Which statement is least consistent with a left-hemisphere stroke pattern for apraxia of speech?

• A. Left inferior frontal gyrus involvement is typical for post-stroke AOS.
• B. Left insula involvement is typical.
• C. Left premotor cortex involvement is typical.
• D. Right parietal involvement is least consistent with left-hemisphere AOS patterns.

Answer: (D)

AOS after a left-hemisphere stroke mainly reflects disruption of the left-side motor planning network for speech. The regions most commonly implicated are the left inferior frontal gyrus, the left insula, and the left premotor cortex. When these areas are damaged, the brain’s ability to plan and sequence the precise movements needed for articulate speech is impaired, leading to the characteristic distorted speech sounds and groping.

Left inferior frontal gyrus is a key site for organizing articulatory movements, so its involvement fits perfectly with left-hemisphere AOS. The insula also contributes to planning and coordinating complex speech movements, and its damage is well documented in AOS cases. The left premotor cortex is essential for sequencing motor actions, so trouble there aligns with the disrupted speech motor programming seen in AOS.

The statement about right parietal involvement being least consistent with left-hemisphere AOS patterns makes sense because right parietal regions are not typically part of the left-lateralized speech motor planning network. In left-hemisphere AOS, you wouldn’t expect the right parietal lobe to be the primary driver of the disorder; its involvement would point to different or additional cognitive issues rather than the canonical left-hemisphere AOS pattern.