Speech and language outcome of 14 children treated for Landau-Kleffner syndrome by multiple subpial transection was evaluated at Rush-Prebyterian-St Luke’s Medical Center, Chicago. Language deficits presented at a mean age of 4 years, with a range of 3.0-6.5 yrs, and previous history of language and cognitive development was normal. The average age at time of surgery was 7.4 years, and the range was 5 to 13 years. Two patients had surgical complications; one developed meningitis and another suffered a stroke. Eleven (79%) had significant postoperative improvement in receptive and expressive vocabulary. The extent of improvement was inversely correlated with age of onset and age of surgery, and directly correlated with the time elapsed between surgery and the time of the most recent postoperative language evaluation. A control group was not available. 
COMMENT. Landau-Kleffner syndrome is an acquired epileptic aphasia that develops in previously normal young children who lose previously acquired speech and language abilities. All patients selected for the study met these diagnostic criteria. The best predictor of language outcome following subpial resection was the amount of time elapsed between surgery and the time of language evaluation. In the absence of a control group, could these results be a function of the natural history of the disease? The following reports suggest that, although the Rush-Presbyterian experience is encouraging, controls may be needed to accurately evaluate the benefits of subpial resection.
Deonna T and associates of Lausanne, Switzerland, have reported an adult follow-up study of 7 patients with acquired epileptic aphasia beginning in childhood . Four showed no improvement, two were partially improved, and one man had made a complete recovery of speech and language. These authors subsequently reported a patient followed from age 3 to 18 years whose language and behavior correlated with abnormalities on the EEC Improvement coincided with the disappearance of continuous spike wave during sleep and the onset of a unilateral focus . Paquier PF et al, Rotterdam, The Netherlands, in a follow-up of 6 patients for periods ranging from 3 to 19 years found the outcome of aphasia variable, with slow improvement in 4, rapid recovery in 1, and fluctuating course in 1 . (see Progress in Pediatric Neurology I. PNB Publishers, 1991;pp217-218; and Vol II, 1994;pp57-58, for several references and commentary regarding outcome of L-K syndrome).
Landau-Kleffner syndrome (LKS) and electrical status epilepticus during sleep (ESES). Eleven patients with LKS and bitemporal ESES were followed for a mean of 9 yrs and 8 mos at the Neurological Institute, University of Bologna, Italy. Complete recovery of language and cognitive abilities occurred in 18%, and 64% were mentally retarded. Poor outcome showed some relation to onset of aphasia before 4 years, duration for longer than 1 year, and long-lasting ESES, probably preexisting speech delay. The common origin of LKS and ESES is confirmed by recent functional brain imaging studies. The elimination of ESES appears to be important in prognosis of LKS.