Technical Report AMI-006:

Review of 2005-2006 RERC-AMI National Student Design Competition: Accessible Blood Glucose Monitor Interface

Authors: Kimberly Carr and Kristen Gingras

Coordinating Editor: John Enderle, Ph.D.

Location: University of Connecticut

Current Version: 1.0 (August 2006)

Table of Contents

Executive Summary

During the 2005-2006 academic year, four engineering student design teams from all over the country participated in a National Student Design Competition concentrating in the area of Glucose Monitors and Interfaces. The competition was sponsored by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation (RERC-AMI). Although there are many glucose monitors available on the market today, there is much improvement that can be done to make these devices significantly better. Areas of improvement include making these devices suitable for patients with disabilities such as hearing loss, decreased eyesight, blindness, and diminished motor skills. Three of the engineering student design teams worked on adding accessories to be used with a current glucose monitor that would expand on its capabilities. While one engineering student design team invented a new monitor that is different from those currently on the market because it has a step-by-step voice prompt system, a simple user interface, and a barcode scanner used to identify assorted vials of insulin.

Background

With over eighteen million Americans diagnosed with diabetes, there is a wide need for a glucose monitor that is able to suit patients with and without certain disabilities. People who have diabetes need to measure their blood glucose levels manually, several times a day with a portable, battery-powered meter. Thus, there is a desire to have a glucose monitor that enables one to live as close to a normal life as possible. As mentioned in the executive summary, diabetes often causes disabilities that can make using commercially available glucose monitors a difficult process; they frequently need to rely on the help from others. Although some talking meters are currently developed, they are not designed for optimal usage and can often be hard to understand.

Aim: A portable, reliable, low-cost interface that is easy to use, works with or is based on an existing, commercially available blood glucose monitor, and meets the needs of all diabetes patients.

Specs: The blood glucose monitor is designed to communicate effectively using both a visual display and voice output. Some of the designs use test strips, these teams must consider their use, calibration, and expiration dates; they must also keep in mind the differing types and vials of insulin. It is also important to consider the ease of learning, using, storage of all components, as well as cleaning and maintenance.

Clients: Lloyd, Arnold, Dave, Wanda, Rose

See http://rerc-ami.org/ami/projects/d/2/2/year3/ for a complete description of these personas and rules for the 2005-2006 competition. The maximum budget for each project was $2,000.

Product Table

Table 1. Comparison of Blood Glucose Monitoring Systems Available on the Market

Product Name

 One Touch Profile One Touch Basic SureStep AccuCheck Advantage AccuCheck Complete FasTake Glucometer Elite

Ease of use
9
9
10
9
9
10
9

Features
10
1
5
8
10
10
10

Speed of results
4
4
6
5
5
10
5

Suitability by children under ten years old
10
10
8
8
8
10
8

Suitability by children over ten years old
10
10
8
10
10
10
8


Cost
7
7
3
8
8
2
3

Total
50
41
40
48
50
52
43

Notes:

Survey of Prototypes

The Product Table (above) provides a summary of the various types of glucose monitors currently available on the market. The table provides pertinent information on ease of use, speed of results and usability features. The table is organized by company name, rating each characteristic on a scale of one through ten. A score of sixty is considered a perfect score. All of the compared monitors are suitable for testing one’s blood glucose. While the SureStep and FastTake were the easiest to use, the more advanced monitors included the One Touch Profile, AccuCheck, and FastTake, which have features that include memory. The fastest monitor tested was the FastTake. The One Touch Profile, One Touch Basic, and FastTake were the best fitting monitors to be used by children. The least expensive monitors were the AccuCheck and AccuCheck Complete, while the most expensive monitor was the FastTake; however, it appears to be worth the cost due to its outstanding ratings in all other categories. Also, justifying the extra cost is one’s consideration for their health and safety when using a monitor.

Evaluation of Prototypes

An accurate glucose reading is the most crucial concern regarding glucose monitors and interfaces. The wrong result can be detrimental to a patient’s health. Each of the four design teams had differing advantages to their design.

Saint Louis University designed an accessory that is able to attach to a glucose meter that is currently on the market and expand upon its properties. Such an expansion is illustrated in their prototype’s capability to send the data that is stored in the glucose meter wirelessly and communicate audibly the last reading to the user. The system is also able to process the reading from the glucose monitor and store this information in the prototype’s SBC processor. The readings will then be sent to the SP03 voice synthesizer which will send the last recorded reading to the external speaker and amplifier. The system can then switch into wireless data transfer mode to send all currently stored readings to a specified terminal via a text message. The commands are all shown through the use of the keypad and LED-screen present on the SBC. Although the final project was not as small as the design group would have wished, people who have vision impairments can find the switch and use the interface much easier than if the system was smaller. The Saint Louis design team stayed within their budget to build their device at $1,030.92. Overall, the Saint Louis University Design group satisfied the requirements to design a portable, reliable, relatively low-cost interface that is easy to use, works with or is based on an existing, commercially available blood glucose monitor, and meets the needs of individuals with visual impairments and diminished tactile sensations. Furthermore, the design group designed the blood glucose monitor to communicate through the use of both a visual display and audio output. There are many ways in which the Saint Louis design team is able to improve their glucose meter. These improvements include changing the switch from a manual DPDT switch to an automated logic switch, considering different materials and a smaller more compact design for the case, integrating an internal rechargeable power supply to provide power for all components, developing an error detection program which would identify errors and provide an audio and visual response to the user, and modifying the main program so it would be compatible with all LifeScan blood glucose monitors.

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Figure 1. Prototype Designed by Saint Louis University

Trinity College designed and fabricated an AID blood glucose monitoring interface device that allows for easier blood glucose level testing for diabetics with additional disabilities such as limited or uncontrollable movement, impaired vision, or limited hearing. The AID interface device utilizes both the FreeStyle® blood glucose meter and lancing device currently available on the market and incorporates an adjustable glucometer frame (rotates along two axes), lancet loading box, and a spring loaded lancing device arm. These components allow the user to easily adjust the position of the lancing device and glucometer along various positions on his/her arm and attain fast and accurate testing results. The results are presented to the user both visually and audibly to accommodate diabetics with a variety of hindering disabilities. The AID interface device was constructed from a single sheet of aluminum (chosen for its light weight and availability), formed using a bending press, and chemically plated to provide excellent corrosion resistance and an attractive finish. The total material and manufacturing costs for the AID interface was $884.61 and the projected cost to manufacture the device is significantly less at around $400. Overall, the engineering student design team at Trinity College fashioned an enhanced, economical, and easy to use blood glucose monitor interface specialized for diabetics with additional disabilities. The main way to improve the blood glucose monitor that the design team at Trinity College devised is to add the audio feature. Initially the group had divided the audio design into several components; communicating with the serial port, processing the information, obtaining correct audio files, outputting audio files to a sound card and automating the process. Currently the only steps that are completed are processing the component and outputting audio files to a sound card. In order to move forward, the group needs to find a way to open serial ports, transmit and receive data using C in order for the audio portion of the project to be compatible with existing code. The design team also would like to be able to have the process automated by having the user input either “f” or “j” from the keyboard. In the future additional research must be done to determine how to access the correct audio file once the desired output is read from the glucometer. The Trinity College design team surmises that the final audio design will most likely consist of connecting the glucometer to a personal computer or PDA. The design team concluded that this provides much bulk. Due to a time constraint the glucometer could not be interfaced with the microcontroller.

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Figure 2. Prototype Designed by Trinity College

The University of Connecticut’s design team worked to fabricate the gPod Glucose Monitor; this is a specially designed glucose meter that is able to meet the needs of vision, hearing, and motor control impaired diabetes patients. The gPod Glucose Monitoring system works by testing fresh capillary whole blood samples. The glucose sample can be measured by using an electro-chemical test strip that produces a current based upon the amount. The meter measures this current for an accurate assessment of the sample. Commercial test strips designed for the One Touch Ultra® glucose meter made by Lifescan and lancet will be used along with the gPod for testing. One key feature that makes gPod stand out from the rest includes a large, high contrast, liquid crystal display (LCD) that can be used for easy viewing of the instructions and results for those patients with hearing loss or slight vision loss. The gPod is also designed to have distinctly colored, textured buttons and rubber side grips for those patients who have motor control difficulties. The gPod Blood Glucose meter is made portable by using two nine volt batteries. The gPod also features a talking feature. For persons with diabetes that also have trouble seeing, the meter can audibly speak the results to ensure that the user has a correct understanding of their glucose level. The meter is also able to upload test results to a PC using the serial connector located on the bottom of the gPod. There is an option to attach a vial scanning module which will allow the user to insert an insulin vial and have its name audibly output by the glucose meter. gPod’s design team fabricated the gPod at $1818.58 within the budget constrain of $2,000.00. The gPod can now be made at $374.19. With these key features it would make gPod the lowest cost glucose meter on the market for diabetes patients with disabilities. There is not much room for improvement in the gPod. Overall the device does not suite those who have extremely large tremors. An attachment could be implemented that would help to secure a patient’s arm when obtaining a reading. A finger attachment is also a smaller possibility. The gPod uses a serial port connector whereas a USB connector would be a better choice. Although the UCONN design team had thought of this, they had run into problems in which they did not have enough time to fix.

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Figure 3. Prototype Designed by the University of Connecticut

Vanderbilt University designed a blood glucose meter using the Accu Check Compact Plus and adding accessories such as a voice box and a finger placing guide. The meter was designed based upon the need of four imaginary patients provided by the RERC competition. These patients have symptoms that people with diabetes suffer with every day. See Table 2 below for a list of the patients.

Table 2. Patients Accommodated in the Vanderbilt University design

Name Age Disabilities
Arnold 54 Have diabetes and Parkinson's disease. Experience hand termors
Dave 22 Has diabetes and limited use of right arm.
Wanda 12 Has diabetes and low vision.
Lloyd 80 Has diabetes, hearing loss and very overweight

The voice box of the meter was composed of a microprocessor (Adapt9s12DP256) and a speech chip (Tigerbotics Speakjet Board and speaker). The finger-placing guide was built using paper machè, where the mold of the finger-placing guide is the plastic coating of the monitor. Once the paper machè has dried, the mold was tore away. The finger-placing guide was then covered with tape and painted. The design team at Vanderbilt University built this guide so that it can effectively guide the fingers of the clients that have Parkinson's disease and have limited use of right arm. It can assist the clients that have hand tremors so that their blood can be effectively applied on the test strip. Although Vanderbilt’s final project did not have a voice as their speaker output they were able to get the meter to beep accordingly with the results displayed on the monitor. For example, if the displayed result is 21mMol/liter, the beeper will first beep two times to represent 2 and it will beep once to represent 1. The total cost of the device is $207.00. Vanderbilt University fulfilled all of their objectives to make a glucose meter that was suitable for certain disabled diabetes patients. However there are some areas that could use improvement and future development. Their blood glucose monitor and the voice box are currently two different systems. This would lead to bulkiness of the entire system and different power sources would be needed for both the voice box and the monitor. Thus these two components should be linked together. Also the prototype could be modified to suite a voice box that outputs an actual voice instead of a beeper. Another recommendation would be to include a vial scanner that is able to read the labels on different vials of insulin. In addition an insulin calculator that would calculate the exact amount of insulin needed for a certain level of blood glucose could be attached.

Figure 4. Prototype Designed by Vanderbilt University

Recommendations

After reviewing the glucose monitor/interface device each of the four schools designed, one can conclude that the optimal design should consist of the following five components: a glucose monitor, audio system, arm stabilizer, lancing device, and barcode scanner (for various vials of insulin). To achieve the optimal design, the glucose monitor with an audio system and barcode scanner designed by the University of Connecticut will be combined with the arm stabilizer and lancing device designed by Trinity College.

Acknowledgment

This work is supported by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation, funded by the National Institute on Disability and Rehabilitation Research, U.S. Department of Education Grant #H133E020729. All opinions are those of the authors.