An old man presented with complaints of frequent giddiness. Examination showed instability in Romberg test with eyes closed. Which of the following condition may give rise to this finding in this patient?

Romberg test: In peripheral vestibular lesions, the patient sways to the side of lesion. In central vestibular disorder, patient shows instability. Central vestibular disorders are, Veebrobasilar insufficiency Posterior inferior cerebellar aery syndrome (Wallenberg's syndrome) Basilar migraine Cerebellar disease Multiple sclerosis Tumors of brain stem and floor of IVth ventricle Temporal lobe epilepsy