Brain : a journal of neurology
-
Ictal hypoxemia has been reported in small series of cases and may contribute to sudden unexpected death in epilepsy (SUDEP). We sought to determine the incidence and severity of ictal hypoxemia in patients with localization-related epilepsy undergoing in-patient video-EEG telemetry. We examined whether seizure-associated oxygen desaturation was a consequence of hypoventilation and whether factors such as seizure localization and lateralization, seizure duration, contralateral spread of seizures, patient position at seizure onset and body mass index influenced ictal-related hypoxemia. ⋯ Ictal hypoxemia occurs often in patients with localization-related epilepsy and may be pronounced and prolonged; even with seizures that do not progress to generalized convulsions. Oxygen desaturations are accompanied by increases in ETCO2, supporting the assumption that ictal oxygen desaturation is a consequence of hypoventilation. Ictal hypoxemia and hypercapnia may contribute to SUDEP.
-
The pathophysiology of auditory verbal hallucinations (AVH) is largely unknown. Several functional imaging studies have measured cerebral activation during these hallucinations, but sample sizes were relatively small (one to eight subjects) and findings inconsistent. In this study cerebral activation was measured using fMRI in 24 psychotic patients while they experienced AVH in the scanner and, in another session, while they silently generated words. ⋯ Lateralization of activity during AVH was not correlated with language lateralization, but rather with the degree to which the content of the hallucinations had a negative emotional valence. The main difference between cerebral activity during AVH and activity during normal inner speech appears to be the lateralization. The predominant engagement of the right inferior frontal area during AVH may be related to the typical low semantic complexity and negative emotional content.