In the diagnostic procedure for patients with symptoms and signs indic
ating VIIIth nerve or brain stem disturbances, the possible presence o
f tumors, infarcts, bleedings or microvascular loops are taken into ac
count. Ten patients with vertigo, balance disorders, tinnitus or unila
teral hearing loss proved to have a similar cause underlying the distu
rbances. They ranged in age from 51 to 80 years and had a duration of
their symptoms of 1-10 years. In the test battery audiology, electrony
stagmography, broad-frequency rotatory testing and dynamic posturograp
hy were used. No uniform pattern was present. The results showed VIIIt
h nerve as well as CNS signs. Trigeminal neuralgia and hemifacial spas
m were observed. CT, NMR or angiography were performed. The common fin
ding for these patients were ectatic vertebral and/or basilar arteries
. The size and position of the vessels indicated that compression of t
he VIIIth nerve or brainstem was the cause underlying their disturbanc
es. To exclude that macrovessels appear in patients without neurotolog
ical symptoms and signs 300 consecutive NMR investigations in patients
referred for other than neurotogic indications were scrutinized. In t
hese patients no macrovessels were found. The findings indicate that e
ctatic vessels may cause disturbances mimicking a pontine angle tumor,
Meniere's disease and other periferal or central conditions with inne
r ear symptoms, vertigo and balance disorders. Arterial loops in the p
ontine angle may give indications for microvascular surgery, but the b
ig ectatic vertebral and basilar arteries may offer surgical decompres
sion possibilities, though with large risks.