The PDA project


The main aim of this project, funded by NIDCD/NIH, is to develop a research interface platform which can be used by researchers interested in exploring new ideas to improve cochlear implant devices. This research platform includes a stimulator unit which can be used for electrical stimulation in animal studies and a portable processor for implementing and evaluating novel speech processing algorithms after long-term use.  The research platform chosen for this project is the personal digital assistant (PDA). The PDA was chosen for several reasons: (1) it is equipped with a variety of input/output ports needed to interface externally with either the recording or stimulating units, (2) it possesses powerful computing capability (some PDAs run as fast as 624 MHz) needed to implement complex speech processing algorithms, (3) it is flexible in as far as being able to program in either assembly language, C language or LabVIEW (can also be interfaced with MATLAB). The PDA environment makes it easy for researchers to explore and test new speech coding algorithms without being constrained or limited by the proprietary nature of commercially-available implant speech processors. The PDA speech processor was recently approved by FDA for clinical studies with Nucleus cochlear implant patients. For a description of the PDA processor, see the following video of our first cochlear implant user tested:

News Release from KERA news: "Smartphone App Opens New World Of Hearing " [pdf]

Quarterly progress reports to the National Institutes of Health (contract N01-DC-6-0002)


No. Title Date Link
QPR1 Filter implementation on the PDA and real-time LabVIEW implementation of a noise-band vocoder April 1, 2006-June 30, 2006 qpr1.pdf
QPR2 EEG recording on the PDA and real-time LabVIEW implementation of a noise-band vocoder July 1, 2006-Sept 30, 2006 qpr2.pdf
QPR3 C implementation of 16-channel noiseband vocoder, wireless approach Oct 2006- Dec 2006 qpr3.pdf
QPR4 Cortical auditory evoked potential (CAEP) recordings on the PDA Jan 1, 2007 - March 30, 2007 qpr4.pdf
QPR5 Interface board development for Freedom cochlear implant, single-channel stimulator for animal studies and post-processing of CAEPs April 1, 2007 - June 30, 2007 qpr5.pdf


QPR6 ACE implementation, modifications to the SDIO interface board July 1, 2007 - September 30, 2007 qpr6.pdf
QPR7 Design of 8-channel stimulator for animal studies, SDIO board (v. 2) October 1, 2007 - December 31 2007 qpr7.pdf
QPR8 Testing signal acquisition circuit of  SDIO board (v. 2), improvements to filtering January 1, 2008 - March 31 2008 qp8.pdf
QPR9 Final PDA prototype, beamforming implementation for bilateral studies, FFT code optimization April 1, 2008 - June 30, 2008 qpr9.pdf
QPR10 Testing of 8-channel stimulator for animal studies, evaluation of beamforming implementation with NH listeners, high-rate implementation mode for Freedom CI24RE implant July 1, 2008 - September 30, 2008 qpr10.pdf
QPR11 Hardware testing of revised SDIO board (v.3), integration of LabVIEW code with SDIO board October 1, 2008 - December 31, 2008 qpr11.pdf
QPR12 MATLAB-to-PDA Winsock Interface January 1, 2009 - March 30, 2009 qpr12.pdf
QPR13 Refinements of bench stimulator for animal studies, real-time wavelet implementation of ACE April 1, 2009 - June 30, 2009 qpr13.pdf
QPR14 Bench-top stimulator and portable stimulator for animal studies July 1, 2009 - September 30, 2009 qpr14.pdf
QPR15 Implementation of protocol used in Nucleus 22 device Oct 1, 2009 - December 31, 2009 qpr15.pdf
FINAL REPORT Final Report   final report.pdf



Ali, H., Lobo, A. and Loizou, P. (2011). "A PDA Platform for Offline Processing and Streaming of Stimuli for Cochlear Implant Research," Proc. IEEE Eng. Med. Biol. Soc. Conference, Boston, MA. [pdf]

Kim, D., Gopalakrishna, V., Guo, S.,  Lee, H.,Torlak, M.,  Kehtarnavaz, N.,  Lobo, A. and  Loizou, P. (2011). "On the design of a flexible stimulator for animal studies in auditory prostheses," Biomedical Signal Processing and Control, (in press).[pdf]

Gopalakrishna, V.,  Kehtarnavaz, V. and  Loizou, P. (2010). "A Recursive Wavelet-Based Strategy for Real-Time Cochlear Implant Speech Processing on PDA Platforms," IEEE Trans. Biomedical Engineering, 57(8), 2053-2063. [pdf]

D. Kim, V.Gopalakrishna, S. Guo, H. Lee, M. Torlak, N. Kehtarnavaz, A. Lobo, and P. Loizou (2009). On the Design of a Flexible Stimulator for Animal Studies in Auditory Prostheses, Proc. 2nd International Symposium on Applied Sciences in Biomedical and Communication Technologies, Nov 24-27, Bratislava, Slovak Republic.

V. Gopalakrishna, N. Kehtarnavaz, and P. Loizou (2009). Real-time PDA-based recursive Fourier transform implementation for cochlear implant applications, Proc. IEEE Conference on Acoustics, Speech and Signal Processing, 1333 1336.

S. Guo, H. Lee and P. Loizou (2008) A 9-bit configurable current source with enhanced output resistance for cochlear stimulators, IEEE Custom Integrated Circuits Conference, San Jose, CA, Sep. 2008.

Ramachandran, R. and Loizou, P. (2007).  Real-time pitch detection on the PDA for cochlear implant applications, IEEE Dallas Engineering in Medicine and Biology Workshop, November 11-12, 2007.

Peddigari, V., Kehtarnavaz, N. and Loizou, P. (2007). Real-time LabVIEW implementation of cochlear implant signal processing on PDA platforms, Proc. IEEE Intern. Conf. Signal, Acoust. Speech Proc, Honolulu, Hawaii.

Lobo, A., Loizou, P., Kehtarnavaz, N., Torlak, M., Lee, H., Sharma, A. Gilley, P., Peddigari, V. and Ramanna, L. (2007). A PDA-based research platform for cochlear implants, to appear in 3rd International EMBS Conference on Neuroengineering, Hawaii, May 2007.

Lobo, A., Loizou, P., Kehtarnavaz, N., Torlak, M., Lee, H., Sharma, A. Gilley, P., Peddigari, V. and Ramanna, L. (2007). A portable research platform for cochlear implants, Conference on Implantable Auditory Prostheses (CIAP), Lake Tahoe, CA, July 15-July 20.

News Releases

National Instruments, Developing a Portable, Real-Time Platform for Cochlear Implant Studies Based on NI LabVIEW Software