[Orbicularis oculi reflex in computerized tomography verified lesions of the posterior cranial fossa].

The blink reflex elicited by electrical stimulation was studied in 60 patients with lesions of the brainstem and cerebellum (ischemic lesions, non-traumatic bleedings or tumors), which were diagnosed by computertomography. The relationship between localized morphological changes in computertomography and changes in blink reflex has been studied. 46 patients (77%) had a pathologic blink reflex. Usually the blink reflex was normal in patients with a tumor of cerebellum. In bleedings or tumors of the brainstem a good relationship existed between localization and extension of the lesion and the pathological pattern of the blink reflex. In patients with thrombosis of the basilar artery no responses or single delayed responses to the electrical stimulation were found. A less good relationship was observed in ischemic lesions of the brainstem. This is interpreted as indicating possible multilocalization of vascular lesions in the brainstem. Nearly half of the patients with ischemic lesions also had supratentorial lesions. The influence of these lesions on the pattern of the blink reflex will be discussed.