[Evaluation of blink reflexes in cerebellopontine angle tumors]

Blink reflexes were analysed in 28 cases with cerebello-pontine angle tumors (22 cases of acoustic neurinoma and 6 cases of meningioma). In patients with acoustic neurinoma, delay or absence of R1 was found in all but two cases (91%) and abnormality of R2 was in 11 (50%). Estimating the mean latency difference of R1 on both sides it was found useful for establishing early diagnosis of small acoustic neurinomas, which had no apparent clinical signs of facial or trigeminal nerve involvement. In patient with obsolete hemorrhage (5 cases) or large cyst (6 cases) within the acoustic neurinomas, which were proven at operation, abnormality of blink reflexes was more prominent than in patient with solid tumors (11 cases). In patients with meningioma, although all were huge tumors, abnormality of R1 was less conspicuous in comparison with acoustic neurinoma. Bilateral delay of R2 was found in 3 of 6 patients. In 13 patients who underwent spinal accessory-facial anastomosis for facial palsy after removal of the tumors, R1-like response were recorded in all but one on the affected side and R2-like response was recorded in only one patient. Observing alteration of blink reflexes in patients with cerebello-pontine angle tumor was useful for establishing early diagnosis and evaluating function of trigeminal nerve, facial nerve and brainstem.