Hi, everyone! For those that have not met me yet, I was a computer engineer for 5 years devloping smart-systems for a number of tech/biotech firms before going back to school to get an MD and train as a Pediatric Neurologist for the last 11 years. Anyway, last Tuesday's discussion on biometric wearables and their application to more humanistic purposes such as aiding people with Panic Disorder was absolutely brilliant and inspiring! I did some google searches and found some interesting wearable devices that are already on the market:
Most of you have probably heard of the fitbit, but you may not know that it is based on a medical device sometimes used in the diagnosis of neurological sleep disorders: the actimetry sensor / actigraph -
https://en.wikipedia.org/wiki/Actigraphy
The hexoskin research webpage gives some tech specifications on what it can do: 1 channel, 256Hz ECG with 4ms QRS detection resolution, 50-60Hz noise filtering. 2 Channel, 128Hz respiratory monitor with tidal volume detections from 80mL-10L at 1Hz. 3 Channel, 64Hz accelerometers. Some of their numbers seem like theoretical marketing claims rather than practical findings, but it should be able to assess the range of physiological ECG and respiratory changes seen in a panic attack.
There are some smart-phone solutions that can measure emotion, but I think these require taking a picture of your face, so this makes them less ideal for passive monitoring and early alert for a panic attack:
https://neumitra.com/research and
http://www.affectiva.com.
I also did a literature search for scientific and medical articles related to biometric detection of panic attacks but it appears that not a lot of research has been done in this area. I did find one patent application for a biometric device to detect anxiety, but based on it's design (a shotgun approach measuring a multitude of quantitative and qualitative physiologic parameters), it looks like something more for research and data gathering rather than clinical application:
http://www.google.com/patents/US20130281798. However, I think it is on the right track. Panic disorder stands out among the neuropsychiatric diseases as the one that classically presents with prominent autonomic/physiologic alterations during an episode: pounding heart, sweating, trembling, shortness of breath.
Wearables already exist that monitor heart rate and respiratory rate. There is already software for the iphone that can detect physiologic tremors (albiet for Parkinson) using the phone's accelerometer, and I would hope repurposing a Fitbit to this function would not be too difficult using it's SDK. The one area that I unfortunately have no advanced experience with is quantitative sweat testing. I found this device:
http://www.wrmed.com/qsweat.aspx which is similar to ones used by neurologists to do autonomic reflex testing (not my area of expertise), but I'm not familiar with the science behind how it works to try to miniaturize it onto a wearable device. Putting it altogether, some plausible designs would be a biometric patch worn on the shoulder blade or maybe a wrist worn device like the fitbit. Of course, this is all just looking at the sensory aspects of such a device. The possibilities for integrating haptics, guided meditation/visualization, and other biofeedback modalities to treat or prevent a panic attack are vast.
As a person who has witnessed and personally suffered panic attacks, I can attest to the dramatic onset of the associated physiologic symptoms. I've read reports that service dogs can be trained to predict and warn its owner of an oncoming panic attack before it happens (similar to service dogs that can detect seizures). It would be amazing to develop a wearable that could do the same thing if not more.