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Isolated Horizontal Positional Nystagmus from a Posterior Fossa Lesion Hyo-Jeong Lee, MD, PhD,1 Eun Soo Kim, MD,2 Minbum Kim, MD,3 Hosuk Chu, MD,4 Hyeo-Il Ma, MD, PhD,5 Joong Seob Lee, MD,1 Ja-Won Koo, MD, PhD,6 Hyung-Jong Kim, MD, PhD,1 and Sung Kwang Hong, MD1 Isolated vertigo with horizontal positional nystagmus as an impending sign of a central lesion has rarely been reported. Here we present neuro-otologic findings of patients with these clinical signs. Lesion overlays from 6 patients with ageotropic positional nystagmus revealed that the nodulus and vermis are common areas of injury. In contrast, 2 patients with geotropic positional nystagmus had cerebellar peduncle and lateral medullary lesions. These clinical findings suggest that vertigo with horizontal positional nystagmus, even in the absence of other initial neurological signs, may indicate a posterior fossa lesion, including that in the nodulus, vermis, and deep cerebellar structures. ANN NEUROL 2014;76:905–910

In this report, we present 8 patients who were initially assumed to have geotropic- or ageotropic-type BPPV involving the lateral SCC (LSCC), but were finally diagnosed as having CPPV due to a posterior fossa lesion. We subsequently attempted to define the central structures responsible for pHN using a lesion analysis technique.

Patients and Methods Subjects Eight patients with vertigo and pHN who were ultimately diagnosed with a central lesion were recruited from 2008 to 2013. Inclusion criteria were: (1) patients who were initially considered to have LSCC BPPV, according to the America Academy of Otolaryngology–Head and Neck surgery 2008 criteria1; (2) no neurological sign other than pN at initial neurological examination; and (3) confirmed presence of a midline posterior fossa lesion by magnetic resonance imaging (MRI) of the brain.

Neurological Examination Spontaneous nystagmus (SN), head-shaking nystagmus, and pN were measured using a 2-dimensional video nystagmography system (System 2000; Micromedical, Chatham, IL). pN was measured during sitting, lying down, supine roll (head turning to the left, head center, and then to the right in a supine position), sitting up, head bending, and the bilateral Dix–Hallpike position, in that order.

Lesion Analysis

A

specific change in head position can result in vertigo associated with nystagmus under pathological conditions, collectively referred to as benign paroxysmal positional vertigo (BPPV), which is thought to be due to inertial changes in endolymph caused by trapped otolithic debris in the semicircular canal (SCC).1 Thus, if a patient presents with brief vertigo spells with positional nystagmus (pN) aligned with the SCC without neurological deficits, BPPV should be considered first in the differential diagnosis. However, vertigo with pN has also been reported as a presenting sign of central lesions,2–5 and is termed central paroxysmal positional vertigo (CPPV). In particular, positional downbeat nystagmus has been reported as the most frequent type of CPPV.6–10 In addition, positional upbeat or pure torsional nystagmus may be a sign of a central lesion.11 In contrast, positional horizontal nystagmus (pHN) of central origin without initial neurologic deficits has rarely been documented. To the best of our knowledge, this clinical presentation has been reported in only 2 cases.5,12

The brain MRI scans of the 8 patients were acquired using a 1.5T scanner (Intera; Philips Healthcare, Best, the Netherlands). The MRI protocol was composed of diffusion-weighted images (DWIs), T1-weighted images (T1WIs), contrast-enhanced T1WIs, T2WIs, and fluid-attenuated inversion recovery (FLAIR). The lesions from tumors and stroke were identified on contrast-enhanced T1WI and DWI sequences, respectively,

From the Departments of 1Otorhinolaryngology and 2Neuroradiology, Hallym University Sacred Heart Hospital, Anyang; 3Department of Otorhinolaryngology, Inha University Hospital, Incheon; 4Hana ENT Hospital, Seoul; 5Department of Neurology, Hallym University Sacred Heart Hospital, Anyang; and 6Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seongnam, South Korea Address correspondence to Dr Hong, Department of Otorhinolaryngology, Hallym University Sacred Heart Hospital, 22, Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang-si, Gyeonggi-do 431-796, South Korea. E-mail: [email protected] Received May 9, 2014, and in revised form Sep 29, 2014. Accepted for publication Oct 5, 2014. View this article online at wileyonlinelibrary.com. DOI: 10.1002/ana.24292

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which then were verified on FLAIR sequence to demarcate the damaged region and perilesional edema. The boundary of the lesion was delineated directly on each transversal slice of individual magnetic resonance images using MRIcron software (http://www.mccauslandcenter.sc.edu/mricro/ mricron) by a neuroradiologist blinded to the clinical details. Both the MRI scan and the lesion frame that were drawn as volumes of interest were mapped into stereotaxic space using the spatial normalization algorithm provided in SPM 8 (http://www. fil.ion.ucl.ac.uk/spm). Then all lesions were overlaid on a T1-weighted template MRI scan according to the Montreal Neurological Institute standard corresponding to Talairach z2coordinates of 252, 242, 232, 227, and 222mm. The lesion of Patient 1 was flipped to the left side, so that all lesions were arranged on the left side for the lesion analysis. The MRI scanning was repeated during the following days in Patient 8, because the initial MRI with DWI was determined to be falsely normal after onset of mild neurologic deficits in addition to pHN. This late scan, which facilitated a definitive diagnosis (lateral medullary infarct), was used for lesion marking. Overlapping images are illustrated as a percentage overlay plot indicating relative frequencies of lesions in patients with ageotropic pHN.

Results Patient Demographics Eight patients (4 men, 4 women; mean age 5 52.5 years; range 5 21–80) were included (Table). All patients presented with dominant pHN with no accompanying neurological sign at the initial visit. Ageotropic pHN was found in 6 patients (6 of 8, 75%), whereas 2 patients had geotropic pHN. Patient 2 also showed SN beating to the right side. In this case, the presence of ageotropic pHN and sudden hearing loss initially masked the possibility of a cerebellar infarct. All subjects showed dominant persistent pHN after repeated canalith repositioning therapy. Brain MRI revealed midline cerebellar tumors in 4 patients (3 ageotropic type and 1 geotropic type, Fig 1), 3 of whom had lesions affecting the bilateral nodulus; the remaining patient had a lesion in the cerebellar peduncle. Newly developed headache was seen in 75% of patients (3 of 4, 75%) with cerebellar tumors. Acute infarction was found in 4 patients (3 ageotropic type, 1 geotropic type, see Fig 1). Two patients with lateral medullary infarcts showed different types of pHN.

Lesion Analysis The main anatomical lesion sites in patients with ageotropic pHN were the cerebellar vermis and nodulus (Fig 2). Four of 6 patients with ageotropic pHN had lesions including the nodulus and vermis, and the remaining 2 had lesions including the medulla. The 2 patients with 906

geotropic pHN had lesions respectively in the superior and middle cerebellar peduncle, and lateral medulla.

Discussion In this study, lesion analysis provided additional evidence that lesions of the midline cerebellum and lateral medulla may cause pHN as initial signs without overt neurologic deficits. Theoretically, lesions of the flocculonodular lobe may exhibit diverse clinical manifestations because of the direct reciprocal connection of this lobe, as the destination of the primary vestibular afferents, with peripheral vestibular networks.13 pN is also known to occur in association with nodular lesions,5 possibly due to the role of the nodulus in the processing of graviceptive and translational otolith signals.13–17 However, the nystagmus associated with such lesions is usually vertical9,10,15 and associated with other neurological signs including periodic alternating and gazed-evoked nystagmus, ataxia, and cerebellar dysmetria.3,7,15,18 In contrast, 4 of the herein-described patients with nodulus lesions initially presented with ageotropic pHN without other neurologic deficits, which is a phenomenal clinical presentation. A previous animal study reported that the trajectory of eye velocity followed the rotation axis rather than the yaw axis eigenvector to the gravitoinertial acceleration after nodulouvulectomy.17 Therefore, we speculated that the eye velocity components of our patients may be aligned with the rotation axis during supine rolling, which in turn may lead to positional ocular drift of the ageotropic type according to the postrotatory eye-holding failure. Interestingly, Patient 3 (see Fig 1C), who had a unilateral nodular infarct, showed subtle SN beating to the lesion side. In contrast, Patients 1, 4, and 5, who had lesions including bilateral nodulus, did not show SN. Therefore, we presumed that bilateral impairment of the central vestibular network did not cause vestibular tonic imbalance in the static state. A combined anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) territory infarct may also generate ageotropic pHN with reference to gravity due to disinhibition of the deep cerebellar and vestibular nuclei. Shaikh et al reported gravity-dependent nystagmus in 2 patients with combined AICA and PICA territory infarcts, but in whom direction-changing ageotropic nystagmus was only induced during head rolling to one side.19 However, our patient with a combined AICA and PICA territory infarct (Patient 2) showed ageotropic pHN on both sides, which is a distinct neurotologic finding. The patient with a tumor on the superior and middle cerebellar peduncle (Patient 7) showed geotropic Volume 76, No. 6

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M/21

M/43

M/48

F/54

F/76

F/80

F/40

M/58

1

2

3

4

5

6

7

8

HTN, DM, MI PSH



DM, HTN PSH

DM, HTN, sigmoid colon cancer

Lung cancer



DM



Past Medical History

Spontaneous episodic vertigo with falling tendency

Positional vertigo with disequilibrium

Spontaneous episodic vertigo

Mild dysphagia Newly developed headache Mild left facial numbness

30

4



3

3



2

Positional vertigo

Left ear hearing loss

2

Newly developed headache

Newly developed headache

60

60

Associated Symptoms at initial visit

Symptom Duration, Days

Positional vertigo with disequilibrium

Spontaneous vertigo aggravated by head turning

Spontaneous vertigo aggravated by head turning

Positional vertigo with disequilibrium

Type of Dizziness

RB









LB

RB



SN

Geotropic

Geotropic

Ageotropic

Ageotropic

Ageotropic

Ageotropic

Ageotropic

Ageotropic

Supine RollingInduced Nystagmus

Left canalolithiasis

Left canalolithiasis

Left cupulolithiasis

Right cupulolithiasis

Left cupulolithiasis

Left cupulolithiasis

Left ear sudden hearing loss with cupulolithiasis

Left cupulolithiasis

Initial Diagnosis

Left lateral medullary infarct

Left cbll high-grade glioma

Left lateral medullary infarct

Bilateral nodular metastatic tumor from colon cancer

Left cbll metastatic tumor from lung cancer

Left isolated nodular infarct

Left PICA 1 AICA territory infarct

Right cbll hemangioblastoma

Final Diagnosis

AICA 5 anterior inferior cerebellar artery; Cbll 5 cerebellar; DM 5 diabetic mellitus; F 5 female; HTN 5 hypertension; LB 5 left beating; M 5 male; MI 5 myocardial infarction; PICA 5 posterior inferior cerebellar artery; PSH 5 past stroke history; RB 5 right beating; SN 5 spontaneous nystagmus.

Sex/ Age, yr

No.

TABLE . Initial Neurotologic Details in Patients

Lee et al: Positional Central Nystagmus

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FIGURE 1: Axial magnetic resonance imaging according to the pattern of positional nystagmus. (A) Patient 1 and (B) Patient 4 showed ageotropic nystagmus in the supine rolling position, but they were ultimately diagnosed as having cerebellar tumors on fluid-attenuated inversion recovery (FLAIR) sequence. (C) Patient 3 and (D) Patient 8 initially presented with ageotropic and geotropic nystagmus, respectively, in the supine rolling test. Magnetic resonance FLAIR imaging revealed acute infarcts in the nodulus and lateral medulla, respectively. H 5 horizontal; V 5 vertical.

pHN. A previous study reported that an isolated plaque on the superior cerebellar peduncle was associated with positional nystagmus in off-vertical head positions.4 However, that case also described initial neurological deficits, such as vertical diplopia, as well as positional vertigo. Interestingly, 2 patients with lateral medullary infarcts (Patients 6 and 8) showed ageotropic and geotropic pHN, respectively, as initial signs. The dorsolateral medulla contains vestibular nucleus complexes that modulate central otolith signals as well as the descending spinothalamic tract, the descending and ascending pathways of cranial nerve V, and the nucleus ambiguous.20 Consequently, positional nystagmus due to central vestibular imbalance and failure of neural integrators may theoretically arise in the early phase of an infarct in this area. 908

We propose that lateral medullary infarcts may lead to gravity-dependent pHN triggered by supine rolling in the early phase. Further study is needed to validate this theory. Of course, LSCC BPPV could have been incidentally observed in our patients. However, considering that there are common areas responsible for pHN, as validated by the lesion analysis; that the pN resolved after its removal in patients with tumors; and that there is a discrepancy between the severity of vertigo and intensity of sustained nystagmus in the supine rolling position, it seems reasonable that the pHN was of posterior fossa origin. In conclusion, clinicians should be cognizant that pHN (especially the ageotropic type), even in the absence of other neurological signs, may be indicative of a posterior fossa lesion, including the nodulus and deep Volume 76, No. 6

Lee et al: Positional Central Nystagmus

FIGURE 2: Lesion analysis plot. (A) Overlay lesion plot in patients with ageotropic nystagmus (n 5 6). The number of overlapped lesions is illustrated by different colors encoding for increasing frequencies and color bar indicates the number of overlapped lesion from purple (n 5 1) to pale yellow (n 5 6). (B) Overlay lesion plot of patients with geotropic nystagmus (n 5 2). Talairach z2coordinates for each axial slice are given.

cerebellar structures. This differential should be considered if persistent pHN is observed after repeated canalith repositioning therapy in patients with vascular risk factors and concomitant cranial nerve signs, newly developed headaches, or a discrepancy between the severity of vertigo and intensity of sustained nystagmus.

acquisition of data, study supervision. S.K.H.: study conception and design, drafting/revising manuscript, study supervision, analysis and interpretation of data.

Potential Conflicts of Interest Nothing to report.

Acknowledgment This study was supported by National Research Foundation of Korea (NRF) grants funded by the Korean Government (NRF-2014R1A1A2A16054791, NRF-2013R1A1A3006 802) and the Hallym University Research Fund (HURF2013-01). We thanks to J-H Kim, research fellow at Hallym vestibulocochlear research lab for raw data collection and technical support.

References 1.

Bhattacharyya N, Baugh RF, Orvidas L, et al. Clinical practice guideline: benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 2008;139:S47–S81.

2.

Kattah JC, Kolsky MP, Luessenhop AJ. Positional vertigo and the cerebellar vermis. Neurology 1984;34:527–529.

3.

Shoman N, Longridge N. Cerebellar vermis lesions and tumours of the fourth ventricle in patients with positional and positioning vertigo and nystagmus. J Laryngol Otol 2007;121:166–169.

4.

Anagnostou E, Mandellos D, Limbitaki G, et al. Positional nystagmus and vertigo due to a solitary brachium conjunctivum plaque. J Neurol Neurosurg Psychiatry 2006;77:790–792.

5.

Kim HA, Yi HA, Lee H. Apogeotropic central positional nystagmus as a sole sign of nodular infarction. Neurol Sci 2012;33:1189–1191.

6.

Bertholon P, Tringali S, Faye MB, et al. Prospective study of positional nystagmus in 100 consecutive patients. Ann Otol Rhinol Laryngol 2006;115:587–594.

7.

Brandt T. Positional and positioning vertigo and nystagmus. J Neurol Sci 1990;95:3–28.

Authorship H.-J.L.: acquisition and interpretation of data, drafting manuscript. E.S.K.: analysis and interpretation of data. M.K.: acquisition of data, study supervision. H.C.: acquisition of data, study supervision. H.-I.M.: acquisition of data. J.S.L: acquisition and interpretation of data. J.-W.K.: acquisition of data, study supervision. H.-J.K.: December 2014

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8.

Sakata E, Ohtsu K, Shimura H, Sakai S. Positional nystagmus of benign paroxysmal type (BPPN) due to cerebellar vermis lesions. Pseudo-BPPN. Auris Nasus Larynx 1987;14:17–21.

9.

10.

11.

15.

Walker MF, Tian J, Shan X, et al. Lesions of the cerebellar nodulus and uvula impair downward pursuit. J Neurophysiol 2008;100: 1813–1823.

Bertholon P, Bronstein AM, Davies RA, et al. Positional down beating nystagmus in 50 patients: cerebellar disorders and possible anterior semicircular canalithiasis. J Neurol Neurosurg Psychiatry 2002;72:366–372.

16.

Walker MF, Tian J, Shan X, et al. Enhancement of the bias component of downbeat nystagmus after lesions of the nodulus and uvula. Ann N Y Acad Sci 2009;1164:482–485.

Solomon D, Cohen B. Stimulation of the nodulus and uvula discharges velocity storage in the vestibulo-ocular reflex. Exp Brain Res 1994;102:57–68.

17.

Buttner U, Helmchen C, Brandt T. Diagnostic criteria for central versus peripheral positioning nystagmus and vertigo: a review. Acta Otolaryngol 1999;119:1–5.

Cohen B, John P, Yakushin SB, et al. The nodulus and uvula: source of cerebellar control of spatial orientation of the angular vestibuloocular reflex. Ann N Y Acad Sci 2002;978:28–45.

18.

Kim DR, Lee HJ, Kim HJ, Hong SK. Dynamic changes in the inner ear function and vestibular neural pathway related to the progression of labyrinthine infarction in patient with an anterior inferior cerebellar artery infarction. Otol Neurotol 2011;32: 1596–1599.

19.

Shaikh AG, Miller BR, Sundararajan S, Katirji B. Gravity-dependent nystagmus and inner-ear dysfunction suggest anterior and posterior inferior cerebellar artery infarct. J Stroke Cerebrovasc Dis 2014;23:788–790.

20.

Rambold H, Helmchen C. Spontaneous nystagmus in dorsolateral medullary infarction indicates vestibular semicircular canal imbalance J Neurol Neurosurg Psychiatry 2005;76:88–94.

12.

Noh K, Park S, Kim H, Choi S. A case of cerebellar hemangioblastoma mimicking benign paroxysmal positional vertigo. Korean J Otorhinolaryngol Head Neck Surg 2013;55:58–61.

13.

Barmack NH. Central vestibular system: vestibular nuclei and posterior cerebellum. Brain Res Bull 2003;60:511–541.

14.

Sheliga BM, Yakushin SB, Silvers A, et al. Control of spatial orientation of the angular vestibulo-ocular reflex by the nodulus and uvula of the vestibulocerebellum. Ann N Y Acad Sci 1999; 871:94–122.

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Volume 76, No. 6

Isolated horizontal positional nystagmus from a posterior fossa lesion.

Isolated vertigo with horizontal positional nystagmus as an impending sign of a central lesion has rarely been reported. Here we present neuro-otologi...
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