Speech has its rhythm and its beats . When we speak we don’t just drop an idea, but we separate the words, we give more emphasis to some than to others and we structure our speech. We pause and give a intonation and melody that make the communication a flow of information that can be understood in different aspects. This is derived from a large number of aspects, including emotionality and a sense of rhythm.

Prosody can be trained, and often greater richness and skill is acquired as we learn. But some people, for different reasons, either do not manage to achieve such learning or even if they have it, they lose it as a result of some kind of brain injury. These people present aprosody , a speech phenomenon that can lead to communication difficulties. Let’s see what it consists of.

What is aprosody?

Aprosody is considered a deficit or inability to understand and/or produce changes in voice pitch, rhythm or intonation . It is an alteration of one of the main paraverbal aspects of language, that is, one of the elements that allow us to vary the acoustics of the message we provide and that can have various effects on the message itself.

Bearing in mind that prosody allows information to be given emotional meaning, to qualify or even to imply the opposite of what is expressed, and also makes the message much more understandable for the receiver, we can consider that a person with aprosody will show an inability to reflect his emotions in his voice , regulating the tone of voice or controlling the timing and rhythm of speech , making his speech much more difficult to interpret.

Your message will be much flatter, not knowing exactly what you want to emphasize unless you explicitly indicate it. In short, the speech of someone suffering from aprosody tends to be monotonous and neutral . In some cases, you may not separate words or phrases well, making understanding even more complicated.

You will also have more difficulty, or even find it difficult, to understand elements such as other people’s voice changes and what they may imply about the message. There may be difficulties in capturing emotions. But we are not dealing with subjects who lack the ability to express their thoughts or who do not have emotions.

They are also not people who have any intellectual deficit or neurodevelopmental disorder (although it is common to see it in some of them). They are simply not capable of imprinting on their language the intonation, rhythm and emotional meaning that other people do.

As a problem affecting communication, it can have different effects on the life of the sufferer. Although in itself it does not usually represent a serious limitation that prevents social participation or the performance of any action, the person may be seen as cold and strange . Their way of expressing themselves may lead to misunderstandings and arguments, and may cause some type of social rejection or even some difficulty on a labour level. It is likely that the person will avoid initiating or maintaining conversations.

Types of aprosody

Not all subjects with aprosody have the same difficulties. In fact, at the time the concept was proposed, different typologies were also proposed depending on the brain location affected . Bearing this in mind, we can find different typologies, but three main types stand out

1. Sensory aposody

In this type of approsody the problem is at the level of understanding. The subject has severe difficulties in understanding and processing changes in the rhythm and intonation of others , and may have difficulty in recognizing the emotions of the receptors.

2. Motor aprosody

In this type of aprosody, the problem is fundamentally one of expression: as we have said before, the subject has a monotonous language and a lack of emotionality , and cannot modulate the voice correctly so that it offers information beyond the content of the message in question and/or does not control the rhythm. It is also frequent that they present certain mutism, facial rigidity and lack of gesticulation.

3. Mixed aprosody

In this case, the two types of difficulties mentioned above occur together.

What are its causes?

The causes of aprosody can be multiple, but usually can be found in the presence of neurological disorders or lesions .

The different investigations carried out indicate that these lesions would generally be found in the temporal and parietal lobes of the right hemisphere of the brain, linking emotional expression and the use of rhythm. Specifically, the damage would correspond especially to Broca’s area and Wernicke’s area of that hemisphere. This is a very common disorder in the clinical population, especially in those who have some kind of aphasic problem.

These injuries can occur from multiple conditions. It is frequent to appear in the face of traumatic brain injury , cerebrovascular accidents or neurodegenerative processes such as dementia (for example, it is common in dementias caused by Alzheimer’s and Parkinson’s disease).

It is also common and very characteristic of subjects with autism spectrum disorder. Aprosody is also associated with the use of substances such as alcohol, such as in subjects with alcohol dependence or those with fetal alcohol syndrome. Finally, it can appear in mental disorders such as schizophrenia, or in some cases in people who have experienced severe trauma.

Possible treatments

The approach to aprosody is usually multidisciplinary. It should be borne in mind that in most cases we are talking about the consequence of a brain injury, so should be considered first of all what has caused it .

One of the main strategies is to apply speech therapy and treatment techniques through modeling and imitation-based techniques in order to reduce their communication limitations. Biofeedback is also frequently used, especially in the motor type. Working on emotional expression through various channels can also be very useful. Psychoeducation and information are also important so that the person and the environment can understand what is going on and know how to handle and understand it.

Bibliographic references:

  • Ardila, A.; Arocho, J.L.; Labos, E. & Rodríguez, W. (2015). Dictionary of Neuropsychology.
  • Leon, S.A. & Rodríguez, A.D. (n.d.). Aprosodia and Its Treatment. American Speech Language Hearing Association. Florida.
  • Stringer, A. Y. (1996). Treatment of motor aprosodia with pitch biofeedback and expression modelling. Brain Inj. 10, 583-590.