RESUMEN
Objectives: A measure to increase the electroencephalogram [EEG] outcome includes a short period of nap sleep during a routine standard EEG with the aim of increasing its sensitivity to interictal abnormalities or provoking seizures. As part of an ongoing auditing of our EEG data, we aimed to investigate the contribution of nap sleep during routine outpatient department based EEGs requested for a variety of reasons
Methods: EEG data at the Department of Clinical Physiology at Sultan Qaboos University Hospital, Oman, from July 2006 to December 2007 and from January 2009 to December 2010 [total 42 months] were reviewed. The EEGs were for patients older than 13-years referred for possible epilepsy, blackouts, headache, head trauma, and other non-specified attacks. The recording period was between 20 to 40 minutes. Abnormalities were identified during waking and nap sleep periods
Results: A total of 2 547 EEGs were reviewed and 744 were abnormal [29.2%]. Of those abnormal EEGs, nap sleep was obtained in 258 [34.7%] EEGs, and 39 [15.1%] showed abnormalities during nap sleep. Nineteen out of the 39 [48.7%] EEGs were abnormal during awake and nap sleep; and 20 [51.3%] were abnormal during nap sleep, which represented only 2.7% of the total abnormal EEGs [n = 744]
Conclusions: The contribution of the short nap sleep to the pickup rate of interictal abnormalities in EEG was minimal. We recommend the EEG service to include one cycle of spontaneous sleep EEG directed at patients with a history suggestive of epilepsy if their awake EEGs are normal
RESUMEN
The aim of this study was to establish the relationship between background amplitude and interictal abnormalities in routine electroencephalography [EEG]. This retrospective audit was conducted between July 2006 and December 2009 at the Department of Clinical Physiology at Sultan Qaboos University Hospital [SQUH] in Muscat, Oman. A total of 1,718 electroencephalograms [EEGs] were reviewed. All EEGs were from patients who had been referred due to epilepsy, syncope or headaches. EEGs were divided into four groups based on their amplitude: group one 50 microV. Interictal abnormalities were defined as epileptiform discharges with or without associated slow waves. Abnormalities were identified during periods of resting, hyper ventilation and photic stimulation in each group. The mean age +/- standard deviation of the patients was 27 +/- 12.5 years. Of the 1,718 EEGs, 542 [31.5%] were abnormal. Interictal abnormalities increased with amplitude in all four categories and demonstrated a significant association [P <0.05]. A total of 56 EEGs [3.3%] had amplitudes that were