Short Tone Research Articles

Pitch priming in sequences of two sounds.

Frequency discrimination limens (FDLs) were measured for pairs of stimuli differing from each other with respect to pitch salience. One of the two stimuli to be compared within a trial was a pure tone of at least 100 ms, evoking a salient pitch, while the other stimulus consisted of only eight sinusoidal cycles (experiment 1), or was a noise band with a Gaussian spectral envelope, evoking a weak pitch corresponding to the peak frequency (experiment 2). From trial to trial, frequency was varied randomly and widely. In both experiments, the FDLs were lower, by an average factor of about 3, when the stimulus with the more salient pitch preceded the other stimulus than vice versa. Evidence is presented against an interpretation of this temporal asymmetry in terms of memory limitations. It is suggested that the asymmetry reflects a pitch-priming effect. In two additional experiments, both of the stimuli to be compared within a trial were very short tone bursts or noise bands; perceptually, they differed only with respect to pitch height. Performance was markedly better than in experiments 1 and 2, and was not improved when the two stimuli were preceded by a 300-ms tone intended to produce pitch priming.

Detection of Saccular Endolymphatic Hydrops in Ménière's Disease Using a Modified Glycerol cVEMP Test in Combination With the Tuning Property Test.

To determine the optimal method for detecting saccular endolymphatic hydrops (EH) in patients with Ménière's disease (MD) using a glycerol cervical vestibular evoked myogenic potential (cVEMP) test in combination with a tuning property test. Prospective patients series. Tertiary referral center. Twenty-three subjects (age: 36-77 years) were enrolled in this study. Seventeen subjects were diagnosed with definite MD. Six subjects were diagnosed with possible MD. Diagnostic. The corrected amplitudes of p13-n23 (cVEMP) were measured before and after the administration of 10% glycerol (500 ml, 2 h, intravenously). A tuning property index and the p13-n23 amplitude improvement ratio were calculated. The positivity rate (PR) during the tuning property test was 55% (definite MD-affected ears), 35% (definite MD-unaffected ears), and 25% (possible MD ears). The PR during the glycerol cVEMP amplitude test was 60, 8, and 0%, respectively. The use of modified criteria for the glycerol cVEMP test in combination with the tuning property test resulted in the PR increasing to 75, 57, and 25%, respectively. The pre-glycerol stage results obtained using the tuning property test almost (except in two ears) completely agreed with the glycerol cVEMP test results by the modified criteria. The tuning property test is an easy and useful way of detecting saccular EH. However, the glycerol cVEMP test is required in patients that do not respond to either 500 or 1000 Hz short tone bursts (STB).

In vivo Whole-Cell Recordings Combined with Electron Microscopy Reveal Unexpected Morphological and Physiological Properties in the Lateral Nucleus of the Trapezoid Body in the Auditory Brainstem.

The lateral nucleus of the trapezoid body (LNTB) is a prominent nucleus in the superior olivary complex in mammals including humans. Its physiology in vivo is poorly understood due to a paucity of recordings. It is thought to provide a glycinergic projection to the medial superior olive (MSO) with an important role in binaural processing and sound localization. We combined in vivo patch clamp recordings with labeling of individual neurons in the Mongolian gerbil. Labeling of the recorded neurons allowed us to relate physiological properties to anatomy at the light and electron microscopic level. We identified a population of quite dorsally located neurons with surprisingly large dendritic trees on which most of the synaptic input impinges. In most neurons, one or more of these dendrites run through and are then medial to the MSO. These neurons were often binaural and could even show sensitivity to interaural time differences (ITDs) of stimulus fine structure or envelope. Moreover, a subpopulation showed enhanced phase-locking to tones delivered in the tuning curve tail. We propose that these neurons constitute the gerbil main LNTB (mLNTB). In contrast, a smaller sample of neurons was identified that was located more ventrally and that we designate to be in posteroventral LNTB (pvLNTB). These cells receive large somatic excitatory terminals from globular bushy cells. We also identified previously undescribed synaptic inputs from the lateral superior olive. pvLNTB neurons are usually monaural, display a primary-like-with-notch response to ipsilateral short tones at CF and can phase-lock to low frequency tones. We conclude that mLNTB contains a population of neurons with extended dendritic trees where most of the synaptic input is found, that can show enhanced phase-locking and sensitivity to ITD. pvLNTB cells, presumed to provide glycinergic input to the MSO, get large somatic globular bushy synaptic inputs and are typically monaural with short tone responses similar to their primary input from the cochlear nucleus.

Great apes and children infer causal relations from patterns of variation and covariation

We investigated whether nonhuman great apes (N=23), 2.5-year-old (N=20), and 3-year-old children (N=40) infer causal relations from patterns of variation and covariation by adapting the blicket detector paradigm for apes. We presented chimpanzees (Pan troglodytes), bonobos (Pan paniscus), orangutans (Pongo abelii), gorillas (Gorilla gorilla), and children (Homo sapiens) with a novel reward dispenser, the blicket detector. The detector was activated by inserting specific (yet randomly determined) objects, the so-called blickets. Once activated a reward was released, accompanied by lights and a short tone. Participants were shown different patterns of variation and covariation between two different objects and the activation of the detector. When subsequently choosing between one of the two objects to activate the detector on their own all species, except gorillas (who failed the training), took these patterns of correlation into account. In particular, apes and 2.5-year-old children ignored objects whose effect on the detector completely depended on the presence of another object. Follow-up experiments explored whether the apes and children were also able to re-evaluate evidence retrospectively. Only children (3-year-olds in particular) were able to make such retrospective inferences about causal structures from observing the effects of the experimenter’s actions. Apes succeeded here only when they observed the effects of their own interventions. Together, this study provides evidence that apes, like young children, accurately infer causal structures from patterns of (co)variation and that they use this information to inform their own interventions.

Frequency response of proud and partially exposed spheres at flat interfaces

The backscattering spectrum of spheres at flat interfaces viewed at small grazing angles depends upon reflections from the sphere's surface and the interface, as well as the sphere's elastic response and Franz wave contributions. For partially exposed spheres, one approach to modeling the reflective contribution is to extend the Kirchhoff approximation [K. Baik and P. L. Marston, IEEE J. Ocean. Eng. 33, 386–396 (2008)] to spheres. Laboratory measurements were carried out using short tone bursts for solid spheres at air-water and sand-water interfaces in such a way that it was typically possible to distinguish between the reflective and delayed elastic contributions viewed in the time domain. For spheres at an air-water interface, the reflective contributions have strong similarities with the Kirchhoff approximation while the strength of the delayed elastic contributions depends strongly on the extent of exposure of elastic guided wave coupling regions. The spectra of proud targets have similarities with i...

Attention demands of language production in adults who stutter

We investigated whether language production is atypically resource-demanding in adults who stutter (AWS) versus typically-fluent adults (TFA). Fifteen TFA and 15 AWS named pictures overlaid with printed Semantic, Phonological or Unrelated Distractor words while monitoring frequent low tones versus rare high tones. Tones were presented at a short or long Stimulus Onset Asynchrony (SOA) relative to picture onset. Group, Tone Type, Tone SOA and Distractor Type effects on P3 amplitudes were the main focus. P3 amplitude was also investigated separately in a simple tone oddball task. P3 morphology was similar between groups in the simple task. In the dual task, a P3 effect was detected in TFA in all three distractor conditions at each Tone SOA. In AWS, a P3 effect was attenuated or undetectable at the Short Tone SOA depending on Distractor Type. In TFA, attentional resources were available for P3-indexed processes in tone perception and categorization in all distractor conditions at both Tone SOAs. For AWS, availability of attentional resources for secondary task processing was reduced as competition in word retrieval was resolved. Results suggest that language production can be atypically resource-demanding in AWS. Theoretical and clinical implications of the findings are discussed.

Band limited chirp stimulation in vestibular evoked myogenic potentials.

Air conducted vestibular evoked myogenic potentials (VEMP) can be elicited by various low frequency and intense sound stimuli, mainly clicks or short tone bursts (STB). Chirp stimuli are increasingly used in diagnostic audiological evaluations as an effective means to obtain acoustically evoked responses in narrowed or extended frequency ranges. We hypothesized in this study that band limited chirp stimulation, which covers the main sensitivity range of sound sensitive otolithic afferents (around 500Hz), might be useful for application in cervical and ocular VEMP to air conduction. For this purpose we designed a chirp stimulus ranging 250-1000Hz (up chirp). The chirp stimulus was delivered with a stimulus intensity of 100dB nHL in normal subjects (n=10) and patients with otolith involvement (vestibular neuritis) (n=6). Amplitudes of the designed chirp ("CW-VEMP-chirp, 250-1000Hz") were compared with amplitudes of VEMPs evoked by click stimuli (0.1ms) and a short tone burst (STB, 1-2-1, 8ms, 500Hz). CVEMPs and oVEMPs were detectable in 9 of 10 normal individuals. Statistical evaluation in healthy patients revealed significantly larger cVEMP and oVEMP amplitudes for CW-VEMP-chirp (250-1000Hz) stimuli. CVEMP amplitudes evoked by CW-VEMP-chirp (250-1000Hz) showed a high stability in comparison with click and STB stimulation. CW-VEMP-chirp (250-1000Hz) showed abnormal cVEMP and oVEMP amplitudes in patients with vestibular neuritis, with the same properties as click and STB stimulated VEMPs. We conclude that the designed CW-VEMP-chirp (250-1000Hz) is an effective stimulus which can be further used in VEMP diagnostic. Since a chirp stimulus can be easily varied in its properties, in particular with regard to frequency, this might be a promising tool for further investigations.

Role of the Insula and Vestibular System in Patients with Chronic Subjective Dizziness: An fMRI Study Using Sound-Evoked Vestibular Stimulation.

Chronic subjective dizziness (CSD) is a common vestibular disorder characterized by persistent non-vertiginous dizziness, unsteadiness, and heightened sensitivity to motion stimuli that may last for months to years after events that cause acute vestibular symptoms or disrupt balance. CSD is not associated with abnormalities of basic vestibular or oculomotor reflexes. Rather, it is thought to arise from persistent use of high-threat postural control strategies and greater reliance on visual cues for spatial orientation (i.e., visual dependence), long after triggering events resolve. Anxiety-related personality traits confer vulnerability to CSD. Anomalous interactions between the central vestibular system and neural structures related to anxiety may sustain it. Vestibular- and anxiety-related processes overlap in the brain, particularly in the insula and hippocampus. Alterations in activity and connectivity in these brain regions in response to vestibular stimuli may be the neural basis of CSD. We examined this hypothesis by comparing brain activity from 18 patients with CSD and 18 healthy controls measured by functional magnetic resonance imaging during loud short tone bursts, which are auditory stimuli that evoke robust vestibular responses. Relative to controls, patients with CSD showed reduced activations to sound-evoked vestibular stimulation in the parieto-insular vestibular cortex (PIVC) including the posterior insula, and in the anterior insula, inferior frontal gyrus, hippocampus, and anterior cingulate cortex. Patients with CSD also showed altered connectivity between the anterior insula and PIVC, anterior insula and middle occipital cortex, hippocampus and PIVC, and anterior cingulate cortex and PIVC. We conclude that reduced activation in PIVC, hippocampus, anterior insula, inferior frontal gyrus, and anterior cingulate cortex, as well as connectivity changes among these regions, may be linked to long-term vestibular symptoms in patients with CSD. Furthermore, altered connectivity between the anterior insula and middle occipital cortex may underlie the greater reliance on visual cues for spatial orientation in CSD patients relative to controls.

Vestibulo-spinal and vestibulo-ocular reflexes are modulated when standing with increased postural threat

We investigated how vestibulo-spinal reflexes (VSRs) and vestibulo-ocular reflexes (VORs) measured through vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) outcomes, respectively, are modulated during standing under conditions of increased postural threat. Twenty-five healthy young adults stood quietly at low (0.8 m from the ground) and high (3.2 m) surface height conditions in two experiments. For the first experiment (n = 25) VEMPs were recorded with surface EMG from inferior oblique (IO), sternocleidomastoid (SCM), trapezius (TRP), and soleus (SOL) muscles in response to 256 air-conducted short tone bursts (125 dB SPL, 500 Hz, 4 ms) delivered via headphones. A subset of subjects (n = 19) also received horizontal and vertical head thrusts (∼150°/s) at each height in a separate session, comparing eye and head velocities by using a vHIT system for calculating the functional VOR gains. VEMP amplitudes (IO, TRP, SOL) and horizontal and vertical vHIT gains all increased with high surface height conditions (P < 0.05). Changes in IO and SCM VEMP amplitudes as well as horizontal vHIT gains were correlated with changes in electrodermal activity (ρ = 0.44-0.59, P < 0.05). VEMP amplitude for the IO also positively correlated with fear (ρ = 0.43, P = 0.03). Threat-induced anxiety, fear, and arousal have significant effects on VSR and VOR gains that can be observed in both physiological and functional outcome measures. These findings provide support for a potential central modulation of the vestibular nucleus complex through excitatory inputs from neural centers involved in processing fear, anxiety, arousal, and vigilance.

The ultra-slow NAT2*6A haplotype is associated with reduced higher cognitive functions in an elderly study group.

N-Acetyltransferase 2 (NAT2) genotype is associated with age-related declines in basic sensory hearing functions. However, the possible modulatory role of NAT2 for higher cognitive functions has not yet been studied. We tested auditory goal-directed behavior and attentional control in 120 NAT2 genotyped subjects (63-88 years), using an auditory distraction paradigm in which participants responded to the duration of long and short tone stimuli. We studied involuntary shifts in attention to task-irrelevant deviant stimuli and applied event-related potentials (ERPs) to examine which cognitive subprocesses are affected by NAT2 status on a neurophysiological level. Relative to the standard stimuli, deviant stimuli decreased performance in the recently described ultra-slow acetylators (NAT2*6A and *7B): The increase in error-corrected reaction times (a combined measure of response speed and accuracy) in ultra-slow acetylators (254 ms increase) was more than twice as high as in the rapid acetylator reference group (111 ms increase; p < 0.01). The increase was still higher than in the other slow acetylators (149 ms increase, p < 0.05). In addition, clear differences were found in the ERP results: Ultra-slow acetylators showed deficits specifically in the automatic detection of changes in the acoustic environment as evidenced by reduced mismatch negativity (MMN, p < 0.005 compared to rapid acetylators). Refocussing of attention after a distracting event was also impaired in the ultra-slow acetylators as evidenced by a reduced re-orienting negativity (RON, p < 0.01 compared to rapid acetylators). In conclusion, the ultra-slow acetylation status was associated with reduced higher cognitive functions.

Ocular vestibular evoked myogenic potentials in response to air-conducted 500 Hz short tones: Effect of stimulation procedure (monaural or binaural), age and gender.

The ocular vestibular myogenic potentials (oVEMP) can be elicited by monaural air-conducted sound stimulation, and are usually recorded from the contralateral eye. In clinical setting a binaural stimulation would save time and require less effort from the subjects. We evaluated the differences between monaural and binaural stimulation, and the possible effect of age and gender on oVEMP parameters. Air-conducted oVEMP were recorded by binaural and by monaural stimulation in a group of 54 normal subjects, aged from 12 to 83 years, and in 50 vestibular patients. From each side, we measured the latency of the N1 component, and the peak-to-peak N1-P1 amplitude. For both parameters we also computed the asymmetry ratio. In normal subjects binaural stimulation produced slightly larger responses than monaural stimulation; detectability, latency and amplitude ratio were the same for the two techniques. We found no differences related to gender, and the age-induced amplitude decline was likely to be negligible.oVEMP recorded not in an acute phase of their disorder, proved to be abnormal in about 20% of the patients, and the normal or abnormal findings obtained either with monaural or with binaural stimulation were always concordant. The oVEMP obtained after binaural and monaural stimulation are very similar, and they are largely independent from age and gender.

An empirical profile of VLF triggered emissions

AbstractThe Siple Transmitter Experiment operated from 1973 to 1988 and generated a wealth of observations of nonlinear wave‐particle interactions including extensive recordings of triggered emissions generated by VLF signals injected into the magnetosphere from the transmitter at Siple Station, Antarctica. Due to their complex appearance and immensely varied behavior, triggered emissions remain poorly described and understood. This work provides a comprehensive statistical description of observed triggered emissions and establishes statistical bounds on triggered emission type (fallers, risers, and positive and negative hooks) and behavior (frequency changes between 1 kHz and 2.5 kHz with initial sweep rates between −2.5 kHz/s and 2.5 kHz/s, with risers undergoing a median frequency change of 556 Hz and fallers a median frequency change of −198 Hz). The statistical study also reveals an apparent dependence of the triggered emission behavior on the transmitted signal itself. Long tones and rising ramps generate more risers and positive hooks, while short tones and falling ramps produce more fallers and negative hooks. Triggered emissions also appear to favorably initiate with sweep rates similar to that of the triggering element, with the 1 kHz/s rising ramps triggering initial risers with a median sweep rate of 1.03 kHz/s and −1 kHz/s triggering initial fallers with a median sweep rate of −0.73 kHz/s. These results improve observations of wave modification resulting from wave‐particle interactions in the radiation belts and can be used to validate numerical simulations of triggered emissions.

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.

Stochastic undersampling steepens auditory threshold/duration functions: implications for understanding auditory deafferentation and aging.

It has long been known that some listeners experience hearing difficulties out of proportion with their audiometric losses. Notably, some older adults as well as auditory neuropathy patients have temporal-processing and speech-in-noise intelligibility deficits not accountable for by elevated audiometric thresholds. The study of these hearing deficits has been revitalized by recent studies that show that auditory deafferentation comes with aging and can occur even in the absence of an audiometric loss. The present study builds on the stochastic undersampling principle proposed by Lopez-Poveda and Barrios (2013) to account for the perceptual effects of auditory deafferentation. Auditory threshold/duration functions were measured for broadband noises that were stochastically undersampled to various different degrees. Stimuli with and without undersampling were equated for overall energy in order to focus on the changes that undersampling elicited on the stimulus waveforms, and not on its effects on the overall stimulus energy. Stochastic undersampling impaired the detection of short sounds (<20 ms). The detection of long sounds (>50 ms) did not change or improved, depending on the degree of undersampling. The results for short sounds show that stochastic undersampling, and hence presumably deafferentation, can account for the steeper threshold/duration functions observed in auditory neuropathy patients and older adults with (near) normal audiometry. This suggests that deafferentation might be diagnosed using pure-tone audiometry with short tones. It further suggests that the auditory system of audiometrically normal older listeners might not be “slower than normal”, as is commonly thought, but simply less well afferented. Finally, the results for both short and long sounds support the probabilistic theories of detectability that challenge the idea that auditory threshold occurs by integration of sound energy over time.

Electrophysiological analysis shows dizziness as the first symptom in human T cell lymphotropic virus type-associated myelopathy/tropical spastic paraparesis.

Dizziness is a symptom in human T cell lymphotropic virus type-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and may occur due to vestibulospinal tract dysfunction. This tract can be assessed by an electrophysiological test called vestibular-evoked myogenic potential (VEMP). The aim was to correlate the result of VEMP generated by acoustic stimuli and dizziness in individuals with human T cell lymphotropic virus type 1 (HTLV-1)-asymptomatic infection and HAM/TSP. VEMP was recorded from the sternocleidomastoid muscle of 60 HTLV-1-negative adults (60±8 years) and 60 individuals infected with HTLV-1, 30 being asymptomatic (59±8 years) and 30 with HAM/TSP (59±8 years). In all groups, 90% of the participants were women. VEMP was generated by acoustic stimuli (short tone bursts), with an intensity of 118 dBHL and band-pass filter from 10 Hz to 1,500 Hz, and presented 200 stimuli at a frequency of 1,000 Hz with a record time of 60 ms. Of 60 HTLV-1-negative individuals, 14 (23%) reported dizziness; VEMP was normal in all. In the HTLV-1-asymptomatic group, 11(37%) complained of dizziness (p=0.31); VEMP was altered in four (40%) subjects with dizziness and in one (5%) without dizziness (p=0.00). In the group with HAM/TSP, dizziness was reported by 17 (57%) subjects (p=0.002); VEMP was altered in 11 (64%) with dizziness and in 5 (38%) without dizziness (p=0.15). Dizziness without an apparent etiology in HTLV-1-asymptomatic carriers deserves attention in terms of a possible subclinical spinal cord involvement that can be clarified through spinal electrophysiological tests. Damage of the vestibulospinal tract seems to occur in the early stages of HAM/TSP.

Increased gain of vestibulospinal potentials evoked in neck and leg muscles when standing under height-induced postural threat

ObjectiveTo measure changes in amplitudes of vestibular evoked myogenic potentials (VEMPs) elicited from neck, upper and lower limb muscles during a quiet standing task with increased postural threat achieved by manipulating surface height. Methods: Twenty eight subjects were tested while standing on a platform raised to 0.8m and 3.2m from the ground. Surface electromyography was recorded from the ipsilateral sternocleidomastoid (SCM), biceps brachii (BB), flexor carpi radialis (FCR), soleus (SOL) and medial gastrocnemius (MG) muscles. Stimulation was with air-conducted short tone bursts (4ms). After controlling for background muscle activity, VEMP amplitudes were compared between heights and correlated with changes in state anxiety, fear and arousal. Results: VEMP amplitude significantly increased in SCM (9%) and SOL (12.7%) with increased surface height (p<0.05). These modest increases in SCM VEMP amplitude were significantly correlated with anxiety (Rho=0.57, p=0.004) and confidence (Rho=−0.38, p=0.047) and those for SOL were significantly correlated with anxiety (Rho=0.33, p=0.049) and fear (Rho=0.36, p=0.037). Conclusion: Postural threat significantly increased vestibulospinal reflex (VSR) gains. Results demonstrate that VEMPs can be used to test different VSR pathways simultaneously during stance. Since fear and anxiety are prevalent with vestibular disorders, they should be considered as potential contributing factors for clinical vestibular outcome measures.

Filling the blanks in temporal intervals: the type of filling influences perceived duration and discrimination performance.

In this work we investigate how judgments of perceived duration are influenced by the properties of the signals that define the intervals. Participants compared two auditory intervals that could be any combination of the following four types: intervals filled with continuous tones (filled intervals), intervals filled with regularly-timed short tones (isochronous intervals), intervals filled with irregularly-timed short tones (anisochronous intervals), and intervals demarcated by two short tones (empty intervals). Results indicate that the type of intervals to be compared affects discrimination performance and induces distortions in perceived duration. In particular, we find that duration judgments are most precise when comparing two isochronous and two continuous intervals, while the comparison of two anisochronous intervals leads to the worst performance. Moreover, we determined that the magnitude of the distortions in perceived duration (an effect akin to the filled duration illusion) is higher for tone sequences (no matter whether isochronous or anisochronous) than for continuous tones. Further analysis of how duration distortions depend on the type of filling suggests that distortions are not only due to the perceived duration of the two individual intervals, but they may also be due to the comparison of two different filling types.

Vestibular evoked myogenic potentials (VEMPs) evoked by air- and bone-conducted stimuli in vestibular neuritis

ObjectiveTo compare and characterise abnormalities for short latency vestibular evoked myogenic potentials (VEMPs) elicited by air- (AC) and two differing types of bone-conducted (BC) stimuli during vestibular neuritis (VN). MethodsAC (500Hz short tone bursts) and two BC stimuli (500Hz at the forehead and impulses at the mastoids) were used to evoke cervical and ocular potentials (cVEMPs and oVEMPs) in VN patients (n=22) and healthy subjects. ResultsMore abnormalities were observed for the oVEMP than the cVEMP when using either AC 500Hz or BC 500Hz. The AC stimulus showed slightly more abnormalities than the BC 500Hz stimulus. In contrast, BC impulses produced frequent abnormalities for both oVEMPs and cVEMPs. The findings were modelled, based upon presumed selective lesions of the superior nerve. ConclusionsAC 500Hz stimulation was slightly better than BC 500Hz in demonstrating abnormalities in patients with VN. BC impulses behave as expected for a predominantly utricular stimulus. The relative contributions of saccular and utricular fibres differ for stimulus type and target reflex. SignificanceAC 500Hz is as effective as BC 500Hz for investigating VN. BC impulses act most strongly on utricular afferents.

Vestibular examinations in apogeotropic positional nystagmus caused by cerebellar tumor

Horizontal, direction changing apogeotropic positional nystagmus (HAPN) is known to be associated with cerebellar lesions [1]. However, the pathophysiologic mechanism of cerebellar HAPN is unknown. We encountered a patient with a metastatic cerebellar tumor who presented with HAPN that disappeared after tumorectomy. Hyperactive vestibular reflexes, indicated by the results of electrophysiologic examinations, might have been the mechanism underlying the HAPN in this patient. A 70-year-old woman with a 2-month history of progressive dizziness and difficulty in walking was admitted to our hospital. She presented with truncal ataxia and HAPN but no other neurologic or neuroophthalmologic abnormalities. Contrast brain MRI revealed a well-enhanced cerebellar tumor. Because chest X-ray and CT showed a left lung tumor suggestive of lung cancer, a cerebellar metastasis was diagnosed. The cerebellar tumor was removed surgically 10 days after the patient’s admission. Pathologic examination of the surgical specimen revealed adenocarcinoma. After the tumorectomy, the HAPN was fully resolved, and the truncal ataxia was improved. The horizontal angular vestibulo-ocular reflex (A-VOR), cervical vestibular-evoked myogenic potential (C-VEMP), and ocular vestibular-evoked myogenic potential (O-VEMP) were evaluated before (when the HAPN was present) and 10 days after tumorectomy (when the HAPN had disappeared). A-VORs were recorded in darkness by means of a video-oculography-basedVORrecording and analysis system (IRN-2, Morita Mfg. Corp., Kyoto, Japan), with the patient seated on a rotating armchair with a headrest [2]. The chair was rotatedmanually in sinusoidal fashion for 20 s (frequency 0.5–0.75 Hz, amplitude 20 ) [2]. VOR gain, i.e., the eye velocity to head velocity ratio, was analyzed. C-VEMP was recorded from the tonically contracting ipsilateral sternocleidomastoid muscle during monaural stimulation with 105-dB clicks or short tone bursts (MEB 2312 testing system, Nihon Kohden, Tokyo, Japan; bandwidth 20–2,000 Hz, 200 averaged signals). Latencies of the first positive wave (p13) and second negative wave (n23) and peak-to-peak p13–n23 amplitude were measured. O-VEMP was recorded from the lower eyelids (inferior oblique muscles) during stimulation with 105 dB clicks or short tone bursts (MEB 2312, Nihon Kohden, Tokyo, Japan; bandwidth 20–2,000 Hz, 200 averaged signals). The patient was instructed to continue looking straight ahead and upward 30 . Because O-VEMP was not adequately elicited by monaural stimulation, binaural sound stimulation was applied. Latencies of the first negative wave (n1) and second positive wave (p1) and peak-to-peak n1–p1 amplitude were measured. Absolute A-VOR gains were reduced in both directions after the tumorectomy (Table 1). Cand O-VEMP amplitudes were also reduced on almost all recordings after tumorectomy (Table 1). Latencies of Cand O-VEMPs did not change. A-VOR is mediated by a semicircular-ocular pathway. C-VEMP reflects the vertical linear vestibulo-ocular reflex Electronic supplementary material The online version of this article (doi:10.1007/s10072-015-2086-4) contains supplementary material, which is available to authorized users.

Video Head Impulse Test, 温度刺激検査, VEMP を用いた前庭神経炎の障害部位の検討

The aim of this study was to classify unilateral vestibular neuritis (VN) with caloric testing, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and the video head impulse test (vHIT). Eight Patients (3 males and 5 females, mean age 55.6 years) with VN were studied. cVEMP and oVEMP (105 dBSPL 500 Hz short tone burst stimulation) were recorded. The caloric test and vHIT for the 3 semicircular canal were performed. The caloric test, cVEMP and oVEMP in combination with vHIT were able to allow the classification of 4 types of VN: entire VN, superior VN, inferior VN, and ampullary VN. In our case, 75% of the cases were entire VN, 12.5% were superior VN, and 12.5% were inferior VN. Three patients had only deficits of the horizontal and/or inferior semicircular canals or their ampullary nerves. One of eight VN patients had symptoms similar to benign paroxysmal positional vertigo after three weeks onset of VN. The results lead us to believe that clinical VN comprises vestibular neuritis and vestibular labyrinthitis. Currently, in Japan it would be essential that there is canal paresis in caloric test for VN diagnosis. We hope to include inferior VN within the diagnosis criteria of VN in the near future.