Although children with achondroplasia demonstrate delays in motor performance across many skill areas, availability of population-based data to evaluate development of individuals is limited. Without this data, clinical examination is based on loose comparisons to typically developing norms, records of developmental progress or difficulties over time and parental reports of functional abilities or limitations. However, the impact that impairments at the body structure and function level has upon activity and participation domains are not well understood in this population. This thesis aims to provide a more comprehensive examination of development in children with achondroplasia across multiple skill areas as well as to examine relationships between impairments, motor skills and functional performance.
This thesis was developed in four parts. Section One (Study 1) aimed to quantify current health care usage by Australian children with achondroplasia to determine the impact of impairments and functional difficulties on health care needs. A parent questionnaire was developed to gather information about the type and timing of medical and allied health consultations, investigations and operative procedures for Australasian children with achondroplasia in the first five years of life (n=53). Data collected over a eleven year period (January 1997- December 2007), demonstrated variable compliance across Australian achondroplasia services with providing examinations and interventions recommended in the ‘Health Supervision for Children with Achondroplasia Guidelines’ published by the American Academy of Paediatrics. However it also provided a new insight into the high utilisation of other services not included in the guidelines, specifically physiotherapy and occupational therapy.
Section Two (Studies 2 & 3) aimed to establish a multi-dimensional profile of developmental milestones for children with achondroplasia including gross motor, fine motor, feeding and communication skills. Study 2 provided the first population-based multi-dimensional audit of developmental skills of Australasian children with achondroplasia in the first five years of life. Data was gathered by retrospective parent questionnaire for 20 children aged 16-60 months and born 1997-2003. Results validated previous reports of delays in gross motor skills and more advanced communication skills, however showed that fine motor skills and early communication skills were not as delayed as previously suggested. Study 3 provided the first prospective, population-based multi-dimensional follow up of developmental for Australasian children with achondroplasia (born 2000-2009, n=48). Results confirmed those from Study 2. This data was then used to develop the first “Achondroplasia Developmental Recording Form” to assist clinicians/therapists in monitoring and recording development across multiple developmental skill areas in young children with achondroplasia.
Section Three (Studies 4 & 5) aimed to profile the development of self care performance in children with achondroplasia and to determine if delays or deficits existed when performance was compared to average statured, typically developing children. Study 4 produced a systematic review examining the clinical utility, reliability and validity of outcome measurement tools used to evaluate self-care performance in children with osteochondrodysplasia. Three potential measures were identified as suitable, the WeeFIMTM, PEDI and ASK, with the WeeFIMTM most appropriate for telephone follow up of a geographically distributed population such as achondroplasia. In Study 5, the WeeFIMTM was used to quantify the age at which independence emerged in self-care in a population-based cohort of children with achondroplasia aged 3, 5 and 7 years. Additional information was yielded regarding functional mobility and social cognition. Results validated observations of parents and clinicians regarding delays in self-care and mobility for young children with achondroplasia and the increased burden of care for caregivers that extends beyond infancy and early childhood. Outcomes support the need for routine early intervention to provide therapy and equipment to overcome these difficulties prior to school.
Section Four (Study 6) examined possible links between the severity of musculoskeletal impairments and gross motor milestone acquisition in children with achondroplasia. Anthropometric data was collected from 48 Australian-born children with achondroplasia for head circumference, body height and body weight and analysed for relationships with timing of acquisition of 13 gross motor milestones. Results showed that earlier lie to sit transitioning is more likely if the child is taller, heavier or has a larger head circumference although head to body disproportion appears to also be a factor in timing of this task.
In summary, this thesis is the most comprehensive report of multi-dimensional developmental progress of young children with achondroplasia ever completed and the first for Australian children. Section One provided specific information regarding health care usage that will assist in future service development planning. In Section Two, a developmental profile was established and a recording form was developed to allow clinicians to more accurately monitor and compare a child’s performance. Section Three identified appropriate outcome measures for self care and used the WeeFIMTM to review functional performance in this group. It is the first study to validate previous parent and clinician observations of delayed self-care performance in this population. Section Four showed that height, weight and head circumference impacts timing of transitional motor skills, but further is needed to determine how other musculoskeletal impairments such as rhizomelia impact acquisition of other motor skills.