Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Landau-Kleffner syndrome ?
    ### Response:
    What are the signs and symptoms of Landau-Kleffner syndrome? Landau-Kleffner syndrome is characterized by the sudden or gradual development of aphasia (the inability to understand or express language) in previously normal children along with an abnormal electro-encephalogram (EEG).
    