Velopharyngeal inadequacy (VPI) is a malfunction of a velopharyngeal mechanism.

The velopharyngeal mechanism is responsible for directing the transmission of sound energy and air pressure in both the oral cavity and the nasal cavity. When this mechanism is impaired in some way, the valve does not fully close, and a condition known as 'velopharyngeal inadequacy' can develop. VPI can either be congenital or acquired later in life.

A common method to treat Velopharyngeal insufficiency is pharyngeal flap surgery, where tissue from the back of the mouth is used to close part of the gap. Other ways of treating velopharyngeal insufficiency is by placing a posterior nasopharyngeal wall implant (commonly cartilage or collagen) or type of soft palate lengthening procedure (i.e. VY palatoplasty).

Environmental influences may also cause, or interact with genetics to produce, orofacial clefting. An example of how environmental factors might be linked to genetics comes from research on mutations in the gene "PHF8" that cause cleft lip/palate (see above). It was found that PHF8 encodes for a histone lysine demethylase, and is involved in epigenetic regulation. The catalytic activity of PHF8 depends on molecular oxygen, a fact considered important with respect to reports on increased incidence of cleft lip/palate in mice that have been exposed to hypoxia early during pregnancy. In humans, fetal cleft lip and other congenital abnormalities have also been linked to maternal hypoxia, as caused by e.g. maternal smoking, maternal alcohol abuse or some forms of maternal hypertension treatment. Other environmental factors that have been studied include: seasonal causes (such as pesticide exposure); maternal diet and vitamin intake; retinoids — which are members of the vitamin A family; anticonvulsant drugs; nitrate compounds; organic solvents; parental exposure to lead; alcohol; cigarette use; and a number of other psychoactive drugs (e.g. cocaine, crack cocaine, heroin).

Current research continues to investigate the extent to which folic acid can reduce the incidence of clefting.

Velopharyngeal insufficiency (VPI) is a failure of the body's ability to temporarily close the communication between the nasal cavity and the mouth, because of an anatomic dysfunction of the soft palate or of the lateral or posterior wall of the pharynx.

The effect of such a dysfunction leads to functional problems with speech (hypernasality), eating (chewing and swallowing), and breathing. This gap can be treated surgically, although the choice of operational technique is still controversial.

The terms velopharyngeal "incompetence", "inadequacy" and "insufficiency" historically have often been used interchangeably, although they do not necessarily mean the same thing (sense distinctions can be made but sometimes are not). Velopharyngeal insufficiency includes any structural defect of the velum or pharyngeal walls at the level of the nasopharynx with insufficient tissue to accomplish closure, or there is some kind of mechanical interference with closure. It is important that the term insufficiency is used if it is an anatomical defect and not a neurological problem.

Velopharyngeal insufficiency (VPI) can be caused by a variety of disorders (structural, genetic, functional or acquired) and is very often associated with a cleft palate. Abnormal physiological separation of the oropharynx from the nasopharynx can lead to VPI and hypernasality.

Cleft lip and palate occurs in about 1 to 2 per 1000 births in the developed world.

Rates for cleft lip with or without cleft palate and cleft palate alone varies within different ethnic groups.

The highest prevalence rates for (CL ± P) are reported for Native Americans and Asians. Africans have the lowest prevalence rates.

- Native Americans: 3.74/1000

- Japanese: 0.82/1000 to 3.36/1000

- Chinese: 1.45/1000 to 4.04/1000

- Caucasians: 1.43/1000 to 1.86/1000

- Latin Americans: 1.04/1000

- Africans: 0.18/1000 to 1.67/1000

Rate of occurrence of CPO is similar for Caucasians, Africans, North American natives, Japanese and Chinese. The trait is dominant.

It caused about 4,000 deaths globally in 2010 down from 8,400 in 1990.

Prevalence of "cleft uvula" has varied from .02% to 18.8% with the highest numbers found among Chippewa and Navajo and the lowest generally in Africans.

The most common complications of the posterior pharyngeal wall flap are hyponasality, nasal obstruction, snoring, and sleep apnea. Rarer complications include flap separation, sinusitis, postoperative bleeding, and aspiration pneumonia. Possible complications of the sphincter pharyngoplasty are snoring, nasal obstruction, difficulty blowing the nose.

Some researches suggest that sphincter pharyngoplasty introduces less hyponasality and obstructive sleep symptoms than the posterior pharyngeal wall flap. Both surgeries have a favourable effect on the function of the Eustachian tube.

The general term for disorders of the velopharyngeal valve is velopharyngeal dysfunction (VPD). It includes three subterms: velopharyngeal insufficiency, velopharyngeal inadequacy, and velopharyngeal mislearning.

- Velopharyngeal insufficiency can be caused by an anatomical abnormality of the throat. It occurs in children with a history of cleft palate or submucous cleft, who have short or otherwise abnormal vela. Velopharyngeal insufficiency can also occur after adenoidectomy.

- Velopharyngeal incompetence is a defective closure of the velopharyngeal valve due to its lack of speed and precision. It is caused by a neurologic disorder or injury (e.g. cerebral palsy or traumatic brain injury).

- Sometimes children present no abnormalities yet still have hypernasal speech: this can be due to velopharyngeal mislearning, indicating that the child has been imitating or has never learned how to use the valve correctly.

Prostheses are used for nonsurgical closure in a situation of velopharyngeal dysfunction. There are two types of prosthesis: the speech bulb and the palatal lift prosthesis. The speech bulb is an acrylic body that can be placed in the velopharyngeal port and can achieve obstruction. The palatal lift prosthesis is comparable with the speech bulb, but with a metal skeleton attached to the acrylic body. This will also obstruct the velopharyngeal port. It is a good option for patients that have enough tissue but a poor control of the coordination and timing of velopharyngeal movement. It is also used in patients with contraindications for surgery. It has also been used as a reversible test to confirm whether a surgical intervention would help.

Individuals with Nager syndrome typically have the malformations of the auricle, external auditory canal, and middle ear, including the ossicles. These malformations were found in 80% of individuals with Nager syndrome. Inner ear malformations, however, are not typically seen in this population. Middle ear disease is common among individuals with Nager syndrome. Chronic otitis media and Eustachian tube deformity can result in conductive hearing loss. For this reason, early detection and treatment for middle ear disease is crucial in this population. Sensorineural hearing loss is not a typical characteristic of Nager syndrome; however, a subset of individuals present with a mixed hearing loss, due to a progressive sensorineural component combined with the typical conductive hearing loss (Herrman "et al.", 2005).

Hearing loss with craniofacial syndromes is a common occurrence. Many of these multianomaly disorders involve structural malformations of the outer or middle ear, making a significant hearing loss highly likely.

It has been estimated that VUR is present in more than 10% of the population. Younger children are more prone to VUR because of the relative shortness of the submucosal ureters. This susceptibility decreases with age as the length of the ureters increases as the children grow. In children under the age of 1 year with a urinary tract infection, 70% will have VUR. This number decreases to 15% by the age of 12. Although VUR is more common in males antenatally, in later life there is a definite female preponderance with 85% of cases being female.

Posterior urethral valves; urethral or meatal stenosis. These causes are treated surgically when possible.

In 2006, the U.S. Department of Education indicated that more than 1.4 million students were served in the public schools' special education programs under the speech or language impairment category of IDEA 2004. This estimate does not include children who have speech/language problems secondary to other conditions such as deafness; this means that if all cases of speech or language impairments were included in the estimates, this category of impairment would be the largest. Another source has estimated that communication disorders—a larger category, which also includes hearing disorders—affect one of every 10 people in the United States.

ASHA has cited that 24.1% of children in school in the fall of 2003 received services for speech or language disorders—this amounts to a total of 1,460,583 children between 3 –21 years of age. Again, this estimate does not include children who have speech/language problems secondary to other conditions. Additional ASHA prevalence figures have suggested the following:

- Stuttering affects approximately 4% to 5% of children between the ages of 2 and 4.

- ASHA has indicated that in 2006:

- Almost 69% of SLPs served individuals with fluency problems.

- Almost 29% of SLPs served individuals with voice or resonance disorders.

- Approximately 61% of speech-language pathologists in schools indicated that they served individuals with SLI

- Almost 91% of SLPs in schools indicated that they servedindividuals with phonological/articulation disorder

- Estimates for language difficulty in preschool children range from 2% to 19%.

- Specific Language Impairment (SLI) is extremely common in children, and affects about 7% of the childhood population.

Ectrodactyly–ectodermal dysplasia–cleft syndrome, or EEC, and also referred to as EEC syndrome (also known as "Split hand–split foot–ectodermal dysplasia–cleft syndrome") is a rare form of ectodermal dysplasia, an autosomal dominant disorder inherited as an genetic trait. EEC is characterized by the triad of ectrodactyly, ectodermal dysplasia, and facial clefts. Other features noted in association with EEC include vesicoureteral reflux, recurrent urinary tract infections, obstruction of the nasolacrimal duct, decreased pigmentation of the hair and skin, missing or abnormal teeth, enamel hypoplasia, absent punctae in the lower eyelids, photophobia, occasional cognitive impairment and kidney anomalies, and conductive hearing loss.

Lujan–Fryns syndrome is a rare X-linked dominant syndrome, and is therefore more common in males than females. Its prevalence within the general population has not yet been determined.

Many studies indicate the effect of a "fight or flight" response on the body that happens with each apneic event is what increases health risks and consequences in OSA. The fight or flight response causes many hormonal changes in the body; those changes, coupled with the low oxygen saturation level of the blood, cause damage to the body over time.

Without treatment, the sleep deprivation and lack of oxygen caused by sleep apnea increases health risks such as cardiovascular disease, aortic disease (e.g. aortic aneurysm), high blood pressure, stroke, diabetes, clinical depression, weight gain and obesity.

The most serious consequence of untreated OSA is to the heart. Persons with sleep apnea have a 30% higher risk of heart attack or death than those unaffected. In severe and prolonged cases, increased in pulmonary pressures are transmitted to the right side of the heart. This can result in a severe form of congestive heart failure known as "cor pulmonale". Dyastolic function of the heart also becomes affected. One prospective study showed patients with OSA, compared with healthy controls, initially had statistically significant increases in vascular endothelial growth factor (P=.003) and significantly lower levels of nitrite-nitrate (P=.008), which might be pathogenic factors in the cardiovascular complications of OSA. These factors reversed to normal levels after 12 weeks of treatment by CPAP, but further long-term trials are needed to assess the impact of this therapy.

Elevated arterial pressure (i.e., hypertension) can be a consequence of OSA syndrome. When hypertension is caused by OSA, it is distinctive in that, unlike most cases (so-called essential hypertension), the readings do "not" drop significantly when the individual is sleeping (non-dipper) or even increase (inverted dipper).

The speech deficits associated with EEC syndrome are numerous. The clefting often causes hypernasal speech and velopharyngeal incompetence. Because of this, compensatory articulation strategies including retruded articulation and glottal compensation are often incorporated into the patient's speech. Articulation is further impaired by the numerous dental anomalies, including missing or malformed teeth found in EEC syndrome.

Language deficits are also associated with EEC syndrome and are attributed to two factors. Conductive hearing loss due to ossicular anomalies is often encountered in patients with EEC syndrome, which can have significant impacts on language acquisition. Also, the impaired cognitive functioning that sometimes accompanies EEC can inhibit language acquisition.

Old age is often accompanied by muscular and neurological loss of muscle tone of the upper airway. Decreased muscle tone is also temporarily caused by chemical depressants; alcoholic drinks and sedative medications being the most common. The permanent premature muscular tonal loss in the upper airway may be precipitated by traumatic brain injury, neuromuscular disorders, or poor adherence to chemical and or speech therapy treatments.

Individuals with decreased muscle tone and increased soft tissue around the airway, and structural features that give rise to a narrowed airway are at high risk for OSA. Men, in which the anatomy is typified by increased mass in the torso and neck, are at increased risk of developing sleep apnea, especially through middle age and later. Women suffer typically less frequently and to a lesser degree than do men, owing partially to physiology, but possibly also to differential levels of progesterone. Prevalence in post-menopausal women approaches that of men in the same age range. Women are at greater risk for developing OSA during pregnancy.

OSA also appears to have a genetic component; those with a family history of it are more likely to develop it themselves. Lifestyle factors such as smoking may also increase the chances of developing OSA as the chemical irritants in smoke tend to inflame the soft tissue of the upper airway and promote fluid retention, both of which can result in narrowing of the upper airway. An individual may also experience or exacerbate OSA with the consumption of alcohol, sedatives, or any other medication that increases sleepiness as most of these drugs are also muscle relaxants.

Acquired disorders result from brain injury, stroke or atrophy, many of these issues are included under the Aphasia umbrella.

Brain damage, for example, may result in various forms of aphasia if critical areas of the brain such as Broca's or Wernicke's area are damaged by lesions or atrophy as part of a dementia.

A number of features involving the heart have been noted in several LFS cases, the most significant being dilation of the aortic root, a section of the ascending aorta. Aortic root dilation (enlargement) is associated with a greatly increased risk of dissection of the aortic wall, resulting in aortic aneurysm. As this presents a possible life-threatening consequence of LFS, routine cardiac evaluation methods such as echocardiogram are implemented when the disorder is first diagnosed, along with MRI scans of the brain to screen for suspected agenesis of the corpus callosum. Additional effects on the heart that have been reported with LFS are ventricular and atrial septal defect.

In babies that are born at term risk factors include problems with the placenta, birth defects, low birth weight, breathing meconium into the lungs, a delivery requiring either the use of instruments or an emergency Caesarean section, birth asphyxia, seizures just after birth, respiratory distress syndrome, low blood sugar, and infections in the baby.

Between 40% and 50% of all children who develop cerebral palsy were born prematurely. Most of these cases (75-90%) are believed to be due to issues that occur around the time of birth, often just after birth. Multiple-birth infants are also more likely than single-birth infants to have CP. They are also more likely to be born with a low birth weight.

In those who are born with a weight between 1 kg and 1.5 kg CP occurs in 6%. Among those born before 28 weeks of gestation it occurs in 11%. Genetic factors are believed to play an important role in prematurity and cerebral palsy generally. While in those who are born between 34 and 37 weeks the risk is 0.4% (three times normal).

22q11.2 deletion syndrome is caused by a heterozygous deletion of part of the long arm (q) of chromosome 22, region 1, band 1, sub-band 2 (22q11.2). Approximately 80-90% of patients have a deletion of 3 Mb and 8% have a deletion of 1.5Mb. The number of genes affected by the deletion has been cited as approximately 30 to 50. Very rarely, patients with somewhat similar clinical features may have deletions on the short arm of chromosome 10. The disorder has an autosomal dominant inheritance pattern.

A French study of 749 people diagnosed between 1995 and 2013 found that the mutation was inherited in 15% of patients, of which 85.5% was from the mother. Other studies have found inheritance rates of 6-10%. The majority cases are a result of a "de novo" (new to the family) deletion. This is because the 22q11 region has a structure that makes it highly prone to rearrangements during sperm or egg formation.

The exact mechanism that causes all of the associated features of the syndrome is unknown. Of the 30–50 genes in the deleted region, a number have been identified as possibly playing a role in the development of some of the signs and symptoms.

22q11.2 deletion syndrome was estimated to affect between one in 2000 and one in 4000 live births. This estimate is based on major birth defects and may be an underestimate, because some individuals with the deletion have few symptoms and may not have been formally diagnosed. It is one of the most common causes of mental retardation due to a genetic deletion syndrome.

The prevalence of 22q11.2DS has been expected to rise because of multiple reasons: (1) Thanks to surgical and medical advances, an increasing number of people are surviving heart defects associated with the syndrome. These individuals are in turn having children. The chances of a 22q11.2DS patient having an affected child is 50% for each pregnancy; (2) Parents who have affected children, but who were unaware of their own genetic conditions, are now being diagnosed as genetic testing become available; (3) Molecular genetics techniques such as FISH (fluorescence in situ hybridization) have limitations and have not been able to detect all 22q11.2 deletions. Newer technologies have been able to detect these atypical deletions.

Recently, the syndrome has been estimated to affect up to one in 2000 live births. Testing for 22q11.2DS in over 9500 pregnancies revealed a prevalence rate of 1/992.