Effects of Hypoxic-Ischemic Encephalopathy and Whole-Body Hypothermia on Neonatal Auditory Function: A Pilot Study

ABSTRACT

We assessed the effects of hypoxic-ischemic encephalopathy (HIE) and whole-body hypothermia therapy on auditory brain stem evoked responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). We performed serial assessments of ABRs and DPOAEs in newborns with moderate or severe HIE, randomized to hypothermia (n = 4) or usual care (n = 5). Participants were five boys and four girls with mean gestational age (standard deviation) of 38.9 (1.8) weeks. During the first week of life, peripheral auditory function, as measured by the DPOAEs, was disrupted in all nine subjects. ABRs were delayed but central transmission was intact, suggesting a peripheral rather than a central neural insult. By 3 weeks of age, peripheral auditory function normalized. Hypothermia temporarily prolonged the ABR, more so for waves generated higher in the brain stem but the effects reversed quickly on rewarming. Neonatal audiometric testing is feasible, noninvasive, and capable of enhancing our understanding of the effects of HIE and hypothermia on auditory function.

Hypoxia-ischemia - hypothermia - auditory evoked potentials - otoacoustic emissions

REFERENCES

• 1 Mencher L S, Mencher G T. Neonatal asphyxia, definitive markers and hearing loss.  Audiology. 1999;  38 291-295
• 2 Robillard T A, Gersdorff M C. Prevention of pre- and perinatal acquired hearing defects, part I: study of causes.  J Aud Res. 1986;  26 207-218
• 3 Borg E. Perinatal asphyxia, hypoxia, ischemia and hearing loss: an overview.  Scand Audiol. 1997;  26 77-91
• 4 Nield T A, Schrier S, Ramos A D et al.. Unexpected hearing loss in high-risk infants.  Pediatrics. 1986;  78 417-422
• 5 Konkle D F, Knightly C A. Delayed-onset hearing loss in respiratory distress syndrome: case reports.  J Am Acad Audiol. 1993;  4 351-354
• 6 Lasky R E, Wiorek L, Becker T R. Hearing loss in survivors of neonatal extracorporeal membrane oxygenation (ECMO) therapy and high-frequency oscillatory (HFO) therapy.  J Am Acad Audiol. 1998;  9 47-58
• 7 Balkany T J, Eshraghi A A, Jiao H et al.. Mild hypothermia protects auditory function during cochlear implant surgery.  Laryngoscope. 2005;  115 1543-1547
• 8 Shankaran S, Laptook A R, Ehrenkranz R A et al.. National Institute of Child Health and Human Development Neonatal Research Network. Whole-body hypothermia for neonates with hypoxic-ischemic encephalopathy.  N Engl J Med. 2005;  353 1574-1584
• 9 Gluckman P D, Wyatt J S, Azzopardi D et al.. Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multicentre randomised trial.  Lancet. 2005;  365 663-670
• 10 Eicher D J, Wagner C L, Katikaneni L P et al.. Moderate hypothermia in neonatal encephalopathy: efficacy outcomes.  Pediatr Neurol. 2005;  32 11-17
• 11 Kaga K, Takiguchi T, Myokai K et al.. Effects of deep hypothermia and circulatory arrest on the auditory brain stem responses.  Arch Otorhinolaryngol. 1979;  225 199-205
• 12 Rosenblum S M, Ruth R A, Gal T J. Brain stem auditory evoked potential monitoring during profound hypothermia and circulatory arrest.  Ann Otol Rhinol Laryngol. 1985;  94 281-283
• 13 Markand O N, Lee B I, Warren C et al.. Effects of hypothermia on brainstem auditory evoked potentials in humans.  Ann Neurol. 1987;  22 507-513
• 14 Rodriguez R A, Audenaert S M, Austin III E H et al.. Auditory evoked responses in children during hypothermic cardiopulmonary bypass: report of cases.  J Clin Neurophysiol. 1995;  12 168-176
• 15 Hett D A, Smith D C, Pilkington S N et al.. Effect of temperature and cardiopulmonary bypass on the auditory evoked response.  Br J Anaesth. 1995;  75 293-296
• 16 Veuillet E, Gartner M, Champsaur G et al.. Effects of hypothermia on cochlear micromechanical properties in humans.  J Neurol Sci. 1997;  145 69-76
• 17 Seifert E, Lamprecht-Dinnesen A, Asfour B et al.. The influence of body temperature on transient evoked otoacoustic emissions.  Br J Audiol. 1998;  32 387-398
• 18 Geal-Dor M, Khvoles R, Sohmer H. Cooling induces a decrease in middle ear compliance.  J Basic Clin Physiol Pharmacol. 1997;  8 127-132
• 19 Lasky R E, Widholm J J, Crofton K M et al.. Perinatal exposure to Aroclor 1254 impairs distortion product otoacoustic emissions (DPOAEs) in rats.  Toxicol Sci. 2002;  68 458-464
• 20 Lasky R E, Soto A A, Luck M L et al.. Otoacoustic emission, evoked potential, and behavioral auditory thresholds in the rhesus monkey (Macaca mulatta).  Hear Res. 1999;  136 35-43
• 21 Gorga M P, Reiland J K, Beauchaine K A et al.. Auditory brainstem responses from graduates of an intensive care nursery: normal patterns of response.  J Speech Hear Res. 1987;  30 311-318
• 22 Kemper A R, Downs S M. A cost-effectiveness analysis of newborn hearing screening strategies.  Arch Pediatr Adolesc Med. 2000;  154 484-488
• 23 Jiang Z D, Zhang Z, Wilkinson A R. Distortion product otoacoustic emissions in term infants after hypoxia-ischaemia.  Eur J Pediatr. 2005;  164 84-87
• 24 Lasky R E, Rupert A, Waller M. Reproducibility of auditory brain-stem evoked responses as a function of the stimulus, scorer and subject.  Electroencephalogr Clin Neurophysiol. 1987;  68 45-57
• 25 Rebillard G, Klis J F, Lavigne-Rebillard M et al.. Changes in 2f1-f2 distortion product otoacoustic emissions following alterations of cochlear metabolism.  Br J Audiol. 1993;  27 117-121
• 26 Jiang Z D, Yin R, Shao X M et al.. Brain-stem auditory impairment during the neonatal period in term infants after asphyxia: dynamic changes in brain-stem auditory evoked response to clicks of different rates.  Clin Neurophysiol. 2004;  115 1605-1615
• 27 Erenberg A, Lemons J, Sia C et al.. Newborn and infant hearing loss: detection and intervention. American Academy of Pediatrics Task Force on Newborn and Infant Hearing, 1998–1999.  Pediatrics. 1999;  103 527-530
• 28 Tomimatsu T, Fukuda H, Endoh M et al.. Long-term neuroprotective effects of hypothermia on neonatal hypoxic-ischemic brain injury in rats, assessed by auditory brainstem response.  Pediatr Res. 2003;  53 57-61