Caution: Beta Blockers and Atrioventricular Block

 Propranolol is a beta blocker and is the only drug approved by the FDA for the treatment of Essential Tremors. Beta blockers cause the heart to beat more slowly and with less force. Beta blockers can also cause a second-degree Mobitz type 1 (Wenckebach) Atrioventricular Block. Medical terminology like this, can and does sound scary. When it is happening to you it is a very scary experience. If you take beta blockers it may not happen to you, but you should be aware of the possibility of an AV Block.

I’ve been on beta blockers for my hypertension for about 35 years. First I was on 80 mg daily of Propranolol. My PCP changed my prescription to 50 mg daily of Atenolol about 6 or 7 years ago.  During this time my Essential Tremor was fairly masked by these beta blockers. When I needed very steady hands I could always self-medicate with 40mg of Propranolol and get 4 or 5 hours relief.

This all changed last Sunday.  We got up late and I took my daily 50mg of Atenolol during breakfast.  I didn’t feel I was at the ‘top of my game’ and Jill encouraged me to check my blood pressure.  It was fine but my heart rate was much lower than my usual mid 60’s.  Checked my oxygen levels with a pulse oximeter.  Oxygen levels were 97% but again I had a very low pulse rate.

I continued to check my vitals during the afternoon but after a couple of readings with a pulse rate of 35 we decided it was time to seek medical help.  I drove myself to the local Urgent Care which had a hand written sign on the door indicating they were closed.  So I headed to Ann Arbor and the University of Minchigan’s hospital ER facility.

After a couple of minutes of admin discussion and a quick talk with who I guess was a triage person, a tech took my BP and heart rate. This was quiclly followed by an EKG snapshot and blood draw, and a chest x-ray.  All this happened in a matter of 15 minutes.  The nurse who took the EKG snapshot mentioned “a block” to no one in particular.   Let’s pile on my anxiety level. I was having visions of needing a heart stent.

Another nurse settled me into bed and wired up to an EKG monitor.  The steady beep of the sinus rhythm from the monitor wasn’t steady.  I turned so I could view the monitor and I could see that the pulses had gaps in them.  Also the monitor was flashing Afib. Sometime during this period the nurse returned and applied two large defibrillator pads to my chest.  This is getting serious!

Doctor #1 comes in with the first good news. The blood work came back clear. “It’s most likely a Wiki Block”.  After he left Google sorted out that it was Wenckebach.  We discussed my general health.  I think it was this doctor who asked if I had seen a cardiologist and/or had an EKG seeing I was on beta blockers. I had not and was surprised at all medical advice I had received in the past had indicated beta blockers were a ‘safe’ medicine.

The beta blockers were delaying the signal for my heart to beat. The other good news was that I wasn’t suffering from AFib (Atrial fibrillation).  It seems that EKG monitors interpret any irregular heart beat as AFib. We also discussed my self-medication of 40mg of Propranolol for my Essential Tremors. In his opinion this was a very bad idea particularly as I was suffering from an AV block.

Now begins the long wait. I didn’t have any of the common symptoms they expected. No sweating, chills, lightheadedness, nor pins and needles, nor weakness nor cognitive impairment. Somewhere around 8 to 10 hours after I took the Atenolol, my heart beat started to steady. Just to be super sure I wasn’t going to collapse on them, I had another blood draw which came back negative.  After a couple more hours they decided I could go home with a referral to a cardiologist, a 5 day heart monitor ordered, and advice to see my PCP later in the day as it was well past midnight.

Later that  day, my PCP didn’t prescribe an alternative to the Atenolol.  “Just monitor the BP and contact me if it starts to move over 90 diastolic. It is difficult to adjust to a resting heart rate 85+ but so far the BP is holding steady.  

The 5x24 heart monitor arrived.  No drama there.  The adhesive irritated my skin. The summary results were posted to myuofmhealth.org but will have to wait until I see the cardiologists for interpretation. That appointment is a couple of weeks from now.

Beta blockers which I always considered a ‘safe’ drug are not always safe. If you take beta blockers for your Essential Tremor, you should monitor and record your heart rate and blood pressure on a regular basis.  Stay safe and healthy.

Ask Me Anything

Tremor Mouse: first Alpha release announcement

It is early days, but we have made progress on the Tremor Mouse adapter. We are using an Adafruit RP2040 USB Host device.   As you can see from the photograph, it has two USB connectors.  You plug your mouse into the USB ‘A’ connector and you plug a cable from your computer into the USB C connector.  Yes, it’s plug and play.  No software to install and it comes pre-configured.  

At present, the configuration needs to be set by a programmer before the software is compiled.  Later versions will have a web interface to allow you to customize the settings so it best suits your needs.

The first Alpha release of the software is ready. If you want to test it out, the pre-compiled software is available here.  The source code is also available for those of you who are a bit more adventurous. You can change the configuration settings and compile your own personal configuration using the Arduino IDE.

This first release only attenuates the speed of mouse movements.  The majority of the time, the mouse needs to move relatively quickly to get to some target destination and precision is not required.  During these faster movements, there is no attenuation of the mouse.  As you approach your target, you usually slow down.  At this slower speed, the mouse is attenuated by 2:1, filtering out some of you tremors.  When you get very close to the target you slow down even more and the attenuation is set at 4:1.  These values are fixed for now, but seem to be about right for someone with mild to moderate Essential Tremors of the hand/forearm.  Testing will refine these values.

This is just the first feature.  More will be released as the project develops.

Credit where credit is due.  This project wouldn’t be possible without Ha Thach and TinyUSB, Adafruit who built the hardware and provided s/w to build applications with the Arduino IDE.  And a big thank you goes to BillB of AtMakers.org who developed the original hardware, pushed it through a couple of generations of refinements and somehow persuaded LadyAda to build and source this board that we are using.

If you want to test drive the Tremor Mouse, please contact me here or over on Reddit  and I will be happy to walk you through the process of getting it working.  Your feedback will help us refine the configuration and perhaps suggest other modifications to make it easier to work with the Tremor Mouse.

If you are a ‘C’ programmer and interested in contributing to the development process, please chime in here in the comments, or the Discussions and/or Issues on github. 

Cala Trio: non-clinical test results

September 1, 2022. Cala Health published the results of long term use of the Cala Trio for the treatment of Essential Tremors of the hand/forearm.  The study included 321 individuals who used the Cala Trio for at least 90 days between August 2019 through June 2021.

This study compared the before and after measurement of tremor amplitude in a 20 second postural hold.  59% of the group had a 50% reduction in the measured tremor amplitude power.  This compares favorably with the best pharmacological treatment of Essential Tremors.

Patients with severe tremors experienced the greatest reduction in their tremors from this treatment.

No significant habituation was observed in patients who use the Cala Trio for more than one year.

In a voluntary survey, patients reported improvements in three areas of activities of daily living: eating 74%, drinking 65%, writing 64%.  65% of the survey preferred treatment with the Cala Trio over both medication and surgical intervention.

The full paper can be found here. 

Whoops! I made a math mistake: It works for me (revised)

In the Discrete Fourier Transform script I wrote to convert from time domain to frequency domain, the constant 2π is used.  I incorrectly entered  6.2318 instead of the correct value of  6.28318.  This not only changed the spectrum but significantly changed the peak amplitude as illustrated by the revised plots below. 

Before stimulus tremor spectrum with the correct constant

After stimulus tremor spectrum with the correct constant.

Instead of reducing my peak tremors by 2/3, it actually reduced the peak amplitude by 40% (3/5). I apologize for any distress that my error might have caused.

-----------------------------------------------revision ends----------------------------------------------------------------

 I can finally announce that my tremor stimulus device works for me.  15 minutes of stimulus reduced the peak amplitude of my forearm tremors by ⅔.

Here is the Discrete Fourier Transform (DFT) chart of my forearm tremor before I used my stimulus device.

And here is the DFT chart after 15 minutes of stimulation

Before the peak tremor amplitude was about 0.6.  After the stimulus was applied the peak amplitude is just a smidge over 0.2  Almost a ⅔ reduction in the peak amplitude!

I’m typing this about 3 hours after recording that data.   Usually I get a large number of double keystrokes.  So far the tremors are mostly not there.  Oh they will return, but I can get relief from my tremors within a few minutes.  A non-drug, non-invasive, inexpensive temporary solution to my tremors.  Maybe I’ll be able to draw again.

My tremor stimulus device is based on Commercial Off The Shelf hardware and some custom software.  It is entirely battery powered so there are no dangerous voltages. The software is Open Source, so you can copy it, and build your own tremor stimulus device. 

How much does it cost?  About $200USD.  Prices vary so much due to the shortages of chips and of course shipping costs are dependent on where you live.  If you change the stick on electrodes every week, the running cost will be less than $1USD/week.

Have tremors in both hands?  Just stick the electrodes onto the appropriate area on the other hand.

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(Please note: This information should not be used as a substitute for medical treatment and advice. Always consult a medical professional about any health-related questions or concerns.)

Video of EssentialTremorLab Electrical Neurostimulation device

This first video is me recording my forearm tremor before applying the electrical neurostimulation.  I’ll run a Discrete Fourier Transform over this data to provide a snapshot of the spectrum of my tremors. 

Here is a rather longer video of the device in action edited down to leave out  the long gaps between the minutes. 

Apologies but the video is too large for blogger to upload so here is a link to it on YouTube

Here is the DFT of before:

and here is the DFT after 15 minutes of electrical neurostimulation.

Technical details and how to build your own device can be found here.

 #EssentialTremorLab

Photograph and description of our prototype

This photograph shows the current stimulus device and all the wiring and components.  A link to most of these components can be found in the parts list.  #9, #12, #13, #14a, and #14b have recommendations but you have the option to locally source these components.

1. Adafruit PyGamer.  I think the name is derived from Python-GameBoy. You can actually play games on it (and write your own games) but not at  the same time as you are running the tremor software.  The full specification can be found from the link in the parts lists.  All the cables are on sockets so no soldering!  Apologies for not powering it up so the LCD screen was easily visible. It also contains a rechargeable battery, and a Micro-SD slot for recording tremor data.
2. Is  a USB cable.  The end that plugs into the PyGamer is a Micro USB port.  Choose a cable that  will plug into your PC/Mac/Linux computer and has a Micro USB connector on the other end.  You will need this cable to load the tremor software onto the PyGamer.
3. 3a provides power and control to the Solid State Relays (10).  Red for power, Black for ground, and 2 white cables are the controller wires.  One white cable is part of the port/connector cable that supplied power and ground.  The other white cable comes from the other port.  3b is the power and ground from the second port and are not used.
4. Is the JST PH to JST SH Cable - STEMMA to QT / Qwiic - 200mm long.  This cable supplies power, ground, contro, and data to the Inertial Measurement Unit (IMU), since it is quite short, we have extended it via #5 and #7 to make it easy to use.
5. Is a Qwiic Adapted to allow us to connect a longer cable (#7) between the PyGamer and the IMU.
6. I made a mistake when labeling the image.  There is no #6.  Sorry!  ;-(
7. Is a 500mm Qwiic cable.  Sockets both ends so again, no soldering!
8. Is the IMU.  There are two options for this component in the parts list. One includes a magnetometer that is not used by the tremor device.  The IMU in the image is the one with the magnetometer.  It was the only one available at the time due to the worldwide silicon chip shortages.  Either IMU will work.  The IMU contains a 3 axis accelerometer and a 3 axis gyroscope.  This is the component that actually measures your tremor.
9. This is a cinch strap.  The IMU is sewn to this strap. It all looks rather mundane but it is quite important. A firm mount is a must to get good repeatable measurements of your tremor.  You need to be able to easily position the IMU on the back of your hand in the same position every day.  The cinch strap, as illustrated, can be adjusted for larger or smaller hands.  There is very little ‘give’ in the strap providing a firm base for the IMU. An alternative would be to use a glove and attach the IMU to it.
10. Are the Solid State Relays.  There is a pair of them. Under software control, these SSRs switch the electrical stimulation provided by the TENS Unit (#15),  between the Median and Radial nerves delivered via the electrodes #14a and #14b
11. #11a adn ##11b is the two sets of leads that are compatible with your TENS unit.  You need  two sets of these leads.  #11a is used to deliver the TENS stimulus to the SSRs (#10) and provides the ‘return path’ via electrode #13.  #11b supplies the TENS signal from the SSRs to the Median and Radial nerves via electrodes #14a and #14b.
12. Is a short jumper wire to connect the TENS output to both center taps of the SSRs.
13. Is the ‘return path’ electrode which should be attached to the back of the wrist.
14. ‘a’ and ‘b’ are the two electrodes that deliver the stimulus to the Radial and Median nerve.  These should be attached to the underside of the wrist.
15. TENS unit. Transcutaneous Electrical Nerve Stimulation (TENS) therapy involves the use of low-voltage electric currents to treat pain.  Because the TENS unit can produce a safe stimulus, it is used by the tremor device to stimulate the Radial and Medial nerve. 

Please Note: This device is not an FDA-approved system or device. The FDA’s responsibility is to regulate products on the commercial market and help safeguard the public. It’s not manufactured or sold anywhere in the world. It’s an open-source designed system that you can choose to build yourself. The FDA doesn’t currently regulate self experimentation. Individuals who build this device are essentially doing an (N=1) experiment, which they have a right to do by themselves, on themselves. If you decide to build anything described herein, you do so at your own risk.

(Please note: This information should not be used as a substitute for medical treatment and advice. Always consult a medical professional about any health-related questions or concerns.)

March 1 should be International Essential Tremor day!!!!

 First a little history: The familial Essential Tremor was first described by the German physician Georg Friedrich Most in 1836, while the term essential tremor (originally from the Italian language ‘tremore semplice essenziale’) was used for the first time in 1874 by the professor of medicine Pietro Burresi, who described the case of an 18-year-old man suffering from severe hand tremor while moving, as well as head tremor. In 1817, James Parkinson was the first to point out that ET was a disorder separate from Parkinson’s disease (PD), but his report was not published until 1887. A classic description of the disease was presented in 1925 by the Russian neurologist Lazar Salomonowicz Minor, after which ET is often also called ‘Minor’s disease’ 

Historical underpinnings of the term essential tremor in the late 19th century

https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3461999/ 

It took until 2013 for Essential Tremors to receive its own medical classification identifier!  

The International Classification of Diseases-10th Revision-Clinical Modification (ICD-10-CM) ushers in, for the first time, a specific diagnostic code for essential tremor (“G25.0, essential tremor”). This milestone should not pass without comment. --Elan D Louis

From: The Lancet Neurology MARCH 01, 2013

The full description reads:

 2021 ICD-10-CM Diagnosis Code is  G25.0  Essential tremor (benign) 

…and that in my opinion is incorrect.  Benign Essential Tremors is an old and now obsolete term. I even doubt the veracity of the term “Essential” but that is the term the medico people use.

Essential: In medicine, of unknown cause… 

There is nothing benign about Essential Tremors. Essential Tremors has the potential to significantly disrupt daily activities and/or social interactions.