Reliability of the Motor Optimality Score-Revised: A study of infants at elevated likelihood for adverse neurological outcomes.

Aim: To assess the inter-assessor reliability of the Motor Optimality Score-Revised (MOS-R) when used in infants at elevated likelihood for adverse neurological outcome.

Methods: MOS-R were assessed in three groups of infants by two assessors/cohort. Infants were recruited from longitudinal projects in Sweden (infants born extremely preterm), India (infants born in low-resource communities) and the USA (infants prenatally exposed to SARS-CoV-2). Intraclass correlation coefficients (ICC) and kappa (κw) were applied. ICC of MOS-R subcategories and total scores were presented for cohorts together and separately and for age-spans: 9-12, 13-16 and 17-25-weeks post-term age.

Results: 252 infants were included (born extremely preterm n = 97, born in low-resource communities n = 97, prenatally SARS-CoV-2 exposed n = 58). Reliability of the total MOS-R was almost perfect (ICC: 0.98-0.99) for all cohorts, together and separately. Similar result was found for age-spans (ICC: 0.98-0.99). Substantial to perfect reliability was shown for the MOS-R subcategories (κw: 0.67-1.00), with postural patterns showing the lowest value 0.67.

Conclusion: The MOS-R can be used in high-risk populations with substantial to perfect reliability, both in regards of total/subcategory scores as well as in different age groups. However, the subcategory postural patterns as well as the clinical applicability of the MOS-R needs further study.