The Landau-Kleffner syndrome is a childhood disorder consisting of acquired aphasia and epileptiform discharges involving the temporal or parietal regions of the brain.74-89
The typical sequence is as follows:
- A seizure disorder develops in the child, but it is usually well controlled with antiepileptic drugs.
- Aphasia develops; its onset may be abrupt or insidious.87 Unlike typical acquired childhood aphasia, receptive dysfunction usually is the dominant feature early in the course of the disorder.74,90
- Spontaneous verbal expression slowly becomes reduced, and the child may use stereotypies, perseverations, and paraphasias.
- In some cases the disorder progresses to the point where the child cannot even recognize sounds, so that total auditory agnosia develops. The child becomes indifferent to auditory stimulation and may not even recognize the sound of a telephone or barking dog, thus often appearing to be deaf or autistic. Reading, writing, and signing may be relatively spared.
- Often an expressive aphasia develops later in the course of the disorder.
In the original description of the syndrome, verbal auditory agnosia was the language disturbance,81 but some patients may have expressive aphasia early in the course.
Only about 70% of patients have seizures. In one-third of cases, a single seizure or status epilepticus occurs, usually early in the course of the syndrome. The seizures usually begin in children who are between 5 and 10 years of age. After age 10, only 20% of patients still have seizures. The patients usually have generalized tonic-clonic and atypical absence seizures. Complex partial seizures with automatisms are uncommon.
In addition to aphasia, most patients have behavioral and psychomotor disturbances that may suggest autism. The neurologic examination, except for the mental status examination, is usually normal.
The clinical course of the disorder fluctuates85,88 and spontaneous remissions can occur.
The EEG is nonspecific in this syndrome. Typical EEG findings are frequent and repetitive spikes, sharp waves, and spike-and-wave activity. Usually, the discharges are bilateral and located in the temporal region or parietal-occipital region.
Sleep usually activates the record, and at times the abnormality is seen only in sleep recordings.79,88 Often patients will have continuous spike-and-wave activity during sleep. There appears to be an overlap between Landau-Kleffner syndrome and the syndrome known as continuous spike-wave discharges during sleep (CSWDS).
Adapted from: Holmes GL. Classification of seizures and the epilepsies. In: Schachter SC, Schomer DL, eds. The comprehensive evaluation and treatment of epilepsy. San Diego, CA: Academic Press; 1997. p. 1-36.
With permission from Elsevier (www.elsevier.com)