Adult Humans 2 adult 2 controlled study 2 female 2 human 2 major clinical study 2 male 2 scoring system Aged 1 Article 1 Chronic Pain Scale for Non Verbal Adults with Intellectual Disabilities score 1 Cross-Sectional Studies 1 Down syndrome 1 Dutchman 1 Female 1 Hospitals, Private 1 Male 1 Pain 1 Pain Measurement 1 Patient Satisfaction 1 Potential patients' loyalty private hospital 1 Psychometrics 1 Quality of Health Care 1 Questionnaires 1 REPOS 1 Reference Values 1 Reproducibility of Results 1 Rotterdam Elderly Pain Observation Scale score 1 SERVQUAL 1