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Low-cost, minimally invasive piezoelectric MEMS sensor monitors critical brain pressure

While attending the MEMS & Sensors Executive Congress 2016 (MSEC2016), I met two very bright and capable young men, Nicholas Fritz and Jonathan Garich, from the Blain-Christen Lab at Arizona State University (ASU), School of Electrical, Computer and Energy Engineering (ECEE). These young research engineers are working with Dr. Jennifer Blain Christen, Assistant Professor and who also the Principal Investigator (PI) working with this team.

The project to which I was introduced is in its early phases, but it intrigued me as these two young engineers excitedly discussed their initial findings.

The MSEC2016 collaborated with ASU this year with a Sensors & Machine Learning Workshop as well as having the research students display their posters at MSEC2016 regarding various MEMS and Sensor-related research projects. Figure 1 shows the poster that caught my eye.

The poster on display
Click here for larger image

The poster on display


Elevated intracranial pressure (ICP), that is, inside the skull, could be deadly if the pressure is not sensed and relieved quickly. This condition can lead to a shortage of oxygen and glucose to the rest of the body that is essential to healthy tissue life in the body. Presently most solutions that monitor ICP are quite invasive as well as inaccurate.

The team is working on a low-cost MEMS piezoresistive sensor that would be easily integrated into an electrocorticography (EC0G) system. An ECoG system takes recordings from the brain’s cerebral cortex monitoring local field potentials in the brain. These types of measurements and their analysis help scientists and doctors understand epilepsy so they might be able to detect seizure zones in the brain area that might lead to surgical treatment of the disease.

The problem is that standard ECoG electrodes and procedure can cause swelling, air or gas in the cranial cavity and foreign body problems—all leading to intracranial pressure. The sensor device that the team is developing can be integrated with ECoG electrodes. They are looking at a very low cost MEMS sensor that may be able to be one-time-use.

The electronics for the epidural ICP monitoring system consists of an instrumentation amplifier to amplify the signal. The voltage regulator is a 6V device that regulates the 9V power from a battery. The calibration factor that translates the sensed voltage into pressure is 0.030 mV/mmHg.

The sensor and electronics block diagram. (Image courtesy of Reference 1)

The sensor and electronics block diagram. (Image courtesy of Reference 1)

An experimental craniotomy procedure was performed on a rat. Intracranial pressure was successfully monitored and analyzed in a benchtop experiment and in an animal model using an epidural ICP monitoring system. The result showed the efficacy of the sensor for epidural ICP monitoring and demonstrated that the system was able to continuously measure ICP.

The basic diagram of the craniotomy electronics (Image courtesy of Reference 1)

The basic diagram of the craniotomy electronics (Image courtesy of Reference 1)

Discrete components were used in the Reference 1 experiment and an integrated system design is the goal with a low cost sensor design that can be embedded into an ECoG electrode grid.

I am hoping to follow the progress of this study as it progresses since I live just across town from the University. More to come on this subject soon.

References

1 Design and Evaluation of a Low Cost Intracranial Pressure Monitoring System, Ranjani Sampath Kumaran, Bradly Greger and Jennifer Blain Christen, IEEE Xplore.

2 Design, Fabrication, and Testing of a Hybrid CMOS/PDMS Microsystem for Cell Culture and Incubation, Jennifer Blain Christen, Student Member, IEEE, and Andreas G. Andreou, Fellow, IEEE, IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS, VOL. 1, NO. 1, MARCH 2007

10 comments on “Low-cost, minimally invasive piezoelectric MEMS sensor monitors critical brain pressure

  1. BPaddock_#2
    November 16, 2016

    My late wife Karen committed suicide on August 7th 2013, as she could no longer stand the excruciating headache caused by Intracranial Hypotension due to Cerebrospinal Fluid (CSF) Leaks. A condition that is more common that many think (for example Actor George Clooney had/has a CSF Leak and considered suicide), yet is so unknown that some doctors argue the condition does not even exist.

    If you want to understand the reality of this disease please read Karen's Journal, that is now required reading at Duke School of Medicine.

    “Karen's first-hand account of her illness gave an honest, heart-wrenching depiction of what it is like to live with debilitating pain day-to-day.” – Cover story of the local news paper from kpaddock dot org .

    Any early draft of her book may be found at kpaddock dot com .

    NASA, as part of the Mars Mission planing, is working on a non-invasive pressure monitor via the tympanic membrane.

    A lot more work needs done on both invasive and non-invasive pressure monitoring as well as new imaging techniques for the spine as the current ones such as Digital Subtraction Myelography (DMS) fail to find CSF Leaks far to often. My hope is that millimeter wave imaging via metamaterials will bring T-Rays out of the lab, hopefully soon.

    The Spinal CSF Leak Foundation at spinalcsfleak dot org has many resources available to learn more. If you want to see the day to day struggles of real sufferers from brain pressure issues look into the spinal-csf-leak support forum at inspire dot com .

    If I may be of service in any way to anyone working in the field of Intracranial Pressure or advance imaging of the spine, with the information I'm collecting, please get in contact with me. – Robert Paddock

     

  2. Steve Taranovich
    November 17, 2016

    Hi Robert,

    I am so sorry for your loss.

    Thank you for alerting me to NASA's development of a non-invasive pressure monitor via the tympanic membrane. I will definitely investigate this further with them. I will also investigate ideas at the Spinal CSF Leak Foundation.

    I will also alert the ASU development team about your comments.

    I will be in touch. Please send me your contact information.

    My e-mail is steve.taranovich@aspencore.com

  3. jenblain
    November 17, 2016

    Robert,

    I wanted to offer my deepest condolences to you. I also wanted to let you know how very important it is for you to share Karen's story with medical researchers. We need to understand more than just the science and equations behind our work; it's stories like Karen's told through their loved ones that fuel us to keep working year after year. I will be sharing the links you have provided to all the students in my course on biomedical technology. Thank you so much for sharing your story, and I will be sure to keep your contact information at hand. Right now we are still early in the research, but I would love to get in touch with you once we are close to piloting a human study.

     

    Sincerely,

    Jennifer Blain Christen

     

  4. BPaddock_#2
    November 17, 2016

    Thank you. My contact information can be found at kpaddock dot com .

    “it's stories like Karen's told through their loved ones that fuel us to keep working year after year. “

    I just completed filming six hours of Karen's story for the upcoming documentary Pandemic of Denial about Chronic Pain: pandemicofdenial dot com

    Sadly not released to sometime early in 2018.

    All of us are trying to raise awareness and find better solutions…

     

  5. Elky
    November 23, 2016

    Hello,

    I wanted to add my condolences to Robert and my biggest of empathy as I too have been suffering from low pressure headaches since April 6, 2008.  I have been suffering for 8.5 years with daily debilitating head pain after I had a spinal tap go wrong on April 6, 2008.

    It left me with a massive leak and I had a blood patch done 4 days later – but the patch didn't hold and ever since then I have had the same pain and the same symptoms *every* day for over eight years.  Despite this, I have yet to have a doctor definitively give the ongoing diganosis of low pressure headache due to CSF leak simply because they don't see it on regular MRI.

    I have been trying to get to see Dr Schievink in LA for over 2 years but cannot afford it, no doctor in my city beyond my pain doctor even believes that an ongoing low pressure headache is even real!  It has negatively affected my entire family, I have 2 children who were just 2 and 6 when this happened, it has lead to a separation from my husband, distance between me and my family simply because I cannot stand up long enough most days to get anywhere. I am on disability but barely scraping by. And now with changes to the way pain medication is being handled, my doctor is reducing my pain meds! The very thing that keeps me alive. I live in Ottawa Canada by the way.

    I hope that you find my message and if I can be of *any* help to your research even if just anecdotally please contact me at lyn.hunter@rogers.com.

    I understand Karen's position completely and I have great sympathy to you Robert for what you have endured at the hands of a CSF leak.

    Best regards,
    Lynda

     

     

  6. Elky
    November 23, 2016

    Hi Robert, I am looking for your contact information but cannot find an email address? I looked on Karen's journal as well. I commented above about my own life with daily low pressure headaches. Please feel free to contact me at lyn.hunter@rogers.com if my story (summarized above) could be of any help. 
    Best regards, Lynda Hunter

  7. BPaddock_#2
    December 13, 2016

    Steve has done an excellent follow up article:

    “Medical Electronics Imaging Innovation needed to relieve sufferers of Cerebral Spinal Fluid leaks and save lives”

    at edn dot com . 

    Sadly the commenting system here won't allow the link to the article.

     

     

     

  8. antedeluvian
    December 13, 2016

    Bob

    Steve has done an excellent follow up article:

    Medical Electronics Imaging Innovation needed to relieve sufferers of Cerebral Spinal Fluid leaks and save lives

    at edn dot com . 

    Sadly the commenting system here won't allow the link to the article.

     

    Unfortunately spamming in the distant past resulted in this limitation, which is waived for bloggers. I added the link.

  9. Steve Taranovich
    December 13, 2016

    Here is the link to my EDN article http://www.edn.com/design/analog/4443157/Medical-electronics-imaging-to-aid-sufferers-of-cerebral-spinal-fluid-leaks

     

  10. Steve Taranovich
    December 13, 2016

    Thanks Antedeluvian! I am taking up the issue with Aspencore IT regarding links.

    We are in the process of deleting all the SPAM on Planet Analog—not sure where that came from or why it was done

     

    Aspencore IT will be taking over duties like this shortly—we are still in transition right now until 2017, when all will be brought over from UBM to Aspencore—it's a monumental task, but I appreciate your frustration—thanks for staying with us—better things are coming in 2017!

     

     

     

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