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.

Otosclerosis or otospongiosis is an abnormal growth of bone near the middle ear. It can result in hearing loss. The term otosclerosis is something of a misnomer. Much of the clinical course is characterised by lucent rather than sclerotic bony changes, hence it is also known as otospongiosis.

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.

Fluid accumulation is the most common cause of conductive hearing loss in the middle ear, especially in children. Major causes are ear infections or conditions that block the eustachian tube, such as allergies or tumors. Blocking of the eustachian tube leads to decreased pressure in the middle ear relative to the external ear, and this causes decreased motion of both the ossicles and the tympanic membrane.

- acute or serous otitis media

- otitis media with effusion or 'glue ear'

- Perforated eardrum

- Chronic suppurative otitis media (CSOM)

- Cholesteatoma

- Otosclerosis, abnormal growth of bone in or near the middle ear

- middle ear tumour

- ossicular discontinuity as a consequence of infection or temporal bone trauma

- Congenital malformation of the ossicles. This can be an isolated phenomenon or can occur as part of a syndrome where development of the 1st and 2nd branchial arches is seen such as in Goldenhar syndrome, Treacher Collins syndrome, branchio-oto-renal syndrome etc.

- Barotrauma unequal air pressures in the external and middle ear. This can temporarily occur, for example, by the environmental pressure changes as when shifting altitude, or inside a train going into a tunnel. It is managed by any of various methods of ear clearing manoeuvres to equalize the pressures, like swallowing, yawning, or the Valsalva manoeuvre. More severe barotrauma can lead to middle ear fluid or even permanent sensorineural hearing loss.

Due to variations in study designs, data on the course of tinnitus showed few consistent results. Generally the prevalence increased with age in adults, whereas the ratings of annoyance decreased with duration.

Myringosclerosis rarely causes any symptoms. Tympanosclerosis, on the other hand, can cause significant hearing loss or chalky, white patches on the middle ear or tympanic membrane.

Tinnitus can be perceived in one or both ears or in the head. It is the description of a noise inside a person’s head in the absence of auditory stimulation. The noise can be described in many different ways.

It is usually described as a ringing noise but, in some patients, it takes the form of a high-pitched whining, electric buzzing, hissing, humming, tinging or whistling sound or as ticking, clicking, roaring, "crickets" or "tree frogs" or "locusts (cicadas)", tunes, songs, beeping, sizzling, sounds that slightly resemble human voices or even a pure steady tone like that heard during a hearing test. It has also been described as a "whooshing" sound because of acute muscle spasms, as of wind or waves. Tinnitus can be intermittent or continuous: in the latter case, it can be the cause of great distress. In some individuals, the intensity can be changed by shoulder, head, tongue, jaw or eye movements. Most people with tinnitus have some degree of hearing loss.

The sound perceived may range from a quiet background noise to one that can be heard even over loud external sounds. The specific type of tinnitus called pulsatile tinnitus is characterized by hearing the sounds of one's own pulse or muscle contractions, which is typically a result of sounds that have been created by the movement of muscles near to one's ear, or the sounds are related to blood flow of the neck or face.

Tympanosclerosis (also known as myringosclerosis or intratympanic tympanosclerosis) is a condition caused by hyalinization and subsequent calcification of subepithelial connective tissue of TM and middle ear, sometimes resulting in a detrimental effect to hearing.

Hearing loss is sensory, but may have accompanying symptoms:

- pain or pressure in the ears

- a blocked feeling

There may also be accompanying secondary symptoms:

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

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

- vertigo and disequilibrium

- tympanophonia, abnormal hearing of one's own voice and respiratory sounds, usually as a result of a patulous eustachian tube or dehiscent superior semicircular canals

- disturbances of facial movement (indicating possible tumour or stroke)

Human hearing extends in frequency from 20-20,000 Hz, and in amplitude from 0 dB to 130 dB or more. 0 dB does not represent absence of sound, but rather the softest sound an average unimpaired human ear can hear; some people can hear down to -5 or even -10 dB. 130 dB represents the threshold of pain. But the ear doesn't hear all frequencies equally well; hearing sensitivity peaks around 3000 Hz. There are many qualities of human hearing besides frequency range and amplitude that can't easily be measured quantitatively. But for many practical purposes, normative hearing is defined by a frequency versus amplitude graph, or audiogram, charting sensitivity thresholds of hearing at defined frequencies. Because of the cumulative impact of age and exposure to noise and other acoustic insults, 'typical' hearing may not be normative.