Pontine lesions mimicking acute peripheral vestibulopathy

Objectirtes-Clinical signs of acute peripheral vestibulopathy (APV) were re peatedly reported with pontine lesions. The clinical relevance of such a me chanism is not known, as most studies were biased by patients with addition al clinical signs of brainstem dysfunction. Methods-Masseter reflex (MassR), blink reflex (BLinkR). brainstem auditory evoked potentials (BAEPs), and DC electro-oculography (EOG) were tested in 232 consecutive patients with clinical signs of unilateral APV. Results-Forty five of the 232 patients (19.4%) had at least one electrophys iological abnormality suggesting pontine dysfunction mainly due to possible vertebrobasilar ischaemia (22 patients) and multiple sclerosis (eight pati ents). MassR abnormalities were seen in 24 patients, and EOG abnormalities of saccades and following eye movements occurred in 22 patients. Three pati ents had BlinkR-R-1 abnormalities, and one had delayed BAEP waves IV and V. Clinical improvement was almost always (32 of 34 re-examined patients) ass ociated with improvement or normalisation of at least one electrophysiologi cal abnormality. Brain MRI was done in 25 of the 44 patients and confirmed pontine lesions in six (two infarcts, three inflammations, one tumour). Conclusions-Pontine dysfunction was suggested in 45 of 232 consecutive pati ents with clinical signs of APV on the basis of abnormal electrophysiologic al findings, and was mainly attributed to brainstem ischaemia and multiple sclerosis. The frequency of pontine lesions mimicking APV is underestimated if based on MRI established lesions only.