(Empatica Inc., Cambridge, MA) is the first
device combining 3-axis
(EDA) sensors to
detect and alert to
generalized tonic-clonic seizures
Clinical evaluation of the Embrace smart watch detection capability of
generalized tonic-clonic seizures recorded at the ankles
C. Caborni1,G.Regalia1,F.Onorati1, R.W. Picard1,2
,the performance of a
GTCS detection algorithm
wrist data has been evaluated on
•Both the Se and FAR indicate that the
algorithm generalizes well
to motor and
autonomic seizures patterns sensed at
previously accepted by the
on wrist EDA and ACM data
tuning the classifier’s thresholds
purposely on ankle data, we could achieve
1false alert per month
•This study suggests that the back of the lower calf is aviable site for
monitoring of GTCS in pediatric patients
•Patients were admitted to top hospitals EMU centers for
monitoring.They were asked to wear
•The seizures experienced during the recordings were labeled by
two independent epileptologists
ILAE 2016 classification
•The dataset consists of
of data from
•81 children (41 females), from 2months old to 18 y/o;
•5adults (4 females) in the age range of 22-25 y/o;
(9 children) experienced
•EDA and ACM recordings were analyzed
trained only on
from clinical settings.
(Se) was computed as the ratio of GTCSs detected by the classifier with respect to the total
number of seizures experienced.
False alarm rate
(FAR) was computed as the overall number of detections not corresponding to GTCS
events, divided by the total of recorded hours, normalized by 24 hrs.
1. Empatica Inc
2. MIT Media Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts, U.S.A
In this work we investigate whether the
Embrace detection algorithm
, designed for
wrist data, shows good
generalizability to ankle data
gathered in clinical settings
Figure 1 Embrace GTC seizure detection and alert system. A wristband embedding ACM and EDA sensors uses machine learning to detect an event and sends an alert to an app, which
generates a call via a cloud-based service to designated caregivers.
Onorati, Regalia et al., 2017, Multi-center clinical assessment of improved wearable multimodal convulsive
seizure detectors, Epilepsia, 8(11):1870-1879.
Caborni et al., 2017, Convulsive Seizure detection improved by setting different parameters for active/rest
periods, 32nd International Epilepsy Congress, Barcelona.
Regalia et al, 2017, Real-time Performance in Outpatient Settings for Embrace Seizure Detection System
with User-Adjustable Sensitivity, American Epilepsy Society meeting, Washington DC..
Performance of a wrist-worn multimodal seizure detection system for more than a year in real-life settings,
12th European Congress on Epileptology, Wien.
Lai et al, 2018, Performance assessment of Embrace, the first FDA approved smartwatch for convulsive
seizure detection, Partners Against Mortality in Epilepsy, Alexandria (VA).
evaluation of the machine learning classifier embedded in Embrace validated
(Se) of the GTCS detector
False Alarm Rate
lower than 0.2/day
settings, Embrace obtained comparable performances:
FAR lower than 1per 24 hrs
location has been reported as less distracting and more comfortable than the wrist by some patients, especially some
pediatric patients with
,but to date
no clinical evidence
on the effectiveness of mobile GTCS detection at the ankle has been available.
Distribution of the individual FAR experienced by the monitored patients (86).
14 out of 15 GTCSs (Se = 93.3%)
were successfully detected by the automated algorithm
(from a 6 y/o female) exhibited an irregular and
FAR was 0.18
, roughly corresponding to 1 false alarm every 6 days.
of the patients (73) experienced
no false alarm
of the patients (9) had a FAR between 0 and 1 (
Only the 5%
of the patients (5 ) had a FAR higher than 1 (
Individual count of seizures for each patient.The bars in green represent the detected seizures, while the
bar in black represent the missed seizure from patient #2.
EDA and 3-axes ACM signals of two seizures are shown. The purple areas indicate the seizures.
: the only missed seizure. The ACM pattern shows a discontinuity of the convulsion and also low values
: a detected seizure. The ACM intensity is higher and there are consistent increases of the
EDA during and after the seizure.