Abstract
Objective:
Insomnia severity index (ISI) is a widely used scale in various demographic groups but its psychometric properties have not been established in a sample of Indian subjects. This study was conducted as a preliminary study to extend and confirm the applicability of ISI to an Indian population of university students and to establish its correlation with the Pittsburgh Sleep Quality Index (PSQI).
Materials and methods:
The study was conducted among the student population of Jamia Millia Islamia, New Delhi, India, with due approval by the institutional ethical committee. Twenty-five poor sleepers with a mean age of 25.24±7.04 years and a BMI of 24.2±2.5 kg/m2 were recruited for the study from the university population. They were administered ISI and PSQI on test day and the same was repeated after 1 week.
Results:
The test-retest reliability for ISI (intra-class correlation coefficient, ICC2,1−0.84) was excellent. It was further established by the Bland-Altman graph and scatter plot. The results also showed that ISI (Pearson’s coefficient r−0.45) had a strong positive correlation with PSQI. Internal consistency for the ISI (Cronbach’s α–0.84) was excellent.
Conclusion:
The study findings suggest that ISI has excellent internal consistency, test-retest reliability and validity for the university population of poor sleepers in India. Hence, it can prove to be a good tool for screening insomnia in the current population.
Future study: The psychometric properties of the scale can be established in predefined sleep disorder patients so that it can be used on them too. Moreover, a correlation can also be established with the Polysomnograph.
Competing interests: The authors hereby declare that there is no conflict of interest regarding the current study.
Author’s contribution and acknowledgement: All the authors have contributed equally toward the development and completion of the article.
References
1. Berger H. Über das elektrenkephalogramm des menschen. Eur Arch Psy Clin Neurosci 1929;87:527–70.10.1007/BF01797193Search in Google Scholar
2. Dement W, Kleitman N. Cyclic variations in EEG during sleep and their relation to eye movements, body motility, and dreaming. Electroen Clin Neuro 1957;9:673–90.10.1016/0013-4694(57)90088-3Search in Google Scholar
3. Madan V, Jha SK. What is sleep and why is it needed. Int J Life Sci Technol 2008;1:9–23.Search in Google Scholar
4. Ancoli-Israel S, Roth T. Characteristics of insomnia in the United States: results of the 1991 National Sleep Foundation Survey. I. Sleep. 1999;22:S347–53.Search in Google Scholar
5. Schlarb AA, Kulessa D, Gulewitsch MD. Sleep characteristics, sleep problems, and associations of self-efficacy among German university students. Nat Sci Sleep 2012;4:1–7.10.2147/NSS.S27971Search in Google Scholar PubMed PubMed Central
6. Buboltz WC, Brown F, Soper B. Sleep habits and patterns of college students: a preliminary study. J Am Coll Health 2001;50:131–5.10.1080/07448480109596017Search in Google Scholar PubMed
7. Manzar MD, Zannat W, Kaur M, Hussain ME. Sleep in university students across years of university education and gender influences. Int J Adoles Med Health 2015;27:341–8.10.1515/ijamh-2014-0037Search in Google Scholar PubMed
8. Engle-Friedman M, Riela S, Golan R, Ventuneac AM, Davis CM, et al. The effect of sleep loss on next day effort. J Sleep Res 2003;12:113–24.10.1046/j.1365-2869.2003.00351.xSearch in Google Scholar PubMed
9. Edinger JD, Bonnet MH, Bootzin RR, Doghramji K, Dorsey CM, et al. Derivation of research diagnostic criteria for insomnia: report of an American Academy of Sleep Medicine Work Group. Sleep 2004;27:1567–96.10.1093/sleep/27.8.1567Search in Google Scholar PubMed
10. Morin CM, Belleville G, Bélanger L, Ivers H. The insomnia severity index: psychometric indicators to detect insomnia cases and evaluate treatment response. Sleep 2011;34:601–8.10.1093/sleep/34.5.601Search in Google Scholar PubMed PubMed Central
11. Morin CM, Stone J, Trinkle D, Mercer J, Remsberg S. Dysfunctional beliefs and attitudes about sleep among older adults with and without insomnia complaints. Psychol Aging 1993;8:463.10.1037/0882-7974.8.3.463Search in Google Scholar
12. Omachi TA. Measures of sleep in rheumatologic diseases: Epworth Sleepiness Scale (ESS), Functional Outcome of Sleep Questionnaire (FOSQ), Insomnia Severity Index (ISI), and Pittsburgh Sleep Quality Index (PSQI). Arthrit Care Res 2011;63:S287–96.10.1002/acr.20544Search in Google Scholar PubMed PubMed Central
13. Smith MT, Wegener ST. Measures of sleep: the insomnia severity index, medical outcomes study (MOS) sleep scale, Pittsburgh sleep diary (PSD), and Pittsburgh sleep quality index (PSQI). Arthrit Care Res 2003;49:S184–96.10.1002/art.11409Search in Google Scholar
14. Bastien CH, Vallières A, Morin CM. Validation of the Insomnia Severity Index as an outcome measure for insomnia research. Sleep Med 2001;2:297–307.10.1016/S1389-9457(00)00065-4Search in Google Scholar
15. Sierra JC, Guillén-Serrano V, Santos-Iglesias P. Insomnia Severity Index: some indicators about its reliability and validity on an older adults sample. Rev Neurol 2007;47: 566–70.Search in Google Scholar
16. Yu DS. Insomnia severity index: psychometric properties with Chinese community-dwelling older people. J Adv Nur 2010;66:2350–9.10.1111/j.1365-2648.2010.05394.xSearch in Google Scholar
17. Savard MH, Savard J, Simard S, Ivers H. Empirical validation of the Insomnia Severity Index in cancer patients. Psychooncology 2005;14:429–41.10.1002/pon.860Search in Google Scholar
18. Manzar MD, Moiz JA, Zannat W, Spence DW, Pandi-Perumal SR, et al. Validity of the pittsburgh sleep quality index in Indian university students. Oman Med J 2015;30:193–202.10.5001/omj.2015.41Search in Google Scholar
19. Kumar S, Bhatia M, Behari M. Excessive daytime sleepiness in Parkinson’s disease as assessed by Epworth Sleepiness Scale (ESS). Sleep Med 2003;4:339–42.10.1016/S1389-9457(03)00105-9Search in Google Scholar
20. Panda S, Taly AB, Sinha S, Gururaj G, Girish N, et al. Sleep-related disorders among a healthy population in South India. Neurol India 2012;60:68.10.4103/0028-3886.93601Search in Google Scholar
21. Walter SD, Eliasziw M, Donner A. Sample size and optimal designs for reliability studies. Stat Med 1998;17:101–10.10.1002/(SICI)1097-0258(19980115)17:1<101::AID-SIM727>3.0.CO;2-ESearch in Google Scholar
22. Bland JM, Altman D. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;327:307–10.10.1016/j.ijnurstu.2009.10.001Search in Google Scholar
23. Weir JP. Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM. J Strength Cond Res 2005;19:231–40.Search in Google Scholar
24. Portney LG, Watkins MP. Single subject designs. Foundations of Clinical Research: Applications to Practice. East Norwalk, Conn: Appleton & Lange 2009;2:223–64.Search in Google Scholar
25. George D, Mallery M. Using SPSS for Windows step by step: a simple guide and reference. Boston MA: Allyn & Bacon. 2003.Search in Google Scholar
26. Lahan V, Gupta R. Translation and validation of the insomnia severity index in hindi language. Indian J Psychol Med 2011;33:172–610.4103/0253-7176.92060Search in Google Scholar
27. Yazdi Z, Haghighi KS, Zohal MA, Elmizadeh K. Validity and reliability of the Iranian version of the Insomnia Severity Index. Malays J Med Sci 2012;19:31–6.Search in Google Scholar
28. Suleiman KH, Yates BC. Translating the insomnia severity index into Arabic. J Nurs Scholarsh 2011;43:49–53.10.1111/j.1547-5069.2010.01374.xSearch in Google Scholar PubMed
29. Blais FC, Gendron L, Mimeault V, Morin CM. Evaluation de l’insomnie: validation de trois questionnaires [Evaluation of insomnia: validation of three questionnaires]. Encephale. 1997;23:447–53.Search in Google Scholar
30. Boysan M, Gulec M, Besiroglu L, Kalafat T. Psychometric properties of the Insomnia Severity Index in Turkish sample. Anatolian Journal of Psychiatry 2010;11:248–52.Search in Google Scholar
31. Morin CM, Bootzin RR, Buysse DJ, Edinger JD, Espie CA, et al. Psychological and behavioral treatment of insomnia: update of the recent evidence (1998–2004). Sleep 2006;29:1398–414.10.1093/sleep/29.11.1398Search in Google Scholar PubMed
32. Fernandez-Mendoza J, Rodriguez-Muñoz A, Vela-Bueno A, Olavarrieta-Bernardino S, Calhoun SL, et al. The Spanish version of the insomnia severity index: a confirmatory factor analysis. Sleep Med 2012;13:207–10.10.1016/j.sleep.2011.06.019Search in Google Scholar PubMed
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