title: Small strokes causing severe vertigo: frequency of false-negative MRIs and nonlacunar mechanisms.
abstract: OBJECTIVE
  Describe characteristics of small strokes causing acute vestibular syndrome (AVS).
  
  
  METHODS
  Ambispective cross-sectional study of patients with AVS (acute vertigo or dizziness, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with at least one stroke risk factor from 1999 to 2011 at a single stroke referral center. Patients underwent nonquantitative HINTS "plus" examination (head impulse, nystagmus, test-of-skew plus hearing), neuroimaging to confirm diagnoses (97% by MRI), and repeat MRI in those with initially normal imaging but clinical signs of a central lesion. We identified patients with diffusion-weighted imaging (DWI) strokes ≤10 mm in axial diameter.
  
  
  RESULTS
  Of 190 high-risk AVS presentations (105 strokes), we found small strokes in 15 patients (median age 64 years, range 41-85). The most common vestibular structure infarcted was the inferior cerebellar peduncle (73%); the most common stroke location was the lateral medulla (60%). Focal neurologic signs were present in only 27%. The HINTS "plus" battery identified small strokes with greater sensitivity than early MRI-DWI (100% vs 47%, p < 0.001). False-negative initial MRIs (6-48 hours) were more common with small strokes than large strokes (53% [n = 8/15] vs 7.8% [n = 7/90], p < 0.001). Nonlacunar stroke mechanisms were responsible in 47%, including 6 vertebral artery occlusions or dissections.
  
  
  CONCLUSIONS
  Small strokes affecting central vestibular projections can present with isolated AVS. The HINTS "plus" hearing battery identifies these patients with greater accuracy than early MRI-DWI, which is falsely negative in half, up to 48 hours after onset. We found nonlacunar mechanisms in half, suggesting greater risk than might otherwise be assumed for patients with such small infarctions.
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Ali S
authors.initials: AS
authors.lastname: Saber Tehrani
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Jorge C
authors.initials: JC
authors.lastname: Kattah
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Georgios
authors.initials: G
authors.lastname: Mantokoudis
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: John H
authors.initials: JH
authors.lastname: Pula
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Deepak
authors.initials: D
authors.lastname: Nair
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Ari
authors.initials: A
authors.lastname: Blitz
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Sarah
authors.initials: S
authors.lastname: Ying
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hanley
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: David S
authors.initials: DS
authors.lastname: Zee
authors.affiliation: From the Department of Neurology (A.S.S.T., J.C.K., J.H.P., D.N.), University of Illinois College of Medicine at Peoria; and Departments of Neurology (G.M., D.F.H., D.S.Z., D.E.N.-T.) and Radiology (A.B., S.Y.), Johns Hopkins University School of Medicine, Baltimore, MD. toker@jhu.edu.
authors.forename: David E
authors.initials: DE
authors.lastname: Newman-Toker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003388:Cranial Fossa, Posterior / Q000473:pathology; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic / Q000502:physiology; D011446:Prospective Studies; D020521:Stroke / Q000150:complications*; D059409:Stroke, Lacunar / Q000473:pathology; D014717:Vertigo / Q000209:etiology*