Cheerios on a Sleeping Baby! Not Unlike EEG Sensors For Science

 

The Father's Day Cheerio Challenge  has inspired today's lab note. One of the most challenging aspects of our work is applying the sensors that read the brain rhythms. The sensors we use are about the size of a Cheerio, and are sponges which become soft when we soak them in salt-water, not unlike when you add milk to your Cheerios. The moisture makes it easier to read the signal from the scalp. 

Reading brain rhythms, using electroencephalography (EEG), dates back to the early 1900's, and was done with only one or a few sensors at a time. Even today, monitoring of brain activity during sleep is typically done using anywhere from one to thirty or so sensors on the head.  Our work is unique, because we use 124 sensors that are linked together with stretchy translucent wire (a bit like light fishing line), into a cap. This makes the application process much faster than applying each sensor one by one, because we can place the cap on the baby's head in minutes, rather than the hours it might take to individually place 124 sensors (or Cheerios!). Removing the cap can be done in just a few seconds.

It takes lots of experience and practice to place these caps on a baby, and especially on a sleeping baby. All babies are different, in terms of how they sleep, and stay asleep.  In general, through experience, we have found that waiting until the baby is in a deep sleep, to apply the cap, offers the greatest success in ensuring the the baby will stay asleep so that we can get anywhere from 15-60 minutes of sleep recording time.  One great thing about studying infant sleep, is that it is inevitable that they will fall asleep!  Here's a video from the manufacturer of these awesome caps, EGI, Inc., which I shortened to about 2 minutes, and shows how easy it is for a trained expert to place a cap on a baby. 

In the next lab note, I'll explain why using so many sensors is so helpful to understanding brain rhythms during infant sleep.