Calibrated systems, devices and methods for preventing, detecting, and treating pressure-induced ischemia, pressure ulcers, and other conditions

A method for calibrating accelerometer data generated by at least one accelerometer provided in a wearable sensor device for monitoring a user based on the calibrated acceleration data, the method comprising:

• securing the wearable sensor device to the user in an aligned orientation relative to a first rotational axis of the user based on visual alignment indicia provided on the wearable sensor device,
• orienting the user in a supine position,
• while the user is in the supine position, determining, by the processor, both (a) a pitch correction factor to adjust for a pitch angle offset between an orientation of the at least one accelerometer relative to a second rotational axis of the user and (a) a roll correction factor to adjust for a roll angle offset between the orientation of the at least one accelerometer relative to a third rotational axis of the user, wherein each of the second rotational axis and the third rotational axis is orthogonal to the first rotational axis,
• receiving, by the processor, multi-axis acceleration data generated by the at least one accelerometer, the multi-axis acceleration data indicating accelerations relative to the orientation of the at least one accelerometer,
• applying, by the processor, the at least one correction factor to the received acceleration data to generate corrected acceleration data indicating accelerations relative to the second rotational axis of the user and the third rotational axis of the user, and
• determining, by the processor, an orientation of the user based on the corrected acceleration data indicating accelerations relative to the second rotational axis of the user and the third rotational axis of the user.

A method for calibrating a wearable sensor device secured to a user and including an accelerometer configured to generate acceleration data for monitoring the user and a calibration sensor for calibrating the acceleration data, the method comprising:

• receiving, by a processor, calibration data generated by the calibration sensor provided in the wearable sensor device secured to the user,
• using, by the processor, the calibration data generated by the calibration sensor to determine an acceleration correction factor as an offset for an angle between (a) an orientation of the accelerometer provided in the wearable sensor device and (b) a defined rotational axis of the user,
• receiving, by the processor, acceleration data generated by the accelerometer, the generated acceleration data indicating accelerations relative to the defined rotational axis of the user,
• applying, by the processor, the acceleration correction factor to the received acceleration data to generate corrected acceleration data indicating accelerations relative to the defined rotational axis of the user,
• determining, by the processor, an orientation of the user based on the corrected acceleration data indicating accelerations relative to the defined rotational axis of the user,
• identifying, by the processor, acceleration data that falls outside a defined range of acceleration values corresponding with normal movements of the human body, and
• in response to identifying the acceleration data that falls outside the defined range of acceleration values, (a) generating, by the processor, an alert notification regarding attachment of the wearable sensor or (b) automatically recalibrating, by the processor, the acceleration data generated by the accelerometer.