Prior to 2007
Professor Ted Clancy Powered Artificial Limbs and Rehab Engineering
Professor Ted Clancy has his hands on the pulse of where biomedical and electrical engineering meet - and it's reading about 10 µV. Since his arrival as a professor here at WPI, Professor Clancy has been exploring the wide variety of applications electrical engineering can have when combined with biomedical engineering. Currently, Clancy is working on no fewer than four separate research projects, utilizing the assistance of students in the Center for Sensory and Physiologic Signal Processing (C(SP)2 for short) as well as collaborating with numerous colleagues around the world. Those four areas of research include i) powered artificial limbs, ii) clinical neurological examinations using sensor arrays, iii) ergonomic assessments in the workplace, and iv) clinical gait (walking) rehabilitation analyses.
Powered Artificial Limbs
Perhaps the longest-running research program that Professor Clancy has been involved with has been his study of ways to improve powered artificial limbs. For years, progress in this broad field of biomedical engineering has been slow and methodical, but with the advent of the Iraq War and the ensuing injuries faced by soldiers the federal government has been increasing funding in this area in the hopes of accelerating discoveries and applications.
Professor Clancy's research has focused on using electronic signal processing to control prosthetic limbs, such as artificial arms and legs. He does this through an analysis of the electrical signals produced by the body's muscles. Whenever you move your arm or leg your body contracts muscles around those limbs to produce the desired motion. Each individual muscle fiber contraction produces a tiny electrical signal - something on the order of millivolts - and the more effort you put into moving that limb, the more muscle fibers that are recruited and the stronger the signal that is generated. By precisely measuring these electrical signals using surface electrodes, Professor Clancy can obtain and create a more accurate view of which muscle areas are controlling specific aspects of limb motion. This, in turn, will translate into more naturally controlled and articulated powered artificial limbs.
Professor Clancy is one of several faculty at WPI seeking funding for artificial limb research. Two other professors at WPI working on artificial limbs are Professor Allen Hoffman of the Mechanical Engineering Department and Professor W. Grant McGimpsey of the Chemistry and Biochemistry Department. Linda Looft, Director of External and Government Affairs, is spearheading these efforts to find research funding. Given the urgent need for better prosthesis for our returning soldiers, there has rarely been a better time to pursue such endeavors.
Right now, when a doctor or clinical technician wants to measure the electrical signals generated by a muscle bundle or fiber, s/he is forced to invasively probe the muscle using a special needle electrode. The essential problem is that the very low level signals generated by individual muscle fibers are diffused by the tissue mass and combined with thousands of other muscle signals at the time they are recorded at the skin surface using a surface electrode recording system. Another of Professor Clancy's research interests is to develop signal processing and laboratory methods that will make the practice of using invasive needle electrodes either obsolete or at least much less common. As a recognized world class expert in the field of EMG signal detection and analysis, his approach uses a combination of an array of tiny electrodes spaced only millimeters apart and placed gently on the skin, coupled with advanced signal processing techniques to mathematically focus the sensitivity of the electrode array on only a few muscle fibers well under the skin surface. Experiments and studies to date have demonstrated the viability of the approach and have shown an ability to replicate the data recorded using traditional needle sensors.
Clancy first considered the idea of using tiny sensor electrode arrays while on a sabbatical in Italy in 1999 while working with his colleague Professor Roberto Merletti when they explored the potential of gathering muscle data from small arrays of densely packed electrodes. Most recently Professor Clancy and his research partner at UMass, Professor Gary Kamen, received a grant from the National Institute of Neurological Disorders and Stroke (NINDS) to further his research.
Currently this research program is in an "engineering" phase, meaning that the technical obstacles of properly gathering data from the electrodes are still being worked on. Once significant progress has been made in overcoming the technical recording and signal processing hurdles, clinical trials and applications can begin. When that time comes - and Professor Clancy is confident it will be sooner rather than later - scientists and engineers will be able to better diagnose such devastating muscles disorders like ALS (commonly known as Lou Gehrig's Disease).
Ergonomic Assessment in the Workplace
Anyone who has spent a summer working in a factory or manufacturing plant is probably familiar with repetitive motion injury. Working in the same space for up to eight hours a day, doing the same activity in a never-ending, repetitive motion can be a recipe for disaster. Professor Clancy is once again on the scene doing his part to develop a scientific understanding of this common affliction, and to develop ways in which it can be minimized or prevented.
One of the challenges facing scientists trying to study repetitive motion is accurately collecting data from a body in motion. Luckily, Professor Clancy is working with new electrode configurations to measure the mechanical forces and electrical potentials generated by moving muscles with better accuracy and area coverage than previously possible. One of the colleagues Clancy is working with is Professor Denis Rancourt of Sherbrooke University in Canada. Together, with funding from the National Institute of Occupational Safety and Health (NIOSH), research is steadily progressing every day. Like the sensor arrays, this research is also still in the engineering phase, where Professor Clancy and his colleagues are still trying to determine, "How do we measure this?" Once a solid foundation has been established for making useful measurements, real workplace repetitive-motion assessments can begin.
Clinical Gait Analysis
After suffering a stroke many people lose important motor functions, including the ability to walk. While rehabilitation is generally available that can help a stroke victim by teaching patients how to walk again, some patients are never able to return to their original gait. Instead, they maintain an inefficient pattern that wastes energy and possibly limits their ability to carry out activities of daily life.
Professor Clancy is working with Spalding Rehabilitation Hospital in Boston to collaborate on new methods for analyzing the needs of stroke patients who exhibit consistently irregular gaits. The object of his research is use a series of sensors to measure the electrical signals generated during a normal gait and then comparing this data to the gait of the stroke patient. The patient would then be coached back to a normal walking pattern by having the patient slowly attempt to match their gait with that of a normal walker.
Whether he is working on powered artificial limbs, sensor arrays, ergonomic workplace conditions, or gait rehabilitation, Professor Clancy is always on the leading edge of convergence between electrical and biomedical engineering. For further information or to contact the WPI ECE Department, please follow one of the links cited below.
WPI and ECE Links
- WPI ECE Department
- Dr. Clancy's C(SP)2 Lab
- Recent posters from graduate student competitions and conference presentations:
- Powered Artificial Limbs
- EMG Tutorials
- Spalding Rehab Hospital
- Spalding Motion Analysis Lab
This article was written by Lawrence Scharpf, a technical communications major at WPI.
May 1, 2006