Cortical representation of the vestibular system as evidenced by brain electrical activity mapping of vestibular late evoked potentials.Abstract
We examined the space and temporal distributions of the rotatory ro·ta·to·ry
1. Of, relating to, causing, or characterized by rotation.
2. Occurring or proceeding in alternation or succession. evoked brain electrical activity patterns (brain electrical activity mapping of vestibular evoked potentials Evoked potentials
Tests that measure the brain's electrical response to stimulation of sensory organs (eyes or ears) or peripheral nerves (skin). These tests may help confirm the diagnosis of multiple sclerosis.
Mentioned in: Multiple Sclerosis [VestEP]) in humans. We performed a longitudinal scalp line analysis, transversal line analysis, and clockwise/counterclockwise rotation analysis of the VestEP principal components in 75 healthy persons aged 22 to 30 years (mean: 25.8). We found that the shortest VestEP latencies and the highest amplitudes were registered in a relatively distinct cortical area that is covered by the transversal electrode line T3-C3-Cz-C4-T4, in accordance with the 10/20 international electrode scheme. This area corresponds to the posterior part of the frontal lobe frontal lobe
The largest portion of each cerebral hemisphere, anterior to the central sulcus.
The largest, most forward-facing part of each side or hemisphere of the brain. (Brodmann's area Brod·mann's area
Any of the areas of the cerebral cortex mapped out on the basis of the cortical cytoarchitectural patterns. 4, the primary motor field of the isocortex) and the anterior parts of the cerebral parietal lobe parietal lobe
The middle portion of each cerebral hemisphere, separated from the frontal lobe by the central sulcus, from the temporal lobe by the lateral sulcus, and from the occipital lobe only partially by the parieto-occipital sulcus on its (the gyrus gyrus /gy·rus/ (ji´rus) pl. gy´ri [L.] cerebral g.
angular gyrus one arching over the superior temporal sulcus, continuous with the middle temporal gyrus. postcentralis, which corresponds to the primary somatosensory somatosensory /so·ma·to·sen·sory/ (so?mah-to-sen´so-re) pertaining to sensations received in the skin and deep tissues.
adj. fields, Brodmann's areas Brodmann's areas
specific occipital and preoccipital areas of the human cerebral cortex, distinguished by differences in the arrangement of their six cellular layers, and identified by number. They are considered to be the seat of specific functions of the brain. 1, 2, and 3). In this article, we discuss a method of investigation that exhibits t he VestEPs, and we review one normal case and three typical cases of pathologic VestEPs.
The existence of cortical representation areas for vestibular efferents has been suggested by many authors. [1-4] These functional (nonmorphologic) observations are based principally on two approaches: evoked potential Evoked potential
A test of nerve response that uses electrodes placed on the scalp to measure brain reaction to a stimulus such as a touch.
Mentioned in: Spinal Stenosis
n study following stimulation of the labyrinth in animal models [1-3] and direct stimulation of the exposed cortex in humans,  which elicits a sensation of vertigo and dizziness. In cats, the area of maximal activation during an evoked potential study was found to be located bilaterally within the anterior sylvian sulcus sulcus /sul·cus/ (sul´kus) pl. sul´ci [L.] a groove, trench, or furrow; in anatomy, a general term for such a depression, especially one on the brain surface, separating the gyri. between the facial somatosensory area and the auditory cortex auditory cortex
The region of the cerebral cortex that receives auditory data from the medial geniculate body. Also called auditory area. . [1,2] An overlap of the vestibular representation existed with the somatosensory zones. Fredrickson et al reported that the primary cortical vestibular projections in rhesus monkeys were located in the postcentral gyrus postcentral gyrus
The anterior convolution of the parietal lobe, bounded in front by the central sulcus and in back by the interparietal sulcus. at the lower end of the intraparietal sulcus in·tra·pa·ri·e·tal sulcus
A horizontal sulcus extending from the postcentral sulcus and dividing into two branches to form with the postcentral sulcus a figure H that divides the parietal lobe into a superior and an inferior lobule. .  This location corresponds to Brodmann's area 2. 
The vestibular sensory area in humans has been thought to be located in the anterior portion of the parietal parietal /pa·ri·e·tal/ (pah-ri´e-t'l)
1. of or pertaining to the walls of a cavity.
2. pertaining to or located near the parietal bone.
1. sulcus (Brodmann's area 2). Moreover, some parts of the somatosensory representation of the upper limbs appear to participate in the integration of the vestibular and proprioceptive Proprioceptive
Pertaining to proprioception, or the awareness of posture, movement, and changes in equilibrium and the knowledge of position, weight, and resistance of objects as they relate to the body. signals. [3, 7]
The purpose of our study was to evaluate the cortical distribution of vestibular evoked potentials (VestEP) elicited by short-duration angular accelerations in humans. Our analysis of the latency and amplitude parameters of the VestEP principal components, registered by multi-channel electroencephalographic e·lec·tro·en·ceph·a·lo·graph
n. Abbr. EEG
An instrument that measures electrical potentials on the scalp and generates a record of the electrical activity of the brain. Also called encephalograph. (EEG EEG: see electroencephalography. ) recordings, served as the basis for a determination of the cortical focus of maximal VestEP activity.
Methods, materials, and subjects
Properties of vestibular stimulation. The vestibular stimuli applied in this study were repetitive short-duration rotatory movements (stepwise stepwise
incremental; additional information is added at each step.
stepwise multiple regression
used when a large number of possible explanatory variables are available and there is difficulty interpreting the partial regression angular accelerations, clockwise [CW] and counterclockwise [CCW (Continuous Composite Write) A magneto-optic disk technology that emulates a WORM (Write Once Read Many) disk. It uses firmware in the drive to ensure that data cannot be erased and rewritten. ] in consecutive trials) of the subject's entire body around a vertical axis, The onset of the positive acceleration served as a trigger impulse for averaging the EEG segments. To prevent emotional stress and muscle artifacts artifacts
see specimen artifacts. , we used a slow Deceleration deceleration /de·cel·er·a·tion/ (de-sel?er-a´shun) decrease in rate or speed.
early deceleration (i.e., not a sudden stop). The rotational motion thus consisted of trials of CW and CCW constant-acceleration impulses. The interstimulus interval was 14.0 seconds, and the duration of the acceleration and deceleration phases was 1,000 msec each (figure 1).
After preliminary investigations, we chose an angular acceleration and deceleration intensity of 15[degrees]/[sec.sup.2]. In this way, the angular velocity rose from 0[degrees]/sec to a maximum peak velocity of 15[degrees]/sec. The common step amplitude for both the positive and negative acceleration phases was 300.
In all, we averaged 25 stepwise rotations for each of the CW and CCW rotations. To avoid the possibility of habituation habituation
Reduction of an animal's behavioral response to a stimulus, as a result of a lack of reinforcement during continual exposure to the stimulus. Habituation is usually considered a form of learning in which behaviours not needed are eliminated. in any patient, we scheduled a lapse of 3 to 5 minutes between consecutive sessions. The average duration of each session was approximately 30 minutes, including the time necessary to mount the electrodes.
Equipment. We used a direct-drive servocontrolled ServoMed AB Rotation Chair RS/6, which had an option for 17 self-contained, self-supplied direct-current (DC) preamplifiers (input resistance: 400 MOhms). The biosignals were transmitted to the main amplifier through a slip-ring assembly; the assembly contained 17 slip rings, and each was equipped with twin sliding contacts. Digital setting and monitoring of the angular speed and acceleration were also available. The stimulus profile was programmed by a function generator. While in operation, the rotating chair was completely silent. Even so, we applied individual hearing protectors to both ears of each subject in order to avoid a possible acoustic contribution to the rotationally evoked potentials.
Each patient was positioned in the chair with his or her head inclined forward by 30[degrees]. To minimize eye-movement artifacts, we used a gaze-fixation target that rotated with the chair. The chair was housed in a semilighted room, which allowed us to examine each patient either in total darkness or in an illuminated environment. Eye movements were monitored on a special electro-oculographic channel.
A set of Ag/AgCl-sintered electrodes was placed over the scalp according to the internationally used 10/20 system. We used several montage schemes and programs, some of which included the middle line electrodes Fz and Cz. Altogether, we used 19 scalp electrodes to study the scalp topography of the VestEP. The amplification and paper monitoring of the raw EEG data were performed by a 17-channel Picker Schwarzer Encephaloscript ES 16000 (input impedance: 100 MOhms).
The reference electrode was fixed to a line connecting both mastoids at the rear center of the skull. Upward deflections indicated scalp negativity. The frequency band of the recorded spontaneous brain electrical activity was determined by a low-frequency cutoff of 0.1 Hz and a high-frequency cutoff of 35 Hz. A 50-Hz notch filter was applied. The responses were monitored online and subsequently processed on a Schwarzer Brain Surveyor BS 2400, which supplied facilities for spatial and chronologic analysis of both spontaneous and evoked brain electrical activity (brain electrical activity mapping [BEAM]).  Following the onset of the stepwise acceleration stimulus, a period of 1,000 msec was used for analysis of the rotatory evoked brain electrical events. Peak-to-peak amplitudes and principal component latencies were measured and subsequently computed on a personal computer for their mean values and standard deviations.
Subjects. The reference data were obtained from 75 healthy volunteers (mostly medical students) who had no diagnosed neurologic or neurotologic disorders. The 40 men and 35 women were aged 22 to 30 years (mean: 25.8). In addition, we also investigated a few children (age: 9 to 11 yr) and a few older persons (age: 37 to 55 yr) to appreciate the age-related variability in the VestEP properties. The addition of these subjects raised the mean age of the entire group to 30.1 years.
Latency properties and scalp distribution of the VestEP components. The VestEP waveforms elicited by the above-described procedures consisted of six positive (P) or negative (N) wave components, which appeared within intervals of 50 to 850 msec after the onset of the acceleration stimulus (table 1). The most prominent part of the compound VestEP complex was the III-IV-V wave segment.
The response was nearly always well structured during the first few applications of the stimuli. Both the CW and CCW accelerations basically elicited similar wave patterns, although some differences or peculiarities do exist among clinically healthy persons. Sometimes an intermediate peak was detected in the initial wave complex (between the Ist (company) IST - Imperial Software Technology. and IInd or IInd and IIIrd wave segments). The response curves show a relatively low to moderately stressed variability intra- and interindividually.
The nomenclature of the VestEP components was established in terms of the negative peaks (the only exception being the IVth component, which was the most dominant and stable positive peak). Thus, the peaks' nomenclature according to their average latency was N75 (N-I), N180 (N-II), N330 (N-III), P480 (P-IV), N630 (N-V), and N800 (N-VI); these values were averaged from the CW and CCW stimuli (table 1).
The scalp placement of the electrodes significantly influences VestEP component latencies. The shortest latencies of the initial VestEP components (Ist, IInd, and IIIrd) were obtained from the central transversal line area (the T3-C3-Cz-C4-T4 electrodes). The shortest latencies of the later components (IVth, Vth, and VIth) were registered from the more frontally located brain regions (Fp1, Fp2, and Fz).
Our statistical analysis according to the Student's t test revealed that there were significant differences in latency among the various VestEP components, depending on the electrode's location on the anteroposterior anteroposterior /an·tero·pos·te·ri·or/ (-pos-ter´e-er) directed from the front toward the back.
adj. Abbr. AP
1. Relating to both front and back. plane (longitudinal line analysis). The VestEP latencies of the Ist and IInd components registered from the Cz electrode (CW rotation) were significantly shorter than those from the P4, T6, O1, and O2 derivations. The latency differences for the IIIrd and IVth VestEP components were even more widely expressed: F8, T6, and O2 (p[less than or equal to]0.001) and P4 and O1 (p[less than or equal to]0.01)
Furthermore, there was also a direction-dependent (labyrinth-related) difference in the VestEP components' latencies. Thus, the VestEP latencies produced by a rotation directed to the left (CCW stimulus) appeared to be slightly shorter, at least for some of the electrode derivations, than the corresponding VestEP latencies that were elicited when rotating toward the right in the CW stimulus (labyrinth-related analysis). These CW/ CCW latency differences were statistically significant for the Ist component registered from the T5, P3, and P4 derivations, for the IVth component registered from the F8, T3, Cz, T4, P3, T6, O1, and O2 derivations, and for the Vth component registered from the P3, P4, T6, O1, and O2 derivations.
The presence of some degree of interhemispheric asymmetry in VestEP component latencies (transversal line analysis) was also notable. In general, the latency differences between the left and right hemispheres were not significant. The only exceptions were the T5-T6 and P3-P4 derivations, in which the latencies obtained from the left hemisphere were significantly shorter than those obtained from the right (p[less than or equal to]0.01).
Amplitude mapping of the VestEP. The amplitude mapping of the VestEP was performed with respect to the IIIrd and IVth peak-to-peak segments. The highest VestEP amplitudes were registered at the Cz, C4, F4, and C3 cortical areas. At the areas more frontal and more occipital occipital /oc·cip·i·tal/ (ok-sip´i-t'l) pertaining to the occiput; located near the occipital bone.
Of or relating to the occipital bone.
n. from the transversal line (the T3-C3-Cz-C4-T4 line), the response was progressively less in its amplitude. The lowest amplitudes were registered in the occipital and frontal areas. The differences with respect to the response obtained from Cz (CW rotation) were highly significant: Fp1, Fp2, F7, T3, T5, T6, P3, O1, and O2 (p[less than or equal to]0.001).
Patient 1: Normal. For comparison purposes, figure 2 shows the normal VestEPs (CW rotation) in a 55-year-old man with no neurotologic complaints.
Patient 2: Complete bilateral vestibular loss. A 47-year-old man was referred to the neurotology department in 1995 with a presumed diagnosis of a total bilateral vestibular loss. His neurotologic complaints included unsteadiness (which worsened when he closed his eyes or was in the dark), oscillopsia, episodic severe vertigo, anacusis on the left, and severe hypoacusis on the right served by a hearing aid. The history of his disease began in 1963, when he was diagnosed with a complete cochleovestibular loss on the left that was the result of Jaffe-Lichten stein syndrome (fibrous bone dystrophy with secondary cyst cyst, abnormal sac in the body, filled with a fluid or semisolid and enclosed in a membrane. Cysts can be congenital but are usually acquired, the most common locations being the skin and the ovaries. formation at the left petrous petrous /pet·rous/ (pet´rus) resembling a rock; hard; stony.
1. Of stony hardness.
2. bone, mastoid process mastoid process
1. A conical protuberance of the posterior portion of the temporal bone that is situated behind the ear and serves as a site of muscle attachment. Also called mastoid bone.
2. , and occipital squama squama /squa·ma/ (skwah´mah) pl. squa´mae [L.] a scale or thin, platelike structure.squa´mate
n. pl. squa·mae
1. A thin platelike mass, as of bone. ).
In 1980, the man experienced right otitis otitis
Inflammation of the ear. Otitis externa is dermatitis, usually bacterial, of the auditory canal and sometimes the external ear. It can cause a foul discharge, pain, fever, and sporadic deafness. herpetica with right facial palsy facial palsy
Unilateral paralysis of the facial muscles supplied by the facial nerve. Also called Bell's palsy, facial paralysis, facioplegia, prosopoplegia. and encephalitis encephalitis (ĕnsĕf'əlī`təs), general term used to describe a diffuse inflammation of the brain and spinal cord, usually of viral origin, often transmitted by mosquitoes, in contrast to a bacterial infection of the meninges herpetica, which led to the progressive and severe hearing and vestibular loss on the right. In 1992, he was diagnosed with type 2 diabetes mellitus Type 2 diabetes mellitus
One of the two major types of diabetes mellitus, characterized by late age of onset (30 years or older), insulin resistance, high levels of blood sugar, and little or no need for supple-mental insulin. and secondary polyneuropathy polyneuropathy /poly·neu·rop·a·thy/ (-ndbobr-rop´ah-the) neuropathy of several peripheral nerves simultaneously.
amyloid polyneuropathy . In 1994, he underwent a retromastoid craniectomy cra·ni·ec·to·my
Surgical removal of a portion of the cranium.
craniectomy (krā·nē·ekˑ·t with an extended cyst resection on the left.
Prior to 1995, the man had undergone brainstem evoked response audiometry brainstem evoked response audiometry
See auditory brainstem response audiometry. (BERA Bera (bē`rə), in the Bible, king of Sodom. ), computed tomography Computed tomography (CT scan)
X rays are aimed at slices of the body (by rotating equipment) and results are assembled with a computer to give a three-dimensional picture of a structure. (CT), and a neurologic examination neurologic examination A battery of clinical tests that evaluates a person's physiologic function and mental status, as well as the presence of any structural–organic lesions that may cause changes in neurologic function. Cf Psychiatric examination. . The BERA revealed no potentials on the left and a pathologic morphology of the curves and a prolonged interpeak latency of the IIIrd, IVth, and Vth waves on the right. CT demonstrated large alterations of the left mastoid mastoid /mas·toid/ (mas´toid)
2. mastoid process.
3. pertaining to the mastoid process.
The mastoid process. , petrous, and temporal bones Temporal bones
The compound bones that form the left and right sides of the skull.
Mentioned in: Temporomandibular Joint Disorders (bone proliferation, fibrosis, chronic inflammation chronic inflammation
Inflammation that may have a rapid or slow onset but is characterized primarily by its persistence and lack of clear resolution; it occurs when the tissues are unable to overcome the effects of the injuring agent. , and cicatrization cicatrization /cic·a·tri·za·tion/ (sik?ah-tri-za´shun) the formation of a cicatrix or scar.
The process of scar formation. ), a slight compression of the left cerebellar hemisphere, and a nonspecific nonspecific /non·spe·cif·ic/ (non?spi-sif´ik)
1. not due to any single known cause.
2. not directed against a particular agent, but rather having a general effect.
1. enhancement of the right labyrinth (figure 3). The neurologic examination detected anacusis on the left, severe hypoacusis on the right, a complete vestibular loss bilaterally, a very slight paresis paresis /pa·re·sis/ (pah-re´sis) slight or incomplete paralysis.
general paresis paralytic dementia; a form of neurosyphilis in which chronic meningoencephalitis causes gradual loss of cortical of the right facial nerve, and no signs of compression of the cerebral structures.
We performed our own complete neurotologic investigation, which included electronystagmography (ENG ENG electronystagmography.
enzootic nasal granuloma. ) and craniocorpography (CCG CCG Chicago
CCG Collectible Card Game
CCG Canadian Coast Guard
CCG Country Commercial Guide
CCG Children's Cancer Group
CCG Commission Canadienne des Grains (Canadian Grain Commission) ). The ENG revealed normal optokinetics, a complete caloric caloric /ca·lo·ric/ (kah-lor´ik) pertaining to heat or to calories.
1. Of or relating to calories.
2. Of or relating to heat. areflexia on the right, an impossible left calorization on the left (which was caused by the obstruction of the external auditory canal external auditory canal
See ear canal. by bone proliferation), and no response to rotatory testing. The CCG revealed extreme ataxia ataxia (ətăk`sēə), lack of coordination of the voluntary muscles resulting in irregular movements of the body. Ataxia can be brought on by an injury, infection, or degenerative disease of the central nervous system, e.g. ; the patient was not able to take more than 30 steps during Unterberger's test (normal: 100) or to remain standing for more than 27 seconds during Romberg's test (normal: 60).
We used the BEAM-VestEP investigation to confirm the presumed diagnosis of a complete bilateral vestibular loss. On BEAM-VestEP, no cortical response/potential to the vestibular stimulation could be recorded because of a complete bilateral destruction of the labyrinth receptors (figure 3).
We found it extremely interesting to observe how this patient was able to use his visual and proprioceptive functions to compensate for his complete lack of vestibular function and his very severe loss of auditory function. The man was able to lead a relatively normal life and enjoy a satisfactory degree of social independence.
Patient 3: Acoustic neuroma. A 55-year-old-man came to our facility with a 10-year history of tinnitus Tinnitus Definition
Tinnitus is hearing ringing, buzzing, or other sounds without an external cause. Patients may experience tinnitus in one or both ears or in the head. and a progressive hearing loss in the same ear. He had no subjective complaints of vertigo and no balance disturbances.
We performed a routine neurotologic examination (figure 4). Caloric testing showed a partial inhibition (cold water) on the left and disinhibition dis·in·hi·bi·tion
1. A loss of inhibition, as through the influence of drugs or alcohol.
2. A temporary loss of an inhibition caused by an unrelated stimulus, such as a loud noise. on the right. The rotatory intensity damping test showed recruitment on the left side, and the CCG showed a peripheral vestibular disturbance with an angular deviation to the left. The BERA was normal (false negative), and a pure-tone audiogram au·di·o·gram
A graphic record of hearing ability for various sound frequencies.
A chart or graph of the results of a hearing test conducted with audiographic equipment. showed a slight middle- and high-frequency hearing loss on the left.
The BEAM-VestEP investigation showed an amplitude reduction of the VestEP (C4 derivation) and a latency delay of the early components during rotation to the affected left side (figure 4). The man was diagnosed with an intrameatal schwannoma of the VIIIth nerve on the left side.
Patient 4: Tinnitus. A 62-year-old man reported that he had been suffering from a severe and disabling bilateral tinnitus for the previous 8 years. A pure-tone audiogram showed a moderate high-tone slope. The patient described his tinnitus as a loud murmur, and he said that a side localization Customizing software and documentation for a particular country. It includes the translation of menus and messages into the native spoken language as well as changes in the user interface to accommodate different alphabets and culture. See internationalization and l10n. was no longer possible. The noise could not be masked. The man had no other neurotologic complaints. We performed a VestEP investigation.
According to previous studies published by members of our working group, patients with tinnitus exhibit three primary findings on VestEP: a shortening of the VestEP latencies, an increased amplitude of the IIIrd and IVth peak-to-peak component, and a DC shift of all VestEP components toward the negative pole. [9-11] Indeed, that is just what we found in this patient (table 2). There was a shortening of the latencies (especially the late waves) during rotation to the right. In addition, there was a slight DC shift of the curve toward negativity. During the left rotation, the shortening of the latencies was less clearly defined, but there was a clear shift of the curve toward negativity, especially in the late waves (figure 5).
Our study revealed that rotatory evoked brain electrical events are broadly distributed over the human cortex. However, the shortest VestEP latencies and the highest amplitudes are registered in the relatively distinct cortical area that is covered by the transversal electrode line T3-C3-Cz-C4-T4 according to the 10/20 international scheme of electrode placement.  This line is a transverse strip between the midtemporal electrodes and the vertex point (Cz electrode).
Longitudinal line analysis of the principal VestEP components indicated that statistically significant differences existed only between the centroparietal and frontopolar areas and between the centroparietal and occipitopolar areas. This indicates that a relatively wide cortical region, covered by the central and parietal EEG electrodes, has prevailing functional connections with the vestibular nuclei and subcortical subcortical /sub·cor·ti·cal/ (-kor´ti-k'l) beneath a cortex, such as the cerebral cortex. vestibular pathways. This area corresponds to the posterior part of the frontal lobe (Brodmann's area 4, the primary motor field of the isocortex) and the anterior parts of the cerebral parietal lobe (the gyrus postcentralis, which corresponds to the primary somatosensory fields, Brodmann's areas 1,2, and 3). [6,12-15] Our opinion is that this area corresponds to the primary vestibular cortex.
The methodology that we used to reach this conclusion ought be considered. The BEAM-VestEP approach is a newly developed technology for conducting functional brain investigations in vivo. Questions regarding the nature of the VestEPs, the sites where they are generated, and the clinical value of these potentials have been addressed in our previously published papers. [9,11,16-25]
Based on the latency values of the principal VestEP components in our study, we conclude that the particular response registered by our experimental paradigm was most likely generated at cortical levels--that is, in both the primarily vestibular and in the non specific associative areas. Our multielectrode arrangement had a special advantage in BEAM in that it allowed us to receive additional topodiagnostic synoptic syn·op·tic also syn·op·ti·cal
1. Of or constituting a synopsis; presenting a summary of the principal parts or a general view of the whole.
a. Taking the same point of view.
Our experience with brain mapping studies of the VestEP with a full set of 19 scalp electrodes and a powerful computer-assisted drawing technique for processing data informs us that the VestEP complex consists of two principal parts. [11,18,19,21,22,24] The first part consists of a relatively early set of components (Ist IInd, and IIIrd), which most likely reflects the activation of the sensory-specific cortical areas. The second part is a relatively late one (IVth, Vth, and VIth), which is associated with the more frontally located scalp areas and thus probably reflects the high level of supramodal processing with sensory information.
In studying evoked potentials, neurophysiology neurophysiology /neu·ro·phys·i·ol·o·gy/ (-fiz?e-ol´ah-je) physiology of the nervous system.
n. is being used to consider the area of shortest latencies and higher amplitudes as a focus of maximal activity--that is, as a representative functional area for the corresponding modality. [26,27]
Despite the fact that the generator sites and physiologic connotations of the VestEP components are still not firmly established, important considerations are necessary regarding the vestibular nature of the VestEP events as registered in published electrophysiologic studies. [11,28-43] We have proven the method in healthy control volunteers under various psychologic (endogenic Adj. 1. endogenic - derived or originating internally
exogenic, exogenous - derived or originating externally
2. endogenic - of rocks formed or occurring beneath the surface of the earth; "endogenic rocks are not clastic" ) and environmental (exogenic adj. 1. same as exogenous.
Adj. 1. exogenic - derived or originating externally
endogenic, endogenous - derived or originating internally ) conditions, including pharmacotherapeutic studies. [11,16,19,21,24,44] The principal VestEP parameters--such as the components' latencies, amplitudes, and distribution in space and time over the cortex- respond very sensitively and specifically relative to those modifications in the intrinsic or extrinsic EVIDENCE, EXTRINSIC. External evidence, or that which is not contained in the body of an agreement, contract, and the like.
2. It is a general rule that extrinsic evidence cannot be admitted to contradict, explain, vary or change the terms of a contract or of a environment. Furthermore, the numerous investigations of patients who had a variety of neurotologic syndromes have demonstrated the depth of information and the reliability of the VestEP approach. [9-11,17,18,20,22,23,25] A special challenge now lies in the field of tinnitology, where we were able to demo nstrate typical cortical hyperactivity phenomena.
Many authors agree that no well-defined cortical area exists for the transfer of vestibular information. [1-3,12-15] As is evident from our data, the vestibular induced afferents did essentially modify the electrical activity of the primary somatosensory cortex, which would indicate that in some aspects the vestibular source is a type of somatosensory sensation. The BEAM-VestEP method is currently unable to differentiate among the semicircular semicircular
shaped like a half-circle.
the passages in the inner ear, in the bony labyrinth concerned with the sense of balance, especially the detection of movement. , otolithic otolithic
emanating from or pertaining to otolith.
gelatinous matrix in the labyrinth of the ear; contains otoliths or otoconia. , and proprioceptive contributions in the complex vestibular afferent afferent /af·fer·ent/ (af´er-ent)
1. conveying toward a center.
2. something that so conducts, such as a fiber or nerve.
adj. impulse. However, physiologically it is also not probable that complex body and head movements are individually stimulating each of those senses independently.
During the rotatory stimulus (angular acceleration steps) that we used in this study, some other nonvestibular sensations were also apparent--for example, delicate vibrations of the turntable and air movements around the face and body. Considering this finding, we believe that a VestEP event represents an elicitation of a compound brain electrical evoked potential by a vestibular stimulus, albeit one that contains some somatosensory and, in particular, proprioceptive contributions. However, in cases of bilateral loss of the inner ear receptors, VestEPs cannot be elicited.
We can now empirically differentiate at least four categories of VestEP response, all of which we illustrated in the case reports: statistically and clinically normal responses (patient 1), absent responses (patient 2), slow and prolonged responses (patient 3), and overactive o·ver·ac·tive
Active to an excessive or abnormal degree: an overactive child.
o responses with shortened latencies (patient 4).
(1.) Walzl EM, Mountcastle VB. Projections of the vestibular nerve to cerebral cortex of cat. Am J Physiol 1949:159:595-8.
(2.) Mickle WA, Ades HW. A composite sensory projections area in the cerebral cortex of cat. Am J Physiol 1952:170:682-9.
(3.) Kornhuber HH, Fredrickson JM, Figge U. Diekortikale Projektion der vestibularen Afferenz beim Rhesusaffen. Pflugers Arch 1965;283:20-5.
(4.) Penfield W, Jasper H. Epilepsy and the Functional Anatomy of the Human Brain. Boston: Little, Brown, 1954.
(5.) Fredrickson JM, Scheid P. Figge U, Kornhuber HH. Vestibular nerve projection to the cerebral cortex of the rhesus monkey. Exp Brain Res 1966;2:318-27.
(6.) Brodmann K. Vergleichende Lokalisationslehre der Gross-hirnrinde. Leipzig: Barth, 1909.
(7.) Gacek RR. Anatomy of the central vestibular system. In: Jackler RK. Brackmann DE, eds. Neurotology. St. Louis: Mosby, 1994:41-58.
(8.) Wachsmuth W, von Lanz T. Praktische Anatomie. Ein Lehr-und Hilfsbuch der anatomischen Grundlagen aerztlichen Handelns. Erster Band-Erster Teil. Kopf. Teil A. Uebergeordnete Systeme. Berlin: Springer-Verlag, 1985:483-9.
(9.) Claussen C, Schneider D, Kolchev C. On the functional state of central vestibular structures in monoaural symptomatic tinnitus patients (BEAM-VbEP Study). Int Tinnitus J 1995;1:5-12.
(10.) Constantinescu L, Schneider D, Claussen C. Vestibular evoked potentials in two patients with bilateral vestibular loss. Int Tinnitus J 1996;2:45-57.
(11.) Schneider D, Kolchev C, Constantinescu L, Claussen C. Vestibular evoked potentials (VestEP) and brain electrical activity mapping--A test of vestibular function--A review (1990-1996). Int Tinnitus J 1996;2:27-43.
(12.) Rauber A, Kopsch F. Anatomie des Menschen, Band III, Nervensystem, Sinnesorgane. In: Lconhardt H, Tondury G. Zilles K, eds. Anatomie des Mensehen. Stuttgart: Georg Thieme Verlag, 1987:273-6.
(13.) Schwarz DW, Tomlinson RD. Physiology of the vestibular system. In: Jackler RK, Brackmann DE, eds. Neurotology. St. Louis: Mosby, 1994:59-98.
(14.) Zilles K, Rehkamper G. Funktionelle Neuroanatomie. Lehrbuch und Atlas. Berlin: Springer, 1993:228-41.
(15.) Duffy FH, Iyer VG, Surwillo WW. Clinical Electroencephalography electroencephalography (əlĕk'trōĕnsĕf'əlŏg`rafē), science of recording and analyzing the electrical activity of the brain. and Topographic Brain Mapping: Technology and Practice. New York: Springer-Verlag, 1989.
(16.) Claussen CF. Neurotology. Sensory system analysis by evoked potentials. Medical Focus 1986;2:2-8.
(17.) Claussen CF, Kolchev C, Schneider D, Hahn A. Neurootological brain electrical activity mapping in tinnitus patients. In: Aran JM, Dauman R, eds. Proceedings of the 4th International Tinnitus Seminar; Bordeaux, France; 1991. Amsterdam: Kugler Publications, 1992:351-5.
(18.) Claussen CF, Kolchev C, Bertora GO, Bergmann JM. Los potenciales evocados equilibriometricos por medio del BEAM -- y su importancia en el diagnostico y traramiento de los pacientes con vertigo. In: Sacristan-Alonso R, Bartual-Pastor J, eds. Compensacion Vestibular y Vertigos. XV Congreso Nacional de la Sociedad Espanola de ORL ORL Oto-Rhino Laryngologie (France)
ORL Orlando Executive Airport (Airport Code)
ORL Optical Return Loss
ORL Journal for Oto-Rhino-Laryngology and its related specialties y Patologia Cervicofacial. Madrid: Gonzales, 1993:27-46.
(19.) Claussen CF, Kolchev C. Vestibular evoked potentials. In: Kaufman Arenberg I, ed. Dizziness and Balance Disorders: An Interdisciplinary Approach to Diagnosis, Treatment, and Rehabilitation. Amsterdam: Kugler Publications, 1993:413-26.
(20.) Claussen CF, Kolchev C, Bertora G, et al. Vestibular late evoked potentials, a complementary tool for neuro-otological topodiagnostics in dizzy patients. In: Claussen CF, Sakata E, Itoh A, eds. Vertigo, Nausea, Tinnitus, and Hearing Loss in Central and Peripheral Vestibular Diseases. Proceedings of the XXIInd Annual Meeting of the International Neuro-otologic and Equilibriometric Society; Hakone, Japan; April 6-9, 1995. Amsterdam: Elsevier, 1995:231-4.
(21.) Kolchev C, Schneider D, Claussen CF, Rohatgi MS. Vestibular evoked response in humans. In: Claussen CF, Kirtane MV, Schneider D, eds. Conservative versus Surgical Treatment of Sensorineural Hearing Loss Sensorineural hearing loss
Hearing loss caused by damage to the nerves or parts of the inner ear governing the sense of hearing.
Mentioned in: Tinnitus
sensorineural hearing loss , Tinnitus, Vertigo, and Nausea. Proceedings of the XVIIIth Scientific Meeting of the Neurootological and Equilibriometric Society; Budapest; April 4-7, 1991. Hamburg: Medicin + Pharmacie, 1992:91-4.
(22.) Kolchev C, Schneider D, Giannakopoulos N. Brain Mapping of the Rotational Evoked Potential in Tinnitus Patients. Proceedings of the IInd International Meeting in Audiology audiology /au·di·ol·o·gy/ (aw?de-ol´ah-je) the study of impaired hearing that cannot be improved by medication or surgical therapy.
n. for the Mediterranean Countries and the VIth Panhellenic Meeting in Otolaryngology; Thessaloniki, Greece; Oct. 5-9, 1991. Thessaloniki: Gamma, 1991:195-6.
(23.) Kolchev C, Claussen CF, Schneider D. Vestibular evoked potentials in central vertigo cases. In: Claussen CF, Kirtane MV, Schneider D, eds. Vertigo, Nausea, and Hypoacusia due to Central Disequilibrium--Visual Mechanisms in Balance Control. Proceedings of the XIXth Scientific Meeting of the Neurootological and Equilibriometric Society; Bad Kissingen, Germany: March 27-29, 1992. Hamburg: Medicin + Pharmacie, 1994:529-36.
(24.) Kolchev C, Claussen CF, SchneiderD, et al. Extended normative data on vestibular evoked potentials displayed by brain electrical activity mapping. In: Claussen CF, Kirtane MV, Schneider D, eds. Drugs and Chemicals in Neurootology--Experimental Neurootology. Proceedings of the XXth Scientific Meeting of the Neurootological and Equilibriometric Society; Linkoping, Sweden; June 3-6, 1993. Hamburg: Medicin + Pharmacie, 1995:195-200.
(25.) Kolchev C, Claussen CF, Schneider D. Vestibular evoked potentials in patients suffering from central dysequilibrium. In: Claussen CF, Kirtane MV, Schneider D, eds. Drugs and Chemicals in Neurootology--Experimental Neurootology. Proceedings of the XXth Scientific Meeting of the Neurootological and Equilibriometric Society; Linkoping, Sweden; June 3-6, 1993. Hamburg: Medicin + Pharmacie, 1995:201-6.
(26.) Donchin E, Callaway E, Cooper R, et al. Publication Criteria for Studies of Evoked Potentials (EP) in Man. Report of a Committee. Attention, Voluntary Contraction, and Event-Related Cerebral Potentials. Progress in Clinical Neurophysiology. Basel: Karger, 1975.
(27.) Niedermeyer E, Lopes da Silva F. Electroencephalography: Basic Principles, Clinical Applications, and Related Fields. Munich: Urban and Schwarzenberg, 1987:940.
(28.) Baloh RW, Furman JM. Modern vestibular function testing. West J Med 1989;150:59-67.
(29.) Bohmer A, Henn V, Lehmann D. Vestibular evoked potentials in the awake rhesus monkey. Adv Otorhinolaryngol 1983;30:54-7.
(30.) Bumm P. Johanssen HS, Spreng M, Wiegand HP. [Slow evoked cortical potentials to rotary stimulation in man]. Arztl Forsch 1970;24:59-62.
(31.) Coale FS, Walsh EJ, McGee J, Konrad HR. Vestibular evoked potentials in response to direct unilateral mechanical stimulation. Otolaryngol Head Neck Surg 1989:100:177-86.
(32.) Durrant JD, Furman IM. Long-latency rotational evoked potentials in subjects with and without bilateral vestibular loss. Electroencephalogr Clin Neurophysiol 1988;71:251-6.
(33.) Elidan J, Langhofer L, Honrubia V. The neural generators of the vestibular evoked response. Brain Res 1987;423:385-90.
(34.) Elidan J. Langhofer L, Honrubia V. Recording of short-latency vestibular evoked potentials induced by acceleration impulses in experimental animals: Current status of the method and its applications. Electroencephalogr Clin Neurophysiol 1987:68:58-69.
(35.) Elidan J. Leibner E, Freeman S, et al. Short and middle latency vestibular evoked responses to acceleration in man. Electroencephalogr Clin Neurophysiol 1991:80:140-5.
(36.) Elidan J, Sohmer H, Nizan M. Recording of short latency vestibular evoked potentials to acceleration in rats by means of skin electrodes. Electroencephalogr Clin Neurophysiol 1982;53:501-5.
(37.) Fredrickson JM, Kornhuber HH, Schwarz DW. Cortical Projection of the Vestibular Nerve. Handbook of Sensory Physiology. Berlin: Springer, 1974:565-82.
(38.) Hamid MA, Hughes GB. Vestibular evoked potentials in man: An overview. Otolaryngol Head Neck Surg 1986;95:347-8.
(39.) Hofferberth B. Evoked potentials to rotatory stimulation. Preliminary results. Acta Otolaryngol Suppl 1984;406:134-6.
(40.) Hood JD. Vestibular and optokinetic evoked potentials. Acta Otolaryngol 1983;95:589-93.
(41.) Hood JD, Kayan A. Observations upon the evoked responses to natural vestibular stimulation. Electroencephalogr Clin Neurophysiol 1985;62:266-76.
(42.) Salamy J, Potvin A, Jones K, Landreth J. Cortical evoked responses to labyrinthine lab·y·rin·thine
Of, relating to, resembling, or constituting a labyrinth.
pertaining to or emanating from a labyrinth. stimulation in man. Psychophysiology psychophysiology /psy·cho·phys·i·ol·o·gy/ (-fiz?e-ol´ah-je) physiologic psychology.
The study of correlations between the mind, behavior, and bodily mechanisms. 1975;12:55-61.
(43.) Speckmann EJ, Elger CE. Introduction to the Neurophysiological neu·ro·phys·i·ol·o·gy
The branch of physiology that deals with the functions of the nervous system.
neu Basis of the ERG and DC Potentials. In: Niedermeyer E, Lopes da Silva F. Electroencephalography: Basic Principles,-Clinical Applications, and Related Fields. Munich: Urban and Schwarzenberg, 1987:1-3.
(44.) Constantinescu L, Schneider D, Claussen CF. The influence of betahistine on the vestibular evoked potentials in patients with peripheral vestibular disorders. In: Ribari O, Hirschberg A, eds. Proceedings of the 3rd European Congress of the European Federation of Oto-Rhino-Laryngological Societies: Budapest; June 1996. Bologna: Monduzzi Editore, 1996:95-8.
Mean principal VestEP component latencies in 75 healthy young adults [*] Component Mean SD [+] Component latency (msec) (msec) denomination Ist 75.0 21.8 N75 IInd 179.6 31.1 N180 IIIrd 336.0 41.0 N330 IVth 478.5 48.0 P480 Vth 634.5 49.0 N630 VIth 804.0 47.8 N800 Peak-to-peak Mean SD amplitude ([micro]V) ([micro]V) IIIrd to IVth 24.0 6.2 VestEP component (*.)Data were obtained from all 19 electrode derivations in accordance with the international 10/20 system of electrode placement. (+.)Standard deviation. Mean peak latencies (msec) of the VestEP components (I through VI) during rotation-to-the-right (ROTR) and rotation-to-the-left (ROTL) stimuli in patient 4 Stimulus I II III IV ROTR 80 135 315 435 ROTL 110 220 330 480 Normal 77 182 336 476 values [+ or -] 10 [+ or -] 9 [+ or -] 18 [+ or -] 16 Stimulus V VI ROTR 530 680 ROTL 600 705 Normal 632 802 values [+ or -] 19 [+ or -] 19