Article
Pre- and early postoperative cognitive functions of patients with frontal gliomas
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Published: | April 28, 2011 |
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Objective: The eloquence of brain areas is defined mostly by its relevance for language and motor function without consideration of other brain functions. Impairment of higher cognitive functions, however, including attention, memory and executive function deficits often remains unnoticed. Still, higher cognitive function deficits considerably affect the patients' quality of life and their ability to cope with daily demands.
Methods: 18 pts harbouring frontal gliomas underwent neuropsychological evaluation. Pts, who underwent stereotactic tumor biopsy were tested only prior to surgery. Pts receiving tumor resection were tested prior to and one week after surgery. The basic test battery included a Token Test and a Mini-Mental-Status-Test (MMST). An extended test battery included tests of attention (TAP, subtests alertness, Go/NoGo and divided attention; d2 test; TMT A), memory (WMS-r, subtests digit and block span forward & backward; VLMT; Rey Osterrieth Complex Figure Test), and executive functions (TMT B, FWIT, RWT). In case of a MMST-score of 18 or below, only basic tests were conducted. Tumor location and entity were assessed.
Results: Mean age was 55 years (28 - 84). 5 pts had low-grade and 13 high-grade gliomas. 17 pts underwent resection, 1 pt had stereotactic biopsy. In 10 pts, the tumor was located in the non-dominant hemisphere, in 5 pts in the dominant hemisphere, 3 pts displayed involvement of the midline and both hemispheres. Pts with lesions of the left hemisphere revealed a lower preoperative MMST-score compared to pts with lesions of the right hemisphere (22.2 vs. 28.1; p < 0.1). The same applied to subtests of the extended test battery (p < 0.05). In pts undergoing resection of right-sided frontal gliomas, we observed no significant deterioration of cognitive functions. Pts with left-sided gliomas revealed an improvement of cognitive functions after glioma resection from MMST-score 22.2 to 26.8 (p < 0.05). The same applied to subtests of the extended test battery as well.
Conclusions: Lesions of the left hemisphere are associated with a more pronounced impairment of cognitive function already prior to surgical resection. In patients with lesions without midline involvement of the non-dominant hemisphere, surgery influenced the test results only slightly. The improvement of cognitive function after resection of left-sided frontal gliomas may be due to reduction of the mass effect on eloquent brain tissue.