WEEK 4

JOURNAL 1


DESIGN AND COSTRUCTION OF STEP COUNTERS FOR DISABLE

PEOPLE: PRELIMINAR EXPERIENCE AT THE ITALIAN INSTITUTE

OF HEALTH by Giovanni Maccioni IEEE Member, Velio Macellari IEEE Member and

Daniele Giansanti IEEE Member, 2007.

The aim of this paper was to set-up a case study based on subjects with Parkinson’ s disease to investigate a new methodology for the step-counting based on the calfpump expansion activity monitoring

Abstract

Step counting is an important index of motion. One of the most diffused wearable systems, designed for this purpose, is the pedometer. The accuracy of commercial pedometers has been tested in literature. Several limits have been found in many commercial systems both in healthy subjects and in disable people. Furthermore, commercial pedometers lack in interoperability. A new wearable system for the step counting has been introduced in this paper. The wearable system is based on a wearable device with a force sensing resistor and a band; it is affixed at the calf gastrocnemius level for the monitoring of the muscular expansion correlated to the gait. The proposed gastrocnemius expansion measurement unit (GEMU) was tested on a three subjects with the Parkinson’ s disease at the Level 2 of the Tinetti test of unbalance who performed five repetition of 200 steps with three different instructions (fast, slow). The mean error was lower than 0.5 %. Results also showed that GEMU performed better than an accelerometer unit (considered in literature the best solution for this disability). The study showed that GEMU had a high performance in a subject with a pathology (the Parkinson’ s disease) causing a high degree of unbalance confounding the motion style and thus pedometers. The next phase will be the optimization of GEMU for long term medical applications at patients’ home with the special care to the material and with a comparison to a golden standard.

Highlight from the journal

•   Pedometer  is an important index of motion activity and it is currently used in the prevention of the obesity, in applications for the prevention of cardiovascular problems, in diabetes care and more in general in motion rehabilitation.

•  Keenan and Wilhelm have enlightened that pedometers could be confounded by movement style, as in the case of the Parkinson’ s disease and found that for this specific pathology accelerometers (ACC)s performed better.

 Three are the principal aspects hampering the use of commercial pedometers in telemedicine.

•  The first aspect is that, in spite of the pedometers have been widely used, there are still opened questions about the accuracy.

•  The second aspect is that the performance of the pedometers deters with the increasing of the degree of a subjects’ s inability ( such as the Parkinson’ s disease) causing a movement style confounding the pedometer.

• The third aspect is that the most part of commercial pedometers are closed systems do not permitting the integration with complex and heterogeneous systems.

General idea

•          The rationale afforded two consecutive aspects; the first consisted on the identification of the optimal position for monitoring the muscular expansion.

•          The second consisted on the design and construction of a device sensor embedded in a band to monitor the pressure variation during the calf muscular expansion

The wearable system consisted on a device sensor embedded in a band to monitor the pressure variation during the muscular expansion.

The μP is programmed in order to allow the step counting. Once a variation of pressure is detected by the FSR, the

step counting is incremented by a trigger mechanism based on a threshold fixed to the 50 % of the supervised maximal signal excursion mediated on five consecutive steps