Low muscle tone and how it affects children with autism

Explaining low muscle tone:

Low muscle tone, also referred to as, hypotonia, is characterised by ‘loose’ or ‘floppy’ muscles. The muscles are not as firm or tight as developmentally expected. Children with low muscle tone normally have delayed motor skills, difficulty with motor coordination and weakness in the muscles to name a few.

Low muscle tone is often seen in children with autism. Signs of low muscle tone include, poor posture (when walking, shoulders might appear rounded and when sitting, children might have a slouched posture), easily fatigued, difficulty carrying out age appropriate fine- and gross motor tasks, poor body awareness, difficulty chewing food and speech production difficulties.

It is clear that low muscle tone can affect a person’s ability to be functional within everyday life. At the Star Academy, we address this in various ways to ensure that children be set up for success in the learning process. This article will further explain the effects of low muscle tone on speech development, specifically in children with autism. We will also look at some ways to work on combatting these effects to ensure improved speech development.

Effects of low muscle tone on speech production:

Children with autism often experience difficulty with speech production. Speech may sound unclear or unintelligible. More often than not, low muscle tone contributes to this. This can take the form of omitting final or initial consonants, cluster reduction and cluster deletion (omitting one or more consonant in a blend, for example, saying ‘nake’ or ‘ake’ instead of ‘snake’), prevocalic voicing (voicing a voiceless consonant in a word, example, saying ‘bink’ instead of ‘pink), producing anterior tongue sounds using the posterior part of the tongue (‘t’ might be produced at ‘k’) producing posterior tongue sounds using the anterior part of the tongue (‘g’ might be produced as ‘d’). Furthermore, low muscle tone will also affect the amount of control and mobility a child has in his/her jaw, lips and tongue. This will, of course, influence the intelligibility of speech output. Children with low muscle tone might struggle to adequately round or retract his/her lips which influences the way they produce certain sounds and words, such as ‘ee’ and ‘oo’. Jaw movement will be less controlled, which influences the adequate use of the jaw in the production of sounds and words. When the tongue is affected, sounds such as ‘t’, ‘d’, ‘k’, ‘r’, etc. will be hard to produce.

These are just a few ways low muscle tone effects speech production, often seen in children with autism.

Addressing low muscle tone in children with autism:

As low muscle tone effects a child’s ability to learn and communicate, strategies to combat the effects, are included in to therapy programs at The Star Academy.
Strategies to work on low muscle tone generally consists of exercises used to increase muscle strength. The same approach is taken when addressing low muscle tone in the facial area. Some exercises that have proven effective, especially with children with autism, include exercises that target increasing strength in the jaw, lips and tongue. These exercises not only strengthen these oral motor structures, but also teach children with autism more control and mobility with regards to movement of these structures.

1. Massages:

Massages are administered to the child’s face. These massages create an increased awareness in the oral motor structures and activates these muscle groups.

2. Oral motor movements:

In therapy, instructors teach children to imitate oral motor movements such as sticking out the tongue, moving the tongue from side to side, moving the tongue up and down, protruding and retracting lips, opening and closing of the jaw. These are just some of the movements used to teach children with autism to move their articulators with more ease as well as to use the correct motor patterns to produce certain sounds, words and phrases.


PROMPT is the use of tactile-kinaesthetic cues on the facial area to develop or restructure speech production output. This therapy technique teaches children how to move their articulators in order to produce certain sounds, words and phrases. This has proven to be a very effective tool in developing and restructuring speech in children with autism who also present with low muscle tone.

4. Tools:

Tools such as chewing toys, horns and whistles, straws, z-vibes, etc. are also used to work on the oral motor structures and address speech articulation difficulties that might have been caused by low muscle tone.