Research Interests

• Effects of deep brain stimulation on posture and locomotion control in Parkinson's Disease

• Neuroprotective effects of exercise in Parkinson's Disease

• Cardiorespiratory function in Spinal Cord Injury

• Modeling cardiovascular physiology

• Application of nonlinear and linear signal processing techniques to electro- and neurophysiological systems.

• Analysis of multi-electrode recordings of cortical activity for repeated perturbations while reaching target in monkeys in an effort to understand the mechanistic aspects of plasticity during learning and adaptation.

• Detection of directional information flow among coupled oscillators with respect to its applications to epileptic seizure prediction and identification of epileptic focus.

Current Research Work (Arizona State University)

Postdoctoral Research (Boston University/Harvard Medical School)

Doctoral Research (Indian Institute of Technology, Madras, India)

PUBLICATIONS

Peer-Reviewed Journal Publications:

1.        K. Narayanan, M. Stefani, P. Mahant, J. Samanta and J.J. Abbas, "Deep brain stimulation amplitude alters posture shift velocity and unsteadiness in Parkinson's disease” (submitted)

2.        L.D. Iasemidis, P.M. Pardalos, D-S Shiau, W.Chaovalitwongse, K. Narayanan, A. Prasad, K. Tsakalis P. Carney and J.C. Sackellares, "Long-term prospective on-line real-time seizure prediction", J. Clin Neurophysiol., 116, 532-544 (2005).

3.        B. Veeramani, K. Narayanan, A. Prasad, L.D. Iasemidis, A. Spanias and K. Tsakalis, "Measuring the direction and the strength of coupling in nonlinear systems - A modeling approach in the state space", IEEE Signal Processing Letters, 11 (7), 617-620 (2004).

4.        Sabesan, K. Narayanan, A. Prasad, A. Spanias, J.C. Sackellares, and L.D. Iasemidis, "Predictability of Epileptic Seizures: A comparative study using Lyapunov exponent and entropy based measures", Biomed Sci Instrum., 39, 129-35 (2003).

5.        B. Veeramani, A. Prasad, K. Narayanan, A. Spanias, and L.D. Iasemidis, "Measuring information flow in nonlinear systems - A modeling approach in the state space", Biomed Sci Instrum., 39, 65-70 (2003).

6.        R. Venugopal, K. Narayanan, A. Prasad, A. Spanias, J.C. Sackellares, and L.D. Iasemidis, "A new approach towards predictability of Epileptic Seizures: KLT Dimension", Biomed Sci Instrum., 39, 123-128 (2003)

7.        L.D. Iasemidis, P.M. Pardalos, D-S. Shiau, W. Chaovalitwongse, K. Narayanan, Shiv Kumar, P.R. Carney and J.C. Sackellares, "Prediction of Human Epileptic Seizures based on Optimization and Phase changes of brain electrical activity", J. Optimization Methods and Software, 18 (1), 81-104 (2003).

8.        Narayanan, K., J.J. Collins, J. Hamner, S. Mukai, and L.A. Lipsitz, "Predicting Cerebral Blood Flow Response to Orthostatic Stress from Resting Dynamics: Effects of healthy aging", The American Journal of Physiology, 281: R716-R722 (2001).

9.        Narayanan, K., R.B. Govindan and M.S. Gopinathan (2000) “Evidence for low dimension chaos in electrically coupled chemical oscillator in batch condition”, Indian J. Chem. A 39: (1-3) 345-355.

10.     Narayanan, K., R.B. Govindan and M.S. Gopinathan, “Unstable Periodic orbits in Human Cardiac Rhythms”, Phys. Rev E 57, 4594-4603 (1998).

11.     Govindan, R.B., K. Narayanan and M.S. Gopinathan, “On the evidence of Deterministic Chaos in ECG: Surrogate and Predictability Analysis”, Chaos 8, 495-502 (1998).

Peer-Reviewed Book Chapters:

1.        S. Sabesan, K. Narayanan, A. Prasad, L.D. Iasemidis, A. Spanias and K. Tsakalis, “Information flow in coupled nonlinear systems: Application to the epileptic human brain", In: Data Mining in Biomedicine, P. Pardalos, Ed., Kluwer Academic Publishers (in press).

2.        R.B. Govindan, K. Narayanan, M.S. Gopinathan and N. Pradhan, “Unstable periodic orbit spectra of theoretical and experimental dynamical Systems”, In: Nonlinear Phenomena In Physical And Biological Sciences edited by S. K. Malik, M. K. Chandrashekharan and N. Pradhan (2000).

3.        R.B. Govindan, K. Narayanan, and M.S. Gopinathan, N. Pradhan, R. Sreenivasan, and P. Dwivedi , “The Spectrum of Unstable Periodic Orbits Of The Human Brain”, In: Nonlinear Dynamics and Brain Functioning edited by R. Sreenivasan, N. Pradhan and Paul E. Rapp, Nova Science Publishers, Inc, 1999.

Peer-Reviewed Conference Proceedings and Abstracts:

1.     K. Narayanan, A. Sitek, P. Mahant, J. Samanta, and J.J. Abbas, "Effects of deep brain stimulation amplitude on gait in Parkinson's disease", abstract submitted to Society for Neuroscience Annual Meeting, 2007.

2.        K. Narayanan, S. Mulligan, P. Mahant, J. Samanta and J.J. Abbas, “Deep brain stimulation alters postural control in Parkinson’s Disease”, presented in Society for Neuroscience Annual Meeting 2006.

3.        K. Narayanan, S. Mulligan, P. Mahant, J. Samanta and J.J. Abbas, “Deep Brain Stimulation Effects on Posture Control in Parkinson’s Disease”,  World Parkinson Congress, February 22-26, 2006, Washington D.C (published in Movement Disorders, Vol. 21, Supp. 13, P209, page S115, 2006).

4.        S. Mulligan, K. Narayanan, P. Mahant, J. Samanta and J.J. Abbas, “Effect of deep brain stimulation on posture control in Parkinson’s disease”, 9^th International Congress of Parkinson’s disease and Movement Disorders, March 5-8, 2005, New Orleans, LA (published in Movement Disorders, Vol. 20, Supp. 10, P478, page S141, 2005).

5.        E.T. Hsiao-Wecksler, K. Narayanan, B.S. Lee, C.A. Laughton, and L.A. Lipsitz, "Does Tai Chi affect postural sway & muscle activity in older adults?" 27th Annual Meeting of the American Society of Biomechanics, Toledo, OH, September 25-27, 2003.

6.        S. Sabesan, K. Narayanan, A. Prasad, and L.D. Iasemidis, "Improved Measure of Information Flow in Coupled Non-Linear Systems", The Proceedings of IASTED International Conference on Modeling and Simulation, Palm Springs, USA, 2003, pp. 329-333.

7.        B. Veeramani, K. Narayanan, A. Prasad, and L.D. Iasemidis, "On the use of Directed Transfer Function for Nonlinear systems", The Proceedings of IASTED International Conference on Modeling and Simulation, Palm Springs, USA, 2003, pp. 270-274.

8.        R. Venugopal, A. Prasad, K. Narayanan and L.D. Iasemidis, "Nonlinear Noise Reduction and Predictability of Epileptic Seizures", The Proceedings of IASTED International Conference on Modeling and Simulation, Palm Springs, USA, 2003, pp. 240-245.

9.        L.D. Iasemidis, A. Prasad, K. Narayanan, J.C. Sackellares, P.M. Pardalos, D.S. Shiau and W. Chaovalitwongse, "Prediction of epileptic seizures by linear and nonlinear methods", International Nonlinear Sciences Conference on Research and applications in the Life Sciences, Vienna, Austria, February 7-9, 2003.

10.        A. Prasad, K. Narayanan, K. Tsakalis and L.D. Iasemidis, "Hysteresis in coupled chaotic oscillators and application to epileptic seizures", International Nonlinear Sciences Conference on Research and applications in the Life Sciences, Vienna, Austria, February 7-9, 2003.

11.     Narayanan, K., D.J. Weber, J. He, A. Prasad, and L.D. Iasemidis, "Analysis of Neuronal Interactions during Adaptation and Learning in Motor Control of Primates: A Model Independent Approach using Information Theory", Proceedings of the Second Joint EMBS/BMES Conference, Houston, TX, USA, Oct. 23- 26, 2002, pp 2552-2553.

12.     Narayanan, K., and L.A. Lipsitz, “Do resting Cerebral Pressure - Flow dynamics predict Cerebral blood flow responses to Orthostatic Stress?” Effects of healthy Aging, presented in Experimental Biology 2001, 31 March - 4 April, 2001, Orlando, FL, USA.

13.     Narayanan, K., R.B. Govindan, M. Ramasubba Reddy and M.S. Gopinathan, “Dynamics of cardiac system through unstable periodic orbits”, Proceedings of 19th International Conference - IEEE/EMBS Oct.30 - Nov. 2 1997, pp 2019-2021.