Resonance Speech Therapy seeks to correct articulation errors related to soft palate closure (velopharyngeal closure) and airflow. Common sources of poor resonance include nasal or oral blockages or learned compensatory articulation errors.
To identify hypernasality in a child, ask them to repeat oral and nasal consonants into a bending straw and listen for any muffled sound through it – this indicates hypernasality is present.
Hypernasality
Hypernasality occurs when speech sounds as though coming through one or both nostrils, rather than through the mouth and nasal cavity during speech – either all or some speech sounds may sound nasalized, known as Velopharyngeal Insufficiency or VPI for short. VPI may result from structural issues, like cleft palate or submucous cleft palate; neurological causes; or large tonsils or adenoids which reduce airway space for breathing during speaking.
Hypernasality can make speech hard to understand from a distance or echolocation situation, even with behavioral resonance tips in place. But sometimes hypernasality will not go away on its own and may require referral to an expert who can evaluate anatomical and velopharyngeal movement issues more thoroughly.
Hyponasality, on the other hand, occurs when there is too little voice vibration in the nasal cavity and causes speech sounds to become too dry and constricted – particularly nasal consonants such as /m/, /n/ and /ng/. Like hypernasality, this condition can range from mild to moderate or severe intensity levels.
Hypernasality and hyponasality can both be identified by listening for nasal resonance on vowels and voice oral consonants in connected speech, such as vowels. While its importance may not be as critical in these instances, knowing whether pressure-sensitive sounds such as plosives, fricatives, or affricates show increased or decreased nasal emission is still useful information.
Be mindful that certain languages may have more nasal sounds than others; if your client speaks an Asian language other than English, a culturally sensitive assessment may be required to determine their needs.
When someone has a resonance disorder causing them to sound nasal in all their speech sounds, it may be best to seek medical help from a velopharyngeal specialist for evaluation and possibly surgery. There may also be instances in which speech therapy alone is sufficient, particularly if their cause lies within a cleft abnormality such as palatal fistula or cleft palate.
Hyponasality
Hyponasality occurs when your child has voiced that sound “stuffy” or congested when speaking, unlike hypernasality where excess nasal resonance occurs on all sounds; rather, this condition mainly impacts vowels, glides and liquids (with potential impacting voiced oral consonants such as “b”, “d” and “g”)
Hyponasality may also be caused by structural issues; examples include velopharyngeal insufficiency (VPI), enlarged tonsils or anatomic obstruction.
Other causes for decreased velar closure may include: an overt or submucous cleft palate; adenoids with atrophic atrophy and post-adenoidectomy, enlarged or hypertrophic turbinates, deviated septum or choanal atresia. When someone is deaf or suffering significant hearing loss, lack of auditory feedback also contributes to decreased velar closure during speech.
Like hypernasality, symptoms of nasal incontinence can range from mild to severe. Accurate diagnosis is key when trying to establish whether the cause is structural (e.g. mislearning) or functional (e.g. asthma) because different causes require different approaches when treating them.
An experienced speech-language pathologist can conduct a comprehensive clinical evaluation to rule out any contributing factors. They will perform an articulation assessment as well as perceptual, aerodynamic and acoustic assessments of each sound affected vocal tract for each affected sound produced. They will also evaluate Velopharyngeal closure. Furthermore, additional evaluation methods such as videofluoroscopy, nasopharyngoscopy or magnetic resonance imaging (MRI) may also assist with diagnosis.
The therapist will then work to treat the structural causes of the issue, such as using continuous positive airway pressure to strengthen velum muscle strength during speech. Exercise to strengthen expiratory muscle strength (EMST) may also be recommended as these exercises not only strengthen other voice muscles but may have an additional beneficial impact on VP stability as well.
Behavior therapy may prove effective for idiopathic hyponasality cases, leading to improved perceptions of articulation and an effective physical management plan involving changing tongue placement on affected sounds. Consultation with an otolaryngologist might also prove fruitful if structural causes for abnormal resonance have been identified.
Cul-de-sac Resonance
Like hypernasality and hyponasality, cul-de-sac resonance is caused by obstruction at the exit point of a vocal tract cavity during speech, leading to muffled and low-volume sounds when speaking; vowels may become muffled as voiced consonants (consonants where vibration of vocal cords can be felt by listeningers) are affected. Cul-de-sac resonance can also result from having large tonsils or reduced space due to maxillary retrusion or having a shallow nasopharynx.
Clinicians evaluating an individual’s nasal airflow must consider norms and linguistic variance when screening for resonance disorders, to distinguish articulation errors from other causes of Velopharyngeal Dysfunction (VPD). When symptoms indicate the existence of VPD, referral may be made to craniofacial teams for further assessment.
Hypernasality, hyponasality, cul-de-sac and mixed resonance are the four types of resonance disorders found among children and adults alike. A change in how sound resonates within your child’s mouth, nose and throat during speech creates this problem; it may result in speech that is difficult to understand or even cause complications such as obstructive sleep apnea if left untreated.
An SLP can assess nasal airflow by having a child produce pressure consonants such as stops, fricatives and affricates and listening for any traces of nasal emission on these sounds. If none exist, this could indicate VPD. Resonance issues may also result from obstruction, inconsistent valve movement or any combination thereof. To properly assess an obstruction and inconsistent movement of the VP valve is key in providing recommendations for treatment; its severity does not alter such recommendations, however. Palate re-repair for VPD can be effective and should be considered by those living with VPD who also have a repaired cleft palate. Studies have demonstrated its efficacy, including reduced instances of obstructive sleep apnea.
Mixed Resonance
Mixed resonance occurs when there is an imbalance in palato-pharyngeal valving with excessive nasalization on vowels and non-nasal consonants, most likely caused by narrow palate, large tonsils or small mouth opening preventing the velum from closing correctly on nasal air flow.
The velum is the soft tissue located between the upper nasal cavity and oral cavity. It consists of a posterior part that extends toward the pharynx and a superior portion which runs parallel with it between pharynx and esophagus. Its purpose is to facilitate consonant sound articulation.
Resonance disorders occur when there is an alteration in how sound moves through your child’s mouth, nose and throat during speech production due to structural or neurogenic causes. There are four different forms of resonance disorders: hypernasality, hyponasality, cul-de-sac resonance and mixed resonance.
First step of diagnosis involves screening for potential issues by conducting an evaluation of your child’s speech and language skills, which includes culturally appropriate perceptual and aerodynamic assessments of voice quality and an articulation evaluation. If an articulation error is identified, speech therapy referral may be necessary in order to address any possible underlying issues that need addressing.
Structural causes of Velopharyngeal Insufficiency include overt, submucous or occult submucous cleft palate; malocclusion as a result of said cleft; history of VPD after surgery; abnormal tongue position due to articulation errors; motor planning/execution problems (Apraxia) that result in inconsistent VP closing/opening; or obstruction due to an enlarged tonsils or deviated septum.
Treatment for resonance disorders focuses largely on using various strategies to facilitate normal velopharyngeal function, including various surgeries such as double-opposing Z-plasty, soft palate elongation and midline incision; Voice Plus; or pharyngeal obturator devices. The goals of such interventions are to reestablish anatomy for normal VP closure, provide support to vowels during pronunciation, and increase vibration on nasal airflow.