What ME research has used actimeters/Fitbits?

[Keela Too]

I think that is a very important observation Keela Too. It seems that as actometer measurements went down you felt that you were happier with your situation because of not inducing crashes. There might be lots of different ways of looking at that but it highlights the fact that what the actometer measures is not actually what matters to the patient.

Yes MY aims and the aims of a study might not be the same. One thing I hate (really hate) is the drunk feeling, and inability to articulate what I want to say when I'm in a relapse. I like to keep myself in a state that I can have a half hour conversation with a friend who calls round - and not feel I have to either put them off, or struggle to communicate.

So keeping my activity levels low enough to maintain that is very important to me... And that entails being consistent (mostly) from day to day.

 

[Esther12]

This is a very peculiar statement - to suggest that the decision was justified by a patient charity 'advising us'. I could understand a patient charity 'funding us' agreeing, but why would a charity have a useful input in terms of advice about trial logitics and scientific merit? They might do, but as it stands it doe s not make much sense. Most of the patients on this list seem to think wearing an actometer would not be a problem.

It would be interesting to know if the researchers involved were aware of and had informed the charity representative of the actometer data from 3 CBT RCTs which had shown CBT did not lead to any increase in the amount of activity patients were able to perform. (The data had not been published yet, but was collected by colleagues).

It is possible that presenting the decision to drop this outcome measure as stemming from concerns that the patient representative had about the burden to patients was just a way of excusing their own desire to avoid collecting this potentially troublesome data. I'd like to see the minutes from the meeting where this was decided.

 

[Sean]

Before we started the trial, we were advised that the number and scope of the outcome measures were too great and that it might reduce the proportion of participants making it through to the end of the trial. Actigraphy was the obvious measure to reject because of its burden in time and effort required by participants. The patient charity advising us agreed that this would be sensible.

Before we started the trial,

This is misleading and irrelevant, they had already collected full baseline actigraphic data.

It is also not clear who advised them that

"the number and scope of the outcome measures were too great and that it might reduce the proportion of participants making it through to the end of the trial. Actigraphy was the obvious measure to reject because of its burden in time and effort required by participants."

The way that statement is worded, it sounds like AFME only agreed with it, not that they originally advised them of it.

It is not even clear to me which parts of it AFME agreed with, the first part (the 'problem') or the second part (the 'solution'), or both.

Nor is it clear that the 'advice' they received included the recommendation that actigraphy is the obvious candidate for rejection, or if they just decided that themselves. There is nothing obvious about it, the reason given certainly doesn't stand up to scrutiny.

Very slippery statement overall, that they (and AFME) need to clarify.

 

[user9876]

That's useful info if anyone is designing a study. Actimeters are basically measuring the acceleration and deceleration of the bit of the body that they're attached to (I think it's done by a little ball that can move in its housing). So it confuses steps with other movements that rattle the ball inside the device.

I seem to remember being told the accelerometer is basically a suspended weight with electrical circuits that detect motion and the relative weight to the sensitivity of the detection circuitry determines how accurate the device is. Over the last few years they have become quite a lot cheaper and more accurate. The cost reductions are partly driven by their use in mobile phones and game controllers rather than just being used for specialized tasks. I assume part of something like the fitbit is the software that tries to interpret the electrical signals into something they believe represent a person moving. But I think that is very hard especially when people travel on bumpy surfaces. However, a daily journey that registers badly may not matter when looking at activity change but occasional journeys would. But where there is something like a heart rate monitor also attached it may be that this could be used in combination with the accelerometer data with the combination providing evidence for physical movement.