One of the reasons the NIA fascinated me so is due to the fact that it operates as a sort of poor-lifeform's EEG coupled with an EMG picking up the electrical activity of the muscles of the scalp and forehead. Another of my interests (of which I have far too many) is non-ordinary states of consciousness. I'm reasonably experienced with meditation and biofeedback techniques so once I got the data collection utility and visual analysis software working (yes, I keep linking to them; the one time I don't, I'll be flooded with requests for it the way my luck goes) I rigged up a harness for my NIA's base unit, put the headband on, and got down to my daily practice. All told, it took about an hour to capture the data.
Download the data set from here. (798kb compressed)
If you're interested, under the cut are my speculations on what happened tonight.
After running the data through my visualizer, I've come to the first order conclusion that I have no bloody idea what happened. Scrolling through the output shows a highly unlikely set of graphs which differ markedly from those my other experiments. There are some low, gentle slopes in the output and a small number of large peaks at very irregular intervals. Most of the data points are unusually close to nothing at all, or the closest approximation thereof that the NIA can register. On the graph, they're practically a flat line.
Note to self: implement zoom function in nia_eeg_chart.py to take a closer look at the charts.
Any number of things may have caused it: loose cables, imperfect contact of the dermatrodes with my skin, dirt and oil accumulated on the electrodes themselves and/or my skin, the unusually humid atmosphere in the apartment (a thunderstorm passed through my area about two hours ago), or even a glitch in the NIA (which could have been corrected by disconnecting and reconnecting the unit). I do not suspect damage to the unit because it worked earlier tonight.
It should be kept in mind that the NIA acts as a EMG as well as an EEG, and when in trance many of the lesser used muscle groups of the body (such as those of the face and scalp) move little if at all, so it would be understandable that the NIA wouldn't have many signals to pick up under these circumstances. If true, this also would strongly suggest that the NIA is less of an EEG and more of an EMG, which would necessitate using it in a different manner. The data collected would then require different methods of interpretation to get anything useful from it.
I need to run a statistical analysis on the data to get a clearer picture of what's going on. I also need to repeat this experiment a few times to collect a larger data set.
In case you're curious, here's my routine: