Effect of hypothermia upon the electrocochleogram and auditory evoked brainstem response.

The effects of hypothermia upon electrocochleogram (ECochG) and auditory evoked brainstem response (ABR) were studied in 10 children who underwent the open heart surgery under hypothermic anesthesia. The latencies of N1, waves III and V in response to click of 115 dB p.e. SPL were prolonged at the rate of 0.12 +/- 0.02, 0.25 +/- 0.04 and 0.43 +/- 0.05 msec/degree C, respectively. The N1 amplitude was initially increased, returned to the precooling value at about 26 degrees C and decreased thereafter. SP was increased in amplitude by hypothermia and never disappeared throughout the observation. At the time of rewarming, SP appeared first, followed by N1 and finally by waves III and V. The results obtained in the present study were discussed in the light of the sensitivity of the sensory hair cells, peripheral nerves and CNS to the hypothermic condition.

[1]  P. Hamrick,et al.  Effects of hypothermia on ionic movement in the guinea pig cochlea , 1980, Hearing Research.

[2]  S. Feldman.  Hypothermia and neuromuscular blockade. , 1979, Anesthesiology.

[3]  E. Reilly,et al.  Visual evoked potentials during hypothermia and prolonged circulatory arrest. , 1978, Electroencephalography and clinical neurophysiology.

[4]  J. Eggermont,et al.  The influence of cochlear temperature on the electrical travelling wave pattern in the guinea pig cochlea. , 1978, Acta oto-laryngologica.

[5]  F. Sharbrough,et al.  Effects of hypothermia on the human brainstem auditory response , 1978, Annals of neurology.

[6]  M. Cohen,et al.  Electroencephalographic and neurological correlates of deep hypothermia and circulatory arrest in infants. , 1977, The Annals of thoracic surgery.

[7]  R. Thornton,et al.  Proceedings: The effect of hypothermia on neuromuscular conduction. , 1976, British journal of anaesthesia.

[8]  J. Eggermont.  The temperature dependency of cochlear adaptation and masking in the guinea pig. , 1974, Audiology : official organ of the International Society of Audiology.

[9]  B Katz,et al.  The effect of temperature on the synaptic delay at the neuromuscular junction. , 1965, The Journal of physiology.

[10]  R. Butler,et al.  Temperature coefficients of cochlear potentials. , 1960, The American journal of physiology.

[11]  C. Fernández,et al.  Effect of short-term hypothermia on cochlear responses. , 1958, Acta oto-laryngologica.

[12]  C. Brooks,et al.  Analysis of effects of hypothermia on central nervous system responses. , 1957, The American journal of physiology.

[13]  W. Rosenblith,et al.  Effect of temperature change on round-window response in the hamster. , 1950, The American journal of physiology.

[14]  H. S. Gasser.  NERVE ACTIVITY AS MODIFIED BY TEMPERATURE CHANGES , 1931 .

[15]  W. Wiederholt,et al.  Hypothermia-induced changes in rat short latency somatosensory evoked potentials. , 1981, Electroencephalography and clinical neurophysiology.

[16]  A. C. Gcoats.  Temperature effects on the peripheral auditory apparatus. , 1965, Science.

[17]  R. Ruben,et al.  Electrical acoustical response to click stimulation after section of the eighth nerve. , 1962, Acta oto-laryngologica.