Laurie Tyrrell-Schroeder, DVM |
Updated on
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I realized my head sensor was accidentally placed backwards after collecting data. Will the analysis be correct?
A head or pelvic sensor can be applied backwards and still provide an accurate analysis because the analysis uses the vertical acceleration of the sensor and the sensing element is fitted in the center of the sensor (not off to a side).
While recent generation Lameness Locator® sensors have the capability of measuring more than just vertical acceleration, these signals are not necessary for the current analysis for lameness and, therefore, are not utilized outside of research applications.
Using special “Research Mode” LL software, other parameters can be reported. Some researchers are extracting raw data signals for conducting their own analysis, and in these cases, a backwards sensor would report incorrect for some signals, for instance rotation.
The right forelimb sensor is a gyroscope measuring angular velocity of the right forelimb in the sagittal plane.
If this sensor is placed upside down, backwards, or rotates to the back of the limb, the signal will be flipped, causing the incorrect inference of right forelimb stance.
The consequence of this is a flipping of sides of reported lameness. I.e. a right fore or right hind lameness will be reported as a left fore or left hind respectively, and vice versa.
Helpful Hints to Ensure Proper Sensor Placement
Look for the Arrow on Each Sensor Label: The sensor labels are designed for intuitive placement on the horse – with arrows pointing in the direction that the small lip of the sensor should be oriented relative to the schematic drawings for the direction the horse is traveling (head & pelvic sensors) or skyward (pastern sensor).
Look for the Blinking Green LED: As an additional cue, recent generations of sensors include head and pelvic sensors with LEDs that blink on the left side of the horse, and a RF sensor that blinks on the lateral aspect of the RF pastern.