Evaluation of brainstem function, using acoustic evoked potentials, in 26 patients harbouring a CSF shunt for non-tumoral aqueductal stenosis hydrocephalus.

26 patients harbouring a CSF shunt for non-tumoral aqueductal stenosis hydrocephalus underwent Brainstem Acoustic Evoked Potentials (BAEPs) recording, to evaluate brainstem function. Only 6 patients presented with normal responses both at standard and at sensitized tests. In the remaining 19 patients, BAEPs were abnormal, bilaterally in 10 cases, monolaterally in 9. Four out of the 6 normal responses belonged to the group recognized of congenital origin. As refers to ventricular size BAEPs were abnormal in 62% of patients with normal ventricle and in 92% of patients with enlarged ventricles. The most significant BAEPs abnormalities were found in patients with maximal ventricular dilation. It appears that BAEPs abnormalities are to the ascribed to both primary and secondary brainstem dysfunction: no reliable criterion to differentiate between these two possibilities is evident. In the individual patient, serial BAEPs recording may contribute to recognize the early phase of supratentorial hypertension due to shunt dysfunction.