Introduction Insomnia as a complaint is a complex, heterogeneous condition. It can be a symptom of medical, psychiatric, or substance abuse disorders or it can be a condition on its own. Even in the latter case, there appears to be considerable variability in complaints and patient characteristics. This heterogeneity makes progress in our understanding of insomnia difficult. A first logical step would be to determine well-defined insomnia subtypes and subsequently unravel the brain mechanisms underlying insomnia complaints in these homogenous subtypes. The need to determine these subtypes, and obtain a large sample to be able to do so, has been recognized by several researchers before (e.g. Edinger et al., 1996; Van Someren et al., 2009; Vgontzas et al., 2012; Roenneberg, 2013). Materials and methods Internet technology has profoundly changed survey methodology and moreover makes web-based cognitive performance testing possible. Freeware implementations of these technologies have been combined in the Sleep Registry (www.sleepregistry.org) to obtain multiple descriptive, subjective and performance parameters in a huge sample of individuals and families. The multidimensional variable space can be subjected to latent class analysis in order to yield homogeneous subgroups. Given the large amount of measurements that will be done in the Sleep Registry, participants are given the opportunity to fill out their set of questionnaires and computer-based tests voluntarily at their own pace. Feedback on performance is given as reward to promote adherence. The setup of the Sleep Registry site is very modular making it possible for individual labs to add questionnaires and tests, or to initiate parallel sampling using different languages. Results Currently, around 14.000 people signed up for the Sleep Registry in the Netherlands and filled out between one and 28 modules, where each module contains one or more validated questionnaires. In addition, modules are available to assess the Consensus Sleep Diary (Carney et al., 2012), as well as common tasks including overnight word pair learning, the psychomotor vigilance test (Dinges and Powell, 1985; Basner and Dinges, 2011) and the digit span. Two modules are available for extensive structured diagnosis of sleep disorders as well as somatic, psychiatric and neurological disorders and medication use. The Sleep Registry is now available in Dutch, English, Spanish, Portugese, German, French, Italian and Polish. Labs can identify their own URL to make sure that they can own the data of their recruited participants, and are free to pool data with colleagues. Conclusion The Sleep Registry thus provides a useful tool for efficiently and flexibly acquiring large samples of descriptive, subjective and performance measurements to facilitate sleep research and truly start a cooperative Human Sleep Project (Roenneberg, 2013). Labs interested to run their own Sleep Registry and cooperate are welcome: e.van.someren@nin.knaw.nl Dinges DF and Powell JW (1985) Microcomputer analyses of performance on a portable, simple visual RT task during sustained attention. Behav Res Meth Instr Comp 17:652–655. Edinger JD, Fins AI, Goeke JM, McMillan DK, Gersh TL, Krystal AD and McCall WV (1996) The empirical identification of insomnia subtypes: a cluster analytic approach. Sleep 19:398–411. Van Someren EJW, Pollmacher T, Leger D, Espie C, Bassetti C and Riemann D (2009) The European Insomnia Network. Front Neurosci 3:436. Basner M and Dinges DF (2011) Maximizing Sensitivity of the Psychomotor Vigilance Test (PVT) to Sleep Loss. Sleep 34:581–591. Carney CE, Buysse DJ, Ancoli-Israel S, Edinger JD, Krystal AD, Lichstein KL and Morin CM (2012) The consensus sleep diary: standardizing prospective sleep self-monitoring. Sleep 35:287–302. Vgontzas AN, Fernandez-Mendoza J, Bixler EO, Singareddy R, Shaffer ML, Calhoun SL, Liao D, Basta M and Chrousos GP (2012) Persistent insomnia: the role of objective short sleep duration and mental health. Sleep 35:61–68. Roenneberg T (2013) Chronobiology: the human sleep project. Nature 498:427–428. Acknowledgements Supported by the VICI Innovation Grant 453-07-001 of the Netherlands Organization of Scientific Research (NWO); The Hague, the Netherlands; co-funding of the Polish translation by an ENSRL travel grant of the ESRS to Michal Jarkiewicz; co-funding of the English translatop by Kevin Morgan, Sleep Research Centre, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK.
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Feb 1, 2016
Emily Hofstetter 
Open Access