Which of the following indicates a loss of function in spastic dysarthria?

• A. Improved coordination of muscle movement
• B. Loss of inhibitory control
• C. Enhanced muscle strength
• D. Increased range of motion

Answer: (B)

The presence of spastic dysarthria is characterized by a specific type of motor speech disorder that arises from damage to the upper motor neurons. One of the hallmark features of this condition is the loss of inhibitory control over the muscle mechanisms that regulate speech production.

In spastic dysarthria, the disruption in normal neural pathways leads to a hyperactive reflexes and increased muscle tone, which is primarily due to the lack of inhibition from upper motor neurons. As a result, individuals may experience stiffness and excessive tightness in their speech muscles, contributing to a strained or harsh vocal quality. The inability to control muscle contractions effectively results in a reduced capacity for fine motor control necessary for smooth and coordinated speech production.

Therefore, the indication of a loss of inhibitory control accurately reflects a key dysfunction in spastic dysarthria, showcasing how the condition affects the execution of speech through a disruption in normal muscle control mechanisms.