Research in Vestibular Science

Myung Whan Suh

20 Articles

The Principle and Methodology of Vestibular Evoked Myogenic Potential: Min Young Lee, Myung Whan Suh; Res Vestib Sci. 2015;14(1):9-14.

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Abstract PDF: Vestibular evoked myogenic potential (VEMP) has developed as a broadly applied vestibular function test in clinics from its introduction in 1992. In the past, there was only one well known VEMP protocol, which is cervical VEMP, however recently ocular VEMP is also popular. Therefore, clarifying the VEMP recording protocol (cervical VEMP or ocular VEMP) before discussing the VEMP
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has become essential. There is considerable difference regarding this VEMP test from other vestibular function tests. VEMP is thought to be assessing the functions of the otolith organs (utricle and saccule) which are evoked by acoustic stimulus. Cervical VEMP is valuable since this is the only available test method which could speculate the function of the saccule and inferior vestibular nerve. Still, there’s less clearly understood part regarding the central pathway of VEMP. However, many clinicians and researchers participating in vestibular research speculate that this functional test will have a more dominant role in the near future. Here we describe the basic principles and methodological considerations regarding VEMP recording.

Multicenter Study on the Clinician’s Diagnostic and Therapeutic Approaches for Benign Paroxysmal Positional Vertigo in Korea: Eun Ju Jeon, Won Ho Chung, Jeong Hwan Choi, Eui Cheol Nam, Hong Ju Park, Jong Dae Lee, Won Sang Lee, Kyu Sung Kim, Eui Kyung Goh, Ja Won Koo, Min Bum Kim, Min Beom Kim, Se Hyung Kim, Young Jin Kim, Chang Hee Kim, Sung Il Nam, Seog Kyun Mun, Ga Young Park, Sang Yoo Park, Shi Nae Park, Chang Hoon Bae, Sung Hyun Boo, Myung Whan Suh, Jae Hyun Seo, Eun Jin Son, Jae Jun Song, Jae Jin Song, Joong Wook Shin, Dae Bo Shim, Seong Ki Ahn, Hye Youn Youm, Shin Young Yoo, Dong Hee Lee, Seung Hwan Lee, Chang Ho Lee, Hyun Seok Lee, Hwan Ho Lee, Hyo Jeong Lee, Yun Hoon Choung, Seung Hyo Choi, Jee Sun Choi, Seok Min Hong, Sung Kwang Hong; Res Vestib Sci. 2013;12(3):79-92.

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Abstract: Background and Objectives: It is necessary to establish the most efficient diagnostic and therapeutic method for benign paroxysmal positional vertigo (BPPV), which is appropriate for Korean healthcare system. We aimed to evaluate current state of Korean clinician’s diagnostic and therapeutic approaches for BPPV. Materials and Methods: A 16-item survey was emailed to the members of dizziness department of Otology Research Interest Group in the Korean Otologic Society (n=68). 43 were returned and analyzed. Results: All respondents (100%) used Dix-Hallpike test as a diagnostic tool for vertical canal-BPPV. Supine roll test was used for diagnosing lateral canal BPPV in nearly all the respondents (97.7%). Epley maneuver was chosen as otolith repositioning maneuver (ORM) for posterior canal BPPV in all respondents and barbecue rotation (BBQ) was used for treating lateral canal BPPV with geotropic nystagmus in 95.3% of respondents. Extreme variation was noted for therapeutic approach of lateral canal BPPV with ageotropic nystagmus BBQ, with 4 kinds of ORM and adjunctive measures to liberate otolith from cupula, while BBQ was again the most commonly used ORM (76.7%). Conclusion: The development of practical and efficient ORM for lateral canal BPPV with ageotropic nystagmus is necessary.

Apogeotropic Positional Nystagmus in Pontine Infarction: Hye Ran Son, Jae Yun Jung, Myung Whan Suh; Res Vestib Sci. 2012;11(3):105-109.

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Abstract: It is thought that horizontal canal benign paroxysmal positional vertigo (BPPV) is the most common cause of apogeotropic direction-changing positional nystagmus (DCPN). But there are many reports about cerebellar or brainstem lesions as the cause of apogeotropic DCPN. We also report a 72-year-old male patient who showed apogeotropic DCPN, but was proven to have a pontine infarction. The patients complained of disequilibrium which has lasted for 3-4 years and aggravated recently. The symptom was present only when he stood up, and was absent as soon as he sat down. He was not able to successfully perform the Romberg test and tandem gait on physical examination. Vestibular function test revealed apogeotropic DCPN without spontaneous nystagmus. Rotation chair test and caloric test results were all within normal limit. On the brain magnetic resonance imaging, newly detected infarction in the left basal ganglia, pons and right parietal lobe was found. Although horizontal canal BPPV is the most common cause of apogeotropic DCPN, we should be aware that there can be patients with central origin DCPN. In this report, we present the detailed history of this patient and tried to point out the clues to suspect central lesion in patients with apogeotropic DCPN.

Gender Difference of Clinical Characteristics in Meniere’s Disease: Se Young An, Hye Ran Son, Myung Whan Suh, Chung Ku Rhee, Jae Yun Jung; Res Vestib Sci. 2012;11(3):88-91.

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Abstract: Background and Objectives: Meniere’s disease (MD) is a clinical cluster of common symptoms by various causes rather than a single disease entity. Many causes such as autoimmune, allergy, vascular insufficiency have been thought to be related with Meniere’s disease. We assumed that different pathologic mechanisms have contribution in each gender. With this premise, we compared clinical characteristics between male and female patients to determine if there is any difference indicating heterogeneous underlying pathology. Materials and Methods: We reviewed medical records of 61 patients (43 female, 18 male) who were diagnosed as unilateral definite MD and underwent vestibular function test and audiologic evaluation (more than two times of pure tone audiometry during the follow-up period) from October 2005 to December 2011. Results: The average duration of dizziness in females was longer than in males. In the worst ipsilateral pure tone audiometry, low frequency thresholds were lower in females than in males. Female had lesser hearing difference at all frequencies between the sides and showed more hearing fluctuation than male. There was no significant difference between male and female in the vestibular function test. Conclusion: These results are insufficient to suggest that the pathogenesis of MD differs between the genders. However, some differences between the genders prompt a need for future studies involving more patients.

A Case of Bilateral Benign Paroxysmal Positional Vertigo in Bilateral Mondini Malformation With Right Enlarged Vestibular Aqueduct Syndrome: Min Young Lee, Sung Do Jung, Myung Whan Suh, Jae Yun Jung; Res Vestib Sci. 2012;11(2):77-80.

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Abstract PDF: Enlarged vestibular aqueduct syndrome (EVAS) is well known congenital bony ear anomaly. It’s audiologic symptoms and radiological findings are reported in many literatures. However vestibular symptoms of EVAS are rarely reported. A patient with right EVAS developed sudden spinning vertigo on casual observation. He is diagnosed as bilateral benign paroxysmal positional vertigo and recovered by canal repositioning maneuver. We present this case with reviews of previous literatures.

Conservative Management of Horizontal Canal Benign Paroxysmal Positional Vertigo Resistant to Treatment: Hye Ran Son, Chung Ku Rhee, Myung Whan Suh, Jae Yun Jung; Res Vestib Sci. 2011;10(4):141-144.

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Abstract PDF: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo. Although it is easily cured by repositioning maneuvers for the majority of patients, it can be resistant to treatment in rare cases. Surgery can be considered for such patients with intractable BPPV. But surgery may be followed by some side effects such as hearing loss and persistent disequilibrium. We report a 77-year-old-female patients who had positional vertigo for 5 years in despite of repositioning maneuver at several hospitals. We performed repeated repositioning maneuvers twice a day for 1 month. Her symptom and nystagmus finally subsided after 2 months. Repeated aggressive repositioning maneuver may be an alternative for surgery for patients with intractable BPPV.

Clinical Comparison Between Ocular and Cervical Vestibular Evoked Myogenic Potentials: Il Kwon Cho, Myung Whan Suh, Tae Hyun Moon, Chung Ku Rhee, Jae Yun Jung; Res Vestib Sci. 2011;10(2):68-73.

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Abstract PDF: Background and Objectives: The goal of this study was to compare the outcome between cervical vestibular-evoked myogenic potential (cVEMP) and ocular VEMP (oVEMP) in the patients with definite vestibular dysfunction. Also, the subjective discomfort level was compared between cVEMP, classic oVEMP and head positioned oVEMP (a new method designed by the authors). Materials and Methods: Eighteen patients with dizziness associated with unilateral vestibular hypofunction were included in this study. Vestibular neuritis, Ramsay-hunt syndrome and sudden sensorineural hearing loss with vertigo were included in unilateral vestibular hypofunction disease. cVEMP, classic oVEMP, and head positioned oVEMP were assessed and compared. To compare the subjective discomfort during the tests, visual analogue scale on discomfort was checked. Results: There was a discrepancy between the cVEMP and classic oVEMP in 31.3% of the cases. The classic oVEMP were associated with more discomfort than the cVEMP. But, there was no difference between the classic and head positioned oVEMP. Conclusion: Since a substantial discrepancy was identified between the cVEMP and oVEMP, the pathways involved in cVEMP and oVEMP are likely different even with the same air conduction tone stimuli. The head positioned oVEMP may be an alternative to the classic oVEMP which has similar results and subjective discomfort levels.

Competence in Suppressing the Visual Fixation among Different Types of Frenzel Glasses: Sungdo Jung, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; Res Vestib Sci. 2010;9(4):134-138.

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Abstract PDF: Background and Objectives: Several manufacturers supply different types of Frenzel glasses, but the quality of these varied Frenzel glasses seems to be quite different. The aim of this study was to compare the competence in suppressing visual fixation (VF) among different types of Frenzel glasses. The second aim was to develop a new type of Frenzel glasses which is cheaper and more convenient to carry, but has an equivalent competence. Materials and Methods: Four different types of Frenzel glasses were evaluated: 30 diopter Frenzel glasses manufactured by Nagashima (N), 10 diopter Frenzel glasses manufactured by Jungang (J), 13 diopter conventional magnifying glasses (M) and 17 diopter Fresnel lens glasses assembled by the authors. The amplitude of the spontaneous nystagmus (SN) was measured though the electronystagmography system. The SN was measured 35 times from 15 patients who were diagnosed as vestibular neuritis. Results: The mean amplitude of the SN was 8.8±3.2°/sec when measured with the videonystagmography goggles. When the same SN was measured through the 4 different Frenzel glasses, it was 7.5±2.8 (N), 6.3±3.0 (F), 6.2±3.0 (M), and 5.7±2.6 (J) °/sec respectively. The amplitude of the SN was significantly bigger when wearing the N glasses compared to the other 3 glasses. The SN was significantly smaller when wearing the J glasses compared to the F glasses. Conclusion: The competence of suppressing VF was significantly different among the varied types of glasses. The F glasses seem to have a similar or better competence with the J glasses. F glasses seems to be a fairly good alternative which is very portable and cheap.

Nystagmus in the Ictal Period of Vertebrobasilar Insufficiency: Kun Woo Kim, Chang Min Lee, Jae Yun Jung, Myung Whan Suh; Res Vestib Sci. 2010;9(3):114-117.

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Abstract PDF: The nystagmus of vertebrobasilar insufficiency (VBI) patients is not clearly understood. In this article we report a videonystagmography (VNG) result which had been recorded in a VBI patient during his ictal period. The spontaneous nystagmus was purely torsional toward the left side. During the various positional tests, up beating left torsional and right horizontal nystagmus was found. Right beating horizontal nystagmus was stronger when the head was turned to the left side. But we were not able to explain the exact mechanism of this nystagmus. Although the mechanism is not fully understood the pattern of nystagmus reported in this article may be helpful in distinguishing VBI from other diseases by means of VNG recording.

Effect of Preset Angle on Subjective Visual Vertical/Horizontal: Comparison between Normal Subjects and Patients with Dizziness: Tae Hyun Moon, Sung Hyen Bae, Myung Whan Suh, Chung Ku Rhee, Jae Yun Jung; Res Vestib Sci. 2010;9(2):52-57.

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Abstract PDF: Background and Objectives Subjective visual vertical (SVV) and subjective visual horizontal (SVH) are well known otolith function tests. Patients with acute unilateral vestibular weakness have a tendency to set the bar toward the side of the lesion in SVV and SVH tests. The object of this article is to identify the effect of preset angle on SVV and SVH tests in normal subjects and patients with dizziness. Materials and Methods From October 2008 to March 2009, thirty healthy volunteers, twenty eight vestibular neuritis (VN) patients (14-uncompensated, 14-compensated), Twenty five patients who had migrainous vertigo (MV) were enrolled. All subjects performed the test two times in each of the clockwise and counter-clockwise preset angle. Results In normal subjects, there was significant influence by preset angle on SVV test, not on SVH test. In VN patients with nystagmus, both SVH and SVV were not influenced by preset angle. In VN patients without nystagmus and in MV patients, there were significant influence by preset angle on both SVV and SVH tests. Conclusion SVV and SVH values depend on the direction of the preset angle in MV and uncompensated VN patients. The preset angle should be considered in the interpretation of SVV and SVH values.

Positional Nystagmus in Acute and Subacute Vestibular Neuritis: Do Joon Lee, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; Res Vestib Sci. 2010;9(1):21-26.

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Abstract PDF: Background and Objectives By understanding the typical pattern of nystagmus during diverse positional change, we might be able to diagnose the subacute vestibular neuritis (VN) more accurately. The aim of this study was to identify the typical pattern of positional nystagmus in compensated and uncompensated VN patients. Materials and Methods The videonystagmography of 182 patients who were diagnosed as VN were reviewed retrospectively. The patients were classified into two groups by the presence or absence of spontaneous nystagumus (SN). The amplitude of nystagmus evoked by head roll test (HRT) and body roll test (BRT) were compared between the lesion side (ipsilateral, i) and the healthy side (contralateral, c). Results In the VN patients with SN, positional nystagmus was stronger on the iHRT and iBRT compared to the cHRT and cBRT, respectively. But in the VN patients without SN, this pattern of nystagmus was not evident. Although a stronger nystagmus was found in the iBRT compared to the cBRT, the mean amplitude of nystagmus was not significantly different. Also there was no difference in the nystagmus between the iHRT and cHRT. Conclusion The typical pattern of positional nystagmus which can be found in the VN with SN was not evident in VN without SN. Positional nystagmus may not be able to give us useful information on diagnosing subacute VN.

Possibility of Misdiagnosing the Lesion Side in Unilateral Vestibular Weakness: Il Kwon Cho, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; Res Vestib Sci. 2009;8(2):168-173.

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Abstract PDF: Sudden sensorineural Hearing Loss with Vertigo (SHLV) is characteristic of sudden onset vertigo and unilateral hearing loss, due to acute and profound deterioration in a vestibular and cochlear system. It is relatively easy to determine the lesion side in SHLV, because the patient will complain of unilateral hearing loss. But, it might not beapplicable to vestibular neuritis case, and several vestibular function tests may be helpful in deciding the lesion side. We have recently encountered a patient with SHLV whose caloric and SHA did not match with the lesion side. We speculated that the uncompensated dynamic defect and imbalance of the cerebellar clamping has been implicated in this lab finding. Although the exact mechanism of this curious finding cannot be explained by this single case report, we should consider that one could make a mistake to determine the involved site just only by lab finding in vestibular neuritis.

Clinical Features and Treatment Pattern of Migrainous Vertigo in Korea: A Nationwide Prospective Multicenter Study: Seong Ki Ahn, Kyusik Kang, Ja Won Koo, Kyu Sung Kim, Beom Gyu Kim, Byung Kun Kim, Ji Soo Kim, Kyoung Ho Park, Shi Nae Park, Eun Ho Park, Hong Ju Park, Jae Yong Byun, Myung Whan Suh, Ki Bum Sung, Sun Young Oh, Chung Ku Rhee, Tae Kyeong Lee, Seong Hae Jeong, Won Ho Chung, Chang Il Cha, Sung Won Chae, Eui Kyung Goh; Res Vestib Sci. 2009;8(2):122-131.

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Abstract PDF: Background and Objectives It is being increasing recognized that the morbidities of migraine and balance disorders are interrelated. In fact, migrainous vertigo (MV) is one of frequent causes of recurrent vertigo in patients presenting to specialized dizziness clinics. Nevertheless, not many studies have reported clinical manifestations and treatment. Therefore, the aim of study was designed to assess clinical features and treatment patterns by a nationwide multicenter study. Materials and Methods Patients between 9 and 74 years of age who visited 17 Korean tertiary referral centers and 1 clinic from February to March 2009 were investigated using two forms of questionnaires. Results Overall, 318 patients with MV were enrolled. MV was responsible for ~8.45% of visits to the specialized dizziness clinics. One hundred seventy-five of these patients had definite MV and were included in assessing the clinical features. Vertigo characteristics of patients with definite MV were various. Vertigo was regularly as-sociated with headache in 87% of the patients. The duration of vertigo ranged from seconds to days. For the treatment patterns, an acute and prophylactic therapies were carried in most clinics. There were no differences in either acute or prophylactic therapies between department of neurology and otorhinolaryngology. Conclusions The results of this study suggest that MV the clinical features of MV also varies in Korea. In addition, most clinics provide similar patterns of practice in treatment for MV. The syndrome of MV deserves further research activity as it is relatively common and clinically relevant.

Auditory Neuropathy Accompanying Unilateral Vestibulopathy: Hye Young Kim, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; Res Vestib Sci. 2009;8(1):60-65.

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Abstract PDF: Auditory neuropathy is a term used to describe abnormal auditory brain stem response (ABR) in the presence of preserved cochlear outer hair cell functions which can be measured by otoacoustic emissions (OAE). We report a case of auditory neuropathy accompanying unilateral vestibular hypofunction and benign paroxysmal positional vertigo. The patient was a 50-year-old man who had experienced hearing loss and tinnitus which started two weeks ago. He had taken several medicines for the last few months due to his lung cancer and tuberculosis. ABR and OAE were checked and the results were compatible with auditory neuropathy. To evaluate his vestibular function, video nystagmography, rotatory chair and oculomotor test were checked. The results were compatible with left unilateral vestibular loss and left lateral canal cupulolithiasis. But the patient experienced nearly no vertigo during his daily life. As presented in this case, most of the auditory neuropathy patients do not complain of vertigo. This is probably due to long term central compensation or maybe due to the decreased nerve conduction of the vertiginous sensation. Vestibular evaluation may be crucial in order to detect masked vestibular dysfunction and to protect these patients from imbalance accidents. Key Words: Auditory neuropathy; Vestibular Neuronitis; Evoked Potentials, Auditory, Brain Stem; Otoacoustic Emissions

Clinical Implication of Dissociation between Subjective Visual Horizontal and Subjective Visual Vertical: Tae Hyun Moon, Sung Hyen Bae, Il Kwon Cho, Myung Whan Suh, Chung Ku Rhee, Jae Yun Jung; Res Vestib Sci. 2009;8(1):37-42.

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Abstract PDF: Background and Objectives Subject visual vertical (SVV) and subject visual horizontal (SVH) is well known otolith function test. Patients with acute unilateral vestibular weakness fail to set the test bar within normal range in SVH/SVV showing abnormal deviation toward lesion side. In some cases, SVH and SVV are deviated towards different directions, and analysis of these findings is rarely reported. The authors analyzed correlation of SVH/SVV and other vestibular function tests in patients with various vestibular diseases. Materials and Methods From April 2005 to July 2007, total 234 patients who had admitted for dizziness were enrolled. All patients were divided in two groups, non-dissociation group (n=215) and dissociation group (n=19). Correlation of SVH, SVV, Videonystagmography (VNG), the rotating chair test was compared. Results 8.1% of patients showed dissociation between SVH and SVV. Clinical features did not showed significant difference between groups. In non-dissociation group, SVH/SVV showed correlation with VNG, rotating chair test. However in dissociation group, VNG and rotating chair test revealed high rate of consistency with deviation of SVH than that of SVV. Also direction of SVH and dizziness had higher consistency (88.9%) than that of SVV (11.1%). Conclusion The SVH showed consistency with other vestibular function test and may be more reliable than SVV when the result is dissociated. Key Words: Subjective visual vertical; Subjective visual horizontal; Dissociation

Bilateral Vestibular Hypofunction Induced by Unilateral Herpes Zoster Oticus: Sung Won Chung, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; J Korean Bal Soc. 2008;7(2):207-212.

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Abstract PDF: Herpes zoster oticus usually accompanies vestibulopathy on the ipsilateral ear. However we have encountered two herpes zoster oticus patients with bilateral vestibulopathies. Bilateral vestibulopathy was detected on the 2nd month and 19th day of herpes zoster oticus, respectively. While the contralateral vestibulopathy was detected 2 month after the ipsilateral vestibulopathy in the first patient, the vestibular function deteriorated simultaneously on the 19th day in the second patient. It seems that the bilateral vestibulopathy was caused by an autoimmune process in both cases, but the initiating event is different. The ipsilateral vestibular damage may have sensitized the immune system in the first patient resulting in sympathetic vestibulopathy. But in the second patient, the ipsilateral cochlear damage may have sensitized the immune system resulting in simultaneous bilateral vestibulopathy. Key words: Herpes zoster oticus, Bilateral vestibulopathy, Autoimmune, Sympathetic vestibulopathy

Delayed Postoperative Vertigo After Tympanomastoidectomy Due to Simultaneous Serous Labyrinthitis and BPPV: Yun Ho Kim, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; J Korean Bal Soc. 2008;7(1):89-95.

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Abstract PDF: Postoperative vertigo after tympanomastoidectomy can be attributed to several causes such as inner ear damage due to excessive ossicle handling, labyrinthitis, BPPV resulting from vibration of drilling, iatrogenic lateral semicircular canal damage, and perilymphtic fistula. Differential diagnosis is critical for the proper management and prognosis of accompanied sensorineural hearing loss, but it may be difficult in some cases. Especially it is quite difficult to distinguish between the serous and suppurative labyrinthitis. In this article we present a case with simultaneous serous labyrinthitis and BPPV. The patient developed whirling vertigo and hearing loss on the 5th day after tympanomastoidectomy. After conservative treatment with steroid and antibiotics, his hearing recovered to preoperative level. We retrospectively reviewed the pitfalls to make a correct diagnosis in this patient and the serial change in nystagmus during the treatment period. The usefullness of the rotation chair test to predict the prognosis of sensorineural hearing loss in labyrinthitis was also discussed.

The Correlation of Benign Paroxysmal Vertigo of Childhood And Migraine: Jae Yun Jung, Hye Young Kim, Myung Whan Suh, Chung Ku Rhee; J Korean Bal Soc. 2008;7(1):55-59.

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Abstract PDF: Background and Objectives: Many authors have suggested close relationship between benign paroxysmal vertigo of childhood (BPVC) and migraine. But the relationship between the two is not clearly determined. Therefore we investigate clinical features and the course in children with BPVC and the possibility of evolution of migraine in BPVC. Materials and Methods: We interviewed 30 subjects having enough medical records and fitted to BPVC category who visited otorhinolaryngology for vertigo from 1995 to 2006 year. Results: The BPVC was the most common diagnosis in our hospital and migraine associated vertigo was followed. The main features of the children with BPVC were in agreement with previous reports. The major differences were later age of onset, having trigger factor and non-spinning type of vertigo. During the follow up, 8 children developed migraine. Females were dominant duration of illness was longer in this group. Almost of them suffered from motion sickness and had more family history of migraine, which was maternal dominant. Conclusions: The long term close follow-up may be needed in BPVC having possibility of evolution to migraine.

Resolution of Canal Paresis after Treatment in Benign Paroxysmal Positional Vertigo of the Horizontal Canal: Kyung Tae Park, Myung Whan Suh, Chae Seo Rhee, Ji Soo Kim, Ja Won Koo; J Korean Bal Soc. 2007;6(2):217-221.

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Abstract PDF: Canal paresis in patients with benign paroxysmal positional vertigo (BPPV) has been variously reported from 26 to 50%. In such cases, BPPVs are developed secondary to accompanying vestibulopathy or other underlying inner ear diseases. Also the side of canal paresis is regarded as involved ear in the lateralization of horizontal canal BPPV (HC-BPPV), in which lateralization is sometimes ambiguous just by Eward’s second law. In this case, authors report a woman who had HC-BPPV and pathologic canal paresis which resolved after canalith repositioning. This case may imply that dislodged particles block the endolymphatic flow resulting canal paresis.

Bilateral Inversion of Initial Nystagmus in Benign Paroxysmal Positional Vertigo of Horizontal Canal: Myung Whan Suh, Sang Wook Kim, Min Hyun Park, Ji Soo Kim, Ja Won Koo; J Korean Bal Soc. 2006;5(2):299-306.

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Abstract PDF: Horizontal canal benign paroxysmal positional vertigo (HC-BPPV) is characterized by direction-changing nystagmus of the horizontal component induced by lateral head turning in supine position. Yet, some patients with HC-BPPV show nystagmus inversion during head turning to one side. And, mostly, the nystagmus started in a geotropic direction and the inversion was observed only when the head is turned to the lesion side. Reversal of the clot movement in the canal and sensory adaptation were suggested as the hypothesis for such finding. However, bilateral inversion of geotropic nystagmus into apogeotropic nystagmus in HC-BPPV has seldom been described before. In this paper, the authors presented the characteristic features and progression during reposition of a patient with bilateral nystagmus inversion and speculated its mechanisms. Key Words : Positional vertigo, Semicircular canal, Diagnosis, Nystagmus

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