Hello,
I'm noticing something about the accelerometer data that is confusing to me and I was hoping I could get some clarification. In particular, I've been examining data from the finger-to-nose tests (ftnr and ftnl task codes). In this data, I've noticed that for some task repetitions, the accelerometer values across all three dimensions remain one sign (either all positive or all negative acceleration values). For a task like finger-to-nose, this doesn't seem to make sense since, at some point, the arm has to reverse direction. So, there should be a change in sign of the acceleration values from positive to negative or vice versa for at least one dimension.
Could someone please shed some light on this? Some of this confusion could be ignorance as to how the accelerator was oriented but I want to make sure I understand how the data is reported.