Seizure detection: It’s all in the wrist

by Nancy Fliesler on May 2, 2012

This comfy wristband can sound an alarm when a child is having a seizure, and can help doctors better time medication dosing.

This is the first post in a series about new approaches for seizures and epilepsy.

Seizures are often hard to track in children with epilepsy, making it difficult for doctors to optimize their treatment. For parents, the greatest worry is that their child will have a life-threatening seizure in the middle of the night or away from home, unable to get help. And what about when that child goes off to college?

“Every parent asks, ‘What can I do to prevent my child from harm?’” says Tobias Loddenkemper, MD, a neurologist in the Epilepsy Program at Boston Children’s Hospital.

Loddenkemper also wanted to better understand his patients’ seizure patterns so he could better time the dosing of their medications. He’s been testing a wristband sensor system, developed by Rosalind Picard, ScD, and colleagues at the MIT Media Lab (Epilepsia, March 20), and thinks it could be part of the solution.

The wristband carries two kinds of sensors: One, a motion detector, used in some iPhones to detect tilts and shakes, detects the repetitive movements of a convulsion. The other, a skin conductance measurer like those used in lie detectors, is sensitive to tiny amounts of sweat, indicating activation of the sympathetic nervous system. Combining this information, the system could be programmed to sound an alarm when a predetermined threshold is reached.

Picard developed the wristband to get objective physiologic measures of emotional states, such as anticipating meltdowns in autistic children. At the time, a graduate student in her lab, Miriam Madsen, was also doing research at Boston Children’s, and connected Picard with her father, Joseph Madsen, MD, a neurosurgeon at the hospital. The two institutions began collaborating, studying the relationships between wristband indicators of emotion and brain signals from children with epilepsy.

The hospital’s Long Term Epilepsy Monitoring Unit, where patients are tracked with EEGs for up to a week to find the source of their seizures in the brain, offered an ideal setting to try out the sensors: Information from the children’s EEG tracings could be readily compared with information from the wristband. Loddenkemper took an interest in the project, and began working with Ming-Zher Poh in Picard’s lab.

During the course of their study, 80 children wore the wristband during EEG monitoring. The EEGs documented 16 generalized tonic-clonic seizures (full-blown seizures involving stiffening and shaking of the body and loss of consciousness, also known as grand mal seizures) in seven children. Fifteen of the 16 were also detected by the wristband.

The other 73 patients never had a seizure. Over the course of some 3,500 monitoring hours, their wristbands sounded a total of 102 false alarms, occurring at least once in about a third of the children. (Four children accounted for a large number of them — through dice-throwing, gaming on the Nintendo Wii or hand flapping, common in developmental delay and autism). Loddenkemper believes these false alarms will diminish as the systems get “trained” with more and more data; eventually, the wristband could be taught to recognize what seizures look like in different individuals.

In the future, the wristband could potentially transmit data wirelessly to physicians, or into a seizure diary. “It is very difficult to obtain a good seizure diary, especially if the seizures are nocturnal,” says Loddenkemper. “We need an independent measure.”

Although his study was limited to generalized tonic-clonic seizures, a new study is underway to test the wristband’s ability to detect more subtle seizures. Loddenkemper, fellow Boston Children’s neurologist Alex Rotenberg, MD, PhD, and Bryan McLaughlin, PhD, at Draper Laboratory have a grant from CIMIT to develop a sensor that would sit under the ear, connecting wirelessly to electrodes on the scalp or implanted on the brain itself.

In a related study, Loddenkemper’s team found evidence that patterns of autonomic nervous system activity, detected by the wristband system, could identify children at heightened risk for sudden death from epilepsy – warranting especially close surveillance. “Children with severe epilepsy have an increased risk of dying during seizures,” notes Loddenkemper. “A closed-loop sensor system may enable us to prevent this.”

9 comments

  • clinicalpeds

    This is fantastic. If the information can be wirelessly
    available – parents and health care providers can record length, intensity and frequency
    of seizures in children. Reporting of these modalities is always a challenge.
    -Written by Clinical Pediatrics Conference at http://www.clinicalpeds.com
     

  • Karen Kestrel

    Any idea when this might be available for purchase?

    • nansona

      Hi, Karen, see reply below to Courtney. –Nancy Fliesler, Vector editor

  • Brian K

    The product is being designed and developed at MIT Media lab so no one is thinking of commercializing this technology. There is however another device for people of all ages (not just children unlike the device described here) that is in clinical trials now. FDA clearance takes a long time.

  • nansona

    For those wanting to get this wristband, Rosalind Picard’s team is now launching a product called Embrace: https://www.indiegogo.com/projects/embrace-a-gorgeous-watch-designed-to-save-lives –Nancy Fliesler, Vector editor

  • Sue Kurrle

    It seems to me that stress..physical exertion..cold temps hot temps and mental nervousness, Food additives ie.sodium nitrate ingestion, natural smoke flavorings, BBQ ed foods,and environmental factors such as bonfire smoke, and crowding are ALL massive triggers to bringing on grand malling
    . SO why is this not being recognized in neurologist’s office visitations nor in recommended treatments or even in pharmaceuticals endeavors These humans are short circuiting on adrenal cortex fatigue. Yes we know this, as caretakers we KNOW this. We need at home injections of some type of relaxant for this anxiety meltdown. Then we can focus on machines that will GPS victims not able to call ambulance’s Siezurr victims should not ever be all alone! We need rescue shots developed PLEASE..like epipens. This is life or death.

  • nansona

    The device is under continued research and development and won’t be available commercially until at least July 2015, according to the company (Empatica). To fund further development, Empatica is accepting pre-payments for the device for a limited time through a crowdfunding campaign (visit their website here: https://www.indiegogo.com/projects/embrace-a-gorgeous-watch-designed-to-save-lives ). Boston Children’s Hospital is not involved in this funding campaign, but our research team, including Dr. Tobias Loddenkemper and others in the Boston Children’s Hospital Epilepsy Center, is actively investigating seizure detection devices, including a prototype of Empatica’s product. We recommend that you consult your epilepsy doctor or visit a specialist at the Boston Children’s Epilepsy Center (617-355-7970) to determine which device works best for your child, as some devices may not pick up on specific seizure types. Our physicians recently published a paper that gives an overview of available devices that you & others may find helpful:
    http://ac.els-cdn.com/S1525505014002297/1-s2.0-S1525505014002297-main.pdf?_tid=8857d9be-
    –Nancy Fliesler, Vector editor

    • courtney

      but will my medcare pay for it if its okay with them

      • nansona

        My guess is no, since it hasn’t been FDA approved yet and isn’t really officially on the market – but you could check with the company: info@empatica.com.

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