Question
A 70-year-old woman attends a neurology follow-up 4 months after a brain infarction. She still has some mild deficits. Her past history includes high blood pressure and elevated cholesterol, for which she takes standard medications including an antiplatelet and statin.
On assessment:
- Speech is smooth and fluent
- She understands spoken language well
- However, she struggles to repeat phrases when asked
Which term best describes this language problem?
a. Motor speech disorder
b. Broca-type aphasia
c. Conduction aphasia
d. Global aphasia
e. Wernicke-type aphasia
Answer
Conduction aphasia
Detailed Explanation
This question is a classic post-stroke language disorder identification problem.
Key clinical clues:
- Fluent speech → rules out Broca (non-fluent)
- Good comprehension → rules out Wernicke (poor comprehension)
- Impaired repetition → highly specific clue
👉 This triad = Conduction aphasia
What is Conduction Aphasia?
It is caused by damage to the arcuate fasciculus, the neural pathway connecting:
- Broca’s area (speech output)
- Wernicke’s area (speech understanding)
Why repetition is affected
Repetition requires:
- Hearing the phrase (Wernicke)
- Transmitting it via arcuate fasciculus
- Producing it (Broca)
➡️ If the connection is damaged → repetition fails
Clinical features of Conduction Aphasia
- Fluent speech ✔
- Good comprehension ✔
- Poor repetition ❌
- Patient often aware of errors (tries to correct)
Why other options are wrong
Motor speech disorder (Dysarthria)
- Problem is muscle control, not language
- Speech is slurred, not a linguistic deficit
Broca aphasia
- Non-fluent, effortful speech
- Comprehension preserved
- Repetition also impaired, but fluency is key differentiator
Wernicke aphasia
- Fluent but nonsensical speech
- Poor comprehension
Global aphasia
- All domains affected: fluency, comprehension, repetition
Cheat Sheet for Exam
Aphasia Quick Table
| Type | Fluency | Comprehension | Repetition |
|---|---|---|---|
| Broca | ↓ | Normal | ↓ |
| Wernicke | Normal | ↓ | ↓ |
| Conduction | Normal | Normal | ↓ |
| Global | ↓ | ↓ | ↓ |
High-yield pearls
- Repetition impaired ONLY → think conduction aphasia
- Non-fluent speech → Broca
- Fluent but nonsense → Wernicke
- Everything impaired → Global
Flashcards
Q1. What structure is damaged in conduction aphasia?
A: Arcuate fasciculus
Explanation: It connects comprehension and speech production centers
Q2. Which aphasia has fluent speech but poor repetition?
A: Conduction aphasia
Explanation: Classic distinguishing feature
Q3. Which aphasia has preserved comprehension and non-fluent speech?
A: Broca aphasia
Explanation: Motor speech production defect
Q4. Which aphasia produces “word salad”?
A: Wernicke aphasia
Explanation: Fluent but meaningless speech
Q5. Which aphasia involves widespread brain damage?
A: Global aphasia
Explanation: Affects all language domains
MCQs (High Difficulty)
MCQ 1
A patient speaks fluently, understands commands, but cannot repeat even simple phrases. The lesion is most likely in:
a. Inferior frontal gyrus
b. Arcuate fasciculus
c. Superior temporal gyrus
d. Internal capsule
Answer: b. Arcuate fasciculus
Explanation: Classic conduction aphasia—disconnection syndrome
MCQ 2
Which of the following is FALSE regarding conduction aphasia?
a. Speech is fluent
b. Comprehension is impaired
c. Repetition is poor
d. Patient may recognize errors
Answer: b. Comprehension is impaired
Explanation: Comprehension is actually preserved
MCQ 3
A lesion in the inferior frontal gyrus produces:
a. Conduction aphasia
b. Wernicke aphasia
c. Broca aphasia
d. Global aphasia
Answer: c. Broca aphasia
Explanation: Inferior frontal gyrus = speech production
MCQ 4
Which feature best distinguishes conduction aphasia from Wernicke aphasia?
a. Poor repetition
b. Fluent speech
c. Preserved comprehension
d. Presence of neologisms
Answer: c. Preserved comprehension
Explanation: Both are fluent, but comprehension differentiates them
MCQ 5
Damage to the arcuate fasciculus primarily disrupts:
a. Motor articulation
b. Language comprehension
c. Transfer of linguistic information between areas
d. Memory formation
Answer: c. Transfer of linguistic information between areas
Explanation: It connects Broca and Wernicke areas
MCQ 6
Which aphasia is most likely if a patient speaks slowly with effort but understands everything?
a. Broca aphasia
b. Conduction aphasia
c. Wernicke aphasia
d. Global aphasia
Answer: a. Broca aphasia
Explanation: Non-fluent but comprehension intact
MCQ 7
A patient produces fluent but meaningless sentences and cannot follow commands. Diagnosis?
a. Broca aphasia
b. Conduction aphasia
c. Wernicke aphasia
d. Dysarthria
Answer: c. Wernicke aphasia
Explanation: Fluent + poor comprehension
Summary for Quick Exam Revision
Conduction aphasia is a classic post-stroke language disorder characterized by fluent speech and preserved comprehension but markedly impaired repetition. It results from damage to the arcuate fasciculus, which connects Broca’s and Wernicke’s areas, disrupting the transmission of linguistic information between comprehension and production centers. Patients are often aware of their mistakes and attempt self-correction. Differentiation from other aphasias is crucial: Broca aphasia presents with non-fluent speech and intact comprehension, Wernicke aphasia presents with fluent but meaningless speech and impaired comprehension, and global aphasia affects all domains. Repetition is the key distinguishing feature in exams—if it is selectively impaired with otherwise preserved function, conduction aphasia is the diagnosis. Understanding the anatomical basis allows rapid identification in clinical scenarios, especially in stroke patients.