Human Visual and Vestibular Motion Perception Study

Inclusion Criteria:

Healthy subjects:

* general good health

Vestibular Disease patients:

* general good health
* specific unilateral or bilateral vestibular loss

Exclusion Criteria:

Healthy subjects:

* subjects who are institutionalized or otherwise not self-sufficient.
* enduring sequelae due to diseases of the nervous system, eyes, ears, head and neck, and limbs, except for changes commensurate with normal aging (e.g. presbyacusic hearing loss, mild cataract, etc.).
* abnormal cognitive function, which if in question can be determined as a score of \<27 on the Mini-Mental State test.
* corrected visual acuity worse than 20/20 up to age 65, worse than 20/40 if \>65
* abnormal binocular stereo-acuity or visual fields.
* any defects in cranial nerve, oculomotor, cerebellar/coordination, and somatosensory functions.
* any abnormal oculomotor and vestibular function (caloric tests)

Vestibular Disease patients:

* Inability to perform the study tasks due to sensory, motor, or postural limitations