Priming recognition in good sleepers and in insomniacs FIORENZA GIGANTI 1 , BEATRICE AISA 1 , CINZIA ARZILLI 1 , MARIA PIA VIGGIANO 1 , MARIANGELA CERASUOLO 2 , FRANCESCA CONTE 2 and GIANLUCA FICCA 2 1 Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy; 2 Department of Psychology, University of Naples II, Caserta, Italy Keywords implicit memory, insomnia disorder, object recognition, perceptual priming Correspondence Gianluca Ficca, MD, PhD, Department of Psychology, University of Naples II, Viale Ellittico 31, 81100, Caserta, Italy. Tel.: +39-0823-274791; Fax: +39-0823-274792; e-mail: gianluca.ficca@unina2.it Accepted in revised form 16 January 2017; received 8 October 2016 DOI: 10.1111/jsr.12511 SUMMARY Insomniacs often report memory and concentration problems, but these complaints have not been consistently supported by performance measurements. Furthermore, while the majority of studies have addressed explicit memory, few have investigated the implicit domain, and very little is known concerning other types of implicit memory besides procedural memory, such as priming. Thus, the purpose of the study was to investigate priming effect for visual stimuli in insomniacs and good sleepers. Twenty-three insomniacs and 20 good sleepers performed a visual priming task in which they were asked to name new and old pictures presented at nine ascending levels of spatial filtering. Both neutral and sleep-related stimuli were used, as previous research evidenced an attentional bias for sleep-related stimuli. Visual priming effect was observed in both groups, suggesting that poor sleep quality does not affect this type of implicit memory. However, the identification process in insomniacs is influenced by the nature of the stimulus to identify: insomniacs recognized both new and old sleep-related stimuli at lower spatial frequencies compared with good sleepers. The tendency to selectively attend to sleep-related stimuli may influence top-down processes occurring during identification of filtering stimuli, by determin- ing a pre-allocation of attentional resources and facilitating identification processes even when sensorial information is scant. Differences in the identification processes of sleep-related stimuli compared with neutral ones should be carefully taken into account as possible pre-clinical markers of insomnia in poor sleepers. INTRODUCTION Insomnia disorder, defined as the presence of difficulties in initiating and maintaining sleep, accompanied by sleep- related daytime impairment, persisting for at least 4 weeks (Baglioni et al., 2010), is a very common disturbance, affecting up to 10–20% of the population (Buysse, 2013; Morin et al., 2006). This disorder can have severe conse- quences, both in terms of personal burden, reflected by decreased quality of life, anxiety and emotional problems (L eger et al., 2001a), and in terms of social costs, such as the higher rate of absenteeism and loss of work efficiency (Daley et al., 2009). Subjectively, insomniac patients often complain that their nighttime sleep troubles provoke massive fatigue and tiredness, associated with the perception of a notable reduction of cognitive performance. In particular, memory and concentration problems, as well as work-related mis- takes, have been frequently reported (L eger et al., 2001b). However, these complaints have not been univocally supported by objective performance measurements. In an extensive literature review, Shekleton et al. (2010) suggest that the seemingly controversial results on this issue actually depend on the different cognitive domains addressed. In fact, according to the authors, impaired performance is most likely to be found on attentional tasks, which require a high cognitive load, and working memory tasks. A recent meta-analysis (Fortier-Brochu et al., 2012) described significant impairments, of small to moderate magnitude, for tasks assessing episodic memory, problem ª 2017 European Sleep Research Society 345 J Sleep Res. (2017) 26, 345–352 Insomnia and priming recognition