Types of Aphasia

Why This Matters

Aphasia isn't just a vocabulary term to memorize—it's your window into understanding how the brain organizes language. When you study these different types, you're really learning about functional localization: the principle that specific brain regions handle specific cognitive tasks. The AP exam loves to test whether you understand why damage to different areas produces different symptoms, not just what those symptoms are.

Each type of aphasia demonstrates a key concept: the distinction between language production and comprehension, the role of neural pathways connecting brain regions, and how damage location predicts deficits. Don't just memorize that Broca's aphasia involves non-fluent speech—know that it proves production and comprehension are handled by different neural systems. That's the thinking that earns you points on FRQs.

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Production vs. Comprehension Deficits

The brain separates "making language" from "understanding language" into distinct processing systems, and damage to each area creates opposite symptom patterns.

Broca's Aphasia

• Non-fluent, telegraphic speech—patients struggle to produce grammatically correct sentences while comprehension remains relatively intact
• Frontal lobe damage to Broca's area disrupts the motor planning required for speech production
• Preserved understanding creates intense frustration; patients know what they want to say but can't get the words out

Wernicke's Aphasia

• Fluent but meaningless speech—patients produce grammatically correct sentences filled with jargon and made-up words (neologisms)
• Temporal lobe damage to Wernicke's area impairs the ability to comprehend spoken and written language
• Lack of awareness—patients often don't realize their speech makes no sense, a phenomenon called anosognosia

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Connectivity Disruptions

Language requires communication between brain regions—when the pathways connecting production and comprehension areas are damaged, unique deficits emerge even though the primary language areas remain intact.

Conduction Aphasia

• Fluent speech with poor repetition—patients can produce meaningful sentences and understand others but cannot repeat phrases accurately
• Arcuate fasciculus damage disrupts the neural highway connecting Wernicke's and Broca's areas
• Phonemic paraphasias—patients substitute incorrect sounds (saying "tevelision" for "television") and are typically aware of their errors

Global Aphasia

• Severe impairment in all language functions—both production and comprehension are devastated
• Extensive damage to multiple language areas, typically from a major stroke affecting the left hemisphere
• Communication limited to gestures—represents the most profound aphasia type, often with only a few recognizable words remaining

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Transcortical Aphasias: The Repetition Paradox

When damage spares the core language areas but affects surrounding cortex, patients show a striking ability: they can repeat phrases perfectly even when they can't produce or understand spontaneous speech.

Transcortical Motor Aphasia

• Non-fluent speech with intact repetition—similar to Broca's aphasia, but patients can repeat sentences verbatim
• Frontal lobe damage sparing Broca's area affects the ability to initiate speech while leaving the repetition circuit intact
• Echolalia may occur—patients repeat what others say automatically, sometimes without comprehension

Transcortical Sensory Aphasia

• Fluent nonsensical speech with intact repetition—similar to Wernicke's aphasia, but patients can accurately repeat phrases they don't understand
• Posterior damage sparing Wernicke's area disrupts meaning processing while preserving the sound-to-speech pathway
• Lack of awareness mirrors Wernicke's aphasia; patients produce jargon-filled speech without recognizing the problem

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Word-Finding Difficulties

The mildest form of aphasia targets a specific function—retrieving words from memory—while leaving the broader language system relatively intact.

Anomic Aphasia

• Word retrieval deficits—patients speak fluently but frequently pause, searching for specific words they can't access
• Circumlocution is the hallmark strategy—describing "the thing you write with" instead of saying "pen"
• Diffuse damage to parietal or temporal regions; considered the mildest aphasia with the best prognosis for recovery

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Quick Reference Table

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Self-Check Questions

1. Which two types of aphasia both feature fluent speech with poor comprehension, and what single feature distinguishes them from each other?

2. A patient can understand everything you say and can repeat sentences perfectly, but struggles to initiate spontaneous speech. Which aphasia type does this describe, and what brain region is likely damaged?

3. Compare and contrast Broca's and Wernicke's aphasia in terms of fluency, comprehension, and lesion location. How do these differences support the concept of functional localization?

4. Why does damage to the arcuate fasciculus specifically impair repetition while leaving spontaneous speech and comprehension relatively intact?

5. If an FRQ asks you to explain how aphasia research supports the idea that language involves multiple specialized brain systems, which three aphasia types would provide the strongest evidence, and why?