Clinical validation studies of seizure detection devices conducted in epilepsy monitoring units (EMUs) can be biased by the artificial environment. We report a field (phase 4) study of a wearable accelerometer device (Epi?Care) that has previously been validated in EMUs for detecting bilateral tonic–clonic seizures (BTCS). Seventy?one patients using the device (or their caregivers) completed the modified Post?Study System Usability Questionnaire. Median time patients had been using the device was 15 months (range = 24 days?6 years).
In 10% of cases, patients stopped using the device due to reasons related to the device. The median sensitivity (90%) and false alarm rate (0.1/d) were similar to what had been determined in EMUs. Patients and caregivers were overall satisfied with the device (median = 5.5 on the 7?point Likert scale), considered the technical aspects satisfactory, and considered the device comfortable and efficient. Adverse effects occurred in 11%, but were only mild: skin irritation at the wrist and interference with home electronic appliances. In 55% the device influenced the number of seizures logged into the seizure diary, and in 40% it contributed to fewer seizure?related injuries. This field study demonstrates the applicability and usability of the wearable accelerometer device for detecting bilateral tonic-clonic seizures.