Neuropsychological assessment of patients undergoing surgery due to low-grade glioma involving the supplementary motor area.

OBJECTIVE

The aim of the study was to establish the usefulness of various neuropsychological tests in patients undergoing surgery due to low-grade glioma (LGG) involving supplementary motor area (SMA).

PATIENTS AND METHODS

21 patients diagnosed with LGG involving the SMA underwent, before and after surgery, screening tests (Mini Mental State Examination - MMSE, Montreal Cognitive Assessment - MoCA and Frontal Assessment Battery - FAB), tests to assess language functions (Addenbrook's Cognitive Examination-III - ACE-III, phonetic fluency tests and semantic fluency tests), tests to assess memory functions (Rey's 15-word test - RAVLT and Diagnostic Test for Brain Damage by Hillers- DCS), tests to assess executive functions (Wisconsin Card Sorting Test - WCST, Ruff Figural Fluency Test - RFFT and Trail Making Test).

RESULTS

Before surgery, in the screening tests the patients obtained below normal scores in the MoCA test only. After surgery, the scores of such tests were significantly worse than the scores before surgery, while the MMSE test scores continued to be within the normal range. In phonetic and semantic fluency tests, the patients obtained worse scores, both before and after surgery. The differences in the test scores between the two periods, i.e. before and after surgery, were statistically significant. Although the patients obtained worse scores both before and after surgery in the ACE III test, the differences in the test scores were not statistically significant. The scores obtained in all tests assessing the executive and memory functions before and after surgery were within the normal range. The scores in such tests (except the WCCT) dropped significantly after surgery.

CONCLUSIONS

Patients diagnosed with LGG involving the SMA reveal the impairment of cognitive functions, in particular language functions. After surgery, a significant impairment of all elementary cognitive functions, such as attention, memory, language and executive functions and complex cognitive functions, occurs. The most sensitive tests to detect cognitive disorders, executive dysfunctions and speech disturbances in patients undergoing surgery due to glioma include the MoCA, FAB and Phonetic and Semantic Fluency Tests.