[Computer analysis of nystagmus]. / Komputerowa analiza sygnalu ENG.

An algorithm for the computer analysis of nystagmus is described in this paper. This algorhythms was based on digital differentiator, which monitors the eye position. The computed eye velocity is next used as an input to the fast phase detector. Several procedures, including minimum velocity test, slope sense test, SPV and FPV relationship test are invoked to extract the fast phases from the recorded signal. Based on three-years experience (approx. 3000 examinations) using the ENG-PC System in clinical practice we can conclude, that application of the nystagmus detector was useful in most cases. In our opinion, despite from system imperfection which is observed during the analysis of recording disturbed by artifacts, this system has unquestionable advantage over the traditional technique.

Wplyw rodzaju bodzca dzwiekowego na oznaczanie progu slichowego metoda ABR. [The effect of brief tone envelopes on ABR and behavioral thresholds].

The present study examines the effect of brief tone envelopes on ABR and behavioral thresholds in small groups of normal and hearing-impaired subjects. The hearing-impaired subjects had very steep high-frequency hearing loss in 2-6 kHz region. The stimuli for both ABR and behavioural estimates were 2 and 4 kHz tone burst with linear and nonlinear envelopes. Behavioural thresholds were estimated using a computer controlled, modified block up-down method. The ABR thresholds were evaluated from the recordings collected in automatic acquisition process. Results of our experiments showed that for different stimulus envelopes both behavioural and ABR thresholds were similar in normal range of hearing. However, for impaired ears at high frequencies, both psychoacoustic and ABR thresholds differ, sometimes quite significantly, depending on stimulus envelope.

[Examination of reaction time--auditory brainstem responses--ABR in noise induced temporary and permanent threshold shift]. / Badania funkcji latencja--natezenie sluchowych potencjalów pnia mózgu--abr, w czasowych i trwalych pohalasowych ubytkach sluchu.

This study was conducted to investigate the differences between auditory brainstem responses--ABR recorded in men with temporary or permanent threshold shifts (TTS or PTS). Behaviorally, the tested ears showed insignificant differences in the hearing thresholds at frequencies in the range 0.25-8 kHz. The latency of waves I, III, V and interwave intervals I-III, III-V, I-V were analysed as functions of stimulus intensity. The comparisons between recordings obtained in groups with TTS and PTS showed significant differences in latencies of wave V at 90 dB nHl only. The latencies of waves I, III and interwave intervals were unaltered.

[Evaluation of the effect of auditory fatigue on the human ear based on the measurement of brain stem auditory potentials (ABR). II. Relation of temporary auditory threshold shift and changes in the latency of wave V]. / Ocena wplywu zmeczenia sluchowego na narzad sluchu czlowieka za pomoca s¿chowych potencjalów z pnia mózgu (ABR). II. Zwiazek miedzy czasowym przesunieciem progu slyszenmia i zmianami latencji fali V.

The relationship between temporary threshold shift (TTS) and latency changes of auditory brainstem responses (ABR) induced by noise exposure was studied in 23 normal-hearing subjects. Shift in latency wave V at 40 dB nHL of stimulus intensity as a result of auditory fatigue showed no significant correlation with TTS at 4 kHz. The great intersubject variability of shifts in latency wave V as a result of auditory fatigue suggests that this shift may be a useful measure of individual susceptibility to noise.

[Evaluation of the effect of auditory fatigue on the human ear by auditory brain stem responses (ABR). I. Effect of auditory fatigue on temporary threshold shifts of ABR]. / Ocena wplywu zmeczenia sluchowego na narzad sluchu czlowieka za pomoca sluchowych potencjalów pnia mózgu (ABR). I. Wplyw zmeczenia sluchowego na wartosci parametrów czasowych ABR.

The effects of auditory fatigue on auditory brainstem responses (ABR) were investigated in 23 normal-hearing subjects. ABR was recorded before and after exposure to fatiguing noise. Behaviourally, the auditory fatigue was tested using a temporary threshold shifts (TTS) paradigm. The latency of waves I, III, V and interwave intervals I-III, III-V, I-V were analysed as functions of stimulus intensity. In post-exposure recordings a threshold elevation, significant increase of all waves latency, increase of interwave-interval III-V at 40,50,60 dB nHL and unaltered intervals I-III, I-V were observed.

Studies on the temporary effect of noise on the auditory function in man.

ECoG and ABR recordings were performed on 22 young, normal-hearing persons, before and after exposure to fatiguing noise. Temporary Threshold Shift (TTS) of up to 35 dB at 4-6 kHz was induced by octave band noise with centre frequency at 2.8 kHz. The latency of waves I, III, V and ACAP (Auditory Compound Action Potential) and intervals between waves I-III, III-V, I-V and ACAP-V were analysed as functions of stimulus intensity in pre- and post-exposure recordings. In post-exposure recordings a threshold elevation, a significant increase of latency and unaltered intervals between the successive waves and ACAP were observed. It was concluded that the noise-induced auditory fatigue, measured as TTS, originates within the cochlea and is transferred to the auditory pathways. The great intersubject variability of the data obtained indicates that the TTS may be a useful measure of individual sensitivity to noise, but prognosis on the presumed Permanent Threshold Shifts (PTS) based on the evaluation of TTS would seem doubtful.