Differentiating psychogenic non-epileptic attack disorder (NEAD) from true epilepsy is difficult. This often results in a misdiagnosis and unnecessary and ineffective treatment. Prolonged EEG/video recording is the most sensitive tool for differentiating NEAD from epilepsy, but is costly and therefore limited in availability. Provocative tests, particularly the use of saline injection, can reduce the length of monitoring but give rise to ethical dilemmas. This study assesses the value of head-up tilt testing as a provocative test for NEAD. Twenty-one patients (17 female, mean age 34.6 +/- 11.5 years) with recurrent seizure-like episodes and a clinical diagnosis of NEAD were studied. Patients were tilted to 80( composite function )on an electric tilt table with footplate support for up to 45 minutes during continuous ECG, EEG and blood pressure monitoring. Seventeen patients (81%) experienced typical symptoms (non-epileptiform limb shaking in 15 patients, absence in one patient, myoclonic jerking in one patient) during head-up tilt without significant EEG abnormalities or haemodynamic changes. The mean time to onset of seizure-like activity was 13.2 +/- 11 minutes (range 0-31 minutes). No patients suffered injury or any other significant side-effect. Provocative testing using suggestion and head-up tilt is a sensitive tool for diagnosing NEAD and represents a safe, simple and inexpensive outpatient technique for investigating patients with suspected NEAD.
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