Landau-Kleffner syndrome is a combination of progressive loss of speech skill with epileptiform changes in the electroencephalogram, clinically manifested in the form of epiprimes in only 70% of patients. The Landau-Kleffner syndrome is diagnosed on the basis of clinical data and the detection of prolonged epileptiform activity on the EEG, provided that organic brain pathology is excluded. The complex therapy includes antiepileptic pharmaceuticals, glucocorticosteroid hormones, speech therapy classes and neuropsychological correction. The prognosis for epilepsy is favorable, for speech dysfunction — serious.
General information
Landau-Kleffner syndrome is a symptom complex that includes a gradual regression of speech developed in accordance with age and the presence of epileptiform activity on the EEG. It was described in 1957. EEG changes do not always have clinical severity: epileptic paroxysms are observed only in 70% of patients. However, the presence of a paroxysmal EEG pattern in 100% of patients suggests that it is the epileptic activity of the brain that underlies the emerging speech disorders. In this regard, the Landau-Kleffner syndrome is synonymously called “acquired epileptic aphasia”.
The incidence is observed among children in the age period from 1.5 to 13 years, most often at the age of 4 to 7 years. Since Landau-Kleffner syndrome is a rare disease, there are no exact data on its prevalence. A study by Japanese scientists conducted at the end of the twentieth century showed that in children aged 5-14, the syndrome occurs with a frequency of 1 case per 1 million people. There is a slight predominance of boys among the patients (the gender ratio is about 1.7:1). In half of the cases, Landau-Kleffner syndrome is accompanied by behavioral disorders, which in some patients come to the fore, which forces their relatives to turn, first of all, to a psychologist or psychiatrist.
Causes
The etiology remains unknown. 12% of patients have a family history of cases of epilepsy in relatives, but Landau-Kleffner syndrome does not have a traceable hereditary character. It is assumed that the pathology is a dysfunction of the speech zone of the cerebral cortex caused by epileptogenic activity. This hypothesis is supported by the extraordinary duration of epileptiform activity recorded on the EEG, which in many patients is almost continuous throughout the slow sleep phase. In rare cases, the syndrome is symptomatic. The literature describes its occurrence in astrocytoma of the brain, localized in the temporal lobe, cerebral cysticercosis, traumatic brain injury.
Symptoms
Before the manifestation of the syndrome, the psychomotor and speech development of the child goes according to age. As a rule, the onset of the disease occurs with impaired perception of speech addressed to the child (sensory aphasia). Parents notice an inadequate reaction of the child to their words. 50% of sick children have emotional lability, increased excitability, behavioral disorders (hyperactivity, aggressiveness, anxiety, negativism, isolation).
The progression of speech disorders occurs in the period from several weeks to months, in some cases — in a few days. Sensory aphasia reaches such an extent that the child has no reaction to external sounds, although hearing is not impaired. Over time, motor aphasia, a disorder of expressive speech, joins the sensory one. In conversation, the child begins to use only simple phrases, then individual words, and finally loses the ability to speak at all — mutism develops.
Epileptic paroxysms accompanying Landau-Kleffner syndrome are represented by atypical absences and partial motor seizures (most often hemifascial or oral). There may be myoclonic and atonic paroxysms, secondary generalization of seizures. In most patients, epiprimes occur during bedtime or waking up. They are observed quite rarely. In 30% of patients, they are absent, a single epiprime is possible in the anamnesis. There is a tendency for the disappearance of epileptic paroxysms as the child grows up. So, at the age of 10, they are observed only in 20% of patients, and at the age of 15, they are absent in almost 100% of patients.
Diagnostics
Diagnosis is carried out by joint efforts of specialists in the field of neurology, speech therapy, epileptology, psychiatry and pediatrics. Often, especially in the absence of epiprimes, it can be quite difficult to diagnose Landau-Kleffner syndrome. Neurological and neuropsychological examination reveals sensorimotor aphasia, behavior changes. To exclude cochlear neuritis and other hearing disorders, patients are referred for a consultation with a hearing therapist, audiometry and a study of auditory VP.
During the EEG, epileptiform changes are detected in all patients. High peak waves recorded in the temporal regions and most pronounced during the slow sleep phase are pathognomonic. The latter dictates the need for a sleep EEG, which often registers the electrical epileptic status of slow sleep — constant diffuse epileptic activity during slow-wave sleep. In the absence of a change in sleep EEG, long-term EEG monitoring is recommended.
MRI and CT scans of the brain reveal pathological changes in its morphology only with the symptomatic nature of the syndrome. Brain PET data usually indicate one- or two-way changes in metabolism in the temporal regions of the brain. It is necessary to differentiate Landau-Kleffner syndrome from autism, other types of epilepsy in children (Lennox-Gastaut syndrome), mental disorders (schizophrenia, psychosis). Organic cerebral pathology should also be excluded: brain tumors, cerebrovascular disorders, encephalitis, demyelinating diseases.
Treatment and prognosis
Antiepileptic therapy is mandatory for all patients, regardless of the presence of epiprimes. It can be prescribed by a neurologist or an epileptologist. In patients without clinical manifestations of epilepsy, the drugs of choice are succinimides or benzodiazepines (klobazam). In the presence of epileptic paroxysms, valproates, topiramate, levetiracetam or their combinations are recommended. In polytherapy, a combination of valproates with klobazam is possible. The use of carbamazepine in the treatment is contraindicated, since clinical observations have shown that in some cases it contributed to increased speech dysfunction and increased frequency of epiprimes.
In parallel with antiepileptic therapy, treatment with glucocorticosteroids can be carried out. It is indicated in the absence of a proper effect from the use of anticonvulsants (reduction of seizures, relief of electrical epistatus on the sleep EEG). The pharmaceuticals of choice are dexamethasone, tetracosactide, prednisone. Treatment begins with intramuscular injection and dose increase. Then gradually reduce the dosage and switch to oral maintenance doses. Along with medical treatment, patients are recommended classes with a speech therapist and neuropsychological correction, psychological counseling of parents is carried out.
Landau-Kleffner syndrome does not have an unambiguous prognosis. Regarding epiprimes, it is favorable: in all patients, the disappearance of paroxysms by the age of 15-16 years is noted. Speech and behavioral disorders may persist throughout the patient’s life. Some recovery of speech skills is possible, but most adult patients have pronounced speech dysfunction. The most common gross speech disorders are noted with inadequate initial therapy of the syndrome due to difficulties in recognizing its epileptic genesis. Some authors point to an unfavorable speech prognosis while maintaining the electric epistatus of slow sleep for more than 3 years.