Noisy intracranial tumours.

Transorbital sound recordings were obtained from 21 patients with intracranial tumours, 28 patients with intracranial aneurysms and 20 control patients. The group of patients with tumours consisted of 12 patients with gliomas, of whom 6 had low-grade gliomas and 6 had high-grade gliomas, and 9 patients with meningiomas. All patients with gliomas, including the subgroup of patients with low-grade gliomas, as well as patients with aneurysms, had significantly different sound recordings in comparison to control patients. Recordings from glioma patients did not differ significantly from recordings of aneurysm patients. Radiological evaluation of the tumours was performed in order to establish which tumour characteristics were associated with abnormal sound recordings. It was found that the type of tumour, i.e., histology or malignancy grade, was a significant associated factor, whereas other tumour characteristics such as size, mass effect and amount of oedema were not. In conclusion, patients with specific types of intracranial tumours produced abnormal sounds which could not be distinguished from abnormal sounds recorded in patients with aneurysms. These results may be important for the interpretation of sounds recorded for the detection of intracranial pathology, especially for aneurysm screening.