Rebecca,
Migraine without headache is not necessarily "vestibular Migraine." A Migraine without a headache is termed an "acephalgic" or "silent" Migraine. You can read Acephalgic or Silent Migraine - The Basics for more information.
"Vestibular Migraine" is actually an old term that is not part of the the International Headache Society's International Classification of Headache Disorders, Second Edition (ICHD-II), which is the gold standard for diagnosing and classifying head pain disorders. The reason I tell you this is that when doctors use diagnoses that are not part of the ICHD-II, it can be very confusing. With no set criteria for those diagnoses, they can mean one thing when given by one doctor and something entirely different coming from another doctor.
The following Migraine diagnoses are defined by the ICHD-II:
1.1 Migraine without aura1.2 Migraine with aura 1.2.1 Typical aura with migraine headache 1.2.2 Typical aura with non-migraine headache 1.2.3 Typical aura without headache 1.2.4 Familial hemiplegic migraine (FHM) 1.2.5 Sporadic hemiplegic migraine 1.2.6 Basilar-type migraine1.3 Childhood periodic syndromes that are commonly precursors of migraine 1.3.1 Cyclical vomiting 1.3.2 Abdominal migraine 1.3.3 Benign paroxysmal vertigo of childhood1.4 Retinal migraine1.5 Complications of migraine 1.5.1 Chronic migraine 1.5.2 Status migrainosus 1.5.3 Persistent aura without infarction 1.5.4 Migrainous infarction 1.5.5 Migraine-triggered seizure1.6 Probable migraine 1.6.1 Probable migraine without aura 1.6.2 Probable migraine with aura 1.6.5 Probable chronic migraine
Teri