I recently saw a patient referred for the generic complaint of “Dizziness.” When he got up from the chair in the waiting room, he had an obvious gait disorder and used both a cane and a family member’s arm to make it back to the examining room.
He did not complain of vertigo or lightheadedness, but reported that he had a history of frequent falls. He had fallen and hit his head a few months earlier, and the referring physician wondered if his “dizziness” might be related to that fall. The patient offered up little useful information.
When the patient was in the hearing test booth, the family reported that he was unsteady long before the fall, and had a 20-year history of alcohol abuse. He had not had a drink in several months.
Clinical Results
He had a symmetrical mild bilateral hearing loss and normal tympanograms. His rotational chair and calorics were perfectly normal. For someone who could not take a few steps without holding on to something or someone, his platform posturography was actually surprisingly good.
He “fell” on conditions 5 and 6, but was normal in conditions 1 through 4. His oculo-motor tests were all grossly abnormal, consistent with or suggestive of cerebellar dysfunction. Informal cerebellar exam showed obvious deficits in rapid alternating hand movements, finger to nose pointing and heel to shin tests.
The auditory evoked potential test was interesting. Waves I and III were prominent, normal and easily identified. Wave V was present at normal latencies, but it took a lot of tweaking to find a repeatable peak. In other words, morphology fell apart after wave III. There has not been much published in recent years about ABR’s and alcoholic related cerebellar degeneration, but back in the 1980’s a study showed ABR abnormalities in the majority of chronic alcoholic patients.
What I find interesting is that his complaints (from the limited perspective of a balance clinic) appear to be strictly related to motor control.
His Vestibular-Ocular Reflex (VOR) was perfectly normal, and his balance wasn’t all that bad either. His problem was that he could not generate efficient movement to take a step and rely on his feet landing where he wanted them to land, or to respond efficiently and quickly to any type of unexpected surface or movement. This is a case of pretty normal ascending pathway function, and severe deficit in the descending pathway.
Neurological Impact of Alcohol Abuse
Excessive alcohol consumption carries a heavy toll on both individual and societal levels, with profound repercussions for health, society, and economics worldwide. Even those who consider themselves moderate or social drinkers may not be immune to the damaging effects of alcohol on the brain.
Evidence suggests that structural and functional abnormalities in the brain are common even in these individuals, manifesting as regional brain damage and cognitive dysfunction. Furthermore, for those who not only indulge in heavy drinking but also suffer from vitamin B1 (thiamine) deficiency, such as in cases of Wernicke-Korsakoff syndrome, the consequences become more severe, affecting a broader spectrum of brain regions.
While the application of advanced neuroimaging and quantitative research has provided valuable insights into these changes, the precise mechanisms underlying alcohol-induced brain damage remain elusive.
Chronic alcohol abuse can lead to a variety of neurologic disorders, and a full discussion is beyond the scope of this blog and beyond my scope of practice and knowledge. For more information on this topic, click here.
I posted this condensed case study because this patient had such a clear presentation of cerebellar dysfunction, it may be helpful for developing diagnosticians to see how the pieces of this puzzle fit together.
About the author
Alan Desmond, AuD, is the director of the Balance Disorders Program at Wake Forest Baptist Health Center, and holds an adjunct assistant professor faculty position at the Wake Forest School of Medicine. He has written several books and book chapters on balance disorders and vestibular function. He is the co-author of the Clinical Practice Guideline for Benign Paroxysmal Positional Vertigo (BPPV). In 2015, he was the recipient of the President’s Award from the American Academy of Audiology.
**this piece has been updated for clarity. It originally published on January 27, 2015
