We continue with the case of the mysterious downbeat positional nystagmus. The patient returned after the weekend, reporting little change in his symptoms, which included brief vertigo with rolling over in bed, and ongoing unsteadiness on his feet for the past three months. At that point, I abandoned my suspicion of the otoconia having settled in the vestibule, and suspected that we had moved the particles from the right posterior canal to the right anterior canal during the previous canalith repositioning treatment a few days earlier. The right anterior canal is maximally stimulated by the left Dix-Hallpike test, so that is where we started. This is what we saw:
The left Dix-Hallpike elicited brief vertigo and upbeat torsional nystagmus that looked more like a right posterior canal response (except we were in the left Dix-Hallpike position). We proceeded to perform canalith repositioning for right anterior canal BPPV (which is an identical series of movements to treating left posterior canal BPPV). In position #2 (now we are rolling the patient’s head from left to right) we got a short burst of vertical upbeat nystagmus. Then we got no response in positions #3 and #4. I asked the patient if he minded grabbing a seat and waiting 30 minutes. I wanted to give any remaining misplaced otoconia particles plenty of time to settle.
A repeat maneuver 30 minutes later, which includes a left Dix-Hallpike, was completely negative in all four positions. We contacted the patient 72 hours later and he reported no vertigo when lying down or rolling over to either side, and 50 to 60% improvement in unsteadiness.
Photo courtesy of John Epley