In today’s post, I will continue to discuss sensory processing by going into details about the 8 different sensory systems in our body as well as how to tell if baby is under or overstimulated (and related tips for sleep!)
First off, just a quick review on what is meant by sensory processing, which I discussed in more detail in my last post, which you can read here. Essentially, it is the way in which the body receives, interprets and responds to signals from its environment. One example is when you put your hand on a hot stove, the nerves in your fingers send a signal to your brain to remove your hand. In my last post, I also discussed the development of sensory processing in infants and related sleep tips for each stage.
A. Introduction to the different sensory systems in humans
Next, what are the 8 different sensory systems in humans? (Yes, there are actually 8 instead of the typical 5 we hear about!) With each sensory system, I will provide you with an interesting fact about each sense in babies.
1. Vision (Sight) ex. Newborn preferred to watch their own mother’s face in contrast to the face of a stranger (Bushnell et al 1989).
2. Auditory (Hearing) ex. Newborns showed preference for infant-directed speech, which includes speaking in a more musical way and with more emotional exaggerations. (Piazza et al, 2017).
3. Olfactory (Smell) ex. Newborns who were going through a painful procedure were soothed by the smell of their own mother’s breast milk (Nishitani et al 2009).
4. Gustatory (Taste) ex. Newborns whose nursing mothers drank carrot juice every day were more accepting of carrot-flavoured cereal at 5-6 months, showing how flavours newborns are exposed to can impact their preferences later (Menella et al, 2017).
5. Tactile (Touch) ex. Babies who received more physical contact from caregivers showed increased mental development in first 6 months of life (Goleman, 1998).
6. Vestibular (Movement) ex. Repetitive motions including swaying, rocking, and gently bouncing helps soothe babies (Karp, 2002) .
7. Proprioception (Body Position) ex. When infants are placed with back down in hammock sling, it snuggles infant in fetal position providing calming proprioceptive input, much like the mother’s womb (Tarver and Martin, 2013).
8. Interoception (Internal Sensations) ex. Infants show feeding cues when they are hungry such as fists moving to mouth or sucking on hands (Bonyata, 2018).
B. A little more detail about Vestibular, Proprioceptive and Interoceptive Sensory Systems
As these three systems are not often discussed as much, I wanted to go into a bit more detail about what exactly these senses are.
This system helps us know we are in space as well as whether we are stationary or moving along with the speed and direction at which we are moving. It obtains information from fluid fill canals located within the inner ear. It helps us move in a coordinated way including being able to open a door with the right amount of force or applying pressure to write properly with a pencil.
ii) Proprioceptive: This system helps us understand our body position in the environment, including where our body parts are and what they are doing. It obtains information from our muscles, tendons and ligaments. An example would be when child plays pin the tail on the donkey, they need to use their proprioceptive sense to try to determine where to place the tail since their eyes are closed.
iii) Interoceptive: This system helps us feel what is happening inside our body. It obtains information using nerve receptors all over our bodies which then send messages to our brain to help us determine how we feel. For example, if your stomach is empty, nerves in stomach send signals to the brain that let you know you are hungry.
C. What is meant by sensory threshold and a sensory diet?
Sensory threshold is the point at which you will feel and thus respond appropriately to a particular stimulus. These sensory thresholds may differ amongst children as well as for different types of sensory input. For example, one child may have a higher threshold for vestibular input, meaning they require more of this input to feel the stimulus whereas perhaps they have a lower threshold for olfactory input, meaning they are more sensitive to scents around them.
Along with this, there is another important concept to help your child best meet their sensory needs for the day which can help with sleep as well! This is called a sensory diet, which is basically ensuring we include a variety of sensory activities in the child’s day so that their bodies are getting the input they require.
D. Tips for helping find child's appropriate sensory diet
Similarly to how we want to tune into our child’s tired cues to figure out when they should sleep, we can also tune into our child’s level of stimulation throughout the day including before, during and after different activities to figure out what types of input they require in order to be functioning at their best. For example, you could take notes on how they react to different situations such as going to a loud, busy place versus staying at home. Another example is what level of vestibular movement are they seeking become they become overstimulated? I notice with my daughter she loves going on the swing but at a certain point, she wants to stop, so to me, this represents when she has reached her sensory threshold for vestibular input. If you notice at bedtime, your child still seems very restless and looking to move around, that may mean that they require more vestibular input throughout the day so you could look at trying to add in more.
E. Signs of Overstimulation/Understimulation in Babies and Toddlers
Similarly to tired signs, these signs can differ for each child, but here are some examples of overstimulation in babies and toddlers.
i. Signs of overstimulation in babies
-clenching fists, waving arms or kicking
-fussiness/turning their head away
ii. Signs of overstimulation in toddlers
-seem cranky, tired or upset
-crying but not able to explain why
-refusing to do simple things
-throwing themselves on the floor in tears or frustration
iii. Signs of understimulation in babies
-actively trying to get you to engage with them by making noises, crying, etc.
-if it is taking a very long time to get them to sleep, this is a potential sign they did not receive enough stimulation
-baby seems uninterested in engaging with things around them and appears zoned out
iv. Signs of understimulation in toddlers
-extra fussy and complaining
-refusing to talk
-may be less cooperative and refuse to do things
-actively seeking out the input they are looking for by jumping, bouncing, running, etc.
F. How do you apply this information to helping your child sleep?
By ensuring child gets the appropriate sensory diet for their needs throughout the day, this should help them build up adequate sleep pressure to fall asleep relatively easily at nap/bedtime
Tuning into what calms them down will help you determine an appropriate nap/bedtime routine; note: their sensory needs could change as they get older so you may need to tweak it
If you figure out the signs of your child being over vs. understimulated, you can adapt the activities you are doing which should help with child’s quality of sleep
G. Ideas for bedtime calming activities related to each sensory system
-dimming lights in play areas an hour before bedtime (affects our brains ability to know it’s bedtime)
-could go for short walk outside to show your body it’s dark outside
-reducing/eliminating use of blue light (from television, cell phones) before nap or bedtime (could use blue light glasses that block blue light) for at least two hours before bed
-can use blackout blinds or put dark sheet over window to help signal to baby it is time to sleep
-could use visual schedule or chart to show them the routine to help them understand it’s bedtime
-are there too many visual distractions in the room (too many toys, are decorations too stimulating such as mobiles or bright decals) à it’s ok for bedroom to be simple
-make sure bedding is right texture and warmth for child’s sensory needs, especially if they are very sensitive to tactile input
-could look at texture as well of pyjamas (for example, breathable cotton is recommended)
-doing skin to skin helps regulate baby’s temperature before bed
-incorporating warm bath as part of bedtime routine
-could use white noise machine to block external noises keeping them from sleeping
-could play calming music before bedtime and/or at bedtime
-using a calm, slower voice
-avoid rotary, high intensity vestibular input as this is alerting to the nervous system as opposed to calming (ex. spinning, jumping on trampoline, swinging really high)
-could use calming types of linear vestibular input such as rocking in a rocking chair, swaying, bouncing gently on exercise ball
-getting some “heavy work” in before bed such as by using push or pull toys, crawling, lots of floor play, downward dog yoga poses
-sucking on pacifier
-breastfeeding or bottle feeding
-sucking through a straw
-using calming scents such as lavender bubble bath
-could give baby blanket that parent has slept with or spill breast milk on blanket to help them still feel connected at bedtime
Note: if child seems to be struggling with dealing with sensory input and it is impacting their daily functioning, you could speak to a pediatric occupational therapist for strategies to help them.
Overall, tuning into your child's sensory preferences is key in terms of helping them receive adequate stimulation throughout the day in order to help them sleep well for naps and bedtimes. Let me know in the comments below...what have you noticed about your child's sensory preferences at sleep times?
Baby-Led Sleep Certification: https://islagrace.ca/sleep-coach-certification/
Bonyata, K. (2018, January 15). Hunger cues - when do I feed baby? • kellymom.com. KellyMom.com. Retrieved March 16, 2022, from https://kellymom.com/bf/normal/hunger-cues/
Bushnell IWR, Sai F, Mullin JT. (1989(. Neonatal recognition of the mother’s face. British Journal of Developmental Psychology 7(1): 3–15.
Goleman, D. (1998). Working with Emotional Intelligence. London: Bloomsbury.
Harkla Sensory Diet Digital Course : https://harkla.co/products/sensory-diet-course
Karp, H. (2002). The happiest baby on the block: The new way to calm crying and your newborn baby sleep longer. Penguin Random House LLC.
Mennella, J. A., Daniels, L. M., & Reiter, A. R. (2017). Learning to like vegetables during breastfeeding: a randomized clinical trial of lactating mothers and infants. The American journal of clinical nutrition, 106(1), 67–76. https://doi.org/10.3945/ajcn.116.143982
Nishitani, S., Miyamura, T., Tagawa, M., Sumi, M., Takase, R., Doi, H., Moriuchi, H., & Shinohara, K. (2009). The calming effect of a maternal breast milk odor on the human newborn infant. Neuroscience research, 63(1), 66–71. https://doi.org/10.1016/j.neures.2008.10.007
Piazza, E. A., Iordan, M. C., & Lew-Williams, C. (2017). Mothers Consistently Alter Their Unique Vocal Fingerprints When Communicating with Infants. Current biology : CB, 27(20), 3162–3167.e3. https://doi.org/10.1016/j.cub.2017.08.074
Tarver, P. & Martin, J. (2013) Advance my baby: The ultimate secrets of healthy development for your baby—birth to 3 years. AuthorHouse.