Detection of seizure-like movements using a wrist accelerometer

Abstract

Caregivers of people with epilepsy are commonly concerned about unwitnessed seizures causing injury and even death. The goal of this study was to determine if a wrist-worn motion detector could detect tonic–clonic seizures. Individuals admitted for continuous video/EEG monitoring wore a wristwatch-size device that was programmed to detect rhythmic movements such as those that occur during tonic–clonic seizures. When such movement was detected, the device sent a Bluetooth signal to a computer that registered the time and duration of the movements. Recorded detections were compared with the routinely recorded video/EEG data. Six of 40 patients had a total of eight tonic–clonic seizures. Seven of the eight seizures were detected. Nonseizure movements were detected 204 times, with opportunity for canceling transmission by the patient. Only one false detection occurred during sleep. In principle, this device should allow caregivers of people with tonic–clonic seizures to be alerted when a seizure occurs.

Introduction

A major concern of people with epilepsy and their caregivers is the possibility that an unwitnessed seizure might cause injury or even death, given that most patients and families cannot predict when a seizure might occur [1], [2]. The ability to detect a potentially dangerous convulsive seizure early in its course could allow caregivers to take appropriate first aid steps, administer “rescue” medication, and alert emergency response services. Seizure detection methods can be based on a variety of methods, including EEG signal analysis [3], [4], analysis of movement patterns in a digital video [5], and motion patterns detected by accelerometry [6], [7]. We evaluated a wrist-worn motion detection device to ascertain if it would detect convulsive seizure movements early in the course of the seizure.