Activity Monitoring: Can It Bolster Patient Compliance?

By Katherine Holtz-Neiderer, DPM, and David G. Armstrong, DPM, MSc

Repetitive stress is a major contributing factor to the rise of most foot problems. In the high-risk diabetic foot clinics at the Southern Arizona Veterans Affairs Medical Center, the most common of these severe complications is the diabetic foot wound. The prime etiology of diabetic foot ulcers is the combination of neuropathy and repetitive moderate stress (walking). Diabetic foot wounds often lead to a host of other maladies including sepsis, amputation and premature death. It has also been shown that people undergoing amputation have higher healthcare costs.1,2 When it comes to treating patients with diabetic foot ulcers, one must address pressure and repetitive stress (activity). One can address pressure externally (through shoe gear modification, bracing or casting) or internally via physical therapy and/or surgery.3, 4 However, manipulating repetitive stress (activity) has been tougher as it has been quite difficult to measure. In the past, most pedometers merely gave a readout of the steps patients took but gave no information about when that activity started or stopped. In the past few years, we and others have tested and utilized many models of accelerometers/pedometers that range in complexity from more basic models to very sophisticated devices that have enabled us to surpass these early hurdles. We believe we are now at a point where we can begin dosing activity as we might dose a drug. We have used several of these monitoring devices and some hold potential practical applications now and in the future. A Closer Look At The Pedometer Options An early predecessor that we used was the Sportbrain (Sportbrain, Campbell, Calif.). It is worn on the waistband or belt and uses a lithium battery, which lasts three months. The Sportbrain counts the number of steps and the time that they were taken. The information is then uploaded via the Internet where the clinician and patient can both view and analyze the data. This requires a monthly monitoring fee to access the data. The Biotrainer Pro (IM Systems, Baltimore, Md.) is another waistband monitor that has a biaxial acceleration sensor. Similar to the Sportbrain, the Biotrainer Pro measures the number of steps and the time when they were taken. One can also take the patient’s caloric measurements when entering the weight and height of the patient into the computer. It uses an AAA battery and can measure up to three months of data. The most sophisticated device that we have used is the Dynastream Amp 331 (Dynastream Innovations, Inc., Alberta, Canada). This device uses an inertial sensor and is held in a nylon sleeve worn around the ankle. The Dynastream Amp 331 measure critical locomotion details such as the distance traveled, speed, cadence and stride length. It also tracks the number of steps the patient takes and the time they were taken. It also computes energy expenditure. The device even documents standing and milling as the information is blocked into one of three activities: inactive, active and locomotion. Recording time is a drawback to the device as it can only record one week of data at a time. What Does The Future Hold For Pedometers? At our facility, we are currently working on transmitting information via phone line similar to the holter monitor or blood sugar readings. By using a LCD screen and a regular phone line, we can eliminate a computer requirement. With this system in place, we should not be limited by time constraints. We also plan on using it to send patients questionnaires and other forms. Pedometers have been used in a variety of clinical situations. They have been used to quantify claudication and evaluate changes in activity in people with chronic obstructive pulmonary disease, and as a biofeedback mechanism in weight loss studies. Activity monitoring could also be used for pre- and postoperative assessment. A prospective surgical patient could wear the monitor before surgery as an activity baseline and then postoperative monitoring could help a surgeon adjust the amount of activity and measure when the amount of activity returns to baseline. An athlete who undergoes reconstructive foot surgery could use monitor driven goals rather than allowing pain to be his or her guide.

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