Landua Kleffner Syndrome is one of a spectrum of childhood epileptic disorders and presents with acquired aphasia (loss of the ability to speak or understand speech after initially being able to).
Characteristics of Landau Kleffner Syndrome
- Sudden or gradual development of aphasia (receptive and expressive) after initially normal speech development.
- Onset usually between the ages of 5 and 7 years.
- EEG abnormalities including continuous spike-and-wave during sleep.
- Many patients, but not all, have seizures.
- Seizure activity typically resolves by teenage years, but speech is permanently lost.
An example of continuous spike-and-wave EEG waveforms can be seen here (from Kanamura and Aihara 2011):
The role of sleep in cortical development
Many studies have now shown that sleep is important for the consolidation of memories. Only a few studies, however, have looked at the specific role of sleep in the development of cortical organization in the mammal. The first to convincingly show a role for sleep in the development of cortical maps was the work of Frank et al., 2001. In this study the authors showed that experience-dependent changes in cortical organization occurred during sleep, and disrupting sleep actually inhibited cortical changes that would otherwise occur.
This has direct implications for disorders like Landau Kleffner because the continuous spike-and-wave activity in young children likely disrupts cortical reorganization that is crucial to environmentally driven learning and brain plasticity. In particular, disruption of night-time plasticity during the sensitive period for language and hearing development almost certainly underlies the loss of language (acquired aphasia) that characterizes Landau Kleffner Syndrome.
Until recently treatment focused on seizure control using anti-epileptic drugs. However, these have typically had little to no effect on the long-term development of aphasia. According to Geva-Dayan et al. (2012) small number of patients with Landau Kleffner Syndrome have benefited from IVIg (IV immunoglobulin) therapy, although even in this series not all patients treated showed benefit.
- Hideaki Kanemura and Masao Aihara (2011). Sequential Prefrontal Lobe Volume Changes in Epileptic Patients with Continuous Spikes and Waves During Slow Sleep, Epilepsy in Children – Clinical and Social Aspects, Z?eljka Petelin Gadz?e (Ed.), ISBN: 978-953-307-681-2, InTech, Available from: http://www.intechopen.com/books/epilepsy-in-children-clinical-and-social-aspects/sequential-prefrontal-lobe-volume-changes-in-epileptic-patients-with-continuous-spikes-and-waves-dur
- Frank, Issa, Stryker. (2001) Sleep Enhances Plasticity in the Developing Visual Cortex. Neuron 30:275–287.
- Geva-Dayan, Shorer, Menascu, Linder, Goldberg-Stern, Heyman, Lerman-Sagie, Ben Zeev, Kramer (2012) Immunoglobulin treatment for severe childhood epilepsy. Pediatr Neurol. 2012 46:375-381.