Dysarthia
Dysarthria is a motor speech disorder caused by damage to the nervous system. Dysarthria will affect an individual’s ability to articulate (ability to speak clearly and coherently) speech sounds, which will cause a difficulty in producing speech effectively. The neurological damage which causes dysarthria results in impairment to any of the muscles used for speech, causing them to become paralysed, weak or uncoordinated.
There are many different types of dysarthria which vary depending on the underlying neurological damage. Each dysarthria will present with different symptoms which will vary in severity.
This type of dysarthria is caused by myoclonic and choreiform disorders (rapid or jerky movements), for example, Huntington’s disease. Hyperkinetic dysarthria is affected by abnormal rate and rhythm of speech, uncoordinated articulation and segments of sounds being deleted from words.
Hypokinetic dysarthria most commonly occurs with Parkinson’s disease. This type of dysarthria is characterised by poor articulation and worsening of speech in sentences and conversation in comparison with single words which will often sound clear.
Spastic dysarthria is caused by damage to the upper motor neurons. This type of dysarthria affects all areas of speech including respiration, voice and intonation. Individuals with spastic dysarthria will commonly have a hoarse voice.
Flaccid dysarthria is caused by damage to the lower motor neurons. Common characteristics include: hypernasality; nasal emission of air; breathiness during speech, audible inspiration and distorted consonants.
Mixed dysarthria is caused by impairment to more than one part of the nervous system. Characteristics can include any of the symptoms seen in any of the other types of dysarthria.
What causes dysarthria?
Dysarthria is caused by damage to the nervous system. Common conditions which cause damage to the nervous system include cerebral palsy, cranial nerve damage, multiple sclerosis, Parkinson’s disease and stroke.
Apraxia of speech
Apraxia of speech occurs after damage to the part of the brain which controls speech. The extent of apraxia depends upon the amount of damage to the brain and to which area. Individuals suffering from this disorder will have difficulty sequencing syllable sounds and words. Apraxia can also occur at the same time as dysarthria.
Cluttering
Cluttering is a type of language and fluency disorder. Patterns of thought become muddled upon speech production, resulting in an abnormal pattern of speech and often including breaks in normal speech production. People who suffer from this may also have difficulty in reading and writing. Awareness of this condition may not always be present, and attention and listening may also be affected.
What causes cluttering?
There are many different causes of cluttering. Some of these may be medical and therefore extremely individual. Side effects of certain medication as well as alcohol can also be a contributing factor of cluttering speech.
Stuttering
A stutter is a disruption of the usual flow of speech and ranges from stoppage of speech, repetition of words or syllables and prolonging sounds. A stutter can affect many people. People who stutter may block certain words out and try to use alternatives. Speech may sound tense, jumbled or forced depending on the severity and type of stutter.
Developmental stuttering affects young children who are still learning speech and language skills. Genetic factors significantly increase a person’s likelihood of developing this type of stutter.
Neurogenic stuttering occurs when damage to the brain prevents proper coordination between the different regions of the brain that play a role in speech.
What causes a stutter?
A combination of factors can cause stuttering, and it is often something which is present from a young age. Some of the causes are listed below:
It may be more likely for someone to have a stutter, if someone in their family has one too.
The amount of pressure on a person, and different situations involved in speech production can affect the severity and extent of a stutter.
Self perception and perception of speech can affect severity and extent of a stutter.
People who stutter can experience the following types of disruption:
The symptoms of stuttering can vary depending on the situation. Stress, excitement, or frustration can cause stuttering to become more severe. Some people may also find that certain words or sounds can make a stutter more pronounced.
Stuttering can cause both behavioral and physical symptoms that occur at the same time. These can include:
Lisp
A lisp develops through incorrect placement of the tongue during speech production most commonly with the sounds of ‘s’ and ‘z’. A lisp can be categorised into the following:
