UPDATE - the current version of the LiftPulse app is only available for Android phones. But there are several other Apps that are low cost that are available for the iPhone.
The article below is an update to an earlier discussion which started in 2013 and contained feedback from other forum members using older versions of the applications... Link to read the original discussion
The typical speed of the Orthostatic Tremor is fast… so fast that it is somewhat unique to OT. If you could record the high speed tremor of OT with a very common and accessible device could this help describe the tremor to others or reduce the time to a diagnosis?
This required an iPhone, a free app, a knee high stocking, a sturdy chair to hold onto and someone to push the button.
Here’s the very unscientific process that we followed:
1. Downloaded a free iPhone app called Lift Pulse - Link to Lift Plus App
2. Attached a smartphone to the calf muscle using a knee-high stocking (phone is rotated so that the record button is accessible above the stocking. (see Fig.1)
3. Pressed the record button during free standing (see Fig.2)
4. Lift Pulse records the tremor for 10 seconds and reports the frequency of the dominant tremor, (see Fig.3)
The results were well within the normal 12-20 Hz range of OT and consistent over 3 consecutive attempts.
18.46 Hz / 18.26 Hz / 18.26 Hz (see Fig.3)
The phone that was used was an older iPhone 4s, the newer models have much better sensors. There have been some tests with pedometer apps, and they have found that newer phones with better sensors and processors are more precise.
Smartphones include an accelerometer which detects movement and speed in 3 dimensions. Lift Pulse is an application that can be installed on a smartphone and interprets the data from the sensor and reports in very easy to understand terms the frequency of the tremor. LiftPulse works on Apple iPhones and Android, although I have only used the iPhone version - Link to Lift Plus App. Liftware has moved on to produce a very successful stabilizing spoon and other devices to help with other tremors. liftware.com
You can read a discussion from 2013 on this forum about smartphone applications. This contains a little of the history and experiences of other users. Some of the applications mentioned may have changed, but the underlying process is similar. Below are 2 quotes from the original discussion by forum members that used iSeismometer an older application that was developed to record earthquakes but is capable of reading human tremors as well:
Joan C - posted a very practical use of the same application:
I find the iPhone app iSeismometer to be a great way to show people (including doctors) exactly what you are telling them about your tremors. Turn it on - have them stand and hold it to their leg (no movement on the iSeismometer). Then stand and hold it to your leg (looks like an earthquake!!). The light goes on in their eyes and I've found that even the people who have helped me cope for the last 12 years seem to finally "get it."
Dwight - posted his experience:
I decided to test the iSensometer with my ET. Holding my iphone in each hand It came up perfectly with a tremor of about 6Hz on several tries. OK, I assumed that it works. Next I held it to my leg. Problem. I kept coming up with 6Hz not the 14 to 15 Hz expected. In a side email JoanC said try straping the iphone to my leg. Take my hands off it as it is probably primarily picking up my ET tremors from my hand.
Guess what. Strapped to my leg I got 14 to 15Hz, exactly as expected.
Link to original discussion
Fig.1 iPhone was placed on the back of the calf muscle, and inverted so that the "Record" button is accessible
Fig.2 Choosing the "View" icon at the bottom of the screen shows the last recording
Fig.3 Series of 3 recordings showing closely aligned results
Hope you found this interesting. If you have any similar experiences, or simply have a comment, please feel free to discuss your thoughts by clicking on "reply" ( you will need to login to the forum to post your message).
And now for the disclaimer...nothing is endorsed or implied other than this being a reporting of the process that we used to record the tremor using an iPhone and Lift Pulse.