Which disorder would be most likely diagnosed when there is a motor planning deficit in speech but not a primary weakness in muscles?

• A. Apraxia of Speech
• B. Dysarthria
• C. Aphasia
• D. Cluttering

Answer: (A)

Distinguishing motor planning from execution in speech. When the trouble lies in planning and programming the movements for speech, the mouth muscles themselves aren’t weak. You’d expect inconsistent articulation errors, groping for sounds, and distortions that vary across attempts, especially with more complex syllable structures, while strength and range of motion remain intact. This pattern fits apraxia of speech, a motor planning disorder affecting how the brain sequences the articulators for speech rather than the muscles themselves. In contrast, issues arising from muscle weakness or poor coordination—dysarthria—show true neuromuscular weakness and more uniform, execution-based errors. Language-processing problems, as in aphasia, affect understanding or formulation of language rather than the motor planning of speech. Cluttering centers on rapid, excessive speech rate and fluency issues rather than a primary planning deficit.