This section describes safety outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
5.1 One or more adverse events (minor and reversible) were reported in 4% (99/2,313) of patients in a case series of 2,313 patients. Some patients reported more than 1 event.
5.2 Local pain or intolerance to paraesthesia induced by the electrical stimulation was reported in 2% (47/2,313) of patients in the case series of 2,313 patients. All patients stopped the treatment.
5.3 Skin problems were reported in less than 1% (9/2,313) of patients in the case series of 2,313 patients. These included transient local skin allergy in 2 patients, reversible forehead skin irritation in 5 patients, and a feeling of bruising on the forehead in 2 patients.
5.4 Arousal and sleep changes were reported in less than 1% (19/2,313) of patients in the case series of 2,313 patients. These included insomnia in 4 patients, fatigue in 3 patients and sleepiness in 12 patients.
5.5 Tension-type headache was reported in less than 1% (12/2,313) of patients in the case series of 2,313 patients.
5.6 Weakness in jaw muscles and in upper and lower extremity muscles was reported in 1 patient 17 minutes after starting the device on the lowest setting. The patient also developed significant dizziness. These symptoms increased until the use of the device was stopped. After stopping the device, the muscle weakness and dizziness took approximately 2 hours to resolve completely. This adverse event was reported in the Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) database by a physician.
5.7 In addition to safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly occur, even if they have never done so). For this procedure, specialist advisers listed the following anecdotal adverse events: hyperalgesia, somnolence and local discomfort. They considered that the following were theoretical adverse events: hyperstimulation of the supraorbital nerve, headache exacerbation or aggravation.