University of Surrey

Test tubes in the lab Research in the ATI Dance Research

A pre-screening questionnaire to predict non-24-hour sleep-wake rhythm disorder (N24HSWD) among the blind

Flynn-Evans, E.E. and Lockley, S.W. (2016) A pre-screening questionnaire to predict non-24-hour sleep-wake rhythm disorder (N24HSWD) among the blind Journal of Clinical Sleep Medicine, 12 (5). pp. 703-710.

Full text not available from this repository.


Study Objectives: There is currently no questionnaire-based pre-screening tool available to detect non-24-hour sleep-wake rhythm disorder (N24HSWD) among blind patients. Our goal was to develop such a tool, derived from gold standard, objective hormonal measures of circadian entrainment status, for the detection of N24HSWD among those with visual impairment. Methods: We evaluated the contribution of 40 variables in their ability to predict N24HSWD among 127 blind women, classified using urinary 6-sulfatoxymelatonin period, an objective marker of circadian entrainment status in this population. We subjected the 40 candidate predictors to 1,000 bootstrapped iterations of a logistic regression forward selection model to predict N24HSWD, with model inclusion set at the p < 0.05 level. We removed any predictors that were not selected at least 1% of the time in the 1,000 bootstrapped models and applied a second round of 1,000 bootstrapped logistic regression forward selection models to the remaining 23 candidate predictors. We included all questions that were selected at least 10% of the time in the final model. We subjected the selected predictors to a final logistic regression model to predict N24SWD over 1,000 bootstrapped models to calculate the concordance statistic and adjusted optimism of the final model. We used this information to generate a predictive model and determined the sensitivity and specificity of the model. Finally, we applied the model to a cohort of 1,262 blind women who completed the survey, but did not collect urine samples. Results: The final model consisted of eight questions. The concordance statistic, adjusted for bootstrapping, was 0.85. The positive predictive value was 88%, the negative predictive value was 79%. Applying this model to our larger dataset of women, we found that 61% of those without light perception, and 27% with some degree of light perception, would be referred for further screening for N24HSWD. Conclusions: Our model has predictive utility sufficient to serve as a pre-screening questionnaire for N24HSWD among the blind.

Item Type: Article
Authors :
Flynn-Evans, E.E.
Date : 2016
DOI : 10.5664/jcsm.5800
Uncontrolled Keywords : 6-sulfatoxymelatonin, Blindness, Circadian rhythms, Melatonin, N24HSWD, Non-entrained, Screening questionnaire, Sleep, 6 hydroxymelatonin o sulfate, adult, Article, blindness, circadian rhythm, cohort analysis, controlled study, female, human, major clinical study, non 24 hour sleep wake rhythym disorder, parasomnia, perception, prediction, predictive value, screening, sensitivity and specificity, urinalysis, urine level, visual impairment, circadian rhythm sleep disorder, complication, male, middle aged, questionnaire, Blindness, Female, Humans, Male, Middle Aged, Predictive Value of Tests, Sleep Disorders, Circadian Rhythm, Surveys and Questionnaires
Depositing User : Clive Harris
Date Deposited : 17 Jun 2020 01:10
Last Modified : 17 Jun 2020 01:10

Actions (login required)

View Item View Item


Downloads per month over past year

Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800