Infant Development and Sleep
By Marina Andrawis
In understanding the connection between sleep patterns and neonatal development, several studies have been unable to provide sufficient evidence on the relationship between prolonged and uninterrupted sleep time and infant development. The following studies have been compiled to demonstrate that studies that have so far been conducted are limited in their findings, and many of them look at different measures and time periods of an infant's growth, therefore making it difficult to conclude the clear connection between sleep and development.
Mindell and Moore compiled a series of studies on sleep and development. A study by Pennestri et al. looked at a total of 369 infants, and found that there was no correlation between sleep and development. Another study by J.A.M. with 117 infants and toddlers found that there was not a strong correlation between sleep and emotional functioning. Fragmented sleep was negatively associated with mental development in a study in Israel with 50 infants. Additionally, a study in New Zealand found a positive relationship between efficient sleep and brain development. A study in Singapore of 159 infants found that wake after sleep onset was a strong indicator of poorer cognitive, language and motor domain scores. Finally, a study in China found no correlation between sleep duration and cognitive development but increased frequency of nighttime awakenings was correlated to poor cognition (Mindell & Moore, 2018).
Extensive research has been used to study infants have been done by Pennestri and other researchers. In a large study with 388 infants in a longitudinal study, the Bayley Scales of Infant Development was used to measure mental and psychomotor development and a self-administered questionnaire was used for the Mother. Other variables were assessed for including education, income, socioeconomic status. When infants were 6 and 12 months old, a questionnaire was administered to mothers asking about the sleep habits of the newborn during the previous 2 weeks. They were asked: During the night, how many consecutive hours does your child sleep without waking up? Mental and psychomotor development measurements were taken at 6, 12, and 36 months of age, maternal mood assessed at 6, 12 and 36 months of age, feeding method assessed at 6 and 12 months of age, and they assessed connection between sleeping throughout the night, and different forms of development, mental and psychomotor. Around 62 percent of mothers reported that their child got 6 or more hours of uninterrupted sleep, 38 percent reported that their child got less than 6 hours of uninterrupted sleep. Interestingly, the proportion of those who did not sleep through the night had a greater percentage of children that were breastfeed. At 6 months of age, sleeping through the night or not was not correlated with mental development or psychomotor development, 57 percent of infants did not sleep the whole night at 6 months of age, 43 percent of infants did not sleep the whole night at 12 months of age and girls were more likely to sleep the whole night. There was no association found between sleeping the whole night and different forms of development, no association between maternal mood and sleeping through the night, but an association found between breastfeeding and not sleeping (Pennestri et al., 2020).
In looking at how sleeping after learning affects declarative memory consolidation, researchers studied how the nap condition impacted declarative memory (Seehagen, Konrad, Herbert, and Schneider, 2015). They hypothesized that if sleep facilitates memory consolidation, then the infants that took a nap would better retain the information. Experiment one consisted of 60 6- month year old and 60 12- month year old healthy infants. The final sample for experiment two was 48 6 month old and 48 12 month old healthy infants. Stimuli included 4 hand puppets, two rabbit and two mice, mitten and bell. Antiwatches for sleep-wake patterns in infants. Activity was recorded for each minute that the watch was on. Caregivers also kept track of the sleep of the infant. Infants assigned to nap, no nap or baseline condition. For experiment 1 demonstration session: 1. experimenter took off the mitten from the puppet, 2. shook the mitten three times, 3. sounded the bell, and the mitten was then replaced. The younger infants received a total of six demonstrations of this while the 12 month year old received half as many demonstrations. In the test session, infants were given 90 seconds to copy the actions and a software known as INTERACT was used to capture whether the three target actions were completed; a frame by frame analysis was done. In Experiment 1, memory was assessed after a 4 hour delay. In Experiment 2, memory was assessed after a 24 hour delay. They discovered a causal role of sleep for declarative memory consolidation. If a nap was taken within 4 hours of learning, there was high retention of the actions, with similar results 4 and 24 hours after (Seehagen, Konrad, Herbert, and Schneider, 2015).
These results emphasize the importance of sleeping after learning: protection against the interference of new information. Taking the data from several research studies indicates that the question is still left unanswered. However, it is believed that sleep does play an important role in development and memory consolidation.
About the Author
Marina Andrawis is a senior at Harvard College concentrating in Neuroscience.
References
Mindell, J. A., & Moore, M. (2018). Does sleep Matter? Impact on development and functioning in infants. Pediatrics,142(6). doi:10.1542/peds.2018-2589
Pennestri, M., Laganière, C., Bouvette-Turcot, A., Pokhvisneva, I., Steiner, M., Meaney, M. J., & Gaudreau, H. (2018). Uninterrupted infant sleep, development, and maternal mood. Pediatrics, 142(6). doi:10.1542/peds.2017-4330
Seehagen, S., Konrad, C., Herbert, J. S., & Schneider, S. (2015). Timely sleep facilitates declarative memory consolidation in infants. Proceedings of the National Academy of Sciences, 112(5), 1625-1629. doi:10.1073/pnas.1414000112
Mindell and Moore compiled a series of studies on sleep and development. A study by Pennestri et al. looked at a total of 369 infants, and found that there was no correlation between sleep and development. Another study by J.A.M. with 117 infants and toddlers found that there was not a strong correlation between sleep and emotional functioning. Fragmented sleep was negatively associated with mental development in a study in Israel with 50 infants. Additionally, a study in New Zealand found a positive relationship between efficient sleep and brain development. A study in Singapore of 159 infants found that wake after sleep onset was a strong indicator of poorer cognitive, language and motor domain scores. Finally, a study in China found no correlation between sleep duration and cognitive development but increased frequency of nighttime awakenings was correlated to poor cognition (Mindell & Moore, 2018).
Extensive research has been used to study infants have been done by Pennestri and other researchers. In a large study with 388 infants in a longitudinal study, the Bayley Scales of Infant Development was used to measure mental and psychomotor development and a self-administered questionnaire was used for the Mother. Other variables were assessed for including education, income, socioeconomic status. When infants were 6 and 12 months old, a questionnaire was administered to mothers asking about the sleep habits of the newborn during the previous 2 weeks. They were asked: During the night, how many consecutive hours does your child sleep without waking up? Mental and psychomotor development measurements were taken at 6, 12, and 36 months of age, maternal mood assessed at 6, 12 and 36 months of age, feeding method assessed at 6 and 12 months of age, and they assessed connection between sleeping throughout the night, and different forms of development, mental and psychomotor. Around 62 percent of mothers reported that their child got 6 or more hours of uninterrupted sleep, 38 percent reported that their child got less than 6 hours of uninterrupted sleep. Interestingly, the proportion of those who did not sleep through the night had a greater percentage of children that were breastfeed. At 6 months of age, sleeping through the night or not was not correlated with mental development or psychomotor development, 57 percent of infants did not sleep the whole night at 6 months of age, 43 percent of infants did not sleep the whole night at 12 months of age and girls were more likely to sleep the whole night. There was no association found between sleeping the whole night and different forms of development, no association between maternal mood and sleeping through the night, but an association found between breastfeeding and not sleeping (Pennestri et al., 2020).
In looking at how sleeping after learning affects declarative memory consolidation, researchers studied how the nap condition impacted declarative memory (Seehagen, Konrad, Herbert, and Schneider, 2015). They hypothesized that if sleep facilitates memory consolidation, then the infants that took a nap would better retain the information. Experiment one consisted of 60 6- month year old and 60 12- month year old healthy infants. The final sample for experiment two was 48 6 month old and 48 12 month old healthy infants. Stimuli included 4 hand puppets, two rabbit and two mice, mitten and bell. Antiwatches for sleep-wake patterns in infants. Activity was recorded for each minute that the watch was on. Caregivers also kept track of the sleep of the infant. Infants assigned to nap, no nap or baseline condition. For experiment 1 demonstration session: 1. experimenter took off the mitten from the puppet, 2. shook the mitten three times, 3. sounded the bell, and the mitten was then replaced. The younger infants received a total of six demonstrations of this while the 12 month year old received half as many demonstrations. In the test session, infants were given 90 seconds to copy the actions and a software known as INTERACT was used to capture whether the three target actions were completed; a frame by frame analysis was done. In Experiment 1, memory was assessed after a 4 hour delay. In Experiment 2, memory was assessed after a 24 hour delay. They discovered a causal role of sleep for declarative memory consolidation. If a nap was taken within 4 hours of learning, there was high retention of the actions, with similar results 4 and 24 hours after (Seehagen, Konrad, Herbert, and Schneider, 2015).
These results emphasize the importance of sleeping after learning: protection against the interference of new information. Taking the data from several research studies indicates that the question is still left unanswered. However, it is believed that sleep does play an important role in development and memory consolidation.
About the Author
Marina Andrawis is a senior at Harvard College concentrating in Neuroscience.
References
Mindell, J. A., & Moore, M. (2018). Does sleep Matter? Impact on development and functioning in infants. Pediatrics,142(6). doi:10.1542/peds.2018-2589
Pennestri, M., Laganière, C., Bouvette-Turcot, A., Pokhvisneva, I., Steiner, M., Meaney, M. J., & Gaudreau, H. (2018). Uninterrupted infant sleep, development, and maternal mood. Pediatrics, 142(6). doi:10.1542/peds.2017-4330
Seehagen, S., Konrad, C., Herbert, J. S., & Schneider, S. (2015). Timely sleep facilitates declarative memory consolidation in infants. Proceedings of the National Academy of Sciences, 112(5), 1625-1629. doi:10.1073/pnas.1414000112