What does daytime actigraphy reveal about an active and awake brain?

Question

I have interest in the study of human motion ( Actigraphy), and have built a couple of smartphone apps using its principles. The apps look at gross motor activity of an individual. Up until now, most of my reading into the field has been focused on the study of sleep. With Actigraphy, there are clear ~90 minute activity patterns visible over the course of the night that roughly correlate with the 4 stages of sleep. There are algorithms by Cole and Sadeh which describe how to score sleep using activity counts.

• Are there any uses of actigraphy for awake patients?
• Are there any investigations of the correlation between the overall activity pattern/level and the brain wave frequency (alpha/beta/...)?
• Are there any wake-related actigraphy algorithms?

Update thank you for answers and comments! Let me clarify the question. I'm interested in comparing a rather long history of events for the same individual wearing an actigraph.

For example we have a person who's both an athlete and also does meditation. I'm interested in using actigraphy to determine the length of the meditation sessions, along with any increase/decrease of overall activity pattern that may accompany meditation activity (ex: deeper concentration moves the brain to a different brainwave and relaxes the body, or nervousness and fidgeting rising, the person cannot get to the correct brainwave and cuts the session short).

Lets say the same person is a runner. Wearing an actigraph during sessions displays two important characteristics: When the person is and is not running. (going out to run is an action that requires conscious action. How long the person is running. If a person is feeling "negative", the person may not go out to run). If a person does go out to run, the running session may be cut short if a person is not in the right state of mind.

Combined with self-reported events (ex: running session started, meditation session started), such actigraphy data may be plotted day by day. I'm interested if there have been studies of such data.

Answer 1

It's obvious that people will move more when awake or doing exercise compared to being asleep or resting, however actigraphy provides a quantitative way to measure that. Therefore actigraphy is useful for studying sleep-wake cycles, activity-rest cycles and circadian rhythms. They have been shown to be reliable in determining when a subject is awake or asleep, so that's why they are generally used for that. Although there still needs to be more standardization and consistency of analysis and reporting in scientific literature to make comparison between studies more useful (Berger et al., 2008).

In order for actigraphy to be useful for understanding brain activity while awake, there needs to be a way to monitor brain activity. When exercise is involved methods such as fMRI, PET, TMS are not suitable since subjects need to stay still. EEG and EMG are really the only options. Winkler et al., 2003 has correlated short-term actigraphy with awake EEG patterns, and results suggest that they can be used to indicate CNS arousal. It probably doesn't affect the results, but you should note that the study was with psychiatric patients who were taking medication. It would have been more thorough to do this with normal population as a control to ensure generalizability. The software/algorithm they used was "Actiwatch Sleep Analysis 2001" (Cambridge Neurotechnology). Maybe you can look that up to find out more, although I'm not sure the algorithm would be published.

References

• Berger, A.M., Wielgus, K.K., Young-McCaughan, S., Fischer, P., Farr, L. & Lee, K.A. (2008). Methodological challenges when using actigraphy in research. Journal of pain and symptom management, 36, 191-199.
• Winkler, D., Pjrek, E., Pezawas, L., Presslich, O., Tauscher, J. & Kasper, S. (2003). Relationship between power spectra of the awake EEG and psychomotor activity patterns measured by short-term actigraphy. Neuropsychobiology, 48, 176-181.

Answer 2

Using activity monitors on awake patients is very domain specific. You need to equate them on some activity parameters and then look at how the individuals vary across some domain. For example, you could monitor athletes and correlate the amount of physical activity with performance. Or, you could monitor grade school children and look at something like childhood obesity.

So no, some general classifications based on Actigraph patterns are not done on awake individuals. Daily activities vary greatly across awake individuals while sleep has very defined patterns of behaviour.