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People with unilateral hearing loss can hear normally in one ear, but have trouble hearing out of the other ear. Causes include physical trauma, or mumps (Epidemic parotitis).

Profound unilateral hearing loss is a specific type of hearing impairment when one ear has no functional hearing ability (91dB or greater hearing loss). It is known to cause:
* Irritability
* Frequent headaches, stress
* Social isolation
* Trouble figuring out where sounds are coming from.
* Variable light dizziness
* Trouble paying attention in what people are saying: evasive behavior.
* Lack of sound depth: any background noise (on the room, on the car) is flat and wrongly interpreted by the brain. The effect is similar to what happens when people with unimpaired hearing try to watch, on a mono TV, someone speaking in a noisy crowd.
* Inability to filter out background noise or selectively listen to only the important portion of the noise in the environment.
* For sensorineural hearing loss, the lack of input coming from the damaged sensory apparatus can cause "ghost beeps" or ringing/tinnitus as the brain attempts to interpret the now missing sensory data. The frequency and the volume of the noise can increase according to one's physical condition (stress, fatigue, etc.). This can aggravate social problems and increase the difficulty of speech comprehension.

A profoundly prelingually deaf individual is someone who was born with insufficient hearing to acquire speech normally, or who lost their hearing prior to the age at which speech is acquired.

Peri-lingual deafness means to contract deafness while acquiring a first language.

Post-lingual deafness means to contract deafness after acquiring a first language.

Hearing impaired persons with partial loss of hearing may find that the quality of their hearing varies from day to day, or from one situation to another or not at all. They may also, to a greater or lesser extent, depend on both hearing-aids and lip-reading. They may perhaps not always be aware of it, but they do admit to it being important to see the speaker's face in conversation.

A person who is tone deaf lacks relative pitch, the ability to discriminate between notes. Thus one who is tone deaf is unable to accurately discriminate between musical notes and is thus also incapable of reproducing them. However, the particular quality of being tone deaf is descriptive of having difficulty or being unable to correctly hear relative differences between notes, while in common usage it refers to a person's inability to reproduce them accurately. The latter inability is most often caused by lack of musical training or education and not actual tone deafness.

The ability of relative pitch, as with other musical abilities, appears to be inherent in healthy functional humans. The hearing impairment appears to be genetically influenced, though it can also result from brain damage. While someone who is unable to reproduce pitches because of a lack of musical training would not be considered tone deaf in a medical sense, the term might still be used to describe them casually. Someone who cannot reproduce pitches accurately, because of lack of training or tone deafness, is said to be unable to "carry a tune." Tone deafness affects ability to hear pitch changes produced by a musical instrument and/or the human voice. However, tone deaf people seem to be only disabled when it comes to music, and they can fully interpret the prosody or intonation of human speech. It has been observed that in societies with tonal languages such as Cantonese and Vietnamese, there are almost no tone deaf people.

Tone deaf people often lack a sense of musical aesthetics, and much like a color blind person would not be apt to appreciate colorful visual art, some tone deaf people cannot appreciate music. Tone deafness is also associated with other musical-specific impairments such as inability to keep time with music (the lack of rhythm), or the inability to remember or even recognize a song. These disabilities can appear separately but some research shows that they are more likely to appear in tone deaf people

Tone deafness is also known variously as amusia, tune deafness, dysmelodia and dysmusia.

Tinnitus is a phenomenon of the nervous system connected to the ear, characterized by perception of a ringing or beating sound (often perceived as sinusoidal) with no external source. This sound may be a quiet background noise, or loud enough to drown out all outside sounds. It is sometimes referred to as "the club disease" as many people get temporary tinnitus at loud clubs or concerts.

Tinnitus can be objective (the sound, e.g., a bruit, can be perceived by a clinician) or subjective (perceived only by the patient).