Abstract

Background
In addition to triad of oculomotor abnormalities, gait ataxia and a global confusion state, incomplete vestibular paresis also possible sign in Wernicke's encephalopathy. We know of only three prior studies on vestibular abnormalities in Wernicke's encephalopathy. Furthermore, previous reports have not described the auditory symptoms such as sensorineural hearing loss. Objectives: To investigate the characteristic pattern of vestibulocochlear dysfunction in Wernicke's encephalopathy.
Methods
Three patients with Wernicke's encephalopathy were evaluated with quantitative vestibulo-ocular reflex and ocular motor testing. Vestibulo-ocular reflex testing included caloric irrigation, earth vertical axis sinusoidal rotational test. Also to evaluate the auditory dysfunction, routine audiological tests such as auditory brainstem response (ABR), pure tone audiometry, speech audiometry, and stapedial reflex threshold testing were performed in 3 patients.
Results
All patients demonstrated hypoactive vestibular response to caloric: 2 patients showed bilateral caloric weakness and one patient showed definite unilateral caloric hypoexcitability. Characteristic findings in rotational chair testing were low gain at multiple low frequencies, increased phase lead at low frequency and low gain at VVOR test. Unilateral (1) or bilateral (1) sensorineural hearing loss of moderate degree on pure tone audiometry was found in two patients. Audiological evaluations suggested the main injury was to the cochlea. Following treatment with thiamine, one patient showed normal caloric response on both sides and much improved pursuit eye movement.
Conclusion
Our results suggest that vestibular abnormalities are essential signs in Wernicke's encephalopathy. Audiologic examinations suggest that hearing loss in Wernicke's encephalopathy is usually due to dysfunction of the cochlea.