Non-epileptic seizures: delayed diagnosis in patients presenting with electroencephalographic (EEG) or clinical signs of epileptic seizures

Abstract

The clinical differentiation between epileptic seizures (ES) and non-epileptic seizures (NES) is often difficult and mostly based on the presence or absence of widely recognized features of ES such as tongue biting, falling, incontinence or concomitant epileptic abnormalities in the electroencephalogram (EEG). We retrospectively analysed the records of all patients referred to our Epilepsy Centre for refractory epilepsy and finally diagnosed with NES between 1980 and 1999 ( n= 103), half of them also exhibiting ES. The mean time-lapse between first attack and NES diagnosis was 8.7 +/- 1.3 years and 16.5 +/- 1.4 years for the NES and NES + ES groups respectively. At least one of the usual signs associated with generalized tonic-clonic seizures (tongue biting, falling or incontinence) was reported by 66% and 60% of patients with NES or NES + ES respectively. Interictal EEG abnormalities were recorded in 16% of NES patients vs. 80% of NES + ES patients. In the NES group, delay before establishing the correct diagnosis was significantly longer when the patients exhibited > or =1 symptom(s) of generalized seizures, or when patients exhibited interictal EEG abnormalities. Upon admission, 72% of NES patients and all NES + ES patients were being treated with antiepileptic drugs (AEDs).We conclude that EEG or clinical abnormalities suggestive of epileptic seizures are common in undiagnosed NES patients. Such diagnostic pitfalls, besides considerably delaying NES diagnosis, also considerably delay appropriate treatment implementation.

Non-epileptic seizures of the elderly

“…This percentage resembles data of other studies focusing on the elderly [18] as well as data of samples of younger patients from most epilepsy centers, ranging from 13 % to 30 % [9,15,20,21,24].A higher percentage was reported by de Timary et al [4]. This may be NES non-epileptic seizures; LOR loss of responsiveness 1 LOR in at least one of the events; 2 No LOR in any of the events; 3 Not tested in any of the events due to the exclusion of most types of physiological NES in their study.…”

“…Krumholz and Niedermeyer [16] reported "marked EEG abnormalities" in 14 % of their patients with psychogenic seizures. In another study [4], the overall rate of interictal abnormalities was 16 % in patients with NES. In studies investigating EEG-abnormalities in normal persons without epilepsy, there is also a wide range (0-10 %) of the reported prevalence rates of ED, with most studies reporting less than 5 % [22].…”

Methodological Issues in Conducting Treatment Trials for Psychological Nonepileptic Seizures

“…29 In the ensuing time, patients are treated with a number of antiepileptic drugs and also with psychotropic medications. 30 Most of the patients in our study had prior exposure to antidepressants. We found, however, that the dosing may have been below optimal pharmacological level.…”

Psychogenic non-epileptic seizures and psychoanalytical treatment: results

“…4 The difficulty in the diagnosis results from the similarity with epileptic seizures, the diversity in the manifestation of these seizures, and the changes found in the electroencephalogram. 5,6 Patients with PNES before the correct diagnosis -which can take decades -are treated as having refractory epilepsy, using maximum doses of anticonvulsant drugs with risk of iatrogenic complications; and will pass through 6 emergency units on average in the six months prior to the correct diagnosis 7 as well as admission to ICUs, resulting in redundancy in diagnostic imaging and laboratory tests. These factors result in significant economic losses for the patient, the family and health services.…”