Landau-Kleffner syndrome

Landau-Kleffner syndrome and continuous spike and waves during slow wave sleep syndromes, frequent or persistent discharges, with or without accompanying seizures, cause impairment of cortical functions.
Landau-Kleffner syndrome is a rare, severely disabling disorder, with an insidious, or sudden, loss of language understanding (auditory agnosia), followed by progressive or fluctuating loss of verbal expression. Age at onset is between 3 and 7 years. Focal seizures represent the initial symptom in 60% of children, but are absent altogether in 25%. They have variable severity but remit before adulthood. EEG abnormalities predominate in the temporoparietal regions, bilaterally, or on either side. Interference by EEG discharges with auditory-evoked responses suggests epileptic-induced dysfunction of auditory processing. The prognosis of aphasia is unpredictable. However, onset before age 5 years and persistent EEG anomalies over the language areas forecast a severe evolution. Patients might be left with normal language or mild-to-severe persistent defects. No cause has been identified, although rare lesional cases have been reported.
Treatment efficacy is empirically investigated.

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