Orofacial Myofunctional Disorders
Orofacial Myofunctional Disorders (OMD) are abnormal movements or positioning of the tongue, lips, and jaw during speech or swallowing, or at rest. One type of OMD is tongue thrust, when the tongue rests too far forward in the mouth or moves too far forward during speech or swallowing. While it is normal for a baby's tongue to thrust forward while swallowing, this behavior should gradually go away as he grows up.
OMD may not affect speech at all, or it may cause some sounds to be said incorrectly. Tongue thrust most often affects production of s, z, sh, ch, and j, as well as sounds made with the tip of the tongue (t, d, n, l). In addition to speech and swallowing problems, OMD may cause significant issues with teeth alignment and jaw function.
There may be no single cause of OMD. When allergies, enlarged tonsils/adenoids, or other issues cause chronic mouth breathing, a child may develop abnormal mouth postures. Chronic bad oral habits (e.g., thumb sucking, pacifier use, or teeth clenching/grinding) and abnormalities like an overly large tongue or weak mouth muscles can also contribute to OMD. Some children may have genetic tendencies toward these and other factors.
Symptoms of OMD
- Chronic open-mouthed posture
- Tongue pushes against teeth or protrudes out of the mouth when swallowing
- Chewing food with lips open
- Tongue pushes between the teeth during speech
- Speech distortions, especially lisp (e.g., sock is pronounced thock)
- Front teeth that stick out
Assessing and Treating OMD
The speech-language pathologist (SLP) will examine the structures of the mouth and face at rest, and watch how they move during different chewing/swallowing and speech activities. A doctor may need to see the child to rule out airway blockages, and if there are effects on teeth, a dentist or orthodontist may evaluate as well.
The SLP's therapy goals will depend on the results of the evaluation, and will likely target several aspects of OMD. He may work to increase the child's awareness of the tongue, lips, and jaw position at rest and during speech and swallowing, and to improve muscle tone, strength, or coordination. Various exercises will be used to retrain patterns of muscle movement for articulation and/or swallowing. The SLP may also work on eliminating any negative behaviors that contribute to OMD (e.g., thumb sucking).