormones - deficiency; Thyroid Hormones - physiology; Transient-evoked otoacoustic emission; Wavelet transform; Wavelet transform; OAE, otoacoustic emissions; STFT, short time Fourier transform; OHC, outer hair cell; Hypothyroidism; RMS, root mean square; T4, thyroxine; TEOAE, transient-evoked otoacoustic emissions; CH, congenital hypothyroid; Newborn; ABR, auditory brainstem responses; WT, wavelet transform; DPOAE, distortion product otoacoustic emissions; TH, thyroid hormone; Transient-evoked otoacoustic emission; Endocrinopathy; Human; Thyroid diseases; Auditory disorder; Evoked otoacoustic emission; Inner ear; Hearing loss; Electrodiagnosis; Hearing; Acoustic stimulus; Wavelet transformation; Thyroxine; Cochlea; Development; Thyroid hormone; ENT disease
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/S0378-5955(02)00307-6

Thyroid hormone plays an important role in hearing development. Both a genetic or non-genetic hypothyroidism is often associated with congenital hearing loss. The exact incidence of hearing impairment in untreated congenital hypothyroid (CH) patients is unknown. This paper will present the results of measuring of the transient-evoked otoacoustic emissions (TEOAE) in a population of 29 newborns, who tested positive on a screening test for hypothyroidism (CH group) and in 68 well babies (control group) randomly chosen from all the newborns, classified as PASS, included in the Hearing Screening Program of the San Raffaele Hospital in Milan. TEOAE were recorded in all newborns within 1 month after birth and before beginning L-thyroxine treatment with conventional commercial instrumentation. Both temporal and time–frequency analyses of the emitted responses were conducted by means of a wavelet transform. The comparison of the characteristics of the temporal and frequency content of the responses of the two groups (CH and control) showed no statistically significant difference. No correlation was found between outer hair cell dysfunction and hypothyroidism.