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.

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.

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.

TTS imperceptibly gives way to PTS.

In addition to hearing loss, other external symptoms of an acoustic trauma can be:

- Tinnitus

- Some pain in the ear

- Hyperacusis

- Dizziness or vertigo; in the case of vestibular damages, in the inner-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.

Many people notice that they have SSHL when they wake up in the morning. Others first notice it when they try to use the deafened ear, such as when they use a phone. Still others notice a loud, alarming "pop" just before their hearing disappears. People with sudden deafness often become dizzy, have ringing in their ears (tinnitus), or both.

The first symptom of noise-induced hearing loss is usually difficulty hearing a conversation against a noisy background. The effect of hearing loss on speech perception has two components. The first component is the loss of audibility, which is something like a decrease in overall volume. Modern hearing aids compensate this loss with amplification. However, difficulty in understanding speech represents selective frequency loss for which hearing aids and amplification do not help. This is known by different names such as “distortion,” “clarity loss,” and “Signal-to-Noise-Ratio (SNR)-loss.” Consonants, due to their higher frequency, seem to be lost first. For example, the letters “s” and “t” are the common letters that are difficult to hear for those with hearing loss due to them being our highest frequency sound in our language. Hearing loss can affect either one or both ears. When one ear is affected it causes problems with directional hearing. Directional hearing provides the ability to determine from which direction a sound came. Lacking this ability can cause confusion within individuals who have hearing loss in one ear.

In hyperacusis, the symptoms are ear pain, annoyance, and general intolerance to many sounds that most people are unaffected by. Crying spells or panic attacks may result from the experience of hyperacusis. It may affect either or both ears. Hyperacusis can also be accompanied by tinnitus. Hyperacusis can result in anxiety, stress and phonophobia. Avoidant behaviour is often a response to prevent the effects of hyperacusis and this can include avoiding social situations.

Hearing loss is classified as mild, moderate, severe or profound. Pure-tone audiometry for air conduction thresholds at 500, 1000 and 2000 Hz is traditionally used to classify the degree of hearing loss in each ear. Normal hearing thresholds are considered to be 25 dB sensitivity, though it has been proposed that this threshold is too high, and that 15 dB (about half as loud) is more typical. Mild hearing loss is thresholds of 25–45 dB; moderate hearing loss is thresholds of 45–65 dB; severe hearing loss is thresholds of 65–85 dB; and profound hearing loss thresholds are greater than 85 dB.

Tinnitus occurring in only one ear should prompt the clinician to initiate further evaluation for other etiologies. In addition, the presence of a pulse-synchronous rushing sound may require additional imaging to exclude vascular disorders.

Hyperacusis (or hyperacousis) is a debilitating hearing disorder characterized by an increased sensitivity to certain frequencies and volume ranges of sound (a collapsed tolerance to usual environmental sound). A person with severe hyperacusis has difficulty tolerating everyday sounds, some of which may seem unpleasantly or painfully loud to that person but not to others.

"Hyperacusis" is often coincident with tinnitus. Both conditions have a prevalence of about 10–15% and hearing loss as a major risk factor. However, there also appear to be important differences between the mechanisms involved in tinnitus and hyperacusis.

Patients with unilateral hearing loss have difficulty in

- hearing conversation on their impaired side

- localizing sound

- understanding speech in the presence of background noise.

- interpersonal and social relations

- difficulty concentrating in large, open environments

In quiet conditions, speech discrimination is no worse than normal hearing in those with partial deafness; however, in noisy environments speech discrimination is almost always severe.

Auditory fatigue is defined as a temporary loss of hearing after exposure to sound. This results in a temporary shift of the auditory threshold known as a "temporary threshold shift" (TTS). The damage can become permanent (permanent threshold shift, PTS) if sufficient recovery time is not allowed for before continued sound exposure. When the hearing loss is rooted from a traumatic occurrence, it may be classified as noise-induced hearing loss, or NIHL.

There are two main types of auditory fatigue, short-term and long-term. These are distinguished from each other by several characteristics listed individually below.

Short-term fatigue

- full recovery from TTS can be achieved in approximately two minutes

- the TTS is relatively independent of exposure duration

- TTS is maximal at the exposure frequency of the sound

Long-term fatigue

- recovery requires a minimum of several minutes but can take up to several days

- dependent on exposure duration and noise level

Vertigo that arises from injury to the balance centers of the central nervous system (CNS), often from a lesion in the brainstem or cerebellum, is called "central" vertigo and is generally associated with less prominent movement illusion and nausea than vertigo of peripheral origin. Central vertigo may have accompanying neurologic deficits (such as slurred speech and double vision), and pathologic nystagmus (which is pure vertical/torsional). Central pathology can cause disequilibrium which is the sensation of being off balance. The balance disorder associated with central lesions causing vertigo is often so severe that many patients are unable to stand or walk.

A number of conditions that involve the central nervous system may lead to vertigo including: lesions caused by infarctions or hemorrhage, tumors present in the cerebellopontine angle such as a vestibular schwannoma or cerebellar tumors, epilepsy, cervical spine disorders such as cervical spondylosis, degenerative ataxia disorders, migraine headaches, lateral medullary syndrome, Chiari malformation, multiple sclerosis, parkinsonism, as well as cerebral dysfunction. Central vertigo may not improve or may do so more slowly than vertigo caused by disturbance to peripheral structures.

Known causes include physical trauma, acoustic neuroma, measles, labyrinthitis, microtia, meningitis, Ménière's disease, Waardenburg syndrome, mumps (epidemic parotitis), and mastoiditis.

Vertigo is a sensation of spinning while stationary. It is commonly associated with nausea or vomiting, unsteadiness (postural instability), falls, changes to a person's thoughts, and difficulties in walking. Recurrent episodes in those with vertigo are common and frequently impair the quality of life. Blurred vision, difficulty in speaking, a lowered level of consciousness, and hearing loss may also occur. The signs and symptoms of vertigo can present as a persistent (insidious) onset or an episodic (sudden) onset.

Persistent onset vertigo is characterized by symptoms lasting for longer than one day and is caused by degenerative changes that affect balance as people age. Naturally, the nerve conduction slows with aging and a decreased vibratory sensation is common.

Additionally, there is a degeneration of the ampulla and otolith organs with an increase in age. Persistent onset is commonly paired with central vertigo signs and symptoms.

The characteristics of an episodic onset vertigo is indicated by symptoms lasting for a smaller, more memorable amount of time, typically lasting for only seconds to minutes. Typically, episodic vertigo is correlated with peripheral symptoms and can be the result of but not limited to diabetic neuropathy or autoimmune disease.

Individuals with hemifacial microsomia, also called oculoauriculo-vertebral spectrum, often have ear malformations. These malformations can be in the form of preauricular ear pits, complete absence of the auricle, stenosis or atresia of the external auditory canal, ossicular malformations, middle ear deformities, and incomplete pneumatization of the temporal bone. Rahbar "et al." (2001) found that 95% of individuals with this syndrome have an ear malformation of some type. In addition to ear malformations, a conductive hearing loss can be present, typically ranging from mild to severe. There are also reported cases of cochlear involvement and sensorineural hearing loss. Rahbar "et al." (2001) found that 86% of patients with Hemifacial Microsomia have a conductive hearing loss and 10% have a sensorineural hearing loss. There is no correlation between the severity of dysmorphic features and the degree of hearing loss, meaning individuals with mild malformations can have severely impaired hearing.

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).

Endaural phenomena are sounds that are heard without any external acoustic stimulation. Endaural means "in the ear". Phenomena include transient ringing in the ears (that sound like sine tones), white noise-like sounds, and subjective tinnitus. Endaural phenomena need to be distinguished from otoacoustic emissions, in which a person's ear emits sounds. The emitter typically cannot hear the sounds made by his or her ear. Endaural phenomena also need to be distinguished from auditory hallucinations, which are sometimes associated with psychosis.

Auditory neuropathy (AN) is a variety of hearing loss in which the outer hair cells within the cochlea are present and functional, but sound information is not faithfully transmitted to the auditory nerve and brain properly. Also known as auditory neuropathy/auditory dys-synchrony (AN/AD) or auditory neuropathy spectrum disorder (ANSD).

A neuropathy usually refers to a disease of the peripheral nerve or nerves, but the auditory nerve itself is not always affected in auditory neuropathy spectrum disorders.

Based on clinical testing of subjects with auditory neuropathy, the disruption in the stream of sound information has been localized to one or more of three probable locations: the inner hair cells of the cochlea, the synapse between the inner hair cells and the auditory nerve, or a lesion of the ascending auditory nerve itself.

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)

Note: "The complete anatomy of the ear is extensive, and can be divided into the inner ear and outer ear. The remainder of this article mainly references the cochlea, outer hair cells, and organ of Corti."

In general, structural damages to any anatomical part of the ear can cause hearing-related problems. Usually, minor bending of the stereocilia of the inner ear is associated with temporary hearing loss and is involved in auditory fatigue. Complete loss of the stereocilia causes permanent hearing damage and is more associated with noise-induced hearing loss and other auditory diseases.

The outer hair cells, or OHCs, can be thought of as microamplifiers that provide stimulation to the inner hair cells. The OHCs are the most fragile of the hair cells, hence their involvement in auditory fatigue and other hearing impairments.

Dysacusis is a hearing impairment characterized by difficulty in processing details of sound due to distortion in frequency or intensity, but not primarily a loss of the ability to perceive sound. The term is sometimes used to describe pain or discomfort due to sound, a condition also known as auditory dysesthesia.

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.

King–Kopetzky syndrome is an auditory disability characterised by difficulty in hearing speech in the presence of background noise in conjunction with the finding of normal hearing test results.

It is an example of auditory processing disorder (APD) or "auditory disability with normal hearing (ADN)".

King–Kopetzky syndrome patients have a worse Social Hearing Handicap index (SHHI) than others, indicating they suffer a significant degree of speech-hearing disability.

The condition is named after Samuel J. Kopetzky, who first described the condition in 1948, and P. F. King, who first discussed the aetiological factors behind it in 1954.