We have begun to thoroughly explore the different viable options for measuring the 3 major components of spasticity, namely, force, range of motion, and velocity. Dr. Engsberg’s lab previously used the KinCom dynamometer to measure these three components. However, this contraption is rather large and bulky, not to mention expensive, and not easily available to hospitals. Thus, alternative options were pursued. To measure the force, a simple force transducer of any sort would be necessary. As we discussed in our previous weekly report, the force could not be measured implicitly or calculated. Thus, we have little choice but to use some sort of force transducer. There are many force transducers on the market that can be purchased that have mechanical to digital transmission capabilities. Dr. Engsberg’s lab has shoe insoles that have build-in force transducers that we have be able to test with. To measure range of motion, we could use smartphones. With built-in accelerometers, both iPhones and Androids have the capability to sense its position relative to gravity, thus allowing us to measure the angle at which the leg is positioned at all times. The range of motion could also be acquired by a video-monitoring system, such as Xbox Kinect or Dartfish. The method for this is fairly obvious--trackers could be used to monitor the position of the leg. Measuring the velocity has proven to be a slightly more difficult task. Most existing velocity measures rely on some sort of contact with a stationary medium, usually relative to the ground for example. However, our device requires that we have real-time velocity measurements through space. Of course, a video-monitoring system could also be used for this. A more clever approach could be employed with the smartphone’s accelerometer. Since the leg is going to start from one fixed position to a final raised fixed position, the change in angle can be measured (by measuring the change in angle of gravity relative to the phone). This value, Δθ, which is applied over a time Δt, can be used to calculate the angular velocity, ω. This implicit measure of angular velocity is plausible in this scenario because the movement of the leg is a constant rotation with a fixed radius. Measuring these three components is absolutely necessary to implement our quantitative measure of spasticity.
Work planned for Next Week:
We will continue to explore the options and narrow them down, keeping in mind that we want our final product to be cheap, convenient to use, and easily implementable in clinics.
Anything needed from client or TA before continuing work:
We are still looking to borrow a force transducer to be able to test with in the future. Dr. Klaesner does not have one, but suggests that we contact other members of the BME department such as Dr. Dan Moran, Dr. Dennis Barbour, Dr. Kurt Thoroughman or Dr. Igor Efimov. While using shoe insoles may be adequate for testing, it may prove difficult to transmit the information, since the force data has to be transmitted in real time with the other acquired data.