Technique helps preserve speech after brain surgery

NEW YORK, Apr 28 (Reuters) Mapping the language areas in the brain prior to surgery for brain tumours is an effective means to preserve essential language function, according to findings presented this week at the American Association of Neurological Surgeons annual meeting.

University of California, San Francisco neurosurgeon Dr Nader Sanai reported his experience with language mapping in 250 consecutive patients with gliomas adjacent to or within the language pathway. Gliomas are the most frequent primary brain tumours in adults, accounting for 40 percent of all tumors and 78 per cent of cancerous tumours.

''In resecting these gliomas, there is a high risk of damaging the person's language function and this is probably one of the most debilitating symptoms after brain surgery,'' Sanai noted in an interview with Reuters Health. ''Awake language mapping is one technique to avoid this that has really been refined in the last several years.'' Before surgery with language mapping, patients undergo a battery of neuropsychological tests to see if they are good candidates.

''Some patients are unable to tolerate the whole experience of being awake during the operation; some are emotionally unable to handle it,'' Sanai said.

At the time of resection of the tumour, various sites on the cortex of the brain are stimulated to find the exact language sites so the neurosurgeon can avoid them, the researcher explained.

Of the 250 glioma patients who underwent language-site mapping, 159 (63.6 per cent) had intact speech before surgery.

One week after surgery, 194 (77.6 per cent) remained at their baseline language function, while 21 (8.4 per cent) worsened and 35 (14.0 per cent) had permanent language deficits.

By six months, 52 of 56 patients (92.8 per cent) with new or worsened language deficits returned to baseline or better, and the remaining 4 (7.1 per cent) had permanent language deficits.

''Therefore, there is an overall risk of about 1.6 per cent of having a permanent language deficit,'' Sanai said, ''despite the fact that these are very large tumors in arguably the most eloquent area of the brain.'' This series of patients, Sanai said, represents the largest study to date examining language mapping for gliomas, and supports the use of language mapping ''as the rule, rather than the exception,'' for gliomas. Currently, language mapping is only being performed at select tertiary neurosurgery centers, such as UCSF.

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