Iconographic validation of the Bristol scale in patient with neurological diseases

Abstract Introduction : The Bristol Stool Scale, published by Heaton et al. in 1988 in a population of patients suffering from irritable bowel syndrome, is a self-assessment tool to estimate stool appearance and therefore the transit time. It is a widely used scale recommended in the 2016 ROME IV criteria to diagnose chronic constipation. Although initially validated in a large population of patients with gastrointestinal disorders, its specific evaluation in a population suffering from neurological diseases has never been validated. Methods : Subjects were asked to orally categorize nine color photos of stool with various consistencies, viewed on a computer screen, according to the Bristol scale that was provided to them in paper and in color. Then, they were asked about the comprehension of the scale, its acceptability, its completeness, and the difficulty to position themselves on a single category. The primary endpoint was the agreement of subjects’ responses by the intraclass agreement coefficient (ICC) on the scoring of a sample of stool photographs by the Bristol scale. Secondary end points were comprehension, acceptability and appropriateness collected during qualitative interviews with subjects. Results : The calculated intra-class correlation index was 0.92. For the stool photographs at the extremities of the scale (Bristol 1 and 7) all subjects responses were the same. The scale was considered as not difficult to be understood and well accepted in the population. Conclusion : The Bristol scale can be used in subjects with neurological diseases, as it is well understood and accepted by this population. It can be helpful in the management of rehabilitation and medical treatment of constipation and/or fecal incontinence observed in this population.