Wernicke’s area recognizes sound as a language , but a higher concept area is required to convert sound into meaning. This concept area is then connected to Broca’s area where speech is generated. A direct connection , the arcuate fasciculus also exists between Wernicke’s area and Broca’s area.
Types Of Dysphasia
Receptive Dysphasia: The patient is unable to understand; his speech is fluent but words are meaningless. The lesion is in the Wernicke’s area in the temporal lobe.
Expressive Dysphasia: The patient is unable to express despite comprehension. Can cause frustration to patients who know in their minds what to say but cannot get the words out. Due to lesion in the Broca’s area in the frontal lobe.
Transcortical sensory dysphasia: It is similar to receptive dysphasia but with preserved repetition and is cause by lesion in the parietal-occipital concept area.
Transcortical motor dysphasia: It is similar to expressive dysphasia but with preserved repetition and is caused by incomplete lesion in Broca’s area.
Conductive Dysphasia: Refers to preserved comprehension and output with loss of repetition and is the result of a lesion in the arcuate fasciculus.
Nominal Dysphasia: Means difficulty naming objects and is a result of an angular gyrus lesion.
Examining a patient with Dysphasia
1. Introduce yourself and ask a few simple questions e.g can you tell me your name and date of birth?
2. Is there receptive dysphasia? Give a simple command e.g Close your eyes / With your right hand touch your nose and then more comlex two step or three step commands.
3. Is there expressive dysphasia? Get the patient talking further e.g Tell me a little more about where you live.
4. Is there global dysphasia? Ask the patient to name some objects e.g what is this? (show pen, tie and watch). If unable to name object, ask Is it a ….?
5. Assess word finding ability e.g name as many animals as you can think of
6. Assess repetition by askink the patient to repeat a sentence e.g A giraffe is a tall graceful animal.
7. Also examine and assess reading and writing as similar categories of problems may coexist like dyslexia and dysgraphia