Flaccid dysarthria

Flaccid Dysarthria is a motor speech disorder resulting from neurological injury of the motor component of the motor-speech system and is characterized by weak, soft, and slow muscular movements. It is one of the several types of dysarthria, with each type resulting from damage to different parts of the nervous system. Flaccid dysarthria specifically arises due to damage to the peripheral nervous system, namely the cranial and spinal nerves that are responsible for activating the muscles of speech.

Causes

Flaccid dysarthria is most commonly caused by damage to the lower motor neurons, which directly innervate muscles. This damage can result from a variety of sources, including:

• Neurological disorders such as Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig's disease, which affects both upper and lower motor neurons.
• Infections that affect the nervous system, such as poliomyelitis or Guillain-Barré syndrome.
• Traumatic Brain Injury (TBI) that affects the nerves responsible for speech.
• Surgical procedures that inadvertently damage nerves involved in speech.
• Strokes that affect the lower motor neurons.

Symptoms

The symptoms of flaccid dysarthria are varied, depending on the specific nerves affected, and may include:

• Weakness in the muscles used for speech, leading to a soft voice.
• Slurred speech, making it difficult to understand the speaker.
• Slow speech due to the inability to move muscles quickly.
• Hypernasality, due to the inability to adequately close the velopharyngeal port.
• Breathy voice, as a result of inadequate closure of the vocal folds.
• Difficulty in articulating consonants, which requires precise movements of the tongue, lips, and palate.

Diagnosis

Diagnosis of flaccid dysarthria involves a comprehensive evaluation by a speech-language pathologist (SLP). This evaluation includes:

• A detailed history of the symptoms and their progression.
• A physical examination of the muscles used in speech.
• Speech assessment to identify the specific characteristics of the dysarthria.
• Neurological examination to identify possible causes of the symptoms.

Treatment

Treatment for flaccid dysarthria is tailored to the individual's specific symptoms and may include:

• Speech therapy to improve articulation and compensate for muscle weakness.
• Use of assistive devices to amplify the voice.
• Exercises to strengthen the muscles used in speech.
• Techniques to improve breath support for speech.

Prognosis

The prognosis for individuals with flaccid dysarthria varies depending on the underlying cause of the nerve damage. In some cases, such as when the dysarthria is caused by a reversible condition, significant improvement in speech may be possible. In other cases, such as with progressive neurological disorders, the goal of treatment may be to maintain speech function for as long as possible.