Biomedical subjects

Yi-Ho Young

Publications and source records attributed to Yi-Ho Young.

At least 19 recordsLinked to original sources

PubMed2007

Effect of intratympanic application of aminoglycosides on click-evoked myogenic potentials in Guinea pigs.

OBJECTIVES: Although numerous studies have identified damage to the cochlear and vestibular end organs as the primary site of aminoglycoside-induced ototoxicity, the effect on the saccule remains poorly understood, possibly due to lack of monitoring saccular function in experimental animals. Therefore, this study applied three kinds of aminoglycosides into the tympanic space of guinea pigs to examine their toxic impact on the saccule by way of click-evoked myogenic potential test coupled with morphologic assessment. DESIGN: Albino guinea pigs were treated with saline, gentamicin, tobramycin, or amikacin, with 10 animals assigned to each group. Each compound was injected directly overlying but not through the round window membrane on the left ear, with the right ear serving as a control. One week after injection, each animal underwent auditory brain stem response, caloric test, and click-evoked myogenic potential test. Animals were then killed for morphologic assessment through the use of light and electron microscopic examinations. RESULTS: The animals treated with saline, gentamicin, tobramycin, or amikacin exhibited abnormal auditory brain stem response in 0%, 30%, 100%, and 30% of cases; abnormal caloric responses were found in 0%, 100%, 40%, and 40% of cases; absent click-evoked myogenic potentials were found in 0%, 100%, 30%, and 40% of cases, respectively. Gentamicin and other groups differed significantly in abnormal rates of caloric responses and click-evoked myogenic potentials. Morphologic study of the gentamicin-treated animals confirmed that the absence of click-evoked myogenic potential originated from the lesion in the saccular macula. CONCLUSIONS: Gentamicin represents the dominant susceptibility of aminoglycoside-induced vestibulotoxicity for eliminating both semicircular canal and saccular functions. This study further confirms the findings of human studies in which the caloric and vestibular evoked myogenic potentials responses were monitored to assess the abolition of vestibular function in patients treated with intratympanic gentamicin injection.

Acoustic Stimulation↗

PubMed2007

Vestibular-evoked myogenic potentials in patients with otosclerosis using air- and bone-conducted tone-burst stimulation.

OBJECTIVE: Otosclerosis is a progressive disease with a remodeling process causing ossicular malformation and conductive hearing loss. The aim of this study was to investigate whether vestibular-evoked myogenic potential (VEMP) correlates with the progression of otosclerosis. DESIGN: Fifteen patients with otosclerosis (21 ears) without operation and 10 healthy subjects (20 ears) underwent VEMP test using air-conducted (AC) and bone-conducted (BC) tone-burst stimulation. SETTING: Tertiary referral university hospital. RESULTS: In 21 unoperated otosclerotic ears, 5 ears (24%) showed present AC-VEMPs, and 16 ears had absent AC-VEMPs. Conversely, 16 ears (76%) displayed present BC-VEMPs and 5 ears with absent BC-VEMPs. In those with both AC- and BC-VEMPs, none of them showed air-bone gap greater than 30 dB; in those with absent AC-VEMPs but present BC-VEMPs, 27% of the ears had air-bone gap greater than 30 dB; and in those with absence of both AC- and BC-VEMPs, 80% of the ears revealed air-bone gap greater than 30 dB. Thus, a significant relationship existed among the presence of AC-VEMPs, BC-VEMPs, and magnitude of conductive hearing loss. CONCLUSION: The presence of an AC-VEMP may indicate an earlier stage of otosclerosis, although absent BC-VEMP infers a later stage. Restated, AC-VEMPs may complement the results obtained with BC-VEMPs to classify the stage of otosclerosis.

Acoustic Stimulation↗

PubMed2006

Caloric and vestibular evoked myogenic potential tests in evaluating children with benign paroxysmal vertigo.

OBJECTIVE: This study applied caloric and vestibular evoked myogenic potential (VEMP) tests to evaluate whether children with benign paroxysmal vertigo (BPV) shares similar vestibular features with basilar type migraine. METHODS: Twenty subjects of each group including healthy and BPV children were enrolled in this study. Each subject underwent audiometry, caloric and VEMP tests. Diagnosis of BPV was based on the International Classification of Headache Disorder, second edition. RESULTS: All BPV children had normal hearing, bilaterally. Caloric test revealed normal responses in 13 patients and abnormal responses in 7 patients (35%). VEMP test showed 50% abnormality in BPV children, including absent and delayed responses. However, when results of caloric and VEMP testing were considered together, 70% of BPV children had abnormality, exhibiting non-significant difference compared with 75% abnormality in basilar type migraine. CONCLUSIONS: A combination of caloric and VEMP results reveals higher abnormality (70%) in BPV children, sharing similar features with basilar type migraine in adults, given the similarity of the two disorders. Thus, caloric and VEMP tests may serve as supplementary diagnostic tools in evaluating children with BPV.

Adolescent↗

PubMed2006

Vestibular evoked myogenic potentials in newborns.

This study presents a novel method for recording vestibular evoked myogenic potential (VEMP) in newborns, used to investigate the maturation of sacculocollic reflex at birth. Twenty full-term newborns aged 2-5 days old were enrolled in this study. During natural sleep, each newborn underwent distortion product otoacoustic emission test, and VEMP test using the head rotation method. For comparison, 20 healthy adults also underwent VEMP test using the same method. Based on adult criteria, 40 newborn ears revealed normal VEMPs in 40%, prolonged VEMPs in 35%, and absent VEMPs in 25%, indicating that great variation exists in the maturation of the sacculocollic reflex at birth. Comparison of VEMP characteristics between healthy newborns and adults revealed nonsignificant difference in the response rate and the latency of n23. However, significant differences existed in the latency of p13, interpeak p13-n23 interval and p13-n23 amplitude between newborns and adults. In conclusion, VEMPs in newborns can be easily recorded by the head rotation method. Prolonged or absent VEMPs in newborns may reflect incomplete maturity of the sacculocollic reflex pathway, especially the myelination. A further large number of newborns receiving MRI scan for other reasons may undergo VEMP test to verify this hypothesis.

Acoustic Stimulation↗

PubMed2006

Vestibular evoked myogenic potentials: optimal stimulation and clinical application.

By easily stimulating the ear with loud sound and recording on tonically contracted neck muscles, vestibular evoked myogenic potential (VEMP) test can reflect inner ear function other than the cochlea and semicircular canal. This expands the test battery for clinicians to explore saccular disease, adding a potential usefulness to the sacculo-collic reflex. The ideal stimulation mode for VEMPs is as follows: 95 dB tone bursts, frequency 500 Hz, stimulation repetition rate 5 Hz, rise/fall time 1 ms, plateau 2 ms, binaural stimulation with bilateral recordings. Animal model using guinea pigs has been established, which sets the stage for useful future studies investigating VEMPs in guinea pigs that would appear to resemble human VEMP responses. Clinically, VEMP test has been widely used in central and peripheral vestibular disorders.

Animals↗

PubMed2006

Clinical investigation on hypotensive patients with vertigo.

The aim of this study was to investigate the characteristic of hypotensive patients with vertigo. Twenty hypotensive patients with rotatory vertigo, 15 hypotensive subjects without vertigo, and 15 mitral valve prolapse subjects without vertigo underwent a battery of tests including audiometry, electronystagmography (ENG), and vestibular evoked myogenic potential (VEMP) test. The abnormal rates in terms of audiometry, eye tracking, optokinetic nystagmus, visual suppression, and caloric tests were 15, 35, 35, 10, and 42% for the first group; 13, 20, 33, 0, and 0% for the second group; and 7, 13, 60, 0, and 3% for the third group, respectively. Comparison of the first group with the other two control groups revealed that significant difference existed only in the abnormality of caloric responses. Fifteen (75%) of 20 hypotensive patients with vertigo having abnormal ENG results, asymmetric caloric responses, or delayed VEMPs were attributed to vertigo of central origin, possibly from ischemic disorder. In contrast, five patients (25%) had neither central signs in ENG nor abnormal VEMPs, but showing bilateral normal or hyperactive caloric responses were classified as autonomic dysfunction. After 3 months of medication, all patients with autonomic dysfunction had their vertigo and autonomic symptoms subsided, whereas 27% of the patients with ischemic disorder had vertigo persisted, showing a significant difference. In conclusion, hypotensive patients with vertigo could be due to either direct autonomic dysfunction or ischemic disorder mediated by autonomic deficits.

Adult↗

PubMed2006

D-Methionine attenuated cisplatin-induced vestibulotoxicity through altering ATPase activities and oxidative stress in guinea pigs.

Cisplatin has been used as a chemotherapeutic agent to treat many kinds of malignancies. Its damage to the vestibulo-ocular reflex (VOR) system has been reported. However, the underlying biochemical change in the inner ear or central vestibular nervous system is not fully understood. In this study, we attempted to examine whether cisplatin-induced vestibulotoxicity and D-methionine protection were correlated with the changes of ATPase activities and oxidative stress of ampullary tissue of vestibules as well as cerebellar cortex (the inhibitory center of VOR system) of guinea pigs. By means of a caloric test coupled with electronystagmographic recordings, we found that cisplatin exposure caused a dose-dependent (1, 3, or 5 mg/kg) vestibular dysfunction as revealed by a decrease of slow phase velocity (SPV). In addition, cisplatin significantly inhibited the Na(+), K(+)-ATPase and Ca(2+)-ATPase activities in the ampullary tissue with a good dose-response relationship but not those of cerebellar cortex. Regression analysis indicated that a decrease of SPV was well correlated with the reduction of Na(+), K(+)-ATPase and Ca(2+)-ATPase activities of the ampullary tissue. D-Methionine (300 mg/kg) reduced both abnormalities of SPV and ATPase activities in a correlated manner. Moreover, cisplatin exposure led to a significant dose-dependent increase of lipid peroxidation and nitric oxide concentrations of the vestibules, which could be significantly suppressed by D-methionine. However, cisplatin did not alter the levels of lipid peroxidation and nitric oxide of the cerebellum. In conclusion, cisplatin inhibited ATPase activities and increased oxidative stress in guinea pig vestibular labyrinths. D-Methionine attenuated cisplatin-induced vestibulotoxicity associated with ionic disturbance through its antioxidative property.

Adenosine Triphosphatases↗

PubMed2006

Audiovestibular evolution in a patient undergoing surgical resection of a temporal bone myxoma.

Primary myxoma in the head and neck region occurs mostly in the maxilla and mandible, and rarely in the temporal bone. A 32-year-old female patient with temporal bone myxoma manifested as acute vertigo, headache, and tinnitus on the right ear. Audiometry and auditory brainstem response revealed normal responses, bilaterally. Vestibular function test displayed spontaneous nystagmus beating toward the left side. Absent ice water caloric response was disclosed on the right ear, whereas vestibular evoked myogenic potential test showed normal responses, bilaterally. MRI scan demonstrated a well-enhanced mass at the anterior middle portion of the right temporal bone with intracranial extension. Tumor excision via craniotomy was performed, and the histopathological study confirmed as myxoma. One year after operation, follow-up audiovestibular function tests revealed normal responses, except for 23 dB conductive hearing loss on the right ear.

Adult↗

PubMed2006

Clinical presentation of posterior fossa epidermoid cysts.

The aim of this study was to investigate the audiovestibular deficits in those with posterior fossa epidermoid cyst including cerebellopontine angle in two patients and cerebellum in one patient. Prior to operation, all three patients showed bilateral gaze nystagmus. Audiometry revealed mild hearing loss in two patients, and caloric test displayed canal paresis in two patients. After operation, subsidence of gaze nystagmus and recovery of caloric responses were disclosed in all patients. Two patients had both hearing and vestibular evoked myogenic potential (VEMP) results recovered to normal. In contrast, the only one who underwent craniotomy twice displayed bilateral mild hearing loss and delayed VEMPs, possibly due to operation sequela. Hence, bilateral gaze nystagmus may present as an initial sign for posterior fossa epidermoid cyst. Audiovestibular deficits in cases of epidermoid cyst are attributable to compression neuropathy, which may resolve and return to normal responses after surgery.

Adult↗

PubMed2006

Experience in the treatment of sudden deafness during pregnancy.

CONCLUSION: Excluding the possibility of acoustic neuroma, therapeutic benefits from dextran 40 can be anticipated in a pregnant woman with sudden deafness, leading to significant hearing improvement, without detrimental effect on the mother or fetus. OBJECTIVE: The aim of this study was to present our experience in the treatment of pregnant women with sudden deafness during the past decade. METHODS: From January 1994 to December 2003, 12 pregnant women with sudden deafness were consecutively encountered at the authors' clinic. With the exception of one patient with acoustic neuroma who underwent craniotomy, six patients were treated with dextran 40 only, while the other five patients preferred no medication, and served as a control group. Each patient underwent audiometry before treatment and at 1 year postpartum. RESULTS: In the dextran group, five (83%) of six patients had hearing improvement 1 year postpartum, compared with one (20%) of five patients in the control group showing hearing improvement; both groups revealed a significant difference. Those receiving intravenous dextran treatment had significant hearing improvement at the frequencies of 1000, 2000, and 4000 Hz, at 1 year postpartum. In contrast, in those who followed a natural course without medication no significant difference existed in the mean hearing level of each frequency, at 1 year after delivery.

Adult↗

PubMed2006

Differentiating the cause of acute sensorineural hearing loss between Ménière's disease and sudden deafness.

CONCLUSIONS: Most patients with Ménière's disease (MD) reveal abnormal vestibular-evoked myogenic potentials (VEMPs) and the recruitment phenomenon, whereas most sudden deafness patients display normal VEMPs without the recruitment phenomenon. We therefore recommend using both the recruitment phenomenon and VEMP testing as a diagnostic algorithm to differentiate between MD and sudden deafness as the cause of acute hearing loss. OBJECTIVE: To recommend a diagnostic algorithm to differentiate between MD and sudden deafness as the cause of acute hearing loss. MATERIAL AND METHODS: Between January 2002 and December 2003, 14 consecutive patients with "probable" MD who also had acute sensorineural hearing loss were enrolled in the study, together with another 14 age- and sex-matched patients with idiopathic sudden deafness. Each patient underwent a battery of audiovestibular function tests, including pure-tone audiometry, a stapedial reflex test, distortion-product otoacoustic emissions (DPOAEs), electronystagmography and a VEMP test. All patients were followed for at least 12 months after presentation. RESULTS: Significant differences were found between MD and sudden deafness in terms of the recruitment phenomenon (86% and 21% of cases, respectively) and abnormal VEMP responses (71% and 21% of cases, respectively). However, the diseases did not differ significantly in terms of abnormal DPOAEs or caloric test results.

Adult↗

PubMed2006

Comparison of the head elevation versus rotation methods in eliciting vestibular evoked myogenic potentials.

OBJECTIVES: Because active and tonic sternocleidomastoid (SCM) muscle contraction is essential for recording the vestibular evoked myogenic potential (VEMP), false-negative VEMPs are sometimes encountered in those who cannot sustain SCM muscle contraction by head elevation. Hence, the goal of this study was to investigate whether the effortless head rotation method can replace the head elevation method in eliciting VEMP responses. DESIGN: Twenty healthy volunteers underwent VEMP testing, using monaural tone burst stimulation. First, the subject was instructed to keep the head elevated in the pitch plane for recording, followed by rotating the head sideways toward one shoulder as head down in the yaw plane for another recording (elevation-rotation sequence). On the next day, VEMP testing was performed in reverse order (rotation-elevation sequence). Twelve patients with cochleo-vestibular disorders were also enrolled in this study and underwent VEMP testing, using the two methods in random order. RESULTS: In the elevation-rotation sequence for subjects without cochleo-vestibular disorders, the response rate for the elevation method (100%) was significantly higher than the response rate for the rotation method (70%). In contrast, no significant difference existed in the response rate between the two methods in the rotation-elevation sequence (85% versus 88%). Comparison of the response rates for the initial elevation (100%) and initial rotation methods (85%) revealed a significantly lower response rate for the initial rotation method. Mean latencies of the onset waveform and peaks p13 and n23 showed significant differences between the two methods when using the elevation-rotation sequence but no differences on the rotation-elevation sequence. Furthermore, the rotation method displayed significantly smaller amplitude than the elevation method when using the elevation-rotation sequence but no significant difference in amplitude between the two methods when applying rotation-elevation sequence. In 12 patients with cochleo-vestibular disorders, the response rates for the elevation method (67%) and rotation method (58%) were significantly reduced compared with the rates for subjects without cochleo-vestibular pathology. However, when either the elevation or the rotation method response was considered, VEMPs were present in 11 (92%) of the 12 patients with cochleo-vestibular disorders. CONCLUSIONS: The head rotation method may serve as an alternative for eliciting VEMPs in those who cannot sustain SCM muscle contraction by head elevation. However, the lower response rate with smaller amplitude prevents the use of the head rotation method as an initial screening test for VEMPs. We therefore recommend that when VEMP responses cannot be elicited by the head elevation method, the head rotation method should be utilized to reduce false-negative results.

Adult↗

PubMed2006

Dehiscent high jugular bulb: a pitfall in middle ear surgery.

OBJECTIVE: The aim of this study was to present our experience on facing the dehiscent high jugular bulb (HJB) during middle ear surgery in the past 2 decades. STUDY DESIGN: Retrospective review. SETTING: Secondary referral hospital. PATIENTS: From January 1982 to June 2002, consecutive 1,657 patients underwent surgical intervention for middle ear cleft diseases, a total of 1,857 operations. Of them, 10 ears (0.5%) in nine patients were proven to have dehiscent HJB during operation for adhesive otitis media in four ears and for chronic otitis media with cholesteatoma in six ears. MAIN OUTCOME MEASURES: Each patient underwent otoscopic examination, radiographic examination, and audiometry before and 6 months after operation. RESULTS: Otoscopic examination revealed atrophic changes in the pars tensa with adhering to the promontory in two ears, attic retraction in one ear, and both findings in seven ears. All lesions were located beneath the basal turn of the cochlea and the round window niche at anteroinferior and/or posteroinferior quadrants. Active bleeding was encountered in two ears (20%) while elevating the tympanomeatal flap, which was treated by pressure compression associated with gelfoam sheet, then covered with an autologous cartilage to protect the dehiscent bulb. For the remaining eight ears, the bulbs were reinforced with fascia, perichondrium, or autologous cartilage. All 10 ears were allowed completion of the planned surgery without complications. CONCLUSION: HJB is not a contraindication for middle ear surgery. Awareness of this pitfall may lessen the operation risk.

Adult↗

PubMed2006

Vestibular evoked myogenic potentials in acute acoustic trauma.

OBJECTIVES: Anatomical proximity of the saccule to the stapedial footplate points to the possibility of acoustic trauma associated with saccular dysfunction. Therefore, it was the authors' premise that abnormal vestibular evoked myogenic potential (VEMP) after acute acoustic trauma may be caused by saccular damage from very high intensity noise; consequently, irreversible hearing loss ensued. The aim of this study was to investigate the VEMP responses in those with acute acoustic trauma. STUDY DESIGN: A prospective study. SETTING: University hospital. PATIENTS: Twenty patients (29 ears) without previous ear disorders diagnosed as acute acoustic trauma were enrolled in this study. MAIN OUTCOME MEASURES: Before treatment, each patient underwent pure tone audiometry and caloric and VEMP tests. Correlations between the hearing outcome and mean hearing level, sources of noise, caloric responses, or VEMP results were investigated. RESULTS: After 3 months of medication, complete recovery was achieved in 4 ears and hearing improvement in 4 ears, whereas hearing in 21 ears (72%) remained unchanged. Eighteen ears presenting normal VEMPs revealed hearing improvement in eight ears (44%) and unchanged hearing in ten ears (56%). However, hearing loss remained unchanged in all 11 ears (100%) with absent or delayed VEMPs, exhibiting a significant relationship between VEMP results and hearing outcome. Thus, VEMP test can predict the hearing outcome after acute acoustic trauma with a sensitivity of 44% and a specificity of 100%. CONCLUSION: The greater the noise intensity, the severer damage on the cochlea and saccule is shown. Absent or delayed VEMPs in ears after acute acoustic trauma may indicate poor prognosis with respect to hearing improvement, whereas normal VEMP is not a powerful indicator for expectation of hearing improvement.

Adult↗

PubMed2006

Posterior cranial fossa tumors in young adults.

OBJECTIVE/HYPOTHESIS: This retrospective study presents our experience on the posterior cranial fossa tumors in young adults during the past 15 years. METHODS: From 1991 to 2005, 16 (0.8%) of 2,091 young adults (range, 16-29 years) with dizziness/vertigo, hearing loss, or tinnitus were diagnosed with posterior fossa tumor. Each patient underwent a battery of audiovestibular tests and image study. RESULTS: Audiometry revealed sensorineural hearing loss in 12 patients (75%). Spontaneous nystagmus was disclosed in eight patients (50%), consisting of bilateral gaze nystagmus in five, unilateral gaze nystagmus in two, and downbeat nystagmus in one. Electronystagmographic examination displayed abnormal eye tracking test in 75% and abnormal optokinetic nystagmus test in 81% of cases. Magnetic resonance imaging scan demonstrated space-occupying lesions at the cerebellopontine angle in 11, cerebellum in two, brainstem in two, and jugular fossa in one. Diagnoses consisted of vestibular schwannoma and neurofibromatosis II in eight patients (50%), glial neoplasm (including astrocytoma, ependymoma, glioma) in four patients (25%), epidermoid cyst in three patients, and glomus jugulare tumor in one patient. At study close, excluding one lost patient, three patients died as a result of recurrent or residual tumor at the primary site. Restated, 12 of 15 (80%) patients were alive. CONCLUSIONS: Unlike predominant medulloblastoma in children, the most frequent posterior fossa tumor in young adults is vestibular schwannoma and neurofibroma. However, the second most frequent one in young adults is glial neoplasm as opposed to meningioma in adults.

Adolescent↗

PubMed2005

Necrotizing external otitis in a patient caused by Klebsiella pneumoniae.

Necrotizing external otitis is a potentially life-threatening infection involving the temporal and adjacent bones. The most frequent pathogen is attributed to Pseudomonas aeruginosa, but is rarely caused by Klebsiella pneumoniae. Recently, we encountered a 47-year-old diabetic man with a swollen obliterated external ear canal with granulation tissue on the right ear. Image study demonstrated skull base osteomyelitis, epidural abscess and cerebral venous sinus thrombi. It was later proved to be necrotizing external otitis caused by Klebsiella pneumoniae. He then underwent craniotomy for drainage of the epidural abscess, followed by intravenous ciprofloxacin and metronidazole for 2 consecutive weeks until both pus and blood cultures depicted no growth of pathogens. Based on this case, synergistic antibiotic therapy using a third-generation cephalosporin or quinolone (ciprofloxacin), accompanied by metronidazole, and even a short-term aminoglycoside is recommended for the treatment of severe Klebsiella-induced necrotizing external otitis. Surgical intervention should be limited without shedding of the pathogens.

Anti-Bacterial Agents↗

PubMed2005

Potential usefulness of Tl-201 SPECT for differentiating radionecrosis in an irradiated nasopharyngeal carcinoma patient.

Differentiation between cerebral radionecrosis and intracranial relapse in irradiated nasopharyngeal carcinoma (NPC) patients challenges the clinicians, especially when clinical manifestation and MRI findings are inconclusive. A 63-year-old NPC patient had intermittent dizziness and unsteady gait 3 years after irradiation. An ice water caloric test revealed absent response on the right ear, which was compatible with an enhanced lesion at the right temporal lobe on MRI scan. Furthermore, abnormal focally increased uptake over the anteriomedial aspect of the right temporal lobe was disclosed on 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET), which suggested intracranial relapse. Conversely, serological study for Epstein-Barr viral titer was within normal limits, arguing against either recurrent or metastatic NPC. Hence, thallium (Tl)-201 single photon emission computed tomography (SPECT) was subsequently conducted, which failed to demonstrate abnormal thallium accumulation in the corresponding area. Accordingly, radiation necrosis of the temporal lobe rather than intracranial relapse is considered. The patient was rather well without locoregional recurrence or distant metastasis 2 years after presentation.

Carcinoma↗

PubMed2005

Radiation-induced oscillopsia in nasopharyngeal carcinoma patients.

PURPOSE: To apply a battery of audiovestibular function tests and magnetic resonance imaging (MRI) to investigate the causes of oscillopsia in nasopharyngeal carcinoma (NPC) patients after irradiation (RT). METHODS AND MATERIALS: Of 300 NPC patients, 12 (4%) developed oscillopsia after RT. The mean accumulated radiation dose to the nasopharynx was 112 +/- 30 Gy. Each patient underwent a battery of audiovestibular function tests, including audiometry and the dynamic illegible E, caloric, and rotational tests. RESULTS: Excluding 3 patients with neck fibrosis who could not perform the head turning movement, the remaining 9 patients displayed 100% abnormal dynamic illegible E test results and 100% abnormal refixation saccades. All 12 patients presented with bilateral hearing loss, caloric reductions, and reduced gains of the vestibular ocular reflex (VOR) on the rotational test, indicating bilateral VOR loss. After excluding tumor relapse and radiation necrosis of the brain by MRI, the oscillopsia in these 12 irradiated NPC patients was attributed to bilateral VOR loss. CONCLUSION: Radiation-induced oscillopsia in our NPC patients was attributed to bilateral VOR loss, possibly as a result of higher radiation doses. Hence, the therapeutic benefits of a second course of RT are associated with the potential risk of oscillopsia after RT.

Aged↗