His episodes have been induced by turning over in or getting in and out of bed, bending over and straightening up, and by reaching for something on a high shelf. One episode awakened him from sleep. Initial episodes were associated with nausea and vomiting. He complains of nonspecific dizziness and imbalance when walking. Hearing is normal for his age.
Neurological examination is uremarkable except for some mild difficulty when walking in tandem.
This patient presents with the classic history for benign paroxysmal positional vertigo, a condition that can be diagnosed at bedside using the Dix-Hallpike positioning test. There is typically a brief latency after the positional change, followed by a burst of torsional vertical nystagmus that typically lasts less than 30 seconds. Benign paroxysmal positional vertigo results from otoconial debris freely moving within the posterior semicircular canal under the influence of gravity. It is important to recognize this condition, as it is by far the most common cause of vertigo in older persons. A vascular cause for the episodic vertigo is unlikely, because all episodes were triggered by position change and there were no associated neurological symptoms suggesting ischemia within the vertebrobasilar system.