Abstracts

Landau Kleffner syndrome (LKS), or acquired epileptic aphasia, affects previously well children and is characterized by a regression in language skills (verbal auditory agnosia), in association with epileptiform activity on electroencephalography (EEG) and rare clinical seizures. The diagnostic EEG finding is electrical status epilepticus of sleep (ESES) defined as almost continuous spike and wave discharges during slow wave sleep. A routine EEG (REEG) may not rule out this finding and overnight video EEG (VEEG) is often employed for diagnosis of LKS. The objective of this study is to compare the diagnostic yield of routine and overnight video EEG in children referred for suspected LKS., A retrospective review of an EEG database was performed to identify all children referred with suspected LKS from January 2000 to April 2006. EEG files were reviewed for electrographic findings. Clinical files of those children with a confirmed diagnosis of LKS were evaluated for clinical history., 135 studies (85 VEEG, 50 REEG) to evaluate for LKS were performed during this 6 year period. 77 children (57%) had a previous diagnosis of autism and speech delay or regression, and 58 (43%) children had a history of speech regression without autism, 23/135 children had a history of seizures. 33/135 children (25%) had repeated studies; a REEG not diagnostic of LKS followed by a 16 hr VEEG. No child with a history of autism and speech regression was found to have ESES and diagnosed with LKS. No child with a normal sleep REEG who had a subsequent VEEG was found to have ESES and diagnosed with LKS. 8/135 children (6 %), were diagnosed with LKS (6 boys), all under the age 10 (4-9 years). 6/8 children presented with partial seizures accompanying the aphasia. Two children had been referred first to ENT for deafness. All children had a REEG that was suggestive of LKS prior to VEEG. In one child an initial 16 hour VEEG was not diagnostic for LKS, but a subsequent REEG done one week later demonstrated ESES., In this study, VEEG was not superior to sleep REEG in the diagnosis of LKS. When a suspected diagnosis of LKS is not supported by sleep REEG a repeat REGG may be considered prior to VEEG. Children with autism or speech regression with a normal sleep REEG are unlikely to demonstrate ESES on prolonged VEEG monitoring.,