QI-Disability

Quality of life refers to a person’s satisfaction with a composite of their life experiences.

The Quality of Life Inventory-Disability, QI-Disability, was developed to specifically assess the quality of life of children and adolescents with intellectual disability (aged 3-18). The instrument was designed by a team of Australian researchers in direct collaboration with the families and carers of individuals across the spectrum of intellectual disability.

Initial qualitative analyses for QI-Disability were conducted for children with Down syndrome, Rett syndrome (a severe genetic neurodevelopmental disorder mainly affecting females), and children with cerebral palsy or autism spectrum disorder who also have an intellectual disability.

Since its development, studies exploring other diagnoses have utilised QI-Disability, including Prader-Willi syndrome (a rare genetic disorder affecting chromosome 15), CDKL5 Deficiency Disorder (a rare X-linked genetic disorder), and other Developmental Encephalopathy and Developmental Epileptic Encephalopathy conditions. Using QI-Disability for a range of conditions will allow for more comprehensive insight into service utility and intervention targeting the complex needs of this population, with the goal of the child’s quality of life as the target.

QI-Disability is being used as a monitoring tool in clinic settings and in observational research studies. It is being used as an outcome measure in clinical trials.

Quality of Life Study Newsletter

QI-Disability measures quality of life. There are 32 questions classified across 6 domains:

Caregivers are instructed to respond to questions on behalf of their child with an intellectual disability about observable aspects of the child’s physical, emotional and social wellbeing. 

For example: “Over the past month, how often has your child had enough energy to participate in daily routines and activities?”

QI-Disability was initially developed for children and adolescents with Down syndrome, Rett syndrome (a severe genetic neurodevelopmental disorder mainly affecting females), children and young people with cerebral palsy or autism spectrum disorder who have additional difficulties with cognition.

We are currently working towards expanding the use of QI-Disability to include a broader range of conditions. For example, QI-Disability is suitable for adults with Rett syndrome, children with the CDKL5 Deficiency Disorder (CDD, a rare X-linked genetic neurodevelopmental disorder) as young as 3 years, and adults with CDD.

QI-Disability helps multi-disciplinary teams identify areas where support is needed. This instrument is also helping to evaluate different treatments, interventions and services that promote successful outcomes for children with complex needs.

Researchers can use QI-Disability as a tool for screening, monitoring, and assessing their participants in research.

The following language translations are available: Czech, Danish, Dutch, French, German, Hebrew, and Hungarian.

For more information, download our QI-Disability Fact Sheet.

QI-Disability was used as an outcome measure for evaluation of Experience Collider, a circus, dance and theatre program for children with high support needs working together with members of an able-bodied circus troupe. See the full report here.

Saldaris JM, Jacoby P, Leonard H, Benke TA, Demarest S, Marsh ED, Downs J. Psychometric properties of QI-Disability in CDKL5 Deficiency Disorder: Establishing readiness for clinical trials. Epilepsy & behavior : E&B 2023; 139: 109069.

Leonard H, Gold W, Samaco R, Sahin M, Benke T, Downs J. Improving clinical trial readiness to accelerate development of new therapeutics for Rett syndrome. Orphanet J Rare Dis 2022; 17: 108.

Leonard H, Whitehouse A, Jacoby P, Benke T, Demarest S, Saldaris J, Wong K, Reddihough D, Williams K, Downs J. Quality of life beyond diagnosis in intellectual disability - Latent profiling. Res Dev Disabil 2022; 129: 104322.

Downs J, Jacoby P, Saldaris J, Leonard H, Benke T, Marsh E, Demarest S. Negative impact of insomnia and daytime sleepiness on quality of life in individuals with the cyclin-dependent kinase-like 5 deficiency disorder. Journal of sleep research 2022: e13600.

Jacoby P, Williams K, Reddihough D, Leonard H, Whitehouse A, Downs J. Modelling quality of life in children with intellectual disability using regression trees. Dev Med Child Neurol 2022; 64: 1145-55.

Leonard H, Downs J, Benke TA, Swanson L, Olson H, Demarest S. CDKL5 deficiency disorder: clinical features, diagnosis, and management. The Lancet Neurology 2022; 21: 563-76.

Whitehouse A, Jacoby P, Reddihough D, Leonard H, Williams K, Downs J. The effect of functioning on Quality of Life Inventory-Disability measured quality of life in children with intellectual disability is not mediated or moderated by parental psychological distress. Quality of Life Research 2021; 30: 2875-85.

Reddihough D, Leonard H, Jacoby P, Kim R, Epstein A, Murphy N, Reid S, Whitehouse A, Williams K, Downs J. Comorbidities and quality of life in children with intellectual disability. Child Care Health Dev 2021; 47: 654-66.

Leonard H, Junaid M, Wong K, Demarest S, Downs J. Exploring quality of life in individuals with a severe developmental and epileptic encephalopathy, CDKL5 Deficiency Disorder. Epilepsy Research 2021; 169: 106521.

Williams K, Jacoby P, Whitehouse A, Kim R, Epstein A, Murphy N, Reid S, Leonard H, Reddihough D, Downs J. Functioning, participation and quality of life in children with intellectual disability: An observational study. Developmental Medicine and Child Neurology 2021; 63: 89-96.

Mendoza J, Downs J, Wong K, Leonard H. Determinants of quality of life in Rett syndrome: new findings on associations with genotype. J Med Genet 2021; 58: 637-44.

Strugnell A, Leonard H, Epstein A, Downs J. Using directed-content analysis to identify a framework for understanding quality of life in adults with Rett syndrome. Disability and rehabilitation 2020; 42: 3800-7.

Jacoby P, Epstein A, Kim R, Murphy N, Leonard H, Williams K, Reddihough D, Whitehouse A, Downs J. Reliability of the Quality of Life Inventory-Disability (QI-Disability) measure in children with intellectual disability, Journal of Developmental and Behavioral Pediatrics, 2020. May 12; 41:534–539.

Glasson EJ, Forbes D, Ravikumara R, Nagarajan L, Wilson A, Jacoby P, Wong K, Leonard H, Downs J. Gastrostomy and quality of life in children with intellectual disability: a qualitative study, Archives of Disease in Childhood. 2020 Oct;105(10):969-974. 

Epstein A, Williams K, Reddihough D, Murphy N, Leonard H, Whitehouse A, Jacoby P, Downs J. Content validation of the Quality of Life Inventory - Disability (QI-Disability). Child: care, health and development. 2019 Jun 21;45(5):654-659.

Downs, J., Jacoby, P., Leonard, H., Epstein, A., Murphy, N., Davis, E., Reddihough, D., Whitehouse, A., & Williams, K. 2018. Psychometric properties of the Quality of Life Inventory-Disability (QI-Disability) measure. Quality of Life Research, 28, 783-94.

Tangarorang, J., Leonard, H., Epstein, A., & Downs, J. 2019. A framework for understanding quality of life domains in individuals with the CDKL5 Deficiency Disorder. American Journal of Medical Genetics Part A, 179(2), 2S49-56.

Epstein, A., Whitehouse, A., Williams, K., Murphy, N., Leonard, H., Davis, E., Reddihough, D., & Downs, J. 2019. Parent-observed thematic data on quality of life in children with autism spectrum disorder. Autism: International Journal of Research and Practice, 23(1), 71-80.

Davis, E., Reddihough, D., Murphy, N., Epstein, A., Reid, S.M., Whitehouse, A., Williams, K., Leonard, H., & Downs, J. 2017. Exploring quality of life of children with cerebral palsy and intellectual disability: What are the important domains of life? Child: Care, Health and Development, 43(6), 854-60.

Murphy, N., Epstein, A., Leonard, H., Davis, E., Reddihough, D. Whitehouse, A., Jacoby, P., Bourke, J., Williams, K. & Downs, J. 2017. Qualitative analysis of parental observations on quality of life in Australian children with Down syndrome. Journal of Developmental and Behavioral Pediatrics, 38(2), 161-8.

Epstein, A., Leonard, H., Davis, E., Williams, K., Reddihough, D., Murphy, N., Whitehouse, A., & Downs, J. 2016. Conceptualizing a quality of life framework for girls with Rett syndrome using qualitative methods. American Journal of Medical Genetics Part A, 170(3), 645-53.