Amusia is the clinical word used to describe the condition popularly known as tone deafness. Those who suffer with this disorder can’t distinguish between different music tonalities, and some of them also have difficulty distinguishing between different rhythmic patterns. The term amusia isn’t generally used to describe every level of inability to perceive tonality, and it’s usually only applied to the most severe cases. People can be born with amusia, and it can also happen when people receive an injury to their brain.
When people with this disorder hear music, it can often sound like nothing but pure noise to them. Some are able to perceive music as a series of rhythmic tones, but they can’t distinguish well between varied notes or perceive melody. For example, if two consecutive piano notes are struck, a person with this condition will probably have difficulty telling the difference. Sometimes, he may be able to perceive the variation if the notes are at different ends of the piano, but not usually with any real precision.
Many people have a lack of ability to perceive tonality, but it may not always be severe enough to qualify as amusia. Studies have generally shown natural variation in tonal perception that can affect a person’s ability to sing in key or create music. Some people are particularly poor at this, while others are particularly good. The reasons for these differences aren’t entirely clear, but many experts think they are caused by a combination of genetic factors and music exposure during the formative childhood years.
Most experts think that amusia may also be caused by a combination of genetics and rearing. Many people with amusia have relatives that also suffer with the condition. Some experts think that the severity of the tone deafness can be affected by how much music exposure a child receives, but most believe that children are generally born with a relatively severe handicap when it comes to perceiving tones.
When people suffer a brain injury, sometimes the part of the brain that perceives music can be damaged, and they will develop amusia. These people are sometimes used to study the condition because they can potentially explain the differences between amusia and regular tonal perception in a way that people born with the condition cannot. Those who develop tonal perception problems after an injury don’t always develop full-on tone deafness, and there can sometimes be a wide range of symptoms from one patient to another.