What is an effect of cranial nerve damage in flaccid dysarthria regarding motor signs?

• A. Muscle spasms and rigidity
• B. Weakened muscles and diminished reflexes
• C. Exaggerated reflex responses
• D. Hyperactive muscle tone

Answer: (B)

The presence of weakened muscles and diminished reflexes is characteristic of flaccid dysarthria, which results from damage to the lower motor neurons, specifically the cranial nerves responsible for innervating muscles of speech. In this condition, the nerve damage leads to muscle weakness and atrophy because the muscles do not receive adequate stimulation. This results in a lack of movement control and affects speech production, leading to soft, breathy, or nasal speech.

Additionally, diminished reflexes are common because lower motor neuron damage interrupts the normal reflex arc. Since the muscles are unable to contract efficiently due to a lack of neural input, they become soft and flaccid. This information connects to flaccid dysarthria by highlighting how cranial nerve impairment directly affects muscle function, demonstrating why weakened muscles and diminished reflexes are the distinguishing features of this motor speech disorder.