hyperacusis , także: hyperacousis

Individuals with Williams syndrome often have hyperacusia and phonophobia which resembles noise-induced hearing loss, but this may be due to a malfunctioning auditory nerve.

This could lead to hyperacusia (dysfunction of the stapedius muscle, innervated by CN VII) and vertigo (wrong interpretation from the vestibular semi-circular canal's endolymph acceleration caused by alteration of CN VIII).