Dysarthria

Dysarthria is a speech disorder that, due to paralysis, weakness, or lack of coordination in the muscles involved in speech, causes difficulty pronouncing words.

In most cases, this muscular dysfunction stems from a neurological lesion that damages tendons, ganglia, and other parts of the nervous system responsible for coordinating the muscles of the face, tongue, palate, vocal cords, and larynx. There are several types of dysarthria depending on the area of the brain affected:

• Spastic dysarthria: occurs in the upper motor neuron and causes spasticity on one side of the body.
• Ataxic or cerebellar dysarthria: located in the cerebellum and results in muscle hypotonia, altered movement, and distortions in speech and voice.
• Flaccid dysarthria: occurs in the lower motor neuron, affecting movement, causing paralysis and muscle flaccidity, and distorted articulation of some sounds.
• Dysarthria due to lesions in the extrapyramidal system: affects regulation of muscle tone at rest.
  • Hypokinetic dysarthria: movements become slow and rigid.
  • Hyperkinetic dysarthria: involuntary movements and tremors occur.
  • Mixed dysarthria: the most complex, as it combines features of several of the above types.

Symptoms

Due to the nature of the condition, people with dysarthria often present a combination of symptoms that affect both motor ability and speech production. The speech-related signs vary depending on the type of disorder:

• Spastic dysarthria:
• Short phrases.
• Low pitch.
• Hoarse voice.
• Slow speech.
• Vowel distortions.
• Nasality.

• Ataxic or cerebellar dysarthria:
  • Harsh voice.
  • Altered stress patterns.
  • Vowel distortion.
  • Prolonged phonemes.

• Flaccid dysarthria:
  • Monotonous and hoarse voice.
  • Nasality.
  • Gasping.
  • Vocal cord weakness.
  • Consonant articulation.
  • Dysarthria due to extrapyramidal system lesions:
    • Hypokinetic dysarthria: short phrases, monotonous tone, variable rhythm.
    • Hyperkinetic dysarthria: vowel distortion, monotonous tone, imprecise articulation.

Causes

Head trauma, neurodegenerative diseases, and the use of certain medications (such as anticonvulsants or sedatives) are the main causes of dysarthria. There are two types of dysarthria depending on how it develops:

• Developmental dysarthria: a lesion that occurs during fetal development, often associated with hereditary factors. It manifests in childhood.
• Acquired dysarthria: occurs after language development is complete, as a result of conditions or events such as:
• Head injuries
• Muscular dystrophy
• Multiple sclerosis
• Amyotrophic lateral sclerosis (ALS)
• Brain tumor
• Stroke
• Parkinson’s disease
• Huntington’s disease

Risk Factors

The main risk factors for developing any type of dysarthria include:

• Advanced age
• Alcohol or drug abuse
• Neurodegenerative disease
• Presence of a brain tumor

Complications

The communication difficulties caused by dysarthria can lead to problems in personal relationships, potentially resulting in social isolation and depression. Additionally, they may limit the person’s ability to work or pursue education.

Prevention

Dysarthria cannot be prevented.

Which specialist treats dysarthria?

Dysarthria treatment is provided by a speech therapist, while diagnosis is performed by a neurologist.