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Monita Chatterjee
Ph.D. (1994, Syracuse University, Neuroscience)
B.E.E. (1987, Jadavpur University, Calcutta, India, Electrical Engineering)
Assistant Professor, Department of Hearing & Speech Sciences
Email: mchatterjee@hesp.umd.edu
Phone: 301-405-7716
Room: 0119E, LeFrak Hall
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**Participants needed for cochlear implant study! Click here for more information**
Research/Clinical Interests:
Auditory Processing
Auditory Scene Analysis
Courses Taught in the Past Five Years
HESP 407: Bases of Hearing Science (Syllabus)
HESP 722: Experimental Audiology (Syllabus)
HESP 848: Seminar in Cochlear Implants (Syllabus)
Research/Clinical Activities:
Grant awards:
1998-2001 Principal Investigator, "Auditory Implant Perception in Ongoing Backgrounds", NIH/NIDCD R03
2002-2007 Principal Investigator, "Complex Stimulus Perception with Cochlear Implants", NIH/NIDCD R01
Current work:
Complex Stimulus Perception with cochlear implants (NIDCD R01, 2002 - 2007)
Summary:
A common problem in hearing impairment is that patients find it very difficult to follow speech in noisy backgrounds. This is also true for cochlear-implant listeners . Although cochlear implants are very successful in quiet surroundings, most cochlear implant users find it very difficult to listen in challenging acoustic environments: the presence of even one competing speaker can pose a significant problem. Part of the problem is that we don't quite understand how the normal auditory system performs this difficult task, or what kind of information about the incoming sound stream is needed for the brain to separate one source of sound from another. The work in my lab attempts to answer some of these questions. Our experiments are designed to quantitatively measure how well cochlear implant users can discriminate between speech-like sounds, both in quiet and in the presence of competing background sounds. These experiments are yielding interesting clues about how the brain separates sounds from each other. We expect that results of these experiments will contribute both to our understanding of how the central auditory system works as well as provide ways to improve cochlear implant speech processors in the future.
Specifics:
We are interested in the ability of cochlear implant listeners to process concurrent stimuli on two or more channels. While much work has been done in the area of cochlear implant research to establish the psychophysics of simple stimuli, the response of the system to complex stimuli is yet to be quantified in depth. Our goal is to establish basic principles underlying the processing of complex stimuli by cochlear implant listeners. Complexity in the tonotopic domain is achieved by presenting pulse trains concurrently on two or more channels. Complexity in the temporal domain is achieved by imposing different envelopes on these stimuli. We are measuring subjects' ability to discriminate changes on one channel in the presence of competing inputs on other channels. Results yield information about channel-interaction at both relatively peripheral (ie, arising from tonotopic overlap) and relatively central (ie., arising from coherence or comparisons of temporal envelopes) levels of processing. So far, our work with two-channel stimuli indicates that dynamic signals on the two and three channels interact more than static signals, implying a role of envelope processors (presumably more centrally located) in shaping perceptual channels.
Another goal of our work is to study the potential effects of external noise on the processing of dynamic signals by the cochlear implanted auditory system. We have found that introducing an optimal level of a randomly fluctuating modulator into a carrier envelope can improve detection of sinusoidal modulation of the envelope (stochastic resonance-like effect, see Chatterjee and Robert, 2001, JARO 2(2), 159-171). We are at present extending these studies to the multichannel stimulation case.
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Selected Publications:
Some papers are available in pdf format. Copyright laws require that published articles are downloaded for personal use only.
Peer-reviewed Publications
Chatterjee, M. and Peng, S.C. (2007) Processing F0 with cochlear implants: modulation frequency discrimination and speech intonation recognition. Hearing Research,235: 143-156. Click here to read this article
Chatterjee, M., Sarampalis, A., Oba, S.I. (2006) Auditory stream segregation with cochlear implants: a preliminary report. Hearing Research, 222, 100-107. Click here to read this article
Chatterjee, M., Galvin, J. J., Fu, Q.J., Shannon, R.V. (2006) Effects of stimulation mode, level, and location on forward-masked excitation patterns in cochlear implant patients. J. Assoc. Res. Otolaryngol. 7 (1): 15-25 (Epub: Nov. 2005)Click here to read this article.
Chatterjee, M. & Oba, S. I. (2005). Noise improves modulation detection by cochlear implant listeners at moderate carrier levels. J. Acoust. Soc. Am., 118(2): 993-1002. Click here to read this article.
Chatterjee, M. & Oba, S. I. (2004). Across- and within-channel envelope interactions in cochlear implant listeners. J. Assoc. Res. Otolaryngol., 5(4), 360-375. Click here to read this article.
Abdala, C. A. & Chatterjee, M. (2003). Maturation of cochlear nonlinearity as measured by distortion product otoacoustic emission (DPOAE) suppression growth in humans. J. Acoust. Soc. Am., 114 (2), 932-943. Click here to read this article.
Chatterjee, M. (2003). Modulation masking in cochlear implant listeners: envelope vs. tonotopic components. J. Acoust. Soc. Am., 113 (4), 2042-2053. Click here to read this article.
Chatterjee, M. & Robert , M. E. (2001). Noise enhances modulation sensitivity in cochlear implant listeners: stochastic resonance in a prosthetic sensory system? J.A.R.O., 2(2), 159-171. Click here to read this article.
Chatterjee, M., Fu, Q.-J. & Shannon, R. V. (2000). Effects of phase duration and electrode separation on loudness growth in cochlear implant listeners. J. Acoust. Soc. Am., 107(3): 1637-1644. Click here to read this article.
Chatterjee, M. (1999). Temporal mechanisms underlying recovery from forward masking in multielectrode implant listeners. J. Acoust. Soc. Am., 105(3): 1853-1863. Click here to read this article.
Chatterjee, M. (1999). Effects of stimulation mode on threshold and loudness growth in multielectrode implants. J. Acoust. Soc. Am., 105(2 Pt 1):850-60. Click here to read this article.
Chatterjee, M. & Zwislocki, J. J. (1998). Cochlear mechanisms of frequency and intensity coding. II. Dynamic range and the code for loudness. Hearing Research, 124, 170-181.
Chatterjee, M. & Shannon, R. V. (1998). Forward masked excitation patterns in multielectrode electrical stimulation. J. Acoust. Soc. Am., 103(5), 2565-2572. Click here to read this article.
Chatterjee, M., Fu, Q-J & Shannon, R. V. (1998). Within-channel gap detection using dissimilar markers in cochlear implant listeners. J. Acoust. Soc. Am., 103(5), 2515-2519. Click here to read this article.
McCreery, D. B., Shannon, R. V., Moore , J. K. & Chatterjee, M. (1998). Accessing the tonotopic organization of the ventral cochlear nucleus by intranuclear microstimulation. IEEE Trans. Rehabil. Eng., 6(4):391-9.
Chatterjee, M. & Zwislocki, J. J. (1997). Cochlear mechanisms of intensity and frequency coding: I. The place code for pitch. Hearing Research, 111, 65-75.
Chatterjee, M. & Smith, R. L. (1993). Physiological overshoot and the compound action potential. Hearing Research, 69, 45-54.
Other Publications
Chatterjee, M. & Robert , M. E. (2003). Stochastic resonance in temporal processing by cochlear implant listeners? Proceedings of SPIE conference Fluctuations and Noise 2003, Santa Fe, NM June 1-4.
Chatterjee, M . (2002). Cochlear Implants: Bridging Auditory Neuroscience and Technology, The Hearing Review, April 2002.
Friesen, L. F., Fu, Q. J., Chatterjee, M. & Galvin, J. J. (2001). Cochlear implant research: overview, current and future trends. ASHA Div. 6 Newsletter.
Chatterjee, M., Shannon , R. V., Galvin, J. J. & Fu, Q.-J. (2001.) Spread of excitation and its effect on auditory perception with cochlear implants. In A. J. M. Houtsma, A. Kohlrausch, V. F. Prijs & R. Schoonhoven (Eds.), Physiological and Psychophysical Bases of Auditory Function. Proceedings of the 12th International Symposium on Hearing. Shaker Publishing BV, Maastricht.
Chatterjee, M. (1998). Mechanisms underlying recovery from forward masking in electrical stimulation. Proceedings of the 16th Intl. Congress on Acoustics and 135th Mtg. Acoust. Soc. Am, Vol. II, 875-876.
Zwislocki, J. J. & Chatterjee, M. (1995). On the neural code for loudness and its cochlear correlates. In Manley et al. (Eds.), Advances in Hearing Research, World Scientific, Singapore.
Chatterjee, M. (1994). Aspects of intensity and frequency coding in the cochlea. PhD Dissertation, Syracuse University and ISR Special Report 31.
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