Latency of epileptic and psychogenic nonepileptic seizures

Abstract

Background Due to their semiological similarities, psychogenic nonepileptic seizures (PNESs) can occasionally hardly be differentiated from epileptic seizures (ESs), and long-term video-electroencephalographic monitoring (VEM) is needed for the differential diagnosis.

Objective To investigate the time of the first clinical event and its distribution on the days of VEM in ES and PNES patients.

Methods In total, a consecutive series of 48 PNES and 51 ES patients matched for gender and age were retrospectively and consecutively evaluated. The time distribution of the seizures during the day was noted. Seizure latency was determined as the time in hours from the start of the video-electroencephalographic recording to the first clinical event.

Results The seizure latency was significantly shorter in PNES patients compared to ES patients (p < 0.001). Seventy-two percent of PNES patients and 49.1% of ES patients had their first seizure in the 24 hours of video-EEG recording (p = 0.023). Recording longer than 48 hours was required for 12.5% of PNES patients and 37.3% of ES patients (p = 0.006). While ESs were almost evenly distributed throughout the day, most PNESs occurred during the evening hours (p = 0.011).

Conclusion We observed that the PNESs appeared earlier than the ESs in the VEM and were concentrated during daylight hours. Although not strictly reliable, seizure latency can contribute to the differential diagnosis of ES and PNES.

Resumen

Antecedentes Debido a sus similitudes semiológicas, las crisis no epilépticas psicógenas (CNEP) en ocasiones apenas se pueden diferenciar de las crisis epilépticas (CE), y se necesita una monitorización video-electroencefalográfica (EEG) prolongada para el diagnóstico diferencial.

Objectivo Investigar el momento del primer evento clínico y su distribución en los días de monitorización video-EEG en pacientes con CE y CNEP.

Métodos Se evaluó retrospectivamente a una serie consecutiva de 48 pacientes con CNEP y 51 con ES emparejados por sexo y edad. Se anotó la distribución temporal de las incautaciones durante el día. La latencia de las crisis se determinó como el tiempo en horas desde el inicio de la grabación del video-EEG hasta el primer evento clínico.

Resultados La latencia de las crisis fue significativamente menor en los pacientes con CNEP en comparación con los pacientes con CE (p < 0,001). El 72% de los pacientes con CNEP y el 49,1% de los pacientes con CE tuvieron su primera crisis en las 24 horas de registro del video-EEG (p = 0,023). Se requirió un registro de más de 48 horas para el 12,5% de los pacientes con CNEP y el 37,3% de los pacientes con CE (p = 0,006). Mientras que las CE se distribuyeron casi uniformemente a lo largo del día, la mayoría de las CNEP ocurrieron durante las horas después del anochecer (p = 0,011).

Conclusión Observamos que las CNEPs aparecieron antes que las CEs en la monitorización video-EEG, y se agruparon durante las horas del día. Aunque no es estrictamente confiable, la latencia de las crisis puede contribuir al diagnóstico diferencial de ES y CNEP.

Keywords

Psychogenic Nonepileptic Seizures - Epilepsy - Electroencephalography

Palabras clave

Convulsiones Psicógenas no Epilépticas - Epilepsia - Electroencefalografía

Authors' Contributions

HO, BG: contributed substantially to the conception or design of the study; HO, MT, NS: contributed to the collection, analysis, or interpretation of data; HO: contributed to the writing or critical review of the manuscript; BG: contributed to the approval of the final version to be published.

Publication History

Received: 02 November 2022

Accepted: 15 February 2023

Article published online:
24 July 2023

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