ABSTRACT
The accuracy of pressure and shear measurements is an often overlooked subject. In clinical settings, pressure measurements are obtained by means of a wide variety of sensors. Unfortunately these sensors have different characteristics, giving rise to a variety of errors. Measurement procedures also vary between institutions. This chapter examines the factors that can affect the accuracy of interface pressure measurements. Regression analysis or the method of least-squares is the most common technique used in fitting a curve to a set of data points. The principle behind the least-squares method is to minimize the sum of the squares of the vertical deviations of the data points from the fitted curve. Hysteresis results when some of the energy applied to the sensor for an increasing input is not recovered when the input decreases. Sensor accuracy can be affected be a variety of external influences, such as temperature, time, humidity, and electromagnetic interference.
