20Q: Ankyloglossia - Myths and Evidence Regarding Its Effects on Function

From the Desk of Ann Kummer

One of the most controversial issues among speech-language pathologists (SLPs), otolaryngologists, and pediatricians is the effect of ankyloglossia (also called “tongue-tie”) on infant feeding and speech production. Many believe that ankyloglossia can affect speech production, despite the lack of evidence. Therefore, I have written this month's 20Q to provide guidance regarding the diagnosis of ankyloglossia and a summary of current research regarding its potential effects on function.

Now…read on, learn, and enjoy!

 

Ann W. Kummer, PhD, CCC-SLP, FASHA, 2017 ASHA Honors
Contributing Editor 

 

Browse the complete collection of 20Q with Ann Kummer CEU articles at www.speechpathology.com/20Q

20Q: Ankyloglossia - Myths and Evidence Regarding Its Effects on Function

Learning Outcomes

After this course, readers will be able to: 

• Discuss the characteristics and prevalence of ankyloglossia; and how it differs from posterior tongue-tie.
• Describe how ankyloglossia is typically diagnosed.
• Summarize current evidence regarding the effect of ankyloglossia on feeding & speech.

Introduction

I have had first-hand experience of the harm that can be done when there is a lack of current knowledge on ankyloglossia. I have served as an expert witness in two malpractice cases that involved a lack of knowledge. They were as follows:

Case 1. A school-based SLP told the parents of a five-year old that the cause of their child’s speech disorder was ankyloglossia and therefore, she recommended a frenulotomy. This was done but did not improve the child’s speech. The SLP then told the parents that the lack of change after the surgery was because the pediatrician did not refer the child for a frenulotomy when the child was younger. As a result, the parents sued the pediatrician for malpractice.

In my review of the clinical reports and in my postoperative evaluation, I found that the child was fronting on sibilants and velars. Of course, fronting would not be caused (and may not even be possible) if there was restricted mobility of the front of the tongue. Fortunately, after my report, the lawsuit was dropped.

Case 2. An SLP, who owned a private practice, was treating a 7-year-old boy for a severe speech disorder and language delay. At one point, the mother noticed that her son’s tongue “looked different” than her daughter’s tongue. She went to an ENT and told him that her son had severe speech problems due to tongue-tie. Based on the mother’s opinion, the ENT did a frenotomy, which resulted in no improvement in speech. The mom sued the SLP for not diagnosing ankyloglossia in the first evaluation.

A review of pictures and videos taken prior to the frenotomy showed normal elevation and protrusion of the tongue, and no evidence of ankyloglossia. Other records showed that this child had a global developmental disorder that included apraxia. Unfortunately, this case went on for years and resulted in a 5-day jury trial. The SLP mostly won, but the jury returned a judgment against her for $10,000 because her evaluation said that she did a “cursory” oral examination. In their minds, this was incomplete. The biggest damage, however, was that this lawsuit severely affected the SLP’s practice and mental health.

As experts in the evaluation and treatment of infant feeding problems and speech sound disorders, SLPs should be knowledge leaders regarding the potential effects of ankyloglossia on feeding, and the lack of evidence of its effect on speech (Kummer, 2023).

1. What exactly is ankyloglossia?

Ankyloglossia is a very common congenital condition that is usually identified at birth. It’s characterized by an anterior attachment of the lingual frenulum to the tongue tip. In some cases, the lingual frenulum is also short or thickened. Ankyloglossia can result in partial fusion or, in rare cases, total fusion of the tip of the tongue to the floor of the mouth. As a result, it causes reduced anterior tongue mobility (Francis, Chinnadurai et al., 2015; Kummer, 2005; Messner et al., 2020).  Because it has the potential to restrict the elevation and protrusion of the tongue, it is commonly referred to as “tongue-tie.”

2. What is the lingual frenulum, and does it have a purpose?

A frenulum is a narrow band of mucosa and elastic fibers that connect a moveable body part to a fixed structure. The purpose of a frenulum is to stabilize and check undue movement of the moveable structure.

There are two types of frenula in the oral cavity, the labial frenula (plural) and the lingual frenulum. The maxillary labial frenulum connects the middle of the upper lip to the mucosa of the anterior maxilla. The mandibular labial frenulum connects the middle of the lower lip to the mucosa of the mandible. Although uncommon, extra lateral labial frenula can occur, particularly with certain syndromes. Finally, the lingual frenulum runs vertically from the floor of the mouth to the undersurface of the tongue to connect the mid part of the tongue to the mandible.

3. What is the difference between the lingual frenulum and the lingual frenum. Are they the same?

In general, a frenulum refers to a small frenum. Although both terms are used for the band of tissue under the tongue, the term lingual frenulum is most commonly used.

4. You said that ankyloglossia (AKA tongue-tie) is characterized by an anterior attachment of the lingual frenulum to the tongue tip. Then, what is a posterior tongue-tie?

That is a very good question! In recent years, posterior tongue-tie has been described as a new diagnosis by lactation specialists. It has been suggested that when the frenulum is short, even when it’s in a normal posterior position, it can affect breast feeding. As you can imagine, posterior tongue-tie would be inherently difficult to diagnose because of the normal posterior position of the frenulum and the normal adhesion of the tongue to the mandible (Hong, et al., 2010). Also, there have been no definitive studies proving that a shortened posterior attachment of the frenulum to the tongue causes impaired lingual movement or any negative effect on feeding. As such, many professionals, including ENTs and SLPs, feel that posterior tongue-tie does not exist as an anatomical anomaly and therefore, the term should be abandoned (Messner et al., 2020).

5. Is there a standardized measurement of the lingual frenulum?

Although there have been attempts to create a standardized clinical assessment measurement, this does not currently exist (Kotlow, 1999; Segal, 2007; Wang et al., 2021). This is mostly because of normal variation of human structures. Just as there are significant differences in normal facial traits among humans, there are also significant differences in intraoral structures. These differences include variations in the length and thickness of the frenulum, and at the points of attachment on the ventral surface of the tongue and floor of the mouth. In addition, ankyloglossia is a continuous variation trait. Unlike threshold traits, where the trait is either present or absent (e.g., blue eyes, cleft palate, and aural atresia), continuous variation traits are those that are on a continuum (e.g., height, weight, intelligence, and blood pressure). As such, the abnormality of a continuous variation trait is not easily distinguished from normal variation because the boundary between normal and abnormal is arbitrary.

6. So, if there is no objective measurement of the lingual frenulum, how is ankyloglossia diagnosed?

In addition to visual inspection of the structures, ankyloglossia is diagnosed by observation of functional limitations of lingual movement (Bargale et al., 2014; Fleiss et al., 1990; Griffiths, 2004; Kotlow, 1999; Kummer, 2005; Messner et al., 2020). The following characteristics are typical of ankyloglossia:

• An attachment of the lingual frenulum on or very near to the tongue tip.
• A notch in the midline of the tongue during protrusion, resulting in the appearance of a heart-shaped edge.

• The inability to touch the alveolar ridge or lick the upper lip with the tongue tip when the mouth is slightly open.
• The inability to protrude the tongue past the edge of the mandibular incisors or past lower gingiva in edentulous children.

7. Does ankyloglossia need to be diagnosed by a medical or dental professional, or can SLPs diagnose it?

SLPs are uniquely qualified to diagnose ankyloglossia based on their knowledge of oral structures and of the causes of feeding and speech disorders. Other professionals may diagnose the condition but may not be able to determine if it is affecting function.

8. It seems like a lot of children are now being diagnosed with ankyloglossia. What is the actual prevalence of this condition?

Unfortunately, the prevalence of ankyloglossia is unclear, partly because the diagnosis is somewhat subjective. In addition, it is often made by professionals who use different diagnostic criteria and/or can’t determine if the frenulum negatively affects function. As such, estimates of prevalence range from .2% to well over 10% (Ballard, Auer, & Khoury, 2002; Bargale, 2014; Lisonek et al., 2017; Messner et al., 2000; Ricke et al., 2005; Segal et al. 2007).

Over the last few decades, the number of newborns diagnosed with ankyloglossia in developed countries has increased significantly. For example, Walsh et al. (2017) reported a fourfold increase in the diagnosis of ankyloglossia in newborns in the United States between 2003 and 2012. They also reported a fivefold increase in the number of frenotomies (surgery to release the frenulum) performed during the same period. Similar trends have been reported in other developed countries (Bin-Nun et al., 2017; Dixon et al., 2018; Lisonek et al., 2017).

9. I’m wondering what would happen if an infant with ankyloglossia doesn’t undergo a frenotomy? Does the lingual frenulum get better with age and growth?

At this time, we don’t have good data to answer this question because the natural history of ankyloglossia has not been studied extensively. However, its severity and functional effects are thought to decrease over time, even when ankyloglossia is significant at birth. This may be because during the first 3 years of life, the oral cavity changes in size, structure, and function, while the face reaches almost 65% of its adult size (Ranly, 1998). As the primary teeth begin to erupt, the alveolar ridges grow in height and the tongue grows and narrows at the tip. Simultaneously, the lingual frenulum recedes, stretches, and may even rupture. Therefore, as the child grows, the initial restrictions on lingual movement due to ankyloglossia may be diminished or even eliminated, although further research is needed to confirm this.

10. I know there are differences of opinion regarding the effects of ankyloglossia on neonatal feeding. What is the consensus on this issue?

You are very right. The association between ankyloglossia and breastfeeding has been debated among medical professionals for decades (Messner et al, 2020; Rowan-Legg, 2011; Ruffoli et al., 2005). In a survey of relevant practitioners, more than half of lactation consultants (69%) felt that ankyloglossia frequently causes breastfeeding problems. They argue that infants with restrictive ankyloglossia have difficulty breastfeeding because they cannot extend their tongues over their lower gum line to form a proper seal against the nipple. Consequently, they are unable to sufficiently latch onto the breast and keep it within their mouth (Brookes & Bowley, 2014; Francis, Krishnaswami et al., 2015). More recently, lactation specialists believe that posterior tongue-tie can also cause neonatal feeding disorders (Ghaheri et al., 2022; O’Callahan et al., 2013; Pransky et al., 2015), while others don’t agree that posterior tongue-tie even exists as an anomaly (Messner et al., 2020; Talmor & Caloway, 2022). In contrast, a minority of physicians (10% of pediatricians and 30% of otolaryngologists) agreed that ankyloglossia commonly affects neonatal feeding (Messner & Lalakea, 2000). The controversy regarding the effect of ankyloglossia on infant feeding could be due, at least in part, to the fact that not all affected infants experience breastfeeding difficulty.

11. Surely, there have been studies that have looked at the effect of ankyloglossia on infant feeding. What have these studies found?

One study estimated that only 25% of infants with ankyloglossia have difficulty latching on to the nipple during breastfeeding (Messner et al., 2000; Flinck et al., 1994). This means that most infants with ankyloglossia can breastfeed without surgical intervention (Emond et al., 2014; Power & Murphy, 2015; Caloway et al., 2019). In addition, affected infants can be bottle-fed without difficulty (Ricke et al., 2005).

Nipple pain has been reported by some breastfeeding mothers of infants with ankyloglossia. A few studies have shown that mothers whose infants underwent a frenotomy reported less pain with breastfeeding (Ballard et al., 2002; Buryk et al., 2011; Dollberg et al., 2006; Riskin et al., 2014). Using ultrasound to evaluate post-frenotomy feeding, Geddes et al. (2008) noted less nipple compression during breastfeeding and hypothesized that this could explain why mothers reported a reduction in nipple pain.

Despite these reports, the overall evidence for an association between ankyloglossia and breastfeeding difficulties remains equivocal. In 2015, a systematic review sponsored by the Agency for Healthcare Research and Quality (AHRQ) concluded that a “small body of evidence suggests that frenotomy may be associated with mother-reported improvements in breastfeeding, and potentially in nipple pain, but with small, short-term studies with inconsistent methodology, the strength of the evidence is low to insufficient” (Francis, Krishnaswami et al., 2015).

In 2017, a Cochrane review of the effects of frenotomy on newborns with ankyloglossia found that breastfeeding mothers reported less nipple pain following frenotomy. However, they did not find a consistent positive effect on infants’ breastfeeding abilities (O’Shea et al., 2017). In 2019, another systematic review concluded that infants with ankyloglossia showed varying degrees of difficulty breastfeeding (Hill, 2019).

In 2020, a panel of pediatric otolaryngologists recruited by the American Academy of Otolaryngology—Head and Neck Surgery (AAO-HNS) created a clinical consensus statement (CCS) based on current evidence. They concluded that anterior ankyloglossia is a potential contributor to infant feeding difficulties and maternal pain; however, these symptoms can be present due to other etiologies (Messner et al., 2020). Finally, a meta-analysis to identify the benefit of frenotomy in reducing maternal pain during breastfeeding found evidence of some improvements following frenotomy, although individual results varied (Shekher et al., 2021).

Finally, in 2021, the Academy of Breastfeeding Medicine published a position statement. In the statement they concluded that tongue-tie can affect neonatal feeding in some cases. They stated that if conservative measures of treatment are ineffective, then frenotomy can be considered to increase the efficiency of breastfeeding, decrease nipple discomfort, prevent the premature cessation of breastfeeding (LeFort, et al., 2021).

12. I know there are differences of opinion regarding the effects of ankyloglossia on speech as well. What is the professional consensus on the possible relationship between ankyloglossia and speech disorders?

As we all know, there is a common belief among the public that tongue-ties are a cause of speech disorders (which makes sense on the surface). However, relevant professionals have differing opinions regarding this assumption. This was clearly illustrated in another survey that found that 60% of ENTs, 50% of SLPs, and 23% of pediatricians believed that ankyloglossia is likely to cause speech problems (Messner & Lalakea, 2000). It has been more than 20 years since this survey was published, and there is still no consensus on this issue within each profession or between the professions.

13. Has there been any research done on the effects of ankyloglossia on speech? If so, what are the findings of this research?

Yes. In the last few decades, there have been a few studies that have reported improvement in speech after frenotomy (Messner & Lalakea, 2002; Walls et al., 2014). However, various reviewers have judged these studies to be of poor quality (Francis, Chinnadurai et al., 2015; Messner et al., 2020) and, therefore, not conclusive.

In contrast, several recent high-quality systematic reviews did not find an association between ankyloglossia and speech disorders. For example, in 2013, a systematic review of studies published between 1966 and 2012 found “no significant data to suggest a causative association between ankyloglossia and speech articulation problems” (Webb, et al., 2013). In 2015, the Agency for Healthcare Research and Quality (AHRQ) published another systematic review in which they concluded that there is “insufficient evidence that surgical intervention for ankyloglossia improves speech” (Francis, Chinnadurai et al., 2015). In 2020, the AAO-HNS consensus group concluded that “ankyloglossia does not typically affect speech” (Messner et al., 2020). In 2021, a systematic review reported “no strong evidence to support that ankyloglossia caused speech problems” (Wang et al., 2022). Finally, a prospective study on the effect of tongue-tie release on speech concluded that most of the children referred for treatment due to the presence of ankyloglossia had only age-appropriate speech errors (Melong et al., 2021). These authors also reported that ankyloglossia was not associated with speech errors related to insufficient tongue mobility. They concluded that there was no benefit of tongue-tie release to improve speech or intelligibility.

14. It seems that ankyloglossia would affect speech in that there are so many lingual-alveolar and lingual-dental sounds. Why is it that speech is typically not affected?

Excellent question! To answer this question, it may be helpful to review how tongue-tip phonemes (e.g., lingual-alveolar and interdental sounds) are produced. The speech sound that requires the greatest amount of lingual elevation is the /l/ sound. This sound is produced with the mandible elevated so that the tongue tip is just under the alveolar ridge. The tongue tip is slightly retroflexed as it articulates against the alveolar ridge.

However, if this is not possible because of tongue tip restriction, this sound can be produced with the tongue tip down, which causes the dorsum of the tongue to articulate against the alveolar ridge. The acoustic product is the same for both placements. In fact, some typical speakers naturally produce /l/ sounds in this manner.

The other lingual-alveolar phonemes (/t, d, n, s, z/) are easier to produce because they do not require retroflexion of the tongue tip. However, if the slight elevation needed for these sounds is not possible, they also can also be produced with the tongue tip down and the dorsum of the tongue against or just under the alveolar ridge (Kummer, 2005; Kummer, 2010; Kummer, 2020, Melong et al., 2021). Interdental sounds (/Θ, ð/) require maximum protrusion of the tongue. These sounds are typically produced with the tip of the tongue behind the maxillary incisors. However, as with lingual-alveolar sounds, interdental sounds can be produced with the tongue tip down (Kummer, 2005; Kummer, 2010; Kummer, 2020).

Some professionals believe that the /r/ and /ɚ/ sounds are produced with the tongue tip, which is either elevated (retroflexed) or depressed (bunched). Therefore, it could be thought that ankyloglossia may affect production of /r/. In reality, the placement of the tongue tip is not relevant to production of these sounds because they are produced at the back of the tongue and not at the front. For production of final /ɚ/, the back of the tongue is elevated on both sides and articulates on the gum ridge just above the molars. This creates a groove in the middle of the tongue. As sound travels through this groove, resonance is modified, thus creating the sound of /ɚ/, which is a vowel. To create the medial and initial /r/, the final /ɚ/ is produced followed by an /ɑ/ sound as the back of the tongue drops (Kummer, 2020). Because these sounds are produced by the back of the tongue, they cannot be affected by ankyloglossia.

It should be concluded that all speech sounds in English can be produced with minimal tongue tip movement; therefore, ankyloglossia is unlikely to affect speech (Lalakea & Messner, 2003; Kummer, 2005; Melong et al., 2021). Children with severe limitations in tongue tip movement can easily compensate for decreased lingual mobility, which results in normal speech (Melong, et al., 2021). However, ankyloglossia may affect the production of the lingual trill (rolled /r/) used in Spanish and other languages worldwide because this sound requires vibration of the tip of the tongue. Research is needed to support this hypothesis.

15. I’m curious. Does ankyloglossia impair French kissing? (Just asking for a friend.)

As you know, a French kiss is performed with the lips apart and the tongues of both individuals touching. Therefore, some individuals with ankyloglossia may have difficulty with French kissing (Walsh & McKenna Benoit, 2019). However, with both mouths combined, the tongue does not need to be extended very far.

16. Are there any other potential concerns with ankyloglossia?

Yes. Dental professionals have thought that if the lingual frenulum is attached to the gingival ridge behind and between the central incisors of the lower mandible, it can potentially pull the gingiva away from the teeth, causing gingival recession and a mandibular diastema (separation of the mandibular central incisors) (Ewart, 1990; Suter & Bornstein, 2009; Salah, 2013). However, a review of the MEDLINE and Cochrane Library databases in 2009 revealed no clear evidence of gingival recession due to ankyloglossia (Suter & Bornstein, 2009). Older children and adults with lingual restrictions may have difficulty clearing food from their oral sulci and molars when eating. Over time, rotting food in the mouth can lead to periodontal disease, tooth decay, and halitosis, if oral hygiene is not adequately maintained.

There may also be a concern about aesthetics. Ankyloglossia causes the tongue to appear to be abnormal during protrusion. This could potentially lead to the child being teased or bullied. The possible effect of this abnormal appearance on the psychosocial health of affected children has not been studied, however.

17. You have mentioned frenotomy as the surgical procedure for ankyloglossia. Would you please describe how that is done?

Sure. A frenotomy is a simple procedure that involves cutting and releasing the frenulum. Because there are limited nerve endings and only a few blood vessels in this tissue, there is little pain and minimal bleeding. This procedure is most often performed on infants with breastfeeding difficulties.

There are other surgical procedures for ankyloglossia with minor variations. A frenectomy (also called frenulectomy) involves complete removal of the frenulum tissue up to its attachment to the underlying bone. This procedure is most likely performed on older children whose frenulum may be pulling on the mandibular gingiva. Finally, frenuloplasty is performed by incising the frenulum and then surgically repositioning it to a more favorable location on the ventral surface of the tongue. The surgeon may opt to do a “Z-plasty” procedure, which is designed to minimize the risk of scar formation. Scars typically contract during healing, and this can cause shortening of the frenulum and further restriction of movement over time. The type of surgical procedure chosen depends on the patient’s age, the severity of the condition, and the provider’s preference.

18. What type of professional typically performs these surgical procedures?

A simple frenotomy can be done by both medical and dental professionals. A Z-plasty is more complicated and is likely to be done by an oral surgeon or plastic surgeon.  

19. What are the risks and potential complications of frenulotomy?

The risks of frenulum surgery are usually minimal and may include temporary pain, minor bleeding, or infection. Rare complications of this procedure include hemorrhage, injury to salivary structures, oral aversion, and scarring. When scarring occurs, adhesions can form between the tongue and floor of the mouth, again limiting tongue mobility. In addition, I saw a few children in my practice who reported difficulty controlling tongue movement with speech immediately after surgery. Fortunately, this feeling resolved on its own.

Frenotomy is contraindicated for infants with upper airway obstruction, retrognathia, micrognathia, hypotonia, or neuromuscular disorders. Patients with Pierre Robin sequence are particularly at risk. This is because release of the frenulum may result in the tongue falling backward, causing the development or exacerbation of glossoptosis (an abnormal retraction of the tongue). This is a potentially serious complication because it can lead to upper airway obstruction and swallowing difficulties (Genther et al., 2015; Walsh & Kelly, 1995).

Finally, there is the danger of disappointment that can result when parents believe that the surgery will correct a feeding or speech problem, which is due to another cause.

20. So, what are some major takeaways? I would like to pass them along to parents who are concerned that their child may have ankyloglossia and to other professionals who may be uninformed about ankyloglossia.

• First, it’s important to recognize that ankyloglossia is a common congenital condition that may improve with time.
• True ankyloglossia is characterized by a lingual frenulum that connects to the tongue tip and causes difficulty elevating the tongue tip and protruding it past the mandibular incisors.
• The diagnosis of posterior tongue-tie is controversial. If it exists as an anomaly (which is highly debated), there is currently no evidence that it affects infant feeding or any other function.
• Although most infants with ankyloglossia can feed normally, a small percentage have difficulty latching on to the nipple. Frenotomy may improve the feeding efficiency in these infants. It may also relieve nipple pain in breastfeeding mothers.
• There is no evidence that ankyloglossia causes a speech disorder. This is because simple compensations in placement result in normal acoustics of the sounds. Theoretically, ankyloglossia could affect the lingual trill used in some languages; however, further research is needed to confirm this.
• If the tongue tip is restricted during production of lingual-alveolar sounds, the SLP should teach a dorsal production for these sounds as compensation if needed.
• Ankyloglossia can potentially cause issues with mandibular dentition, bolus manipulation during eating, French kissing, and aesthetics.
• A significant number of children are over-diagnosed with ankyloglossia, and as a result, they have unnecessary frenotomy surgeries.
• Frenotomies are generally safe. Rare complications of frenotomy include hemorrhage, injury to salivary glands, oral aversion, and scarring. This procedure is contraindicated for infants with upper airway obstruction, retrognathia, micrognathia, hypotonia, or neuromuscular disorders. Patients with Pierre Robin sequence are particularly at risk. This is because release of the tongue may cause glossoptosis, resulting in further upper airway obstruction and swallowing difficulties.
• Finally, SLPs should be very careful about diagnosing a child with ankyloglossia. They should also be very cautious and thoughtful before referring a child for a frenotomy, especially if the reason is for improvement of speech.

References

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