The Landau-Kleffner syndrome of acquired epileptic aphasia: unusual clinical outcome, surgical experience, and absence of encephalitis.

The syndrome of acquired verbal auditory agnosia in childhood with mutism and epileptic discharges has been described in over 100 cases. An encephalitic etiology has often been postulated but never proved. We report two patients with this syndrome who were treated surgically. Despite careful search, no pathologic evidence of encephalitis was found. One patient, with the typical course, had no seizures but striking positive correlation between epileptic discharge and language disorder; the second, after classic onset, developed intractable temporal lobe epilepsy, a previously unreported outcome of this syndrome. EEG discharges are generalized, bilateral, multifocal, or with shifting predominance but mainly temporal in 85% of reported cases, and unilateral, also predominantly temporal, in 15%. Language areas are preferentially involved. This syndrome has certain biologic features that resemble the benign epilepsies of childhood and may be the result of the unusual localization of the epileptic abnormality.