There are several interesting options out there:
a) heart rate and heart rate variability
It turns out that iPhone 5 rear camera can be used as a heat rate monitor. You put a finger on it, the flashlight lights up and it works pretty much like an oximeter. There are a few apps that use this option:
- Cardiio app measures heart rate and feeds back your fitness level
- Stress Check measures heart rate variability and records self-reported level of stress
- iRelief does breathing exercises while measuring heart rate and then feeds back percentage of coherence (whatever that is)
- CalmZone has some nice sounds and gives you some feedback on your heart rate variance (same as variability?)
- StressCheck meaures heart rate variability and reports your stress level, with an ability to record data over time (mind you, this is buggy in the free version, may be better in the non-free app)
I have to admit that I haven't been really impressed by any of these. None of them does all they should, which would be feedback on heart rate variability, with clear explanations and maybe visual feedback, e.g. colour change, as the parameters improve. Also, I have to admit that I am still not comfortable with the idea of heart rate variability, and can't quite wrap my head around it. OK, I've never tried terribly hard, but then again, if it takes trying terribly hard, then explaining it to the clients is going to be a tricky task.
Les Posen recommends a set of sensors with a dedicated computer program from emWave for heart rate variability training. They also have an option of attaching a sensor to an iPhone and monitoring heart rate variability on the go. Probably a more accurate and elegant option (but more expensive, drat). Has anybody tried this in clinical practice?
b) skin conductivity
I like this idea of biofeedback much more. As Michael Carr-Gregg explained in his recent talk - you just tell the client that it works the same as a lie detector test, with more anxiety causing more sweating and more skin conductivity. Simple and convincing. He uses the sensors while teaching relaxation training to teenagers, so that they can see that it works.
The sensor is called eSense, fits on fingertips, attaches to an iPhone/iPad and can be linked to an app called eSense GSR. Very tricky to buy, as the original company's website is buggy, but can be bought from third parties for around $100. Don't try Amazon - they don't want to sell it to Australia. Seems a much better option for an average neuropsych who does not want to get too deep into biofeedback, but may want to convince a client that relaxation works.
There are apps that use the iPhone's accelerometer to teach deep belly breathing. You put your phone on your stomach and breathe away. One of these is BellyBio. Feels a touch silly, somehow, but I am impressed with the creative use of sensors.
And that's all I've discovered. If anybody knows a nice and useful gadget, please write a guest post or let me know at IzaWalters at gmail.com, and I'll post it up.