A slow brain stem response for low-frequency audiometry
| Autor: | Hallowell Davis, S. K. Hirsh |
|---|---|
| Rok vydání: | 1979 |
| Předmět: |
Linguistics and Language
medicine.medical_specialty Tone pips Acoustics Premedication Low frequency Audiology Language and Linguistics Speech and Hearing Audiometry Medicine Humans Center frequency Latency (engineering) Child Hearing Disorders medicine.diagnostic_test business.industry Auditory Threshold Audiogram Secobarbital Audiometry Evoked Response Rise time Child Preschool Evoked Potentials Auditory Crest business Brain Stem |
| Zdroj: | Audiology : official organ of the International Society of Audiology. 18(6) |
| ISSN: | 0020-6091 |
| Popis: | Proper choices of stimuli and of brain stem electric responses allow us to estimate peripheral auditory thresholds at 500, 1 000, 2 000 and 4 000 Hz with an accuracy of about +/- 10 dB. With the help of sedation (secobarbital), such audiograms may be obtained from each ear of a child of any age in a single session. Tone pips (filtered clicks) or very brief tone bursts give a frequency selectivity that is clinically adequate. The rise time must be adjusted to the center frequency. A rise time of two periods with a plateau from zero to one period gives a good compromise between frequency specificity and a synchronous neural discharge. The best threshold indicator for tone pips of 2 000 Hz or higher (or unfiltered clicks) is P6 (Jewett V). At 60 dB nHL its latency is 6.0-7.0 ms (for children of 1 year or older), but near threshold it is 8.0-9.5 ms. An input pass-band of 140-3 000 Hz is appropriate. The best threshold indicator at 500 or 1 000 Hz is a nearly neglected slower wave with a scalp-negative crest at about 10 ms following a 60-dB click. Latency is 15 ms following a 500-Hz tone pip at 15 dB SL. We call this wave "slow negative (ten)" or SN10. To see it well a wider input pass-band such as 40-3 000 Hz is needed. SN10 is usually obscured by P6 or by frequency-following response at stimulus levels above 35 dB SL. The details are given of a clinical routine that allows the determination (+/- 10 dB) of 8 threshold endpoints within about 80 min. Several precautions and limitations are discussed, and also the origin of the SN10 wave. |
| Databáze: | OpenAIRE |
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