Neurology · MU Sofia

20. Dysfunctions of speech, aphasia

Explains how speech depends on the cortex, cranial nerves, respiratory and phonatory muscles and hearing, and outlines the roles of Broca's area, Wernicke's area and the arcuate fasciculus. It then distinguishes dysarthria from aphasia and sets out five aphasia types (Broca, Wernicke, global, conduction and anomic) with their lesion sites and features, including a sample utterance. It closes with the bedside examination steps for assessing aphasia.

Inside: 4 sections · 2 labelled pictures · 15 flashcards · 2 min

Topic 20 of 88 in the MU Sofia syllabus for Neurology (Medicine, Year 4). The free AceMed note covers it in 4 sections, about 289 words (2 min of reading), with 15 flashcards.

In this note

  1. Dysfunctions of speech. Aphasia
  2. Speech and Language
  3. Dysfunctions of Speech
  4. Examination of Aphasia

Speech and Language

Speech is the motor expression of language and depends on:

  • Intact cerebral cortex
  • Cranial nerves (V, VII, IX, X, XII)
  • Respiratory and phonatory muscles
  • Normal hearing

Main Language Areas

1.Broca's area (dominant frontal lobe) → speech production

2.Wernicke's area (dominant temporal lobe) → language comprehension

3.Arcuate fasciculus → connects Broca and Wernicke areas

Dysfunctions of Speech

1. Dysarthria: A motor speech disorder caused by impaired control of speech muscles.

  • Causes: Cerebellar disease. Parkinson disease. Bulbar palsy. Stroke
  • Features: Slurred speech. Poor articulation. Language comprehension and content remain normal

2. Aphasia: Aphasia is an acquired disorder of language caused by lesions of the dominant cerebral hemisphere (usually the left hemisphere).

  • The patient has difficulty with: Speaking. Understanding. Reading. Writing
  • Consciousness and speech muscles are intact.

Types of Aphasia

1. Broca (Motor, Expressive, Non-Fluent) Aphasia

  • Lesion: Broca area (inferior frontal gyrus)
  • Features: Non-fluent, slow, effortful speech. Short "telegraphic" sentences. Comprehension relatively preserved. Repetition impaired. Patient aware of deficit
  • Example: "Want... water..."

2. Wernicke (Sensory, Receptive, Fluent) Aphasia

  • Lesion: Wernicke area (superior temporal gyrus)
  • Features: Fluent speech. Meaningless or inappropriate words. Poor comprehension. Repetition impaired. Patient often unaware of deficit

3. Global Aphasia

  • Lesion: Large lesion involving Broca and Wernicke areas
  • Features
  • Severely impaired speech production
  • Severely impaired comprehension
  • Reading and writing impaired

4. Conduction Aphasia

  • Lesion: Arcuate fasciculus
  • Features: Fluent speech. Good comprehension. Markedly impaired repetition

5. Anomic Aphasia

  • Lesion: Usually temporoparietal region
  • Features: Difficulty naming objects (anomia). Fluent speech. Good comprehension. Repetition preserved

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