Cervical vestibular evoked myogenic potential with chirp sounds.

BACKGROUND: There are only a few reports concerning cervical vestibular evoked myogenic potential (cVEMP) using chirp sound, and clinical indications/advantages of it are still unclear. OBJECTIVE: To compare cVEMP using CE-chirp LS® with cVEMP using 500 Hz and 1000 Hz tone bursts (TB) and to investigate clinical indications/advantages of CE-chirp LS® for recording cVEMP. METHODS: Sixteen patients with vestibular disorders (2men and 14 women) (18∼62, mean 42.9 years of age) were enrolled in this study. Participants underwent cVEMP testing using 500 Hz and 1000 Hz tone bursts (TB) and CE-chirp LS®. Response rate of P1-N1, corrected/normalized amplitude of P1-N1, latencies of P1 and N1, asymmetry ratio, and correlation of P1 latency to SLOPE in tuning property test (an index of endolymphatic hydrops) were compared. RESULTS: Corrected/normalized amplitude of P1-N1 to CE-chirp LS® was smaller than corrected/normalized amplitude of P1-N1 to 500 Hz TB. Peak latencies to CE-chirp LS® were the shortest among the 3 types of stimulation. EH-positive ears according to the tuning property test had tendency of prolonged P1 latencies to CE-chirp LS®. CONCLUSION: CE-chirp LS® is applicable for recording cVEMP with a similar diagnostic accuracy to TB. Prolongation of P1 latency in CE-chirp LS® might be an indicator of endolymphatic hydrops in the saccule.

Simultaneous Presentation of Definite Vestibular Migraine and Definite Ménière's Disease: Overlapping Syndrome of Two Diseases.

Objectives: To review the clinical records of patients that exhibited the clinical features of both vestibular migraine (VM) and Ménière's disease (MD) during each episodic vertigo attack and to discuss the possible pathophysiology of such combination of symptoms. Subjects: Ten patients that were selected according to criteria based on a combination of the diagnostic criteria for definite MD and VM (9 females and one male, age: 22-54 years) were enrolled. They were required to show features of both diseases in each vertigo attack. Methods: The patients' medical histories and pure-tone audiometry, cervical vestibular evoked myogenic potential (cVEMP), video head-impulse test (vHIT), and caloric test results were examined. cVEMP was recorded using 500 and 1,000 Hz short tone bursts (125dBSPL, air-conducted), 500 Hz-1,000 Hz cVEMP slope, an index of endolymphatic hydrops in the saccule was calculated using normalized amplitudes of p13-n23. For performing vHIT, each subject was seated 1.5 m in front of a target and asked to keep watching it as their head was passively rotated by the examiner. Their eye movements were evaluated using video-oculography while their head movements were recorded using inertial sensors. Results: The patients were predominantly female. On average, the onset of migrainous headaches occurred 9 years earlier than the onset of vertigo attacks. All of the patients but one had migraines with auras. Five of the 10 patients had a family history of vertigo attacks accompanied by both migrainous and auditory symptoms. The patients mainly displayed hearing loss at low frequencies. Nine patients exhibited 500-1,000 Hz cVEMP slope < -19.9, which was suggestive of endolymphatic hydrops. None of the patients who underwent vHIT showed abnormal canal function. One patient showed unilaterally decreased caloric responses. Conclusions: These patients presented with simultaneous MD and VM signs/symptoms might be referred to "VM/MD overlapping syndrome (VM/MD-OS)" as a new clinical syndrome.

[Case report of anesthetic management for an infant with tricho-hepato-entric syndrome].

Tricho-hepato-entric syndrome is a rare congenital disorder characterized by hair anomalies, neonatal hemochromatosis and intractable diarrhea. A three-year-old girl with this syndrome received general anesthesia for inguinal hernia repair. Anesthesia was induced with nitrous oxide and sevoflurane, and maintained with sevoflurane and fentanyl without muscle relaxant. Rectal acetaminophen was administered and ilioinguinal block was performed for postoperative analgesia. The anesthetic course was uneventful.

Is Alteration of Tuning Property in Cervical Vestibular-Evoked Myogenic Potential Specific for Ménière's Disease?

OBJECTIVE: The aim of this study is to show sensitivity and specificity of cervical vestibular-evoked myogenic potential (cVEMP) tuning property test to Ménière's disease (MD) in comparison with healthy controls (HC) and patients with other vestibular diseases. SUBJECTS: Totally 92 subjects (50 women and 42 men, 20-77 years of age) were enrolled in this study. Subjects were composed of 38 definite unilateral MD patients, 11 unilateral benign paroxysmal positional vertigo patients, 14 vestibular migraine patients, 19 unilateral vestibular neuritis patients, and 10 HC. METHODS: The subjects underwent cVEMP testing to 500 and 1,000 Hz short tone bursts (125 dBSPL). The corrected amplitudes of the first biphasic responses (p13-n23) (cVEMP) were measured. Then, a tuning property index (the 500-1,000 Hz cVEMP slope) was calculated. RESULTS: The area of under the ROC curve (AUC) was 0.75 in comparison with other vestibular disease patients, while AUC was 0.77 in comparison with other vestibular disease patients plus HC. The best cutoff point of the 500-1,000 Hz cVEMP slope was -19.9. Sensitivity of the tuning property test to MD was 0.74, while specificity was 0.76 to other vestibular disease patients. CONCLUSION: The tuning property test of cVEMP is useful as a screening test of MD.

Is otolithic vertigo accompanied by hearing loss caused by sacculocochlear endolymphatic hydrops?

CONCLUSION: Otolithic vertigo is sometimes accompanied by hearing loss. Otolithic vertigo accompanied by hearing loss seems to be caused by sacculocochlear endolymphatic hydrops. OBJECTIVES: To clarify the lesion site and pathophysiology of otolithic vertigo (OV) accompanied by hearing loss. METHODS: The clinical records of four patients (two men and two women) that had been diagnosed with OV accompanied by hearing loss according to pre-determined diagnostic criteria were reviewed. RESULTS: The patients' main symptoms involved a sensation of movement in the pitch plane. All of the patients had low frequency-dominant hearing loss and either exhibited decreased cervical vestibular evoked myogenic potentials (cVEMP) or did not produce cVEMP. Two patients produced normal ocular VEMP (oVEMP). Caloric tests obtained normal results in all patients.

[The consumption of nitrous oxide used for general anesthesia has been markedly reduced in recent years in our institute].

We reported the incidence of general anesthesia using nitrous oxide (N2O), one of the greenhouse gases in the atmosphere, and the total consumption of N2O in our institute in 1990, 1995, 2000, and 2004. Nitrous oxide was used in 93%, 97%, 89%, and 49% of general anesthesia in 1990, 1995, 2000, and 2004, respectively. The consumption of N2O was markedly reduced from 1314 kl in 1990 to 413 kl in 2004. In 1996, propofol was introduced for total intravenous anesthesia. Moreover, low flow anesthesia (total gas flow not exceeding 2 l x min(-1)) was vigorously introduced. We consequently decreased the amount of N2O consumed during inhalational anesthesia despite the increase in cases of general anesthesia in recent years.

Frequency preference in cervical vestibular evoked myogenic potential of idiopathic otolithic vertigo patients. Does it reflect otolithic endolymphatic hydrops?

CONCLUSION: Idiopathic otolithic vertigo (IOV) with relatively long duration of attacks might be caused by endolymphatic hydrops in the otolith organ. OBJECTIVES: To clarify the pathophysiology underlying IOV, episodic tilting or translational sensation attacks by unknown causes, especially the possibility of endolymphatic hydrops in the otolith organ. METHODS: Sixteen patients (6 men and 10 women) diagnosed with having IOV were enrolled. In these subjects, frequency preference in cervical vestibular evoked myogenic potential (cVEMP) was studied. The subjects underwent cVEMP testing using 500 Hz and 1000 Hz short tone bursts (STB) (125 dB SPL, air-conducted sound). The 500-1000 Hz cVEMP slope was calculated and assessed in comparison with data from healthy subjects in the preceding study. RESULTS: Twelve of the 16 examined patients had a significant preference of 1000 Hz to 500 Hz, which was suggestive of endolymphatic hydrops in the saccule. Patients with frequency preference of 1000 Hz to 500 Hz showed a tendency for longer vertigo attacks than patients without preference of 1000 Hz.

Do patients who experience episodic tilting or translational sensations in the pitch plane have abnormal sacculo-collic reflexes?

The otolith-collic and otolith-ocular reflexes of patients who experienced episodic tilting or translational sensations in the pitch plane without any other vestibular symptoms were assessed using cervical vestibular evoked myogenic potentials (cVEMP) and ocular vestibular evoked myogenic potentials (oVEMP). Eleven patients (4 men and 7 women, mean age=40.4) were enrolled. All of the patients complained of episodic tilting or translational sensations in the pitch plane. Patients with a medical history of rotatory vertigo, loss of consciousness, head trauma, or symptoms of central nervous dysfunction or proprioceptive dysfunction and those who had been definitely diagnosed with a disease that causes disequilibrium were excluded. All 11 patients underwent cVEMP and caloric tests. Ten patients participated in the oVEMP tests. Seven of the 11 patients exhibited unilateral cVEMP absences, two displayed bilateral cVEMP absences, one demonstrated unilaterally decreased cVEMP, and one displayed normal cVEMP. Concerning oVEMP, 2 of the 10 patients showed unilateral oVEMP absences, 2 displayed bilateral oVEMP absences, 2 exhibited unilaterally decreased oVEMP, and 4 displayed normal oVEMP. All patients exhibited normal bilateral caloric responses. These findings were distinct from the results obtained for patients who experienced episodic lateral tilting sensations in previous studies. While most of the latter patients exhibited abnormal oVEMP, the patients in the present study tended to display abnormal cVEMP. These results suggest that patients with episodic tilting or translational sensations in the pitch plane suffer from saccular dysfunction. We propose "idiopathic otolithic vertigo" as a clinical entity and suggest that it is caused by idiopathic saccular dysfunction and/or utricular dysfunction.

Damaged utricular function clarified by oVEMP in patients with benign paroxysmal positional vertigo.

CONCLUSION: Utricular dysfunction in patients with posterior canal benign paroxysmal positional vertigo (pBPPV) was supported by findings for ocular vestibular evoked myogenic potential (oVEMP). OBJECTIVE: To evaluate the utricular and saccular function in patients with pBPPV. METHODS: This study focused on 12 patients definitively diagnosed with pBPPV showing typical nystagmus by Dix-Hallpike maneuver and 12 controls. In these subjects, oVEMPs and cVEMPs to air-conducted 500 Hz tone burst (125 dB SPL) were measured. The patients also underwent caloric tests. RESULTS: More of the patients with pBPPV showed abnormal responses in oVEMPs by stimulation on their affected side than the controls, while the results of cVEMPs showed no significant differences between pBPPV patients and controls. The abnormal results for oVEMPs on the affected side showed a higher percentage than those for cVEMPs and caloric tests in pBPPV patients. There was no significant association between any of the tests. These findings support the possibility that oVEMP reflects the specific abnormal condition in pBPPV, i.e. that the urticular function in pBPPV patients was highly damaged.

Assessment of the otolith-ocular reflex using ocular vestibular evoked myogenic potentials in patients with episodic lateral tilt sensation.

The otolith-ocular reflex in patients with episodic lateral tilt sensation without any other vestibular symptoms was assessed using ocular vestibular evoked myogenic potentials (oVEMP). Ten patients (6 men and 4 women, mean age=53.5) were enrolled. All patients had episodic lateral tilt sensation. Patients with a medical history of rotatory vertigo, loss of consciousness, head trauma, or symptoms or signs of central nervous dysfunction or proprioceptive dysfunction and those who had been definitely diagnosed with a disease that causes disequilibrium were excluded. All of the 10 patients had oVEMP tests and cervical VEMP (cVEMP) tests and underwent caloric tests. Eight of the 10 patients showed unilateral absence of oVEMP, one displayed a bilateral absence, and one displayed normal oVEMP. Concerning cVEMP, 4 patients showed a unilateral absence of cVEMP, one displayed unilaterally decreased responses and 5 displayed normal cVEMP. All patients showed normal bilateral caloric responses. The present study showed that patients with episodic lateral tilt sensation displayed abnormal otolith-ocular reflexes, as shown by their oVEMP, suggesting that these patients were suffering from utricular dysfunction.

Association of air-conducted sound oVEMP findings with cVEMP and caloric test findings in patients with unilateral peripheral vestibular disorders.

CONCLUSION: This study showed that the ocular vestibular evoked myogenic potential (oVEMP) in response to air-conducted sound (ACS) reflects functions of different parts of the vestibular labyrinth from cervical VEMP (cVEMP). OBJECTIVE: To determine whether the origin of the vestibular end organs of the oVEMP in response to ACS (500 Hz tone bursts) is the same as that of cVEMP. METHODS: Twenty patients definitively diagnosed with unilateral Meniere's disease (MD), 6 patients with unilateral vestibular neuritis (VN), and 7 healthy subjects were enrolled. In these subjects, the oVEMP and cVEMP to air-conducted 500 Hz tone bursts (125 dBSPL) were measured. The patients also underwent caloric tests. RESULTS: The MD patients did not show a significant association between their ACS oVEMP findings and ACS cVEMP findings but there was an association of ACS oVEMP findings with caloric test findings. When the MD patients were classified into four stages based on their hearing levels, the patients showed abnormal findings at earlier stages on ACS cVEMP than on other tests. While all six VN patients showed abnormal findings on ACS oVEMP and caloric tests, only two patients showed abnormal ACS cVEMPs. These findings support the hypothesis that the oVEMP in response to ACS predominantly reflects utricular functions while ACS cVEMP reflects saccular functions.

Airway obstruction involving a laryngeal mask airway during arthroscopic shoulder surgery.

Several earlier reports have described life-threatening airway obstruction during arthroscopic shoulder surgery performed under regional anesthesia, caused by the leakage of irrigation fluid out of the shoulder joint space into the surrounding soft tissues and then the neck and the pharynx. Here, we present a case of airway obstruction that occurred in a patient under general anesthesia. A 77-year-old woman with a rotator cuff rupture who was to undergo right-shoulder arthroscopic surgery was anesthetized with fentanyl and propofol. Her airway was secured with a flexible laryngeal mask airway (LMA). During surgery, the compliance of her breathing bag became gradually poorer, and finally we were not able to ventilate her at an airway pressure of 60 cmH2O. We found that her chest wall, neck, and face were swollen and tense. Laryngoscopy revealed massive swelling of the pharyngeal soft tissues. The vocal cords were not visible. Her trachea was intubated blindly, and adequate ventilation was re-established. She was placed in the Fowler position and furosemide was given intravenously. Her neck and chest swelling were reduced over the next 2 h and she was extubated without any problem. We recommend that physicians should periodically examine the neck of any patient undergoing arthroscopic shoulder surgery, especially when general anesthesia is used, because anesthetized patients cannot complain of breathing difficulty and the airway swelling may progress until it becomes life-threatening.