Artikel
Frequency-specific objective audiometry: tone-evoked brainstem responses and 40 Hz and 90 Hz steady-state potentials
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Autoren
Veröffentlicht: | 31. Mai 2005 |
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Gliederung
Text
Introduction
Auditory Brainstem Responses evoked with tone bursts (t-ABRs) and Auditory Steady-State Responses (ASSRs) with 40 or 90 Hz amplitude modulation (AM) were compared to determine which method most accurately approached the behavioural hearing thresholds to 500 and 2000 Hz stimuli in awake adults with normal hearing.
Materials and Methods
This study was unique because identical measurement parameters were used for both methods (viz. recording time, stimulation and recording hardware and electrode positions). Measurements were performed in quasi-random order; presentation levels were in dB SL. Ten normal hearing adults participated in the measurements.
Results
ASSR thresholds at 40 and 90 Hz AM approached the behavioural thresholds more accurately than the t-ABR thresholds for 500 and 2000 Hz. E.g. the estimated thresholds and standard deviations were measured from ASSRs with 40 Hz AM stimuli: 13 dB SL (S.D. 7 dB) at 500 Hz and 12 dB SL (S.D. 4 dB) at 2000 Hz. Average thresholds with the t-ABR were 27 dB SL (S.D. 10 dB) at 500 Hz tones and 18 dB SL (S.D. 8 dB) at 2000 Hz. Results from ASSRs with 90 Hz AM stimuli were in between.
Conclusions
It is concluded that when measurement conditions are kept the same (as far as possible), the ASSR with 40 Hz AM is the best choice while t-ABR gave the poorest results.