The fine structure of sleep electrocortical activity reflects health and disease. The current study provides normative data for sleep structure and electroencephalography (EEG) spectral power measures derived from overnight polysomnography (PSG) and examines the effect of age and sex among Korean middle‐aged and older adults with or without obstructive sleep apnea (OSA). We analysed home PSG data from 1,153 adult participants of an ongoing population‐based cohort study, the Korean Genome and Epidemiology Study. Sleep stages were visually scored and spectral power was measured on a single‐channel EEG (C4‐A1). We computed spectral power for five frequency ranges. The EEG power was reported in relative (%) and log‐transformed absolute values (µV2). With ageing, the proportion of N1 sleep increased, whereas N3 decreased, which is more noticeable in men than in women. The amount of N3 was relatively low in this cohort. With ageing, relative delta power decreased and alpha and sigma power increased for the whole sleep period, which was more pronounced during REM sleep in non‐OSA. For men compared with women, relative theta power was lower during REM and sigma and beta were higher during N1 sleep. The differences of relative powers by age and sex in OSA were comparable to those in non‐OSA. In a community‐based Korean population, we present normative data of sleep structure and spectral power for middle‐aged or older adults of a non‐Caucasian ethnicity. The values varied with age and sex and were not influenced by sleep apnea.
Background and PurposeElectroencephalography (EEG) is often used as a screening tool for selecting pilots despite controversy regarding its contribution to aviation safety. We investigated EEG abnormalities in Korean commercial pilot applicants in order to identify the usefulness of EEG screening in this population.MethodsWe retrospectively analyzed the EEG results of 740 unselected pilot applicants who underwent waking EEG at Inha University Hospital from January 2013 to May 2017. EEG recording was performed for 30 minutes, which included 3 minutes of hyperventilation and intermittent photic stimulation.ResultsThe pilot applicants were predominantly male (95.3%) and had a mean age of 27.8 years (range: 16–40 years). Nine of them (1.2%) exhibited EEG abnormalities; the most common abnormality (six applicants) was a small amount of generalized irregular slow activities, while the other three applicants (0.4%) exhibited epileptiform discharges, with two showing generalized spike-and-wave complexes and one showing a few spike-and-wave complexes in the left frontotemporal area. The two applicants with generalized spike-and-wave complexes were found to have experienced clinical seizures by a neurologist during detailed history-taking.ConclusionsThis study found that 2 of 740 pilot applicants (0.3%) were diagnosed with epilepsy by routine EEG screening in an unselected population. Considering the low predictive value of EEG without the relevant clinical history in an unselected healthy young population, our findings raise questions regarding the cost-effectiveness of the current EEG screening protocol applied to pilot applicants. We suggest that a more-targeted and standardized EEG screening approach be applied to pilot applicants with epilepsy risk factors or a seizure history as determined by thorough medical history-taking.
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