Dispelling Mist That Obscures Positional Vertigo in Vestibular Migraine

Abstract

(1) Background: Patients with vestibular migraine (VM) often present with positional vertigo. A portion of these patients have features of benign paroxysmal positional vertigo (BPPV). It is a challenge to rapidly identify the BPPV component of VM associated with positional vertigo. (2) Methods: Retrospective data collected from 60 VM and 47 VM + BPPV patients were used to build a diagnostic model, and then prospective data from 47 patients were used for the external validation. All patients had VM manifesting as positional vertigo, with or without accompanying BPPV. The clinical manifestations and the results of vestibular function tests were comprehensively analyzed using logistic regression. (3) Results: The univariate and multivariate analyses showed that the age, symptom duration, tinnitus, ear fullness, nausea, head shaking nystagmus, the direction of the Dix-Hallpike and roll tests, and horizontal gain could help differentiate between the two groups. A nomogram and an online calculator were generated. The C-index was 0.870. The diagnostic model showed good discriminative power and calibration performance during internal and external validation. (4) Conclusions: This study provided a new perspective for diagnosing VM with positional vertigo by identifying the BPPV component and, for the first time, offers a prediction model integrating multiple predictors.

Keywords: benign paroxysmal positional vertigo; differential diagnosis; positional nystagmus; prediction model; vestibular migraine.

Figure 1

Timeline of the dynamic changes of positional nystagmus in 3 VM + BPPV patients throughout the course of the disease. Changes in positional nystagmus, including direction, SPV, and duration, during the course of the disease (left). Visual change in the direction of the patient’s positional nystagmus (right). (a) Patient 1 underwent one repositioning maneuver. And the typical BPPV nystagmus on the left side disappeared after the treatment. (b) Two repositioning maneuvers were performed in patient 2. However, the typical BPPV nystagmus on the left side did not disappear completely and new nystagmus appeared. (c) Patient 3 initially presented with typical ageotropic nystagmus. Subsequently, the nystagmus changed and could not be easily localized centrally or peripherally. DHR: Dix–Hallpike right; DHL: Dix–Hallpike left; RTR: roll test right; RTL: roll test left; LL: to the lower left; LR: to the lower right; L: to the left; R: to the right; UB: upbeating; DB: downbeating; T: torsional; UR: to the upper left; UL: to the upper right; -: negative; NA: not available. ¹ The patient’s nystagmus changed from a mixed vertical (upbeat)-torsional (the upper pole of the eyes beats toward the lower ear) nystagmus for 15 s to persistent rightward nystagmus. The red-colored block indicates that repositioning maneuvers have been performed.

Figure 2

Nomogram. The nomogram predicts the diagnostic probability for the 100th patient of the dataset. Red dots represent the value of this predictor for this patient. The total score can be obtained by adding up the scores corresponding to these red dots. The predicted probability can be calculated from the total score. The probability of this patient is 0.829 from the graph and is greater than 0.471, indicating that the patient is more likely to have VM + BPPV. HSN: head shaking nystagmus; DHR: Dix–Hallpike right; DHL: Dix–Hallpike left; RTR: roll test right; RTL: roll test left; SC: semicircular canal; Pr: probability. * p < 0.05.

Figure 3

Validation and clinical utility of the diagnostic model. (a) Calibration curve of development cohort; (b) calibration curve of validation cohort; (c) ROC curve of development cohort; (d) ROC curve in validation cohort; (e) DCA reveals that the nomogram provides a net benefit better than that of treating everyone (the grey line) or treating no one (the black line), with a broad range of probability threshold; (f) CIC. The red line indicates the number of people who were judged by the model to be at high risk for different probability thresholds. The blue line denotes the number of people who were judged by the model to be at high risk and actually had an outcome under a given probability threshold. A cost: benefit ratio is also at the bottom, denoting the cost-to-benefit ratio under different probability thresholds. ROC: receiver operating characteristic; AUC: the area under curve; DCA: decision curve analysis; CIC: clinical impact curve.

Figure 4

Flowchart of diagnosis and treatment for positional vertigo. PN: positional nystagmus; SC: semicircular canal; DHT: Dix–Hallpike test; RT: roll test; CNS: central nervous system; PV: positional vertigo; BPPV: benign paroxysmal positional vertigo; VM: vestibular migraine.