In working with little ones with Down Syndrome…I felt like I needed more information in reference to the movement of the tongue in infants during bottle feeding, breast-feeding, spoon-feeding, cup drinking and straw drinking. This post below is specific to your infant’s tongue movement during bottle/breast-feeding, cup drinking, spoon-feeding and chewing. I find the information very interesting…not only regarding children with Down Syndrome, any child with low tone..and children presenting with an interdental lisp or a vocalic R. And knowing all of this information just continues to support the need for therapeutic straw drinking..for children with Down Syndrome…children with low muscle tone…and children with an interdental lisp or the dreaded vocalic R. I hope you find it helpful too!
Development and movements of tongue:
1. Bottle/Breast Feeding:
During bottle feeding or breast-feeding the tongue does a back and forth motion in order to draw the liquid from the breast or bottle. There is 50% retraction of the tongue and 50% protrusion of the tongue. This is the normal movement of the tongue during bottle or breast-feeding. I was able to get specific information from Lori Overland (I like the specific details…so thank you once again Lori for getting back to me so quickly when I have a question!!). Okay so here are the more specifics: the motor skills for sucking from a bottle are slightly different from motor skills for breast-feeding. During bottle feeding there is more use of the buccinator and orbicularis oris muscles and less use of the masseter and mentalis muscles.
Okay…now some anatomy!
Its purpose is to pull back the angle of the mouth and to flatten the cheek area, which aids in holding the cheek to the teeth during chewing. It aids in whistling and smiling and in neonates it is used to suckle.
Orbicularis Oris Muscle-
This muscle closes the mouth and puckers the lips when it contracts.
The masseter muscle is the primary chewing muscle, and covers the sides of the jaw just behind the cheek.
The Mentalis is a paired central muscle of the lower lip, situated at the tip of the chin. It raises and pushes up the lower lip, causing wrinkling of the chin, as in doubt or displeasure. It is sometimes referred to as the “pouting muscle.”
Lori also stated that it was thought that milk was released because of a wave-like movement of the tongue. However, more recent ultrasound studies revealed that is not true. Milk flows due to negative pressure created when the back of the tongue and jaw drop during sucking. If a baby is unable to breast feed…it is prefered that the Platex nurser is used for a number of reasons: shape, size, seal, and the option of using pressure on the bag to help the infant draw the liquid.
All of that being said…it is especially important to me to understand actually what the tongue is doing during eating…so I can then help…far in advance with speech production.
Okay…back to the tongue and what it is doing….
Now around three months of age…the hyoid bone…which was up higher in the throat prior to the three-month mark…is now in a different position… At 3 months the tongue base pulls back into the laryngeal cavity. During feeding you will see less of your little one’s tongue in between her lips…she still is presenting with 50% retraction and 50% protrusion.
2. Spoon feeding and cup drinking:
When spoon-feeding and cup drinking is introduced your little one will anticipate either the spoon or the cup. This anticipation will promote 75% retraction of the tongue and 25% protrusion of the tongue…great because this is what we want…she will be developing the muscles of the tongue for the right amount of protrusion and retraction. So…spoon feeding and open cup drinking will help with this skill.
3. Finger feeding with foods such as Cheerios:
When a little baby first starts finger feeding with cheerios…she is learning the very first level of tongue retraction…which is…as she is chewing on the cheerio..and her tongue is retracting to the 75% position and stabilized…her tongue will/should naturally go from midline to the right and midline to the left. When she puts the cheerio in her mouth on the right side (for example)…the cheerio will stimulate the chew and the tongue will then move to the place of stimulation…great! The tongue is lateralizing to either the right side or the left side from midline.
So during chewing…when the cheerio is in her mouth…she will retract her tongue to the 75% position and stabilize it their..Great again!!…and then lateralize to the right or left from midline…another important skill. You can see why feeding is a prerequisite for speaking…everything your tongue is doing during eating…will help her with speech production. Awesome! With the 75% retraction and stability of the tongue the tongue will not only go from midline to the right or left…it will also then go across midline.
4. Next….with 75% retraction and stability of the tongue…this will allow the tongue tip to elevate and depress. Another important skill for speech production. If you do not have 75% retraction with stability you will not see elevation and depression of the tongue….which is needed for speech production!!!
5. Finally….the sides of the tongue become so strong that you will see side spread of the tongue. That is the lateral margin spread of the tongue. This movement is needed for the production of the following sounds: SH, CH, J and the vocalic R.
All of this information I believe is very important in understanding what exactly is happening to children that have Down Syndrome or children with low muscle tone…specific to how their tongue is functioning with regard to strength and mobility. This is also important to the children we may see presenting with an interdental lisp, tongue thrust or the dreaded vocalic R. Knowing all of this information…helps me to better understand the necessity of following the straw hierarchy….as I said…I only have posted about one of them…but will do the 7 others as soon as I can.
I hope this was helpful..it was for me!!!