ABSTRACT
PURPOSE: Digital EEG has brought about greater flexibility in data interpretation but has also resulted in new and unique artifacts. As digital EEG has evolved, an increase in intensive care unit monitoring has occurred, bringing more sources of artifact to light. Aliasing as a result of a combination of compressed time base and display monitor resolution can result in appearance of spurious waveforms that can potentially skew interpretation. METHODS: A portion of a digital EEG from an intensive care unit patient acquired at a sample rate of 1,024 Hz was reviewed at a time base of 15 mm/second on a monitor with a resolution of 1,920 × 1,080. RESULTS: At a time base of 15 mm/second, a 60-Hz artifact resulted in the appearance of a 4-Hz delta artifact that resolved when the time base was changed to a more standard 30 mm/second. CONCLUSIONS: A software malfunction of the digital antialiasing filter for display resulted in the appearance of a novel 4-Hz artifact.
Subject(s)
Artifacts , Data Interpretation, Statistical , Electroencephalography/standards , Signal Processing, Computer-Assisted , Humans , Intensive Care UnitsSubject(s)
Antidepressive Agents, Second-Generation/poisoning , Bupropion/poisoning , Coma/chemically induced , Drug Overdose/complications , Antidepressive Agents, Second-Generation/therapeutic use , Brain/diagnostic imaging , Brain/drug effects , Brain/physiopathology , Bupropion/therapeutic use , Coma/diagnostic imaging , Coma/physiopathology , Depressive Disorder/drug therapy , Drug Overdose/diagnostic imaging , Drug Overdose/physiopathology , Electroencephalography , Humans , Male , Young AdultABSTRACT
INTRODUCTION: Both structural and functional abnormalities have been reported in patients with psychogenic nonepileptic events (PNEEs), although no truly consistent abnormalities have been found. METHODS: We retrospectively identified patients discharged from our EMU with video-EEG diagnoses of epileptic seizures, PNEEs, epileptic seizures plus PNEEs, interictal epileptiform abnormalities only, and nondiagnostic admissions. We then collected brain MRI results for analysis. RESULTS: We found significant brain MRI abnormalities in 33.8% of patients with PNEEs, clearly higher than the rate of brain MRI abnormalities in the healthy population. In addition, we found statistically significant differences in the locations of brain MRI abnormalities in patients with epileptic seizures (more frequently temporal) versus PNEEs (more frequently multifocal). CONCLUSION: This multifocal nature of abnormalities in patients with psychogenic nonepileptic events may help to explain the underlying pathophysiology as it relates to psychiatric disorders which are so frequently comorbid with PNEEs.
Subject(s)
Brain/diagnostic imaging , Magnetic Resonance Imaging , Seizures/diagnostic imaging , Seizures/epidemiology , Adult , Brain/physiopathology , Comorbidity , Electroencephalography/methods , Epilepsy/diagnostic imaging , Epilepsy/epidemiology , Female , Humans , Magnetic Resonance Imaging/methods , Male , Mental Disorders/diagnostic imaging , Mental Disorders/epidemiology , Mental Disorders/physiopathology , Middle Aged , Patient Discharge , Prevalence , Retrospective Studies , Seizures/physiopathologyABSTRACT
INTRODUCTION: Studies of the effect of a full moon on seizures have yielded mixed results, despite a continuing prevailing belief regarding the association of lunar phase with human behavior. The potential effect of a full moon on psychogenic nonepileptic events has not been as well studied, despite what anecdotal accounts from most epilepsy monitoring unit (EMU) staff would suggest. METHODS: We obtained the dates and times of all events from patients diagnosed with psychogenic nonepileptic events discharged from our EMU over a two-year period. The events were then plotted on a 29.5-day lunar calendar. Events were also broken down into lunar quarters for statistical analysis. RESULTS: We found a statistically significant increase in psychogenic nonepileptic events during the new moon quarter in our EMU during our studied timeframe. CONCLUSION: Our results are not concordant with the results of a similarly designed past study, raising the possibility that psychogenic nonepileptic events are not influenced by lunar phase.
