Native Language Shifts Across Sleep-wake States in Bilingual Sleep-talkers Juan A. Pareja, Eloy de Pablos, Ana B. Caminero, Isabel Millán and José LDobato Presented by Kimberley Chen

Introduction  What is sleep-talking? Common parasomnia that range from mumbled nonsense to coherent sentences but without detailed awareness of the event Occurs spontaneously; sometimes due to emotional stress Happens during NREM sleep and REM sleep More frequent in children and teenagers than in adults

Previous research & Research Question  Multi-language patients always use their dominant language during sleep-talking episodes  To study the language used by healthy bilingual children during episodes of sleep-talking

Methods  Subjects:  3 bilingual schools in Northern Spain  681 children ( 336 males and 341 females, 4 unknowns)  Age 3-17 (mean age: 9.0; SD: 2.6)  1000 parents agreed to participate too  Languages: Spanish & Euskera

Methods  Procedure - Parents had to complete self-administered questionnaire - Sample questions:  What was the 1 st language learned by your child?  Does your child sleep talk?  If you child sleep-talks, what language does he/she speak while sleeping? *To ensure reliability in answers, parents were told to skip any question in doubt and they could call the investigator to discuss any doubts

Results  Sleep-talking occurred in 56.3% of the 681 children

Results

Percentage of subjects Native Language

Discussion  Dominant bilinguals found to use native language during episodes of sleep-talking  <4% found to use non-dominant language persistently during sleep-talking  Balanced bilinguals showed tendency to sleep-talk in either of the two native languages without preference  Environmental factors like cultural and social atmosphere  tip balance towards one language

Discussion  Differences in intra-hemispheric organization  Two languages learnt early in infancy at the same time  Represented in same cortical areas of dominant cerebral hemisphere  One language learnt first and then second language learnt  Represented in different brain areas

Discussion  Emotional stress  Released in an unconscious way during episodes of sleep-talking  Some elements with negative content* usually occur in second-acquired language. * Research done on bilingual patients with auditory hallucinations: hear aggressive voices in second language and protective voices in native language

Conclusion  Predominance of bilingual subjects used their native language during episodes of sleep-talking

Strengths & Limitations Strengths - Easy to read - Large sample size - Balance of genders Limitations - Only one region of the world was tested - Parents may be bias - Did not link to specific brain areas - No clear hypothesis

Future experiments  To test on multi-linguals (more than 3 languages)  Test other areas in the world where bilingualism exists  Narrow the age range  Use a voice recorder to record sleep-talking

Thank you for listening!!! Any questions?