In this study, a frequency domain formulation of continuous loop averaging deconvolution (CLAD) of overlapping evoked potentials is developed and applied for the extraction of transient responses from recordings obtained at high stimulation rates. This formulation allows for a faster execution of CLAD by using fast Fourier transform algorithms. The frequency characteristics of the deconvolution filter depends exclusively on the stimulus sequence and determines whether the noncoherent noise is amplified or attenuated in different frequencies. A formula for calculating the signal-to-noise ratio (SNR) achieved by the deconvolution process is developed. The newly developed theory and the methodology is applied to the extraction of the auditory brainstem and middle latency responses using various sequences. The effects of the sequence used and the number of sweeps averaged in ongoing acquisition on SNR are examined by using single sweep recordings. The results verify the deconvolution theory and the methodology and show its limitations. Depending on the frequency characteristics of the sequence, the deconvolution process can amplify or attenuate the EEG noise. Proper selection of the stimulus sequence can increase the SNR enhancement obtained with conventional averaging.
REFERENCES
1.
Bell
, S. L.
, Allen
, R.
, and Lutman
, M. E.
(2001
). “The feasibility of maximum length sequences to reduce acquisition time of the middle latency response
,” J. Acoust. Soc. Am.
109
, 1073
–1081
.2.
Bell
, S. L.
, Allen
, R.
, and Lutman
, M. E.
(2002
). “Optimizing the acquisition time of the middle latency response using maximum length sequences and chirps
,” J. Acoust. Soc. Am.
112
, 2065
–2073
.3.
Bohórquez
, J.
, and Özdamar
, Ö.
(2006
). “Signal-to-noise-ratio analysis of Maximum Length Sequence (MLS) deconvolution of overlapping evoked responses
,” to be submitted.4.
Burkard
, R.
, McGee
, J.
, and Walsh
, E. J.
(1996a
). “Effects of stimulus rate on the feline brain-stem auditory evoked response during development I. Peak latencies
,” J. Acoust. Soc. Am.
100
, 978
–990
.5.
Burkard
, R.
, McGee
, J.
, and Walsh
, E. J.
(1996b
). “Effects of stimulus rate on the feline brain-stem auditory evoked response during development. I. Peak amplitudes
,” J. Acoust. Soc. Am.
100
, 991
–1002
.6.
Burkard
, R.
, Shi
, Y.
, and Hecox
, K. E.
(1990
). “A comparison of maximum length sequences and Legendre sequences for the derivation of brainstem auditory evoked responses at rapid rates of stimulation
,” J. Acoust. Soc. Am.
87
, 1656
–1664
.7.
Chan
, F. H. Y.
, Lam
, F. K.
, Poon
, P. W. F.
, and Du
, M. H.
(1992
). “Measurement of human BAERs by the maximum length sequence technique
,” Med. Biol. Eng. Comput.
30
, 32
–40
.8.
Delgado
, R. E.
, and Özdamar
, Ö.
(2004
). “Deconvolution of evoked responses obtained at high stimulus rates
,” J. Acoust. Soc. Am.
115
, 1242
–1251
.9.
Eysholdt
, U.
, and Schreiner
, C.
(1982
). “Maximum Length Sequences—a fast method for measuring brainstem evoked responses
,” Audiology
21
, 242
–250
.10.
Galambos
, R.
, Makeig
, S.
, and Talmachoff
, P. J.
(1981
). “A auditory potential recorded from the human scalp
,” Nicolet Potentials
1
, 8
–12
.11.
Hansen
, J. C.
(1983
). “Separation of overlapping waveforms having known temporal distributions
,” J. Neurosci. Methods
9
, 127
–139
.12.
Hecox
, K.
, Cone
, B.
, and Blaw
, M.
(1981
). “Brainstem auditory evoked response in the diagnosis of pediatric neurologic diseases
,” Neurology
31
, 832
–840
.13.
Jewett
, D. L.
, Caplovitz
, G.
, Baird
, B.
, Trumpis
, M.
, Olson
, M. P.
, and Larson-Prior
, L. J.
(2004
). “The use of QSD (q-sequence deconvolution) to recover superposed, transient evoked-responses
,” Clin. Neurophysiol.
115
, 2754
–2775
.14.
Jiang
, Z. D.
, Brossi
, D. M.
, Wang
, J.
, Xu
, X
, Chen
, G. Q.
, Shao
, X. M.
, and Wilkonson
, A. R.
(2003
). “Time course of brainstem pathophysiology during first month in term infants after perinal asphyxia, revealed by MLS BAER latencies and intervals
,” Pediatr. Res.
54
, 680
–687
.15.
Lasky
, R. E.
, Perlman
, J.
, and Hecox
, K. E.
(1992
). “Maximum Length Sequence Auditory Evoked Brainstem Responses in Human Newborns and Adults
,” J. Am. Acad. Audiol
3
, 383
–389
.16.
Leung
, S.-M.
, Slaven
, A.
, Thornton
, R. D.
, and Brickley
, G. J.
(1998
). “The use of high stimulus rate auditory brainstem responses in estimation of hearing threshold
,” Hear. Res.
123
, 201
–205
.17.
Lina-Granade
, G.
, Collet
, L.
, and Morgon
, A.
(1994
). “Auditory-evoked brainstem responses elicited by maximum-length sequences in normal and sensorineural ears
,” Audiology
33
, 218
–236
.18.
Marsh
, R.
(1992
). “Signal to Noise Constraints on Maximum Length Sequence Auditory Brain Stem Responses
,” Ear Hear.
13
, 396
–400
.19.
Özdamar
, Ö
, and Delgado
, R. E.
(1996
). “Measurement of signal and noise characteristics in ongoing auditory brainstem response averaging
,” Ann. Biomed. Eng.
24
, 702
–715
.20.
Özdamar
, Ö.
, Delgado
, R. E.
, Thombre
, K. V.
, Yavuz
, E.
, and Anderson
, M.
(2003a
). “Acquisition of ABRs at very high stimulation rate using CLAD (Continuous Loop Algorithm Deconvolution)
,” ARO Abstr.
40
, 44
.21.
Özdamar
, Ö.
, Delgado
, R. E.
, Yavuz
, E.
, Thombre
, K. V.
, and Acikgoz
, N.
(2003b
). “Deconvolution of auditory evoked potentials obtained at high stimulus rates
,” Proc. 1st Int. IEEE EMBS Conf. Neural Engineering
, Capri
, Italy, pp. 285
–288
.22.
Picton
, T. W.
, Champagne
, S. C.
, and Kellet
, A. J. C.
(1992
). “Human auditory evoked potentials using maximum length sequences
,” Electroencephalogr. Clin. Neurophysiol.
84
, 90
–100
.23.
Talsma
, D.
, and Woldorff
, M. G.
(2005
). “Methods for estimating and removal of artifacts and overlap in ERP waveforms
,” in Event-Related Potentials: A Methods Handbook
, edited by T. H.
Handy
(MIT
, Cambridge, MA), pp. 115
–148
.24.
Thornton
, A. R. D.
(1993a
). “High rate otoacoustic emissions
,” J. Acoust. Soc. Am.
94
, 132
–136
.25.
Thornton
, A. R. D.
(1993b
). “Click evoked otoacoustic emissions: new techniques and applications
,” Br. J. Audiol.
27
, 109
–115
.26.
Thornton
, A. R. D.
, and Slaven
, A.
(1993
). “Auditory brainstem responses recorded at fast stimulation rates using maximum length sentences
,” Br. J. Audiol.
27
, 205
–210
.27.
Van Veen
, B. D.
, and Lasky
, R. E.
(1994
). “A framework for assessing the relative efficiency of stimulus sequences in evoked response measurements
,” J. Acoust. Soc. Am.
96
, 2235
–2243
.28.
Woldorff
, M. G.
(1993
). “Distortion of ERP averages due to overlap from temporally adjacent ERPs: Analysis and correction
,” Psychophysiology
30
, 98
–119
.© 2006 Acoustical Society of America.
2006
Acoustical Society of America
You do not currently have access to this content.