Oropharyngeal dysphagia in preschool children with cerebral palsy: relationship to gross motor function, dietary intake, and nutritional status

Context: Oropharyngeal dysphagia (OPD) is common in preschool children with cerebral palsy (CP), and may negatively influence children’s dietary intake and nutritional status. Prevalence estimates range from 19% to 99%, with this large variability owing to study methodology. Most studies detected OPD through parent report, and recruitment has focused on children with moderate-severe CP and from a broad age range. Understanding the prevalence and patterns of OPD in preschool children with CP across the full range of gross motor functional levels will promote earlier detection and interventions. Objective: The broad aim of this doctoral research was to determine the prevalence and patterns of OPD in preschool children with CP from 18 to 36 months; and its relationship to dietary intake, nutritional status and gross motor function. Design: This doctoral research forms part of 2 larger longitudinal cohort studies, CP Child: Growth, Nutrition and Physical Activity (GNPA); and CP Child: Brain Structure and Motor Function. Four substudies comprise this doctoral thesis: (1) systematic review of OPD measures, and validity and reproducibility, (2) cross sectional studies of OPD, (3) longitudinal study of OPD, (4) cross-sectional study of OPD in a low-resource country. Participants: Participants in all substudies were children with a confirmed diagnosis of CP aged 18 to 36 months corrected age. One hundred and thirty children participated in the main GNPA sample; inclusion of Queensland-born children from birth years 2006-2009, and exclusion of children with neurodegenerative conditions or syndromes influencing growth. Forty children with typical development (TD) were recruited as a reference sample. Eighty-one Bangladesh-born children were recruited to the sample from a low-resource country. Procedure: Children attended the hospital for mealtime and gross motor assessment, and growth anthropometry. Mealtimes were evaluated using the Schedule for Oral Motor Assessment (SOMA), Dysphagia Disorders Survey (DDS), Pre Speech Assessment Scale (PSAS), 16 clinical signs suggestive of pharyngeal phase impairment, and the Thomas-Stonell & Greenberg Saliva Severity Scale. Parents reported on their child’s mealtime using the Queensland CP Child Feeding Questionnaire, which was developed for the study. Gross motor function was classified on the Gross Motor Function Classification System (GMFCS), motor type (spasticity, dyskinesia, ataxia and hypotonia) and distribution. Parents completed a 3-day weighed food record at home, from which dietary intake was calculated. Nutritional status was indicated by height, weight, and body mass index, converted to z scores using age and gender reference data. Results: A systematic review of the clinimetric properties of OPD measures identified the SOMA and DDS to have the strongest psychometric properties and clinical utility. Our validity and reproducibility substudy found the SOMA, DDS and PSAS to all have strong reproducibility (agreement >85%, κ >0.5). The SOMA had the best specificity (100%), but reduced sensitivity (53%); whereas the DDS and PSAS had high sensitivity (100%) but reduced specificity (47% and 71%, respectively). Modified OPD cut-points were calculated for each measure based on a high prevalence of OPD in children with TD. OPD prevalence based on 1 or more measures (SOMA, DDS, clinical signs) was identified in 85% of preschool children with CP. The prevalence estimate calculated using latent-class methods was 65%, and estimates using the modified cut-points ranged from 46% (PSAS) to 62% (SOMA). OPD was prevalent across all levels of gross motor function, with a stepwise increase in the proportion with OPD with increasing GMFCS level. Children who were nonambulant (GMFCS V) had significantly increased odds of OPD compared to those who were ambulant (GMFCS I) (OR = 17.9, P = .036). Almost all children had oral phase impairments (94%, using modified cut-points 79%). The proportion of children with clinical signs suggestive of pharyngeal phase impairments was lower (68%, using modified cut-points 51%). Longitudinally, the prevalence of OPD reduced marginally between 18 to 24 months and 36 months, from 62% to 59% (n=53). The greatest number of children whose OPD improved were from GMFCS I (n=6, 27%), although the greatest proportion of a GMFCS level were children from GMFCS IV (n=3, 75%). GMFCS was the only risk factor which was consistently associated with OPD at both assessment points. OPD prevalence (based on DDS modified cut-points) was greater in Bangladesh (total n=81, 68%) compared to Australia (total n=130, 56%). However, prevalence and severity did not differ significantly between high- and low-resource countries when stratified for GMFCS (prevalence OR=2.4, P = .051; severity β=1.2, P = .08). Conclusions: The findings support that OPD is prevalent in about 60% of preschool children with CP, and is present even in children with ambulatory CP (GMFCS I-II). GMFCS was the strongest predictor of OPD in preschool children with CP, and this persisted across time, and in different resource and ethnic contexts. This thesis provides useful information as a basis for earlier identification of children at risk of growth or respiratory consequences associated with OPD, as well as to assist in planning optimal oropharyngeal sensorimotor therapies and nutritional interventions.