1. How is a “syndrome “defined and what are its key features?
A syndrome is a recurring pattern of symptoms.
The main syndromes are classified according to three key areas:
1. Severity of comprehension deficit
2. Linguistic features of spontaneous verbal expression
3. Repetition ability compared to spontaneous expression
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2. What are the neurological and linguistic characteristics of the following types of aphasia syndromes: Broca’s, Wernicke’s and Conduction aphasia.
Broca’s aphasia
Localization: BA 44, 45, 6 and underlying white matter (it extends to anterior insula and neighboring anterior temporal and inferior parietal areas)
Features:
- Dominant feature: agrammatism
- Word finding is preserved better than sentence formulation
- Auditory comprehension is slightly or moderately impaired
- Proximity to primary motor areas: usually accompanied by right hemiplegia and mild right facial weakness.
Wernicke’s aphasia
Localization: BA 40, 39, Posterior 22, and neighboring temporal and parietal regions, often the posterior insula is involved
Features:
- Poor language comprehension, jargon, often lacks awareness of semantic or neologistic paraphasias.
Conduction aphasia
Localization Disconnection syndrome: a dysfunction is caused by an impaired connection between structurally intact centers. In these cases it is due to a disruption in the arcuate fasciculus, which is an association tract that carries impulses from Wernicke’s area for listening to Broca’s area for speaking. This connection enables us to repeat and it is thought to be damaged in conduction aphasia.
Features:
- Expression deteriorates precipitously when repeating phrases of increasing length and complexity
- Identifying characteristic: disruption of repetition
- Word finding problems and paraphasias (production of unintended syllables, words, or phrases during the effort to speak).
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3. Why do we say that these syndromes have localizing value?
Aphasias have localizing value because the characteristic symptoms are associated with a specific part of the brain (to the exclusion of others). This is called functional localization value (question: what function? KEY!).