BACKGROUND AND PURPOSE: Epilepsy is most common in lower-income settings where access to electroencephalography (EEG) is generally poor. A low-cost tablet-based EEG device may be valuable, but the quality and reproducibility of the EEG output are not established. METHODS: Tablet-based EEG was deployed in a heterogeneous epilepsy cohort in the Republic of Guinea (2018-2019), consisting of a tablet wirelessly connected to a 14-electrode cap. Participants underwent EEG twice (EEG1 and EEG2), separated by a variable time interval. Recordings were scored remotely by experts in clinical neurophysiology as to data quality and clinical utility. RESULTS: There were 149 participants (41% female; median age 17.9 years; 66.6% ≤21 years of age; mean seizures per month 5.7 ± SD 15.5). The mean duration of EEG1 was 53 ± 12.3 min and that of EEG2 was 29.6 ± 12.8 min. The mean quality scores of EEG1 and EEG2 were 6.4 [range, 1 (low) to 10 (high); both medians 7.0]. A total of 44 (29.5%) participants had epileptiform discharges (EDs) at EEG1 and 25 (16.8%) had EDs at EEG2. EDs were focal/multifocal (rather than generalized) in 70.1% of EEG1 and 72.5% of EEG2 interpretations. A total of 39 (26.2%) were recommended for neuroimaging after EEG1 and 22 (14.8%) after EEG2. Of participants without EDs at EEG1 (n = 53, 55.8%), seven (13.2%) had EDs at EEG2. Of participants with detectable EDs on EEG1 (n = 23, 24.2%), 12 (52.1%) did not have EDs at EEG2. CONCLUSIONS: Tablet-based EEG had a reproducible quality level on repeat testing and was useful for the detection of EDs. The incremental yield of a second EEG in this setting was ~13%. The need for neuroimaging access was evident.
Epilepsy , Adolescent , Electroencephalography , Epilepsy/diagnosis , Female , Guinea , Humans , Male , Reproducibility of Results , Seizures/diagnosis
Both ventricular enlargement and reduced P3 amplitudes are consistent findings in schizophrenic patients, suggesting that the two measures reflect a common underlying pathophysiological process in schizophrenia. Investigating 14 stabilized schizophrenic outpatients, a relationship between the size of the lateral ventricles as well as of the third ventricle on CT scans and the auditory event-related P3 amplitude was, however, not found. This negative result suggests that ventricular enlargement and reduced P3 amplitudes in schizophrenics reflect different pathophysiological processes. It is assumed that the P3 amplitude is related rather to abnormalities in the temporal lobe of schizophrenic patients.
Arousal/physiology , Attention/physiology , Cerebral Ventricles/physiology , Evoked Potentials, Auditory/physiology , Schizophrenia/physiopathology , Schizophrenic Psychology , Tomography, X-Ray Computed , Adult , Brain/pathology , Electroencephalography , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales , Schizophrenia/diagnosis
