Neuropsychological Assessment of Children with Landau-Kleffner Syndrome

Landau–Kleffner syndrome (LKS) is an epileptic encephalopathy that is marked by sudden onset of verbal auditory agnosia and subsequent deterioration in expressive language. The primary deficit is in phonological processing, possibly at the level of impaired phonological short-term memory, and it appears to create a cascade of cognitive deterioration that impacts all aspects of speech comprehension. Inability to recognize nonverbal auditory stimuli may also be present but may not emerge until later in the condition. Language recovery may occur in about one-third of patients and appears to be precipitated by resolution of the EEG abnormalities. Nonverbal intelligence is typically normal, but language skills are globally impaired. Some studies suggest deficits in visual-spatial processing and/or visual-motor integration in up to 50% of cases, but other aspects of cognitive functioning, such as memory and executive functioning, have not been well studied. Auditory working memory, however, is a consistent area of difficulty for children with LKS and appears to persist regardless of functional outcome. Behavioral disturbance is also pervasive in LKS and can sometimes be the feature requiring the most clinical attention. Recent studies have emerged that provide more thorough neurodiagnostic information about the cognitive and behavioral features of LKS, but the reported literature on expected neuropsychological findings in LKS remains sparse.