The Toileting Habit Profile Questionnaire (THPQ): Examining Construct Validity Using the Rasch Model

PURPOSE: Preliminary reports indicate that sensory issues may be related to atypical defecation habits in some children. Clinical practice in this area is limited by the lack of availability of validated measures that can distinguish children with sensory related defecation issues from those without such problems. The Toileting Habit Profile Questionnaire (THPQ) is a parent-report screening questionnaire designed to: 1) differentiate children with typical toileting habits from those with atypical toileting habits and 2) to identify toileting habits potentially related to sensory concerns in children with functional defecation disorders (FDD; i.e. constipation, fecal incontinence, and stool toileting refusal). While preliminary studies regarding the THPQ are promising, further examination of its characteristics is warranted before recommending its use in practice.

DESIGN: As part of a larger study, in this descriptive study we utilized a combination of qualitative and quantitative methods to examine the construct and content validity of the THPQ. First, we analyzed existing data collected with the THPQ from 2 groups parents of children aged 3 to 5 years old; those with typically developing children and those with children with FDD that had not responded to conventional medical management. Participants had been recruited from local schools, pediatric gastroenterology clinics and pediatric occupational therapy clinics. We then collected data with a revised version of the THPQ (THPQ-R). This time participants were parents of children aged 3 to 6 years with FDD and no other diagnosis or with FDD and autism. We recruited participants from several Spanish and English speaking countries using social media and other web based methods.

METHODS: This study included two phases of validity testing. Phase 1: we used Rasch analysis of existing data to assess construct validity; directed content analysis of recent literature to determine the extent to which items captured clinical concerns; and expert review to validate the THPQ. Based on Phase 1 outcomes, we adjusted THPQ items, formulating the revised THPQ (THPQ-R). Phase 2: we examined the construct validity of the THPQ-R using Rasch analysis.

RESULTS: Phase 1: Scale category structure supported use of dichotomous rather than Likert scale. Content and Rasch analysis lead to revision of some items, and creation of new items. This resulted in a 17-item questionnaire: 15 items designed to identify habits linked to sensory over-reactivity and 2 items meant to identify habits linked to sensory under-reactivity and/or perception difficulties. Phase 2: Analyses failed to support the inclusion of the sensory under-reactivity/or perception difficulties items for scoring purposes; these were removed. Remaining items were evenly distributed relative to item difficulty, an acceptable item hierarchy, and acceptable item fit.

CONCLUSION: Caregiver report of toileting behavior using the THPQ-R adequately captures challenging defecation behaviors related to sensory over-reactivity. The items Identifying challenging behaviors related to sensory under-reactivity and/or perception issues did not fit the model, however they appear to be tapping into useful clinical information. Clinicians can include these items to support clinical reasoning, but using these exclusively to identify sensory under-responsiveness or poor perception related to FDD is not recommended.

References

Beaudry-Bellefeuille, I., Booth, D., Lane, S. J. (2017). Defecation-specific behavior in children with functional defecation issues: A systematic review. The Permanente Journal, https://doi.org/10.7812/TPP/17-047.

Beaudry-Bellefeuille, I. & Lane, S. J. (2017). Examining sensory over-responsiveness in preschool children with retentive fecal incontinence. American Journal of Occupational Therapy. 71, 7105220020. https://doi.org/10.5014/ajot.2017.022707

Beaudry-Bellefeuille, I., Lane, S. J., & Ramos-Polo, E. (2016). The Toileting Habit Profile Questionnaire: Screening for sensory-based toileting difficulties in young children with constipation and retentive fecal incontinence. Journal of Occupational Therapy, Schools, & Early Intervention, 9(2), 163-175

Linacre, J. M. (2014). Reliability and separation of measures. A user’s guide to Winsteps Ministep Rasch-model computer programs (version 3.81. 0). Retrieved from http://www.winsteps.com/winman/reliability.htm.