Treatment of Hypernasality in Children with Down Syndrome

Abstract:

Adenoidectomy has been reported to be a causal factor of velopharyngeal insufficiency (VPI) and associated hypernasal speech in patients with and without palatal and oral-pharyngeal defects. Children with Down Syndrome (DS) often have tonsillectomy and/or adenoidectomy to treat otologic, upper airway and sinonasal disease. Secondary to their altered head and neck structures, there is an increased possibility for VPI. Treating hypernasality may require surgical intervention including sphincter pharyngoplasty or pharyngeal flap, prosthetic devices or behavioral speech therapy to improve velar contact with posterior and lateral pharyngeal walls. Specific speech treatment regimens may include direct articulation-phonological therapy, biofeedback and muscle training. Combined surgical intervention and speech therapy may also be implemented. The following discussion addresses previous and current surgical, physical and behavioral treatment regimens to improve hypernasality in patients with VPI.

Introduction:

Down Syndrome or chromosome 21-trisomy syndrome is a type of mental retardation, occurring in approximately 1 in 800 live births. Typical physical deficits in children with DS include abnormal head and neck structures which result in sinonasal disease, upper airway and otologic problems (Price, Orvida, Weaver & Farmer, 2004). Anatomical differences include macroglossia, hypoplastic nasal bones, a narrower, less voluminous nasopharynx and oropharynx and eustachian tubes which have a less acute angle to the hard palate and a smaller diameter (Brown, Lewis, Parker, and Maw, 1989).

VPI is described by any of the following: velopharyngeal inadequacy, velopharyngeal insufficiency, velopharyngeal incompetence, or velopharyngeal dysfunction. These terms are used interchangeably to denote any type of velopharyngeal closure problem. This article uses the term velopharyngeal insufficiency or rhinolalia aperta to describe the failure of apposition of the soft palate and orophayngeal wall during speech, which is the main cause of hypernasality. In hypernasality, air escapes into the nose causing difficulty with speech, especially high pressure consonants such as plosives and fricatives. However, in the clinical management of these disorders, various etiologies require different management approaches.

As a result of anatomical differences, children with DS often present with symptoms such as; snoring, sleep apnea, nasal drainage, nasal congestion, mouth breathing, acute and chronic otitis media, drooling and tongue protrusion. Due to upper respiratory and structural differences, children with DS often undergo surgical procedures to help alleviate these symptoms. One procedure regularly performed is tonsillectomy with/without adenoidectomy ("T&A"). These procedures are often recommended to correct sleep apnea and other obstructive symptoms, despite controversy regarding their effectiveness (Price, et.al., 2004). Often, these surgical treatments do not account for the possible complications or side effects that may occur secondary to changing the anatomical structures in these patients. DS children have smaller-than-normal adenoidal pads and adenoidectomy may not have the expected positive result on nasal respiration and otologic problems as was previously thought (Kanamori, Witter, Brown, Williams-Smith, 2000). Furthermore, it has been noted that reducing the already small adenoidal pad in DS children may cause associated velopharyngeal insufficiency and therefore possibly creating hypernasal speech (Kavanagh, Kahane & Kordan, 1986).

Estimates of the incidence of velopharyngeal insufficiency after an adenoidectomy in non-syndromic patients has been estimated between 1 in 1500, to 1 in 10,000 procedures (Parton, & Jones, 1998). Other studies indicated that DS children post-T&A have benefited from the procedure by eliminating or reducing symptoms such as snoring, sleep apnea, nasal drainage, and mouth breathing, but not drooling or tongue protrusion. This data was reported via a parental questionnaire survey of 74 parents of children with DS (Price et al., 2004). The same report indicated two children had hypernasality after surgery. The children were given complete speech and language evaluations and additional assessment using cinefluoroscopy. Structural and functional causes of hypernasality were identified. Structural abnormalities included a high-arched short hard palate and a short soft palate. Contributing functional factors included hypotonia, slowed motor learning and oral motor developmental delay. The incidence of postoperative hypernasality found in these patients was higher than in the general population and therefore is essential to consider prior to the performance of an adenoidectomy in DS children (Kavanagh, 1986). The likelihood of post-surgical complications and possible secondary surgical procedures included chronic ear drainage and subsequent ear surgery, post-extubation stridor and respiratory problems. Whichever decision is made regarding adenoidectomy, the surgeon and family should be well informed of these recent findings to appropriately weigh the potential benefits and risks.