Test selection per patient (in DuLIP)

In this video, we will introduce you to the test battery used intraoperatively in several hospitals in the Netherlands and Flanders, the Dutch Linguistic Intraoperative Protocol or DULIP. The DULIP is a collaboration between Flanders and the Netherlands. And it is a standardised linguistic test battery to detect language impairments in all phases of awake brain tumour surgery pre-, intra- and post-operatively. We designed tests that can be administered during electrical stimulation– meaning with a time constraint of four seconds and tests that can be suitable only during resection– the meaning without a time constraints of four seconds to monitor language functions.

Test items were selected from formal databases to control for linguistic variables such as word frequency, which influences the degree of complexity of the task, phonology– that is sound, semantics– that is meaning, and syntax– that is grammar and also articulation– that we consider to be part of speech but not of language production. It is also important to continuously monitor language with spontaneous speech as slight deterioration can occur during resection. And this may be an indication to resume the stimulation procedure. Underneath this video, you can see an overview of the test divided into suitable for direct electrical stimulation or no direct electrical stimulation within the different linguistic levels– phonology, semantics, and syntax.

There is a link to the paper about the entire protocol for you to check out. Task selection of DULIP is patient tailored and based on two aspects, namely pre-operative language level of the patients. For instance, a patient with the mild aphasia should receive an adapted intraoperative test battery with relatively easy items as the linguist needs to be certain that paraphasias are caused by the simulation procedure and are not pre-existent The second is tumour location. It is known that a cortical level certain brain areas are commonly associated with specific language functions. In this table, we provide recommendations for task selection. For instance, if a tumour is located in the middle inferior temporal gyrus, we suggest to administer a semantic odd-picture-out task.

The aim of the semantic odd-picture-out test is to assess semantic judgments and naming. Two of the three pictures belong to the same semantic category, which is animals. The patient is requested to name the odd one out within four seconds– in this case, brush.

Also at subcortical level, certain networks are commonly associated with specific language functions. In the second slide underneath this video, we provide recommendations for task selection. For instance, if a tumour is located near the arcuate fasciculus, we suggest to administer repetition of words.

For example, the repetition tests consists of three syllabic words with different complexity levels, where a gorilla is the easiest item followed by caramel with phonemic similarity, spaghetti with a consonant cluster, and finally, microphone with a consonant cluster and phonemic similarity, which is visualised in bold. You’ve got an idea now of the variety of tests we designed. In the next steps, you will see how we decide which tests to use for patients.