Title:
Psychometrics and utility of Psycho-Educational Profile-Revised as a developmental quotient measure among children with the dual disability of intellectual disability and autism.

Abstract:
There is no agreement about the measure to quantify the intellectual/developmental level in children with the dual disability of intellectual disability and autism. Therefore, we studied the psychometric properties and utility of Psycho-Educational Profile-Revised (PEP-R) as a developmental test in this population. We identified 116 children with dual disability from the day care and inpatient database of a specialised Autism Clinic. Scale and domain level scores of PEP-R were collected and analyzed. We examined the internal consistency, domain-total correlation of PEP-R and concurrent validity of PEP-R against Gesell's Developmental Schedule, inter-rater and test-retest reliability and utility of PEP-R among children with dual disability in different ages, functional level and severity of autism. Besides the adequate face and content validity, PEP-R demonstrates a good internal consistency (Cronbach's α ranging from 0.91 to 0.93) and domain-total correlation (ranging from 0.75 to 0.90). The inter-rater reliability (intraclass correlation coefficient, ICC = 0.96) and test-retest reliability (ICC = 0.87) for PEP-R is good. There is moderate-to-high concurrent validity with GDS (r ranging from 0.61 to 0.82; all Ps = 0.001). The utility of PEP-R as a developmental measure was good with infants, toddlers, pre-school and primary school children. The ability of PEP-R to measure the developmental age was good, irrespective of the severity of autism but was better with high-functioning children. The PEP-R as an intellectual/developmental test has strong psychometric properties in children with dual disability. It could be used in children with different age groups and severity of autism. PEP-R should be used with caution as a developmental test in children with dual disability who are low functioning.