Landau-Kleffner syndrome

Landau-Kleffner syndrome (LKS) is characterized by the sudden or gradual development of aphasia (the inability to understand or express language). Children affected with LKS have developed normally until signs and symptoms begin between the ages of 2 and 8.^[1][2] This syndrome is also characterized by an abnormal electroencephalogram (EEG), especially during sleep.^[3] About 70% of children with LKS have seizures.^[4] The seizures associated with LKS are known as complex partial, generalized clonic, and atypical absence seizures and are generally easy to control with medications. 

Some children with Landau-Kleffner syndrome may develop behavioral problems including hyperactivity, attention deficits, temper outbursts, impulsivity, and/or withdrawn behaviors.^[3] Some children with Landau Kleffner syndrome may also have intellectual disability.^[4] As researchers continue to learn more about LKS, it seems that there may be a wider variety of signs and symptoms associated with this syndrome than originally thought. There may be a variability of symptoms associated with LKS even within the same family.^[5]