The interpretation of static positional nystagmus in a balance clinic

Abstract

Objective: To review the current criteria for the interpretation of positional nystagmus (PN). Design: Videonystagmography data on PN was collected for 90 patients presenting for balance testing with a history of vertigo or imbalance (excluding those diagnosed with benign paroxysmal positional vertigo). These were compared to normative data from 90 asymptomatic subjects. A literature review was carried out regarding threshold criteria for clinically significant PN. These were evaluated using the data collected. Study sample: Clinic group: 90 patients; 37 male, 53 female. Age range 15–82 years. Normative group: Ninety subjects; 31 male, 59 female. Age range 21–79 years.

Results: PN was seen in 75.6% of the clinic group and in 50% of the normative group. The prevalence of nystagmus of slow phase velocity (SPV) > 3°/s was significantly higher in the clinic group than the normative group. The maximum SPV recorded in each position was greater from the clinic group than the normative group. Conclusions: This study supports the use of normative thresholds for SPV for both horizontal and vertical PN. A normative threshold of >3°/s for horizontal and >7°/s for vertical nystagmus is proposed.

Key Words:

• Static
• positional
• nystagmus
• VNG
• vestibular
• balance

Acknowledgements

This study was conducted with the approval of the Research and Development Departments of Aneurin Bevan University Health Board and Betsi Cadwaladr University Health Board.

Declaration of interest

No potential conflict of interest was reported by the authors.