Perception and comprehension of linguistic & affective prosody in children with Landau- Kleffner syndrome

Introduction Landau-Kleffner syndrome, aka acquired epileptic aphasia in children, is a type of epilepsy in which the most characteristic symptom is word deafness (aphasia) evolving into auditory agnosia and/or mutism. Since Landau-Kleffner syndrome was discovered by Dr. Landau and Dr. Kleffner in 1957 [1], there have been some case studies examining language outcomes in children suffering from this disease [2], [3], [4], [5], [6]. But most studies tested vocabulary in the context of short-term phonological memory. To our knowledge, there have been no investigations of the use of prosodic cues in children with Landau-Kleffner syndrome. We thus tested oral language perception/comprehension with linguistic and affective prosodic cues: rhythmic vs arrhythmic sentences and neutral vs anger sentences. With regard to linguistic prosody, we chose not to use the intonation pattern that distinguishes statements from questions because a) rhythm – the temporal organization of the prominences [7] – is also a very important prosodic element, b) most tests of prosody use this pattern [8], [9], [10], and c) more subtle prosodic elements need to be tested than statement vs question pattern in order to better examine language capacity in children who have already undergone speech-language therapies. With regard to affective prosody, the emotion anger was chosen for its precocity (even a baby gets angry when he doesn’t get what he wants immediately whereas we cannot be sure of sadness, for example, in a baby) and salient prosodic features compared with neutral. Given the clinical manifestation of LKS (word deafness), it is hypothesized that children with LKS would have fewer difficulties than healthy subjects in perceiving delexicalized sentences with affective prosody, i.e. sentences without semantic information.