Individuals with Treacher Collins syndrome often have both cleft palate and hearing loss, in addition to other disabilities. Hearing loss is often secondary to absent, small, or unusually formed ears (microtia), and commonly results from malformations of the middle ear. Researchers have found that most patients with Treacher Collins syndrome have symmetric external ear canal abnormalities and symmetrically dysmorphic or absent ossicles in the middle ear space. Inner ear structure is largely normal. Most patients show a moderate hearing impairment or greater, and the type of loss is generally a conductive hearing loss. Patients with Treacher Collins syndrome exhibit hearing losses similar to those of patients with malformed or missing ossicles (Pron "et al.", 1993).

Persons with Pierre Robin sequence (PRS) are at greater risk for hearing impairment than persons with cleft lip and/or palate without PRS. One study showed an average of 83% hearing loss in PRS, compared to 60% in cleft individuals without PRS (Handzic "et al.", 1995). Similarly, PRS individuals typically exhibit conductive, bilateral hearing losses that are greater in degree than in cleft individuals without PRS. Middle ear effusion is generally apparent, with no middle ear or inner ear malformations. Accordingly, management by ear tubes (myringotomy tubes) is often effective and may restore normal levels of hearing (Handzic "et al.", 1995).

Mondini dysplasia, also known as Mondini malformation and Mondini defect, is an abnormality of the inner ear that is associated with sensorineural hearing loss.

This deformity was first described in 1791 by Mondini after examining the inner ear of a deaf boy. The Mondini dysplasia describes a cochlea with incomplete partitioning and a reduced number of turns, an enlarged vestibular aqueduct and a dilated vestibule. A normal cochlea has two and a half turns, a cochlea with Mondini dysplasia has one and a half turns; the basal turns being normally formed with a dilated or cystic apical turn to the cochlear. The hearing loss can deteriorate over time either gradually or in a step-wise fashion, or may be profound from birth.

Hearing loss associated with Mondini dysplasia may first become manifest in childhood or early adult life. Some children may pass newborn hearing screen to lose hearing in infancy but others present with a hearing loss at birth. Hearing loss is often progressive and because of the associated widened vestibular aqueduct may progress in a step-wise fashion associated with minor head trauma. Vestibular function is also often affected. While the hearing loss is sensorineural a conductive element may exist probably because of the third window effect of the widened vestibular aqueduct. The Mondini dysplasia can occur in cases of Pendred Syndrome and Branchio-oto-renal syndrome and in other syndromes, but can occur in non-syndromic deafness.

Superior canal (SCD) can affect both hearing and balance to different extents in different people.

Symptoms of SCDS include:

- Autophony – person's own speech or other self-generated noises (e.g. heartbeat, eye movements, creaking joints, chewing) are heard unusually loudly in the affected ear

- Dizziness/ vertigo/ chronic disequilibrium caused by the dysfunction of the superior semicircular canal

- Tullio phenomenon – sound-induced vertigo, disequilibrium or dizziness, nystagmus and oscillopsia

- Pulse-synchronous oscillopsia

- Hyperacusis – the over-sensitivity to sound

- Low-frequency conductive hearing loss

- A feeling of fullness in the affected ear

- Pulsatile tinnitus

- Brain fog

- Fatigue

- Headache/migraine

- Tinnitus – high pitched ringing in the ear

The vestibular aqueduct acts as a canal between the inner ear and the cranial cavity. Running through it is a tube called the endolymphatic duct, which normally carries a fluid called endolymph from the inner ear to the endolymphatic sac in the cranial cavity. When the endolymphatic duct and sac are larger than normal, as is the case in large vestibular aqueduct syndrome, endolymph is allowed to travel back from the endolymphatic sac into the inner ear. This often results fluctuations in hearing levels. Enlarged vestibular aqueducts often occur with other inner ear development problems, such as cochlear deformities. Enlarged vestibular aqueducts are part of the classic Mondini deformity. Enlarged vestibular aqueducts with enlarged endolymphatic sacs occur in Pendred syndrome which is caused by a defect on chromosome 7q31.. Enlarged vestibular aqueducts can also occur in Branchio-oto-renal syndrome, CHARGE syndrome and Renal Tubular Acidosis.

Enlarged vestibular aqueducts can be bilateral or unilateral.

Hearing loss caused by large vestibular aqueduct syndrome is not inevitable, although people with the syndrome are at a much higher risk of developing hearing loss than the general population. Hearing loss is very likely.

Although large vestibular aqueducts are a congenital condition, hearing loss may not be present from birth. Age of diagnosis ranges from infancy to adulthood, and symptoms include fluctuating and sometimes progressive sensorineural hearing loss and disequilibrium.

Michel aplasia, also known as complete labyrinthine aplasia (CLA), is a congenital abnormality of the inner ear. It is characterized by the bilateral absence of differentiated inner ear structures and results in complete deafness (anacusis).

Michel aplasia should not be confused with michel dysplasia. It may affect one or both ears.

"Aplasia" is the medical term for body parts that are absent or do not develop properly. In Michel aplasia, the undeveloped (anaplastic) body part is the bony labyrinth of the inner ear. Other nearby structures may be underdeveloped as well.

SSHL is diagnosed via pure tone audiometry. If the test shows a loss of at least 30db in three adjacent frequencies, the hearing loss is diagnosed as SSHL. For example, a hearing loss of 30db would make conversational speech sound more like a whisper.

Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body. Genetic changes are related to the following types of nonsyndromic deafness.

- DFNA: nonsyndromic deafness, autosomal dominant

- DFNB: nonsyndromic deafness, autosomal recessive

- DFNX: nonsyndromic deafness, X-linked

- nonsyndromic deafness, mitochondrial

Each type is numbered in the order in which it was described. For example, DFNA1 was the first described autosomal dominant type of nonsyndromic deafness. Mitochondrial nonsyndromic deafness involves changes to the small amount of DNA found in mitochondria, the energy-producing centers within cells.

Most forms of nonsyndromic deafness are associated with permanent hearing loss caused by damage to structures in the inner ear. The inner ear consists of three parts: a snail-shaped structure called the cochlea that helps process sound, nerves that send information from the cochlea to the brain, and structures involved with balance. Loss of hearing caused by changes in the inner ear is called sensorineural deafness. Hearing loss that results from changes in the middle ear is called conductive hearing loss. The middle ear contains three tiny bones that help transfer sound from the eardrum to the inner ear. Some forms of nonsyndromic deafness involve changes in both the inner ear and the middle ear; this combination is called mixed hearing loss.

The severity of hearing loss varies and can change over time. It can affect one ear (unilateral) or both ears (bilateral). Degrees of hearing loss range from mild (difficulty understanding soft speech) to profound (inability to hear even very loud noises). The loss may be stable, or it may progress as a person gets older. Particular types of nonsyndromic deafness often show distinctive patterns of hearing loss. For example, the loss may be more pronounced at high, middle, or low tones.

Nonsyndromic deafness can occur at any age. Hearing loss that is present before a child learns to speak is classified as prelingual or congenital. Hearing loss that occurs after the development of speech is classified as postlingual.

Symptoms in people with Treacher Collins syndrome vary. Some individuals are so mildly affected that they remain undiagnosed, while others have moderate to severe facial involvement and life-threatening airway compromise. Most of the features of TCS are symmetrical and are already recognizable at birth.

The most common symptom of Treacher Collins syndrome is underdevelopment of the lower jaw and underdevelopment of the zygomatic bone. This can be accompanied by the tongue being retracted. The small mandible can result in a poor occlusion of the teeth or in more severe cases, trouble breathing or swallowing. Underdevelopment of the zygomatic bone gives the cheeks a sunken appearance.

The external ear is sometimes small, rotated, malformed, or absent entirely in people with TCS. Symmetric, bilateral narrowing or absence of the external ear canals is also described. In most cases, the bones of the middle ear and the middle ear cavity are misshapen. Inner ear malformations are rarely described. As a result of these abnormalities, a majority of the individuals with TCS have conductive hearing loss.

Most affected people also experience eye problems, including colobomata (notches) in the lower eyelids, partial or complete absence of eyelashes on the lower lid, downward angled eyelids, drooping of upper and lower eyelids, and narrowing of the tear ducts. Vision loss can occur and is associated with strabismus, refractive errors, and anisometropia. It can also be caused by severely dry eyes, a consequence of lower eyelid abnormalities and frequent eye infections.

Although an abnormally shaped skull is not distinctive for Treacher Collins syndrome, brachycephaly with bitemporal narrowing is sometimes observed. Cleft palate is also common.

Dental anomalies are seen in 60% of affected people, including tooth agenesis (33%), discoloration (enamel opacities) (20%), malplacement of the maxillary first molars (13%), and wide spacing of the teeth. In some cases, dental anomalies in combination with mandible hypoplasia result in a malocclusion. This can lead to problems with food intake and the ability to close the mouth.

Less common features of TCS may add to an affected person's breathing problems, including sleep apnea. Choanal atresia or stenosis is a narrowing or absence of the choanae, the internal opening of the nasal passages. Underdevelopment of the pharynx, can also narrow the airway.

Features related to TCS that are seen less frequently include nasal deformities, high-arched palate, macrostomia, preauricular hair displacement, cleft palate, hypertelorism, notched upper eyelid, and congenital heart defects.

The general public may associate facial deformity with developmental delay and intellectual disability, but more than 95% of people affected with TCS have normal intelligence. The psychological and social problems associated with facial deformity can affect quality of life in people with TCS.

Only 10 to 15 percent of the cases diagnosed as SSHL have an identifiable cause. Most cases are classified as idiopathic, also called sudden idiopathic hearing loss (SIHL) and idiopathic sudden sensorineural hearing loss (ISSHL or ISSNHL) The majority of evidence points to some type of inflammation in the inner ear as the most common cause of SSNHL.

- Viral - The swelling may be due to a virus. A herpes type virus is believed to be the most common cause of sudden sensorineural hearing loss. The herpes virus lays dormant in our bodies and reactivates for an unknown reason.

- Vascular ischemia of the inner ear or cranial nerve VIII (CN8)

- Perilymph fistula, usually due to a rupture of the round or oval windows and the leakage of perilymph. The patient will usually also experience vertigo or imbalance. A history of trauma is usually present and changes to hearing or vertigo occur with alteration in intracranial pressure such as with straining; lifting, blowing etc.

- Autoimmune - can be due to an autoimmune illness such as systemic lupus erythematosus, granulomatosis with polyangiitis

"20% to 40% of children with microtia/anotia will have additional defects that could suggest a syndrome."

Treacher-Collins Syndrome: (TCS) A congenital disorder caused by a defective protein known as treacle, and is characterized by craniofacial deformities; malformed or absent ears are also seen in this syndrome. The effects may be mild, undiagnosed to severe, leading to death. Because the ear defects are much different in this disorder and not only affect the outer ear, but the middle ear as well, reconstructive surgery may not help with the child's hearing and in this case a Bone Anchored Hearing Aid would be best. BAHA will only work, however if the inner ear and nerve are intact.

Goldenhar Syndrome: A rare congenital birth defect that causes abnormalities of facial development. also known as Oculoauricular Dysplasia. The facial anomalies include underdeveloped, asymmetric half of the face. The defect is capable of affecting tissue, muscle, and the underlying bone structure of the side of the face with the abnormality.

Ablepharon-macrostomia Syndrome: (AMS) A rare genetic disorder characterized by various physical anomalies which affect the craniofacial area, the skin, the fingers, and the genitals.

This is an inherited disease. The primary form of hearing loss in otosclerosis is conductive hearing loss (CHL) whereby sounds reach the ear drum but are incompletely transferred via the ossicular chain in the middle ear, and thus partly fail to reach the inner ear (cochlea). This usually will begin in one ear but will eventually affect both ears with a variable course. On audiometry, the hearing loss is characteristically low-frequency, with higher frequencies being affected later.

Sensorineural hearing loss (SNHL) has also been noted in patients with otosclerosis; this is usually a high-frequency loss, and usually manifests late in the disease. The causal link between otosclerosis and SNHL remains controversial. Over the past century, leading otologists and neurotologic researchers have argued whether the finding of SNHL late in the course of otosclerosis is due to otosclerosis or simply to typical presbycusis.

Most patients with otosclerosis notice tinnitus (head noise) to some degree. The amount of tinnitus is not necessarily related to the degree or type of hearing impairment. Tinnitus develops due to irritation of the delicate nerve endings in the inner ear. Since the nerve carries sound, this irritation is manifested as ringing, roaring or buzzing. It is usually worse when the patient is fatigued, nervous or in a quiet environment.

Abnormal development of the skeletal portions of the second arch

1. Nondifferentiation of the stapes, with resultant absence of round and oval window.

2. Abnormal course of the facial nerve.

Skull base abnormalities

1. Hypoplasia of the petrous temporal bone.

2. Hypoplastic and sclerotic petrous apex may mimic labyrinthitis ossificans.

3. Platybasia.

4. Aberrant course of jugular veins.

The hearing loss of Pendred syndrome is often, although not always, present from birth, and language acquisition may be a significant problem if deafness is severe in childhood. The hearing loss typically worsens over the years, and progression can be step-wise and related to minor head trauma. In some cases, language development worsens after head injury, demonstrating that the inner ear is sensitive to trauma in Pendred syndrome; this is as a consequence of the widened vestibular aqueducts usual in this syndrome. Vestibular function varies in Pendred syndrome and vertigo can be a feature of minor head trauma. A goitre is present in 75% of all cases.

Conductive hearing loss makes all sounds seem faint or muffled. The hearing loss is worse in low frequencies.

Congenital conductive hearing loss is usually identified through newborn hearing screening or may be identified because the baby has microtia or other facial abnormalities. Conductive hearing loss developing during childhood is usually due to otitis media with effusion and may present with speech and language delay or difficulty hearing. Later onset of conductive hearing loss may have an obvious cause such as an ear infection, trauma or upper respiratory tract infection or may have an insidious onset related to chronic middle ear disease, otosclerosis or a tumour of the naso-pharynx. Earwax is a very common cause of a conductive hearing loss which may present suddenly when water gets behind the wax and this blocks the ear canal.

Nasodigitoacoustic syndrome is congenital and is characterized by a number of nasal, facial and cranial features. These include a broad and high, sometimes depressed nasal bridge (top of the nose, between the eyes) and a flattened nasal tip. This can give the nose a shortened, arch-like appearance. Hypertelorism (unusually wide-set eyes), prominent frontal bones and supraorbital ridge (the eyebrow ridge), bilateral epicanthic folds (an extra flap of skin over the eyelids), a broad forehead and an overall enlarged head circumference have also been observed. A bulging of the upper lip with an exaggerated cupid's bow shape, and maxillary hypoplasia (underdevelopment of the upper jaw) with retraction have also been reported.

Several anomalies affecting the digits (fingers and toes) have been observed with the syndrome. A broadening of the thumbs and big toes (halluces) was reported in two brothers. The broadening was apparent in all distal phalanges of the fingers, although the pinkies were unaffected yet appeared to be clinodactylic (warped, or bent toward the other fingers). Additional eports described this broadness of the thumbs and big toes, with brachydactyly (shortness) in the distal phalanges of the other digits except the pinkies in affected individuals. On X-rays of a two-year-old boy with the disorder, the brachydactyly was shown to be caused by shortening of epiphyses (joint-ends) of the distal phalanges. The broadness and brachydactyly of the big toes in particular may give them a stunted, rounded and stub-like appearance.

The auditory, or "acoustic" abnormalities observed with the syndrome include sensorineural hearing loss and hoarseness. Two affected Turkish brothers with a mild form of this hearing loss, and a hoarse voice were reported. A laryngoscopic examination of both brothers revealed swelling of the vocal cords, and a malformed epiglottis. Sensorineural-associated hearing impairment and hoarsness was also observed in a 10-year-old girl and her father, and in a number of other cases.

Other characteristics seen with the syndrome include developmental delay, growth retardation, pulmonary stenosis (an obstruction of blood-flow from the right ventricle of the heart to the pulmonary artery) with associated dyspnea (shortness of breath), and renal agenesis (failure of the kidneys to develop during the fetal period). Undescended testes, hyperactivity and aggressive behavior have also been noted.

There are four grades of microtia:

- Grade I: A less than complete development of the external ear with identifiable structures and a small but present external ear canal

- Grade II: A partially developed ear (usually the top portion is underdeveloped) with a closed [stenotic] external ear canal producing a conductive hearing loss.

- Grade III: Absence of the external ear with a small peanut-like vestige structure and an absence of the external ear canal and ear drum. Grade III microtia is the most common form of microtia.

- Grade IV: Absence of the total ear or anotia.

Anotia ("no ear") describes a rare congenital deformity that involves the complete absence of the pinna, the outer projected portion of the ear, and narrowing or absence of the ear canal. This contrasts with microtia, in which a small part of the pinna is present. Anotia and microtia may occur unilaterally (only one ear affected) or bilaterally (both ears affected). This deformity results in conductive hearing loss, deafness.

Superior canal dehiscence syndrome (SCDS) is a set of hearing and balance symptoms, related to a rare medical condition of the inner ear, known as "superior canal dehiscence". The symptoms are caused by a thinning or complete absence of the part of the temporal bone overlying the superior semicircular canal of the vestibular system. There is evidence that this rare defect, or susceptibility, is congenital. There are also numerous cases of symptoms arising after physical trauma to the head. It was first described in 1998 by Lloyd B. Minor of Johns Hopkins University in Baltimore.

Conductive hearing loss occurs when there is a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane (eardrum), or middle ear (ossicles).

This type of hearing loss may occur in conjunction with sensorineural hearing loss (mixed hearing loss) or alone.

The goal of medical intervention is to provide the best form and function to the underdeveloped ear.

Primary symptoms:

- sounds or speech becoming dull, muffled or attenuated

- need for increased volume on television, radio, music and other audio sources

- difficulty using the telephone

- loss of directionality of sound

- difficulty understanding speech, especially women and children

- difficulty in speech discrimination against background noise (cocktail party effect)

Secondary symptoms:

- hyperacusis, heightened sensitivity to certain volumes and frequencies of sound, resulting from "recruitment"

- tinnitus, ringing, buzzing, hissing or other sounds in the ear when no external sound is present

- vertigo and disequilibrium

Usually occurs after age 50, but deterioration in hearing has been found to start very early, from about the age of 18 years. The ISO standard 7029 shows expected threshold changes due purely to age for carefully screened populations (i.e. excluding those with ear disease, noise exposure etc.), based on a meta-analysis of published data. Age affects high frequencies more than low, and men more than women. One early consequence is that even young adults may lose the ability to hear very high frequency tones above 15 or 16 kHz. Despite this, age-related hearing loss may only become noticeable later in life. The effects of age can be exacerbated by exposure to environmental noise, whether at work or in leisure time (shooting, music, etc.). This is noise-induced hearing loss (NIHL) and is distinct from presbycusis. A second exacerbating factor is exposure to ototoxic drugs and chemicals.

Over time, the detection of high-pitched sounds becomes more difficult, and speech perception is affected, particularly of sibilants and fricatives. Patients typically express a decreased ability to understand speech. Once the loss has progressed to the 2-4kHz range, there is increased difficulty understanding consonants. Both ears tend to be affected. The impact of presbycusis on communication depends on both the severity of the condition and the communication partner.

Otosclerosis is traditionally diagnosed by characteristic clinical findings, which include progressive conductive

hearing loss, a normal tympanic membrane, and no evidence of middle ear inflammation. The cochlear promontory may have a faint pink tinge reflecting the vascularity of the lesion, referred to as the Schwartz sign.

Approximately 0.5% of the population will eventually be diagnosed with otosclerosis. Post-mortem studies show that as many as 10% of people may have otosclerotic lesions of their temporal bone, but apparently never had symptoms warranting a diagnosis. Caucasians are the most affected race, with the prevalence in the Black and Asian populations being much lower. In clinical practice otosclerosis is encountered about twice as frequently in females as in males, but this does not reflect the true sex ratio. When families are investigated it is found that the condition is only slightly more common in women. Usually noticeable hearing loss begins at middle-age, but can start much sooner. The hearing loss was long believed to grow worse during pregnancy, but recent research does not support this belief.

Congenital hearing loss is a hearing loss present at birth. It can include hereditary hearing loss or hearing loss due to other factors present either in-utero (prenatal) or at the time of birth.