HRV Finger Sensor Troubleshooting Guide

The general information of this guide is applicable to both Exagon Sense and iMORE 2.0 Finger sensor as the hardware technology essentially is the same.

To properly troubleshoot the Finger sensor, you need to first understand the working of the technology. iMORE/SENSE is using photoplethysmogram (PPG) technology, which uses optically obtained plethysmogram to detect blood volume changes in the microvascular bed of tissue. It illuminates the skin and measures changes in light absorption. PPG reading used for Heart Rate Variability (HRV) runs at a much higher sampling rate as it needs to pick up every heartbeat and the differences in the millisecond range, as compared to general heartbeat monitoring sensor which they usually just take beats average or using extrapolation technique.

The iMRS HRV assessment is based on per-minute intervals. The system will evaluate the heartbeat variability within each minute window, and report a value between 1-7 as an indicative range of your HRV. The iMRS software will use this value to adjust the session intensity accordingly – as a form of bio-feedback to the system. In general, people with higher HRV (higher value) means he/she has higher recovery potential, able to take more stress, and hence is able to subject to higher exposure of external stimulation (PEMF). If there are too many missing beats during the reading interval, the system may refuse to report a value for that specific interval, hence you will not see any value in the HRV chart for that interval.

Typical Problems for SENSE/iMORE

There are basically 2 type of problem with SENSE/iMORE.

1. Unable to detect the hardware. This can be faulty hardware (very rare), or someone accidentally disabled the software feature. This is especially prevalent in the old iMRS system, as user can turn on/off the feature globally, or the software license is not activated. In Prime, there is no such problem as the SENSE feature is always enabled regardless of the software license, and the SENSE can be turn on/off at individual session level instead globally.
   
   Take note SENSE/iMORE will only work (or activated) when using with the full body mat (or Hybrid FIR Mat).
   
   
2. The reading is not accurate. This is a more common problem reported by users. Most of the time this is due to environmental and usage condition (users). Refer to the following checklist on possible reasons why you are not getting a good and consistent reading. Always get another person to try out to have an idea if this is person and environment specific issue.

Key reasons for intermittent and inaccurate reading are:

• Bright Ambient light. Make sure it ambient light is not too bright as this will impact the accuracy and sensitivity of the reading. You can also place a piece of cloth over the finger sensor to cut off the ambient light.
• Hand/Sensor movement. Do not move the hand or finger during the session. Sensor movement is the largest cause of artifact in the BVP signal because it creates very wide deviations which can drown out the signal completely and cause missed or extra beats.
• Sensor too tight. If the sensor is strapped on the finger too tightly, the pressure against the finger pad can cut off the circulation and dampen or flatten the pulse wave completely.
• Cold hand. If the user is very nervous, their stress reaction can cause the circulation in the hands and finger to be drastically reduced. This can be seen as a very weak pulse or no pulse at all.
• Skin tones and low peripheral perfusion rate of the finger can affect the accuracy of the reading. Perfusion is the process of a body delivering blood to capillary beds. Low perfusion, especially in arms, can present challenges for such PPG sensor because the signal-to-noise ratio may be drastically reduced, as lower perfusion correlates with lower blood flow signals.
• Nail polishes (especially dark colour). This is non-conclusive from various studies, but this is something worth to take note and observe in an individual case.

For Prime Users:

In the Prime system, you will be prompted to activate the SENSE for every session started.

There are several applications in Prime that SENSE (bio-feedback) is disabled by design, as the system doesn’t want the biofeedback system to interfere with the predefined intensity for the intended effect. This includes:

• Fast Start Programs
• iGuide.
• Trial mode

Split Mode: Make sure you are plugging the SENSE to the correct side (Right/Left) when using Split Mode. For instance, if you are plugging the SENSE to the right side, and your full body mat is plugged to the left side, then during session setup, you may not be able to see the SENSE option.

SENSE/SPO2 diagnostic menu:

With firmware version 2.20, Prime has a new independent SPO2 reading menu built into its diagnostic menu. Go to Settings –> System Information. Touch and hold the System Information menu bar for about 5 seconds to activate the new diagnostic menu. Now you can run the SENSE independently without the need of having a full-body mat, or activating a PEMF session.

Simply connect the SENSE into the left/right sensor port. On the top, you will see if the sensor is connected or not connected. This will give you an indication whether the system is able to detect the sensor.

Insert your finger into the sensor. There is no start/stop button. The system may takes 10-30 seconds to initialize and calibrate the sensor before you are able to see anything appear on the screen. The screen will show the Heart Rate and Oxygen level readings

Why this diagnostic is a more accurate assessment of the working of SENSE as compared to when using with the full body mat session, especially if you think the sensor is not providing a reliable reading. When you are lying on the PEMF mat, your body is subjected to PEMF stimulation, and your Autonomous Nervous System (ANS) will react to it, and hence your heart rate. Sometimes customers will report abnormal HR or inaccurate reading as compared to your normal reading due to how their body react, and believe the sensor if faulty instead.

For iMRS (iMRS 2000) Users:

How to check your iMRS controller is configured correctly (applicable to older iMRS system)

• Make sure the iMORE feature is turned on. Go to Options -> iMORE -> ON.
  
• iMORE works only with Full-body Mat. So if your applicator selection is set to Pillow or Probe, the IMORE will be disabled.
• If the iMORE feature is turned on, you will notice the following symbol at the top right of the LCD when the applicator is set to Mat
  nc – when the iMORE is not physically plugged in
  sc – when the iMORE is physically plugged in but not clipped on to a finger
  heartbeat sign & rate – when the iMORE is clipped on to a finger

Of course, there is a possibility of hardware sensor failure. Contact the us for further support.