Complexity of language (in the brain)

As we explained in Week 1, language consists of three levels– sentences, built out of words and those words built out of sounds. We mentioned that we need to distinguish between spoken and written language. And we are assuming a whole system of brain sites and connections via subcortical tracts in the left hemisphere. Depending on the site and the size of the tumour in a patient, different aspects of language may be impaired. However, the low-grade glioma tumours grow slowly. And thus allows the brain to compensate. A function that was once situated in the now infiltrated area will move to a different site.

This implies that in low grade glioma patients, there may be a shift in language involved areas, making it even more difficult to localise the precise spot, per individual. We need to test patients, pre-operatively, at different levels, in the different modalities, speaking, understanding spoken language, reading and writing. [DUTCH:] Can you give it a try? Testing The girl cooks in the pan

The boy listens to the bird In Wernicke’s area, the vocabulary is stored. If the lesion is found in this area, we need to focus on testing word retrieval. As we saw here week one, Broca’s area is important for articulation, but also for grammar. A tumour situated here means that we need to focus on the grammatical and articulation facilities of the patient. Notice that testing for nouns with an object naming test is insufficient, tests aiming at verbs also assess grammatical skills. The arcuate fasciculus brings the retrieved word forms to the frontal area.s A tumour infiltrating these tracts will result in an impairment to the sound structure of the words. The angular gyrus, was, as mentioned, crucial for reading and writing.

Realise, however, that this is a strong simplification. If you want to assess the word-finding problems and monitor them intra-operatively, we can use tests as the aforementioned object naming. We just show a picture of an object that the patient should name. The leading phrase triggers him or her to look for the ojects on the picture. For testing grammar, we show a picture of an action, like a man walking. The patients can see the beginning of the sentence, the man, and has to complete the sentence with a verb. So he has to retrieve the verb and to inflect it. This is a good measure of grammatical skills.

A very straightforward way to test the function of the arcuate fasciculus is the repetition of words. [DUTCH:] airplane wing airplane wing roadblock If the arcuate fasciculus is damaged, the patient will have problems with this task. For reading and writing, we developed a test for pre-surgical testing that is now available in Dutch and Italian. We will dive deeper next week into the language testing procedures and show many more tests.