What is Dysarthria?

Dysarthria is a motor speech disorder (or neuromuscular) disorder, which is caused by paralysis, weakness (paresis), or incoordination of the muscles of speech as a result of brain damage. Weakness in the muscles of speech can make a person’s speech difficult to understand and more effortful for the person to produce.

Affected Areas

Respiration – Breathing
The lungs are the energy source for speech. The individual may not have sufficient air or breath control when speaking. The individual may run out of breath before finishing speaking or may develop unnatural phrasing patterns. The speech may sound choppy. It may be slow and effortful or rapid in rate. The volume may be low due to shallow breathing.

Phonation – Voicing
The vocal cords may not vibrate adequately to produce good or consistent sound. The voice may be whispered or alternate between phonation and whispering.

  • Vocal Quality – When the vocal cords are weakened the voice may be affected in a number of ways:
    • Pitch The voice may sound too high or too low. There may be pitch breaks or sudden changes in pitch.
    • Tone Speech may be monotone or flat with a lack of the natural rise and fall of normal speech.
    • Vocal sound Speech may sound:
      • Hoarse or harsh
      • Breathy or weak
      • Strained or strangled

Articulation – Pronunciation
Weakness and incoordination of the oral musculature (lips, tongue and soft palate) causes the speech to sound “slurred, muffled or mumbled.” Pronunciation may be distorted and unclear.

Resonance
When there is poor movement of the soft palate (roof of the mouth) and of the throat muscles, speech may sound:

  • Nasal
    This occurs when too much air passes through the nose due to poor closing of the passageway from the mouth to the nose. The individual may sound like he is “speaking through his nose.”
  • Denasal
    This occurs when there is too much closure between the nose and the mouth and air is blocked from passing out through the nose. The individual sounds like he has a cold.
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