Decoding Saccadic Directions Using Epidural ECoG in Non-Human Primates

A brain-computer interface (BCI) can be used to restore some communication as an alternative interface for patients suffering from locked-in syndrome. However, most BCI systems are based on SSVEP, P300, or motor imagery, and a diversity of BCI protocols would be needed for various types of patients. In this paper, we trained the choice saccade (CS) task in 2 non-human primate monkeys and recorded the brain signal using an epidural electrocorticogram (eECoG) to predict eye movement direction. We successfully predicted the direction of the upcoming eye movement using a support vector machine (SVM) with the brain signals after the directional cue onset and before the saccade execution. The mean accuracies were 80% for 2 directions and 43% for 4 directions. We also quantified the spatial-spectro-temporal contribution ratio using SVM recursive feature elimination (RFE). The channels over the frontal eye field (FEF), supplementary eye field (SEF), and superior parietal lobule (SPL) area were dominantly used for classification. The α-band in the spectral domain and the time bins just after the directional cue onset and just before the saccadic execution were mainly useful for prediction. A saccade based BCI paradigm can be projected in the 2D space, and will hopefully provide an intuitive and convenient communication platform for users.

Traumatic Internal Maxillary Artery Pseudoaneurysm Caused by Fracture of the Mandible Ramus: A Case Report

Traumatic pseudoaneurysms in the head and neck region are very rare. Particularyly, pseudoaneurysms of the internal maxillary artery are known to be very rare. The authors report a 20-year old male who was diagnosed as having a pseudoaneurysm of the internal maxillary artery. The cause was assumed to be a mandible ramus fracture. When he visited our emergency room, we did not consider a pseudoaneurysm because of his other life-threatening conditions. Fortunately, he re-visited our hosipital before the aneurysm ruptured. He was diagnosed with angiography and was treated by using embolization with glue. The rupture of the pseudoaneurysm could have caused a life-threatening hemorrhage.

Timing of Sequential Bilateral Mastoidectomy and Functional Recovery with Respect to Taste / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: After bilateral mastoidectomy, taste change is common because of injury to chorda tympani nerve. We aimed to understand about the appropriate interval of sequential bilateral mastoidectomy. SUBJECTS AND METHOD: Retrospective review was carried out for 25 patients who underwent sequential bilateral mastoidectomy from March 2004 to November 2011. RESULTS: Among the 25 patients, there were 19 patients whose chorda tympani nerve was injured after bilateral mastoidectomy, and eight of those 19 patients complained of taste disturbance. The rates of dysfunction according to operation interval were within 6 month (55%, 5/9), between 6 and 12 months (33%, 2/6), and above 12 months (10%, 1/10). Compared to canal wall up mastoidectomy, for canal wall down mastoidectomy, taste disturbance was more common (p=0.001). CONCLUSION: The result supports that at least 6 months interoperative period for bilateral chronic otitis media may be needed to avoid taste disturbance. A further large study may validate this result.

Clinical Characteristics of Pediatric Dizziness / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Pediatric dizziness is difficult to diagnose because of the nonspecific nature of symptom, and difficulty in history taking, physical examination or diagnostic tests. The authors tried to analyze the proportion of diseases in children suffering from dizziness, and introduce cases with atypical clinical characteristics and uncommon diagnosis. MATERIALS AND METHODS: The medical records of 53 pediatric patients suffering from dizziness were analyzed retrospectively. We analyzed the findings of history taking, physical examination for nystagmus and cerebellar function, pure tone audiogram and caloric tests in all patients. RESULTS: Diagnosis of migrainous vertigo was most common (32.7%), followed by psychological cause (11.5%) and labyrinthitis due to the otitis media (7.7%). Cases of cerebellar hemangioblastoma, neurofibromatosis and drug intoxication were also found. CONCLUSION: The clinical characteristics and causative diseases of pediatric dizziness are different from those of adults. Appropriate history taking and diagnostic tests are improtant for differential diagnosis.

Influence of Head Position in Rotation Test / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Rotation test is a widely used method to evaluate the function of the vestibular system. Generally, the head position to be tilted forwards 30degrees during rotation is preferred in order to bring the horizontal semicircular canals into the plane of rotation, thus ensuring maximum response. However literatures do not provide a clear reference concerning head position during the rotation test. So, we evaluated the vestibuloocular reflex (VOR) induced by sinusoidal rotation in the horizontal plane in the two different head positions: the head tilted forward 30degrees and with the head upright. MATERIALS AND METHODS: A total of 20 men with no known neuro-otological disorders and 9 guinea pigs were studied. The rotations of slow harmonic acceleration on various frequencies were performed with the subject's head in the upright position and in the 30 pitched down position. Computerized electronystagmography in human and magnetic coil in guinea pigs were used to measure the maximum velocity of slow component of horizontal nystagmus and to calculate gain, phase and symmetry of VOR responses. RESULTS: In both groups, results showed no significant differences in gain, phase and symmetry. CONCLUSION: In the two different head positions, there were no significant differences in gain, phase and symmetry. The posture of head upright is more comfortable for the patient and gives enough response for the evaluation of vestibular function.

Age and Gender Specific Reference Value of Ocular Torsion by Using Funduscope in Korean / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Ocular torsion may be a result of vestibulopathy. The funduscopy is the most reliable method of measuring an ocular torsion. However, the reference value of ocular torsion in Korean is available at only limited ages. Therefore, we analyzed the angle of ocular torsion more age-specific than previous study. MATERIALS AND METHODS: We used the fundus photograph of health check-up visitor. And age and sex specific average angle of ocular torsion was measured. RESULTS: The right and left average angle of ocular torsion were 7.7+/-3.6degrees, 5.3+/-3.0degrees, respectively. In addition, there was no significant difference in age or sex specific angle of ocular torsion. CONCLUSION: This result might give an aid to evaluating the function of otolithic organ by measurement of ocular torsion.

A Case of Lermoyez' Syndrome / 대한평형의학회지

Lermoyez's syndrome is usually regarded as a rare variant of Meniere's disease which is characterized by the disappearance of aural symptoms after vertiginous attacks. It is recognized as an uncommon paroxysmal clinical syndrome caused by pathological endolymphatic change in the labyrinth. It is thought that the cause of Lermoyez's syndrome is due to cochlea hydrops which result from endolymphatic blockage of the ductus reunions. With its distinct characteristic manifestations, the diagnosis is not difficult, but Lermoyez's syndrome has been rarely reported universally. Otologists are in a whirl about its rare occurrence. We report a unique case of a 46-year-old woman, who showed typical clinical features of Lermoyez's syndrome with review of literatures. We focused on the sequential clinical change during our observation.

A Case of Tumarkin Otolithic Crisis: Failed to Treat with Intratympanic Gentamicin Injection / 대한평형의학회지

Tumarkin otolithic crisis is an unusual manifestation of Meniere's disease that shows sudden falling without loss of consciousness. As a kind of life-threatening otologic emergency due to high risk of injury, the surgical ablation therapy rather than the medical one is preferred. Intratympanic injection of gentamicin (ITIG) is being introduced as a treatment by chemical ablation of vestibular function. The authors report a case of life-threatening Tumarkin otolithic crisis in 76-year-old female, after onset of Meniere's disease, failed to treat with multiple application of ITIG, and successfully eradicated the symptom with total labyrinthectomy after then. Also we introduce her clinical feature of Tumarkin otolithic crisis. A 76-year-old female visited clinic suffering from recurrent rotatory vertigo accompanied with fluctuating hearing loss and tinnitus on her left ear, and diagnosis of Meniere's disease was made. Four months after medical treatment, the patient experienced sudden drop attack during walking on the street without any prodromes, and her right wrist and skull base were fractured as a result. She denied to got surgery and ITIG was applied. During 1 year after initial drop attack, she experienced 7 times of severe drop attack and 4 times of ITIG, and finally she accepted to get surgery. The patient no longer suffered from drop attack after total labyrinthectomy later. Tumarkin otolithic crisis is an otologic emergency, may cause life-threatening falling. Our experience from this case is that vestibular ablation by surgical method is needed for safety and quality of life of patients.

Acute Low Tone Sensorineural Hearing Loss: Consideration for Progression to Meniere's Disease / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Low tone sensorineural hearing loss is deterioration in audiometric low frequencies (250 and 500 Hz), preservation of high frequencies (2, 4, and 8 kHz). The aim of this study is to find out differences of clinical manifestation and prognosis of acute low tone sensorineural hearing loss (ALHL), a subtype of sudden sensorineural hearing loss, and potential progression to Meniere's diseases. MATERIALS AND METHODS: Among 465 patients with unilateral hearing loss initially diagnosed with sudden sensorineural hearing loss, we analyzed clinical characteristics of 96 patients who had acute low tone sensorineural hearing loss, but had no history of previous ALHL. RESULTS: The clinical features of ALHL include a predominance of female suffers (72.9%), more dizziness (36%), high incidence of sound perception change (16.7%), tinnitus (42.8%), and ear fullness (20.8%). The prognosis shows recovery in 67.7% of patients. However, 24.0% of patients show recurrence of low tone loss, and 15.6% develop Meniere's disease. Specially, if the dizziness symptoms were accompanied, progression to Meniere's disease was more common (31.4%). CONCLUSION: Our RESULTS: appear that clinical characteristics were different in the ALHL patients compared to the idiopathic sensorineural hearing loss patients. Therefore, when dizziness, ear fullness and tinnitus are accompanied with low tone hearing loss, an appropriate patient education on possible progression to Meniere's disease is necessary.

Diagnostic Value of Cochlear Hydrops Analysis Masking Procedure in Meniere's Disease / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The diagnosis of Meniere's disease is based on audiological test and clinical symptoms. Cochlear Hydrops Analysis Masking Procedure (CHAMP) was introduced as a test for detecting changes in physical characteristics of basilar membrane by hydrops of endolympahtic system. The aim of this study is to evaluate the diagnostic value and usefulness of CHAMP tests for detection of endolymphatic hydrops. SUBJECTS AND METHOD: This study was performed on 11 cases of Meniere's disease and 10 cases of vestibular neuritis who visited ENT outpatient clinic and 25 cases of normal healthy volunteers. We defined the positive value as being less than 0.3 ms in latency delay (0.5 kHz HPN-click alone) and less than 0.95 nV in compound amplitude ratio (click alone 0.5 kHz HPN/ click alone) regardless of age or sex. RESULTS: There were significant latency delays in the Meniere's disease group compared with the vestibular neuritis and normal control group. The amplitude ratio gave significant differences between the Meniere's disease group and the normal group but there were no differences between the Meniere's disease group and the vestibular neuritis group. Without assuming the test failure, the sensitivity and specificity of latency delay was 81% and 100%, respectively, and the sensitivity and specificity of amplitude ratio was 100% and 84%, respectively. In 8 of 54 cases (14.8%), we couldn't get interpretable wave. CONCLUSION: CHAMP test is a clinically useful method that can detect endolymphatic hydrops and it can be used as an objective test for the diagonosis of Meniere's disease.

Benign Recurrent Vertigo: Clinical Manifestations And Vestibular Function Test

BACKGROUND AND OBJECTIVES: Benign recurrent vertigo has been defined as recurrent spells of vertigo lasting minutes to hours without cochlear and neurologic signs. The etiology is still unclear, but viral and vasospastic etiology as migraine equivalent has been suggested. We attempt to analyze the symptoms and vestibular function test of Benign recurrent vertigo that has clinically diagnosed. MATERIALS AND METHODS: We analyzed retrospectively the clinical characteristics and vestibular function test including ocular-motor test, rotation test and computerized dynamic posturography from 100 patients with a Benign recurrent vertigo diagnosis. RESULTS: Eight two percent of the patients were female, mean age was 52 years, and mean duration of prevalence was 47.3 months. In the characteristics of vertigo, 91% of patients have spinning sensation during attack. The vertigo attacks most commonly lasts several hours (57%), and frequency of attack is three to twelve time per year in 47%. A high incidence (40%) of headache was detected, but incidence of other associated symptoms including fluctuating hearing loss (3%), tinnitus (27%), aural fullness (9%) was relatively low. The incidence of spontaneous nystagmus and positional nystagmus was 18% and 10% each. Saccadic undershoot was observed in 21% of patients, but it was not associated with other ocular-motor test abnormalities. In rotation test, low gain, phase lead and asymmetry was observed in 18%, 3% and 9%, respectively. There were no abnormal findings in posturography. CONCLUSIONS: Although benign recurrent vertigo did not show any characteristic clinical findings or vestibular function test, it deserves to be considered for differential diagnosis of episodic vertigo.

Recurrent Dizziness of Cardiac Origin Confirmed by Holter Monitoring

Ineffective cerebral perfusion by low cardiac output may cause various types of dizziness like mild lightheadedness, vertigo or presyncope, and sometimes it can be the only heralding symptom. Differential diagnosis with other causes of dizziness is important because the symptom may progress into life-threatening bradyarrythmia and loss of consciousness. There are several literatures that reporting the association between cardiac disease and dizziness and their improvement with treatment of cardiac problem including pacemaker placement. But these are only indirect evidences to explain the cause-symptom relationship. We experienced 48-year old woman who has had recurrent dizziness of rotatory type lasting for about 5 seconds since first year, and then diagnosed atrioventricular block after. She has been having anti-hypertension medications for 2 years. She didn't have any abnormalities in electrocardiography, chest x-ray, or routine blood tests. There were no abnormalities in vestibular function test and electronystgmography. Her result of 24-hour Holter monitoring clearly elucidated temporal relationship between arrhythmia and her episodic symptoms of dizziness. The authors report a case with review of literatures about cardiogenic dizziness.

Assessment of Saccular Function in Patients With Noise Induced Hearing Loss

BACKGROUND AND OBJECTIVES: Considering saccular receptors are coupled physically with the auditory receptors, VEMP test may provide the information that in the noise induced hearing loss with or without dizziness, damage to the vestibular system, especially saccule is a potential organ with cochlear damage. MATERIAL AND METHODS: 11 patients (22 ears) with HF-SNHL greater than 55dB and 10 patients (10 ears) with sudden hearing loss of varying degree HL as positive control but without clinical manifestations of vestibular pathology tested for vestibular function test was enrolled. VEMP test was done. The results were compared with those of 9-healthy referents (18 ears) examined in the same way. RESULTS: VEMP wave was significantly abolished as twelve of 22 (54.5%) with HF-SNHL, five of 13 (38.5%) and Control group (100%). Though there was no statistically significant relation with P13, N23 latency delay in each group, NIHL showed P13, N23 latency delay trend compared with controls. CONCLUSIONS: Patients with noise induced hearing loss showed significantly more saccular deterioration, estimated as negative VEMP responses than did the controls. This suggests subclinical disturbances of the vestibular system especially of the saccule in noise induced hearing loss.

Comparative Analysis of Vestibular Asymmetry Parameters in Acute Unilateral Peripheral Vestibulopathy

BACKGROUND AND OBJECTIVES: There are known parameters that indicate vestibular asymmetry, such as directional preponderance (DP) on caloric test, asymmetry on slow harmonic acceleration (SHA) test, asymmetry of time constant (Tc) and slow cumulative eye position (SCEP) on velocity step test. Aim of this study is investigate the sensitivity and predictability of the vestibular asymmetry parameters among them. MATERIALS & METHODS: Twenty six patients who were diagnosed as acute unilateral peripheral vestibulopathy were enrolled in this study. We compared each parameter with site of lesion based on the direction of spontaneous nystagmus and canal paresis (CP) which were totally correlated in this group of patients. RESULTS: Positive predictability of each parameter showed 58% in DP, 62% in SHA asymmetry, 62% in SCEP, 38% in Tc. In the cases that each parameter showed positive result, all of DP and SHA asymmetry indicated site of lesion, and showed high correlation coefficient(r=0.89). But in 27% of SCEP and 23% of Tc did not indicate site of lesion. CONCLUSION: All parameters showed low sensitivity for identifying laterality of lesion even the tests were performed within one week after vertigo attack. DP and VOR asymmetry showed high positive predictability for indicating lesion site.

Cerebellopontine Metastatic Carcinoma of Small Cell Lung Cancer Mimiking of Vestibular Neuritis

A 77-year-old man visited our department because of dizziness from one month ago. Dizziness was continuous and non-whirling and this type of dizziness was the first time. He also complained of tinnitus and hearing impairment of the right ear. On physical examination, he showed spontaneous left-beating horizontal and torsional nystagmus and rightward head thrust was positive. He was admitted under the first impression of right vestibular neuritis. On inner ear MRI, there was a well-demarcated 2.5x2.3 cm sized mass of right cerebellopontine angle. This mass showed somewhat low signal intensity in both T1 and T2-weighted image and modest enhancement with Gadolinum. And approximately 4.5x3 cm sized mass could be seen in the simple chest roentgenogram. On chest CT, there was a poorly demarcated 3x2.5 cm sized mass in left lower lobe of lung. The patient was diagnosed as small cell lung cancer with brain metastasis by Per-Cutaneous Needle Aspiration of lung. In spite of radiotherapy and concurrent chemotherapy, he expired after 5 months.