A new Russian-language fMRI protocol allows preoperative mapping of language areas.

Neurolinguists from HSE University, together with radiologists from the Pirogov National Medico-Surgical Center, have developed a protocol in Russian for functional magnetic resonance imaging (fMRI), which maps the different areas of language before neurosurgical operations. The study was published in Frontiers of Human Neuroscience.

When neurosurgeons operate on brain tumours, their goal is to remove diseased tissue while preserving as much of the adjacent areas essential to various motor and cognitive functions, including language, as possible. The ability to preserve language areas determines whether the patient will have language impairment after the operation and will be able to communicate easily with others, hold a job and lead an ordinary life.

The exact location of language areas differs from person to person, so special methods must be used to map them in each patient. The most accurate method is direct electrical stimulation during neurosurgery. But sometimes the neurosurgeon needs to know in advance where the language areas of a given patient are located in order to best plan the operation. This preoperative mapping is carried out using functional MRI, or fMRI. While in an MRI scanner, the patient performs language-related tasks. Data analysis shows which areas of the brain are activated.

Until now, most preoperative language mapping protocols using this method were developed in English. Scientists from HSE University have developed the first Russian-language fMRI protocol that uses a linguistic task recommended by the international scientific community: sentence completion.

The patient should read aloud a sentence that is missing the last word (eg, “The audience watched a long…”) and end the sentence with an appropriate word (eg, “game” or “movie”) . This task is unique in that it involves both the production and comprehension of language at the sentence level, which allows a comprehensive mapping of the patient’s language areas.

The researchers validated the protocol in a control group of 18 healthy Russian-speaking volunteers between the ages of 30 and 53. The protocol was found to successfully map the most important areas of language in the frontal and temporal lobes of the brain and reveal the individual lateralization of language function, i.e. the degree to which this function relies on the left and right hemispheres of the brain. The researchers also demonstrated the high reliability of the protocol: each volunteer underwent the procedure twice several weeks apart and the results were similar. This is the first protocol in the Russian language that has undergone such extensive validation.

The first stage of the study has been completed, showing the validity and reliability of the protocol in the control group. We are now in the process of realizing the most important part: testing the protocol in clinical practice, using it for preoperative speech mapping in patients with brain tumors and epilepsy. We plan to analyze whether the protocol works equally well in the clinical groups as in the control group. We will check to what extent its results correspond to those of intraoperative mapping and, therefore, to what extent it should be applied in clinical practice. »

Svetlana Malyutina, researcher at the HSE Center for Language and Brain and co-author of the article.

Source :

National Research University – Graduate School of Economics

Journal reference:

Elin, K. et al. (2022) A new functional magnetic resonance imaging locator for preoperative language mapping using a sentence completion task: Validity, baseline condition choice, and test-retest reliability. Frontiers in human neuroscience. doi.org/10.3389/fnhum.2022.791577.

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