Phase Distortion of Averaged Electroencepha

Lane, R. H.; Mendel, Maurice I.; Kupperman, Gerard L.; Vivion, M. C.; Buchanan, L. H.; Goldstein, R.

doi:10.1001/archotol.1974.00780030442008

Cited by 18 publications

(2 citation statements)

References 4 publications

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“…A number of workers have investigated the effects of frequency filtering on the MLAER (7,8,9,15,26,29,30). The dominant frequency components of the MLAER in young children are found in the range of 20-30 Hz (30).…”

Section: Discussionmentioning

confidence: 99%

Middle Latency Auditory Evoked Responses in Normal Term Infants: A Longitudinal Study

Rogers¹,

Edwards²,

Henderson‐Smart³

et al. 1989

Neuropediatrics

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Middle latency auditory evoked responses (MLAERs) were measured in 21 normal term infants, three to five days after birth and then at 6 weeks, 7 months and 1 year of age. A polyphasic waveform was elicited during natural sleep in all infants at each recording session by monaural click stimulation at a rate of 9 per second. A 70 dBHL stimulus was found to be optimal as the MLAER became less well defined when the stimulus intensity approached the threshold hearing level. The first 60 to 70 msec of the waveform was found to be most stable, with decreasing detectability of peaks at longer latencies. There was no change in wave latency or reproducibility of MLAERs recorded during different sleep states. Waves Po and Na showed a significant decrease in latency with increasing stimulus intensity at term and/or 6 weeks of age. This was not evident for the remainder of the waveform. Waves Po, Na, Pa, Nb, Pb and Nc exhibited significant decreases in latency with age, attaining values indistinguishable from adults by 7 months of age.

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Section: Discussionmentioning

confidence: 99%

Middle Latency Auditory Evoked Responses in Normal Term Infants: A Longitudinal Study

Rogers¹,

Edwards²,

Henderson‐Smart³

et al. 1989

Neuropediatrics

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show abstract

“…If an open recording filter is used, wave P0 will show a decrease in latency and will be recorded in the time domain of the ABR (2,3). The increase in latency of PB with LP analog filtering is due to phase shift distortion of the response (2,3,6). Mendel and Kupperman (7) described a P wave which splits the Na trough into two waves (Na, and Naz).…”

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confidence: 99%

High Pass Digital and Analog Filtering of the Middle Latency Response

Kavanagh¹,

Domico

1987

Ear and Hearing

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Digital filtration with zero and standard-phase shift characteristics was performed on unfiltered auditory evoked potentials recorded from 10 adult subjects. Standard-phase shift filters were seen to distort the response. Mild phase shift distortion often augmented the IV/V-Nal amplitude (auditory brain stem response). When recording the IV/V-Na, amplitude on a narrow timebase (20 msec), we recommend using a phase shift filter that has a high-pass cutoff frequency approximating 15 Hz and a slope of 12 to 24 dB/octave, in order to take advantage of the observed phase shift augmentation. The augmentation of the IV/ V-Nal amplitude is at the expense of the IV/V-Na2 amplitude. Thus, this phase shift distortion is not desirable if a long timebase (50 msec) is used. If a high-pass standard-phase shift filter of 100 Hz is used to eliminate muscle artifact, a reduction in the IV/V-Nal amplitude from phase shift distortion is seen compared to the zero-phase shift control. In site-of-lesion testing, a nondistorted waveform produced by digital zero-phase shift filtration is also desirable over a distorted analog response. It is recommended that the slow wave activity of the response be recorded with a timebase of at least 40 to 50 msec and with a filter that produces minimal or no phase shifting. The major recorded response will be the Na trough and Pa peak. Evoked response units with steep filters will phase shift the response and produce a reduction in the IV/V-Na amplitude and a concomitant augmentation of the latter middle latency response waveforms. This augmentation has a variable configuration and therefore, recording with a long timebase (100 msec) will be required to record this activity.

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Clinical status of evoked response audiometry

Vivion¹

1980

The Laryngoscope

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In the past decade there has been a widespread renewal of interest in the clinical utilization of electroencephalic responses evoked by auditory stimulation. In particular, there has been considerable research conducted on the brain stem response, the frequency following response, and the middle latency response. An overview discussion of some of the latest findings from recent and ongoing investigations is presented. Discussion is centered initially on current ideas, findings, and controversies regarding the origins or site of generation of these responses. Clinical application of the responses is discussed from two perspectives, audiologic applications and neurologic applications. Essential parameters for evoking, recording and analyzing clinically these responses are summarized. Some of the problems resulting from a lack of standardized clinical testing protocols are also mentioned. Key findings from recent clinical studies of some investigators are cited. Also recent data concerning the developmental aspects of the responses on clinical testing are included. Finally, some directions for future research on these responses are discussed. One of the latest techniques for recording and analyzing the responses and its implications for site of lesion neurologic testing are described.

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Phase Distortion of Averaged Electroencepha

Cited by 18 publications

References 4 publications

Middle Latency Auditory Evoked Responses in Normal Term Infants: A Longitudinal Study

Middle Latency Auditory Evoked Responses in Normal Term Infants: A Longitudinal Study

High Pass Digital and Analog Filtering of the Middle Latency Response

Clinical status of evoked response audiometry

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