Object Permanence and the Relationship to Sitting Development in Infants with Motor Delays

Mihee An, Emily C. Marcinowski, Lin Ya Hsu, Jaclynn Stankus, Karl L. Jancart, Michele A. Lobo, Stacey C. Dusing, Sarah W. McCoy, James A. Bovaird, Sandra Willett, Regina T. Harbourne

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Purpose: This study examines object permanence development in infants with motor delays (MD) compared with infants with typical development (TD) and in relation to sitting skill. Methods: Fifty-six infants with MD (mean age = 10 months) and 36 with TD (mean age = 5.7 months) were assessed at baseline and then at 1.5, 3, and 6 months postbaseline. A scale was developed to measure object permanence (Object Permanence Scale [OPS]), and the Gross Motor Function Measure sitting subsection (GMFM-SS), and the Bayley Scales of Infant and Toddler Development, 3rd Edition (Bayley-III) were administered. Results: Interrater reliability of the OPS was excellent and correlation between the OPS and Bayley-III cognitive scores was moderately positive. Compared with TD, infants with MD were delayed in development of object permanence but demonstrated increased understanding over time and as sitting skills improved. Conclusion: In children with MD, object permanence, as quantified by the OPS, emerges in conjunction with sitting skill.

Original languageEnglish (US)
Pages (from-to)309-316
Number of pages8
JournalPediatric Physical Therapy
Issue number3
StatePublished - Jul 1 2022


  • motor delay
  • object permanence
  • reliability
  • sitting
  • validity

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Physical Therapy, Sports Therapy and Rehabilitation


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