Prevalence of sleep talking in an Italian sample, association with other altered nocturnal behaviours and quality of sleep: preliminary findings

Introduction: Sleep talking (ST) was described by the ICSD-II as "the utterance of speech or sounds during sleep without simultaneous subjective detailed awareness of the event" (ICSD-II, 2001), while the recent revision of the ICSD reports the phenomenon as "Isolated symptoms and normal variants" of parasomnias (ICSD-3, 2014). A cross-sectional epidemiological study reported a high presence of ST both in the lifetime (66%) and current prevalence (17%) (Bjorvatn et al., 2010). ST has been recently addressed as a diagnostic marker to differentiate Lewy body dementia from other kind of dementia (Honda et al., 2013; ICSD-3, 2014). Nonetheless, specific investigations about its quantitative features and the influence on sleep quality still lack. Materials and methods: 783 subjects (18-69 years) completed an on-line questionnaire about sleep quality and presence/frequency of parasomnia-related behaviours. The protocol included the Pittsburgh Sleep Quality Index Questionnaire (PSQI, Italian version - Curcio et al., 2013) and the Munich Parasomnia Screening (MUPS, 2008 - Fulda et al., 2008). The MUPS is a self-rating questionnaire, assessing the frequency of 21 nocturnal behaviors (from "never" to " every or nearly every night").In order to evaluate the relation between ST frequency and frequency of other altered nocturnal behaviours in the whole sample, correlational analyses have been performed. Results: ST prevalence was of 72% in the lifetime of our sample, and 11.49% of declared a current prevalence (MUPS frequency 6 " one or more times per week", or 7 "every night or nearly every night"). 90 subjects (M= 33, F=57; 18-68 years, M= 25.15, SD= 6,24) declared a frequency of at least once a week and have been selected for further analyses. In a comparison between frequent ST and a control group (no self-report of altered nocturnal behaviours), values at PSQI showed a sleep quality significantly lower for ST compared to controls. The results of the correlational analysis showed a significant positive trend for: hypnic jerks, rhythmic movement disorder, hypnagogic hallucinations, sleep-related bruxism, sleep-related groaning, nightmares, sleep terrors, confusional arousal, sleepwalking, violent behaviour, REM sleep behaviour disorder (p< 0.02).Conclusions: The results confirm a high presence of declared ST in an Italian sample and a significant co- presence with other altered nocturnal behaviours, coherently with previous findings (ICSD-II, 2001; Bjorvatn et al., 2010; Nielsen et al., 2009). Nonetheless, the ICSD-3 (2014) defines this phenomenon as non-pathological parasomnia, the self-reported poor sleep quality suggests ST could be interesting to study as an independent factor influencing sleep quality. Due to these results, sleep studies on the quantitative EEG changes in ST and on the assessment of the association with cognitive performance are needed, both in healthy individuals and in pathological cohorts (i.e., dementia patients). Acknowledgements: This work was supported by the grant AR11715C545C9CF7 from "Sapienza", University of Rome.