Below is an instruction from Human. Write a response.
    ### Instruction:
    How to diagnose Landau-Kleffner syndrome ?
    ### Response:
    How is Landau-Kleffner syndrome (LKS) diagnosed? LKS is diagnosed based on clinical features and the results of an electroencephalogram (EEG), a recording of the electric activity of the brain. All LKS children have abnormal electrical brain activity on both the right and left sides of their brains.
    