The purpose of this study is to explore the diagnostic values associated with both a positive and negative Skull Vibration Induced Nystagmus Test (SVINT) performed in room light (with fixation). The hypotheses include: 1. A positive room light SVINT will be identified in individuals with moderate to severe vestibular asymmetries. 2. A positive room light SVINT will be present when 10 beats or more (counted over 10 seconds) of nystagmus are found with fixation blocked.

Dizziness and vertigo account for about four million visits to the Emergency Department per year and costs for management in the Emergency Department are estimated to be about four billion dollars per year. Vestibular problems are a major cause of dizziness. Simple to perform and inexpensive bedside vestibular tests are needed. The Skull Vibration-Induced Nystagmus Test (SVINT) with fixation blocked has been considered a vestibular gold standard test with strong psychometric values. No studies on the diagnostic accuracy of the SVINT in room light have been performed.

Inclusion Criteria:

• Clients 18 years and older with complaint of dizziness, vertigo, and/or imbalance who are willing to proceed with procedures of study.
• Inclusion for control group: no history of dizziness, vertigo, and/or imbalance.

Exclusion Criteria:

• Conditions that warrant immediate referral to the Emergency Department or Primary Care Physician (undiagnosed and unstable disorders relating to cardiac, neurologic, metabolic, etc, dysfunction); no history of dizziness, vertigo, and/or balance problems.
• Clients with conditions that therapists believe may be aggravated by testing including, but not limited to: variants of head injuries, migraines, seizure disorders, panic/anxiety, claustrophobia, severe headache and/or nausea, and hypersensitivity to sensory stimuli

Patients with complaints of dizziness, vertigo, and/or imbalance referred to the hospital outpatient physical therapy department.