Positional Nystagmus in Patients Evaluated for Dizziness and Imbalance

There is variability in the literature regarding the presence of positional nystagmus in healthy participants with reportedly normal vestibular and central nervous system function. This ranges from 7.5% to 88% and raises an important clinical question. If 88% of healthy participants have positional nystagmus then how is the clinician to interpret the presence of positional nystagmus in a patient presenting with dizziness and/or disequilibrium? The primary purpose of this investigation was to examine the prevalence and characteristics of positional nystagmus in patients evaluated specifically for dizziness and imbalance. Data was collected using retrospective chart review. 200 charts were randomly selected from all patients seen for evaluation of dizziness and imbalance over a period of eight months. Clinicians independently reviewed the data from positional testing for each chart. Nystagmus was present if there was a clear slow and fast phase component and there were three beats in a 10 s time window. Nystagmus direction and intensity data were collected. Results indicate positional nystagmus is present in 10.5% to 21% of patients evaluated for dizziness and imbalance. Use of liberal criteria for determining presence of positional nystagmus (i.e., 3 beats in 20 sec) may account for higher prevalence rates across other studies.