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Influence of supine sleep positioning on early motor milestone acquisition
Annette Majnemer1, Ronald G Barr
1School of Physical and Occupational Therapy, Departments of Neurology and Neurosurgery and Pediatrics, McGill University, Montreal, Quebec, Canada. annette.majnemer@mcgill.ca
Insights
Infants sleeping on their backs may experience delayed motor skills by 6 months, linked to less "tummy time." Increased prone positioning is associated with better infant motor development.
Area of Science:
- Pediatric developmental neuroscience
- Infant motor development research
- Clinical child psychology
Background:
- Supine sleep positioning, recommended for SIDS prevention, may impact infant motor skill acquisition.
- Limited prone (tummy) time exposure is a growing concern in infant development.
Purpose of the Study:
- To investigate if supine sleep positioning is associated with delayed motor skills in infants at 4 and 6 months.
- To determine if reduced prone positioning exposure correlates with these motor delays.
Main Methods:
- Recruited healthy, full-term infants at 4 and 6 months.
- Assessed motor skills using the Peabody Developmental Motor Scale (PDMS) and Alberta Infant Motor Scale (AIMS).
- Collected infant behavior diaries to quantify awake prone (tummy) time.
Main Results:
- At 4 months, motor scores were near normative, with no significant delays.
- At 6 months, mean scores on AIMS and PDMS were lower than norms, with 22% exhibiting gross motor delays.
- Awake prone (tummy) time was significantly correlated with higher AIMS and PDMS scores (gross and fine motor).
Conclusions:
- Supine sleep-positioned infants showed delayed motor development by 6 months, associated with decreased awake prone positioning.
- Findings highlight the importance of 'tummy time' for optimal infant motor development.
- Results have implications for interpreting motor assessments and preventing unnecessary referrals in at-risk infants.
Abstract:
This study aimed to determine whether supine sleep-positioned infants have delayed motor skills at age 4 and 6 months, and if delays are associated with decreased exposure to prone position. One 4 and one 6-month-old sample of healthy infants born at term were recruited. Motor assessments included the Peabody Developmental Motor Scale (PDMS) and Alberta Infant Motor Scale (AIMS). Parents completed an infant behavior diary for 3 consecutive days. Seventy-one 4-month-old infants were assessed (38 males; mean age 4.4 mo, standard deviation [SD] 0.2). Mean motor scores were close to normative standards (AIMS 47.7, SD 19.6; PDMS gross motor quotient [GMQ] 96.3, SD 6.5; PDMS fine motor quotient [FMQ] 99.2, SD 4.8). No infant scored below cut-off values used to identify motor delay. Milestones less likely to be achieved included extended arm support in prone, hands to feet in supine, and sitting with arm support. Exposure to 'tummy time' while awake was correlated with AIMS scores (r = 0.38, p < 0.01). F i fty 6-month-old infants were assessed (21 males; mean age 6.4 mo, SD 0.4). Mean scores were shifted down for all scales, and as much as 1 SD for PDMS (AIMS 44.5, SD 21.6; PDMS GMQ 85.7, SD 7.6; PDMS FMQ 88.9, SD 9.0). Only 22% of 6-month-olds could sit without arm support versus 50% expected in a normative sample. Remarkably, 22% of our sample exhibited gross motor delays (quotient <78). Tummy time (awake) was significantly associated with the AIMS (r = 0.64) and PDMS GMQ (r = 0.55) and FMQ (r = 0.33) quotients, even after adjusting for confounders. Typically developing infants who were sleep-positioned in supine had delayed motor development by age 6 months, and this was significantly associated with limited exposure to awake prone positioning. This has important implications for interpreting motor assessments of infants at risk and for preventing inappropriate referrals.
