Patients with an impaired voice or speech are sometimes difficult to understand, but the symbolic meaning of their words has not changed. Patients with aphasia can be clearly understood, but the meaning of the words is impaired. Patients with aphasia usually have a lesion in the left hemisphere. Depending on the site and size of the lesion, the aphasia can be accompanied by symptoms of the pyramidal tract involving the right side of the body.
There are different forms of aphasia:
- Expressive or motor aphasia where the patient speaks hesitantly, searching for words, but does comprehend what is said to them or what is being asked of them;
- Receptive or sensory aphasia where the patient speaks fluently, but constantly uses incorrect words or makes grammatical errors and does not understand or poorly understands what is said to them. These two forms are the most well-known and are caused by lesions in Broca’s area and Wernicke’s area, respectively [Figure 1].
- There is also conduction aphasia where the pathways connecting Broca’s area and Wernicke’s area are disrupted. The patient has trouble repeating words and sentences, but spontaneous use of language is more or less intact.
Figure 1. Lateral view of the left hemisphere
There are, of course, various combinations of the above, depending on the site and extent of the lesion.
In the case of impaired use of language, the doctor must be able to differentiate between a lesion in the language centre and more global loss of brain function, as seen with dementia. To do this, the doctor should employ their knowledge of the patient’s past history and carry out an examination of the other higher cerebral functions.
Important focus points during the examination:
- During the history-taking, you should usually start with open questions (‘tell me, what can I do for you?’). Note whether the patient speaks fluently or less fluently.
- You should also ask closed ‘yes / no’ questions. In these cases it is important to assess whether the patient has understood your question.
- If you doubt whether the patient understands your questions, name some objects in the room and ask them to point them out.
- Ask the patient to repeat words and sentences.
- Ask the patient to name objects in the room (for example, objects on your desk).
If the patient can answer and carry out these questions and tasks faultlessly, aphasia is unlikely. If problems do arise during these tasks, further investigation is indicated.