Vertical nystagmus in normal subjects: Effects of head position, nicotine and scopolamine

2000 ◽  
Vol 10 (6) ◽  
pp. 291-300
Author(s):  
J.I. Kim ◽  
J.T. Somers ◽  
J.S. Stahl ◽  
R. Bhidayasiri ◽  
R.J. Leigh
Keyword(s):  
Nicotine Patch ◽  
Head Rotation ◽  
Normal Subjects ◽  
Head Position ◽  
Slow Phase ◽  
Head Orientation ◽  
Slow Phase Velocity ◽  
Gaze Stability ◽  
Normal Humans ◽  
Vertical Nystagmus

We measured gaze stability in darkness of four normal humans using the search coil technique. Subjects were tested first with their heads erect, and then with their heads positioned 180 degrees upside-down. In each position, subjects held their head stationary for one minute, and then actively performed pitch rotations for 20 sec. All subjects showed sustained chin-beating nystagmus in the upside-down position. Each subject showed a significant increase of slow-phase velocity directed towards their brow after 40 sec in the inverted versus erect position. Pitch head rotation had little effect on subsequent nystagmus, except for transient reversal in one subject. The sustained changes of vertical eye drifts induced by 180 deg change of head position suggest that otolithic factors may contribute to vertical nystagmus in normals. The subjects were retested after wearing a nicotine patch for 2 hours. In three subjects, nicotine induced brow-beating nystagmus; adopting a head-hanging position increased this nystagmus in two subjects. In a third session, subjects were tested after wearing a scopolamine patch for 2 hours; results were generally similar to the control condition. We conclude that normal subjects may show chin-beating (“downbeating”) nystagmus in a head-hanging position in darkness, reflecting a normal, physiological change in otolithic inputs brought about by the head orientation.

Monocular Nystagmic Responses to Caloric Stimulation

1979 ◽  
Vol 88 (1) ◽  
pp. 79-85 ◽  
Author(s):  
James W. Wolfe
Keyword(s):  
Phase Velocity ◽  
Rhesus Monkeys ◽  
Cold Water ◽  
Normal Subjects ◽  
Closed Circuit ◽  
Slow Phase ◽  
Vestibular Nystagmus ◽  
Differential Activation ◽  
Slow Phase Velocity ◽  
Left And Right

Twenty-five normal subjects and 173 clinical patients received standard bithermal caloric testing. Vestibular nystagmus was evaluated for cumulative slow phase velocity from the summated horizontal eye recording and independent recording of the left and right eye. These data revealed that cold water stimulation produced more intense activation of the ipsilateral eye. Simultaneous closed-circuit video and D.C. electro-oculographic recordings from eight normal rhesus monkeys in response to cold water irrigations confirmed the fact that this stimulus leads to differential activation of the extraocular muscles. A possible explanation for this finding is discussed.

Variability and habituation of nystagmic responses to hot caloric stimulation of normal subjects

1982 ◽  
Vol 96 (7) ◽  
pp. 599-612 ◽  
Author(s):  
P. G. Davey ◽  
E. S. Harpur ◽  
F. Jabeen ◽  
D. Shannon ◽  
P. M. Shenoi
Keyword(s):  
Phase Velocity ◽  
Screening Method ◽  
Normal Subjects ◽  
Mean Value ◽  
Slow Phase ◽  
Caloric Test ◽  
Maximum Frequency ◽  
Slow Phase Velocity ◽  
Caloric Stimulation ◽  
Vestibular Toxicity

AbstractExperiments were performed on 25 otoneurologically ‘normal’ subjects to evaluate the hot caloric test as a screening test for aminoglycoside vestibular toxicity.Using portable equipment under non-ideal conditions, it was found that there was a large inter-subject variability in nystagmic response and that, instead of a random test-retest variability, a systagmic variation in response occurred on repeated caloric stimulation with water at 44°C.A response deline (habituation) evident in both the maximum slow phase velocity and the maximum frequency occurred at second test, although the inter-test interval ranged from 24 to 72 hours.After a 3-month interval with no intervening tests, the mean value of the maximum frequency reverted back to the original level. However, there was still a significant reduction in maximum slow phase velocity at this time. Some individuals had a sustanined reduction in both parameters.Hence it is concluded that the hot caloric test, used under the conditions described in this study, is not a suitable serial screening method for aminoglycoside vestibular toxicity. The reproducibility of this test under other conditions, or any other caloric test, should be established in normal subjects befre employing, it as a serial screen for aminoglycoside vestibular toxicity.

scholarly journals Static Positional Nystagmus in the Healthy Vestibular System

2019 ◽  
Vol 30 (10) ◽  
pp. 883-895
Author(s):  
M. Dawn Nelson ◽  
Larissa Mann ◽  
Christine Nicholson ◽  
Mark Lehman
Keyword(s):  
Neurological Disorders ◽  
Current Data ◽  
Descriptive Statistics ◽  
Slow Phase ◽  
Positional Nystagmus ◽  
Clinical Criteria ◽  
Slow Phase Velocity ◽  
The Mean ◽  
Horizontal Nystagmus ◽  
Vertical Nystagmus

AbstractA repeat of the seminal 1973 study on static positional nystagmus (PN) using more accurate recording techniques.The purpose was to further characterize PN and, using current data, introduce new clinical criteria for its identification.Static PN was recorded in ten positions with vision denied. Each position was analyzed using age, gender, presence, direction, and persistence of nystagmus while taking into account the number of beats and mean slow-phase velocity (SPV).One hundred healthy patients who were asymptomatic with no known neurological disorders were tested.No intervention was used.Analysis of variance, descriptive statistics, and confidence intervals were used to describe results.Results showed 74% of normal participants had horizontal nystagmus in at least one position. Only 7% of the observed nystagmus was persistent. The average SPV was 2°/sec. The mean number of positions in which nystagmus was observed was three. Neither age nor gender influenced the occurrence of nystagmus. Forty-three percent of the participants had vertical nystagmus in at least one position; however, the SPV was 2°/sec or less.The present study demonstrated that intermittent or persistent PN in four or fewer positions should not be considered pathological when the SPV is 4°/sec or less (n = 100). Observance of vertical nystagmus in one position should not be considered pathological if the SPV is 2°/sec or less. Suggested positions for positional testing should include seated-upright, supine, head right, head left, head-hanging, and the precaloric (30° supine) positions. Fixation when PN is observed is indicated.

scholarly journals Role of Eye, Head, and Shoulder Geometry in the Planning of Accurate Arm Movements

2002 ◽  
Vol 87 (4) ◽  
pp. 1677-1685 ◽  
Author(s):  
D.Y.P. Henriques ◽  
J. D. Crawford
Keyword(s):  
Visual Information ◽  
Arm Movements ◽  
Head Rotation ◽  
Head Position ◽  
Open Loop ◽  
Target Line ◽  
Head Orientation ◽  
Complex Process ◽  
Hand Coordination ◽  
Shoulder Geometry

Eye-hand coordination requires the brain to integrate visual information with the continuous changes in eye, head, and arm positions. This is a geometrically complex process because the eyes, head, and shoulder have different centers of rotation. As a result, head rotation causes the eye to translate with respect to the shoulder. The present study examines the consequences of this geometry for planning accurate arm movements in a pointing task with the head at different orientations. When asked to point at an object, subjects oriented their arm to position the fingertip on the line running from the target to the viewing eye. But this eye-target line shifts when the eyes translate with each new head orientation, thereby requiring a new arm pointing direction. We confirmed that subjects do realign their fingertip with the eye-target line during closed-loop pointing across various horizontal head orientations when gaze is on target. More importantly, subjects also showed this head-position–dependent pattern of pointing responses for the same paradigm performed in complete darkness. However, when gaze was not on target, compensation for these translations in the rotational centers partially broke down. As a result, subjects tended to overshoot the target direction relative to current gaze; perhaps explaining previously reported errors in aiming the arm to retinally peripheral targets. These results suggest that knowledge of head position signals and the resulting relative displacements in the centers of rotation of the eye and shoulder are incorporated using open-loop mechanisms for eye-hand coordination, but these translations are best calibrated for foveated, gaze-on-target movements.

scholarly journals Alexander's Law During High-Speed, Yaw-Axis Rotation: Adaptation or Saturation?

2020 ◽  
Vol 11 ◽  
Author(s):  
Claudia Lädrach ◽  
David S. Zee ◽  
Thomas Wyss ◽  
Wilhelm Wimmer ◽  
Athanasia Korda ◽  
...  
Keyword(s):  
Eye Movements ◽  
Phase Velocity ◽  
High Speed ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Normal Subjects ◽  
Vestibular Nuclei ◽  
Slow Phase ◽  
Slow Phase Velocity ◽  
Alexander’S Law

Objective: Alexander's law (AL) states the intensity of nystagmus increases when gaze is toward the direction of the quick phase. What might be its cause? A gaze-holding neural integrator (NI) that becomes imperfect as the result of an adaptive process, or saturation in the discharge of neurons in the vestibular nuclei?Methods: We induced nystagmus in normal subjects using a rapid chair acceleration around the yaw (vertical) axis to a constant velocity of 200°/second [s] and then, 90 s later, a sudden stop to induce post-rotatory nystagmus (PRN). Subjects alternated gaze every 2 s between flashing LEDs (right/left or up/down). We calculated the change in slow-phase velocity (ΔSPV) between right and left gaze when the lateral semicircular canals (SCC) were primarily stimulated (head upright) or, with the head tilted to the side, stimulating the vertical and lateral SCC together.Results: During PRN AL occurred for horizontal eye movements with the head upright and for both horizontal and vertical components of eye movements with the head tilted. AL was apparent within just a few seconds of the chair stopping when peak SPV of PRN was reached. When slow-phase velocity of PRN faded into the range of 6–18°/s AL could no longer be demonstrated.Conclusions: Our results support the idea that AL is produced by asymmetrical responses within the vestibular nuclei impairing the NI, and not by an adaptive response that develops over time. AL was related to the predicted plane of eye rotations in the orbit based on the pattern of SCC activation.

scholarly journals Comparing mastoid and posterior cervical muscles vibration effects on eye movement in normal subjects

2019 ◽  
Author(s):  
Moslem Shaabani ◽  
Najmeh Naghibi ◽  
Enayatollah Bakhshi
Keyword(s):  
Eye Movements ◽  
Phase Velocity ◽  
Eye Movement ◽  
Vestibular System ◽  
Healthy Subjects ◽  
Normal Subjects ◽  
Slow Phase ◽  
Vestibular Disorders ◽  
Rehabilitation Hospital ◽  
Slow Phase Velocity

Background and Aim: Vibration is a method for stimulating the vestibular system. This met­hod can unmask asymmetry between two vesti­bular systems (such as unilateral peripheral ves­tibular disorders). The occurrence of vibration-induced nystagmus (VIN) in healthy subjects can affect the diagnosis of patients with uni­lateral peripheral vestibular disorders. Thus, the evaluation of VIN in healthy subjects is critical to help the diagnosis of unilateral peripheral vestibular disorders. Methods: This study was carried out on 72 hea­lthy subjects (mean ± SD age: 27.12 ± 4.97 years) in the Auditory and Balance Clinic of Rofeideh Rehabilitation Hospital. Vibration sti­mulation with a frequency of 30 and 100 Hz was used on mastoid and posterior cervical mus­cles (PCMs) and simultaneously eye movements were recorded and analyzed using videonystag­mography. Results: The mastoid vibration with a frequ­ency of 30 and 100 Hz, respectively produced VIN in 16.67% and 27.78% of subjects and VIN observed in PCMs vibration with a frequency of 30 and 100 Hz in 4.17% and 9.72% of the subjects. Conclusion: The occurrence of VIN in healthy subjects was more probable with mastoid vib­ration in 100 Hz. In this study, VIN was pre­dominantly horizontal, its direction was toward the stimulated side, and its slow phase velocity was lower than 5 deg/s. These criteria could be used for differentiation between normal and abnormal subjects.

Vertical Optokinetic Nystagmus and Optokinetic Afternystagmus in Humans

1991 ◽  
Vol 1 (3) ◽  
pp. 309-315
Author(s):  
A. Böhmer ◽  
R.W. Baloh
Keyword(s):  
Phase Velocity ◽  
Optokinetic Nystagmus ◽  
Body Position ◽  
Normal Subjects ◽  
Lateral Position ◽  
Velocity Storage ◽  
Slow Phase ◽  
Lateral Side ◽  
Slow Phase Velocity ◽  
Optokinetic Afternystagmus

Vertical optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN) were recorded in 6 normal subjects using the magnetic scleral search coil technique in order to reevaluate the up-down symmetry of these responses. The effects of body position relative to gravity were investigated by comparing OKN and OKAN elicited with the subjects in an erect and in a lateral side position. No consistent up-down asymmetry in vertical OKN was found but OKAN was asymmetric (up slow phase velocity > down slow phase velocity). Most subjects had an immediate reversal in OKAN slow phase velocity after downward stimuli. No significant effects of static head position (upright versus lateral position) on vertical OKN and OKAN were found. These features of human OKAN can be explained by the summation of two oppositely directed velocity storage mechanisms.

Measurement of Optokinetic Nystagmus for Otoneurological Diagnosis

1981 ◽  
Vol 90 (1_suppl2) ◽  
pp. 1-12 ◽  
Author(s):  
Sharon M. Abel ◽  
Hugh O. Barber
Keyword(s):  
Phase Velocity ◽  
Optokinetic Nystagmus ◽  
Normal Subjects ◽  
Error Rates ◽  
Slow Phase ◽  
Brainstem Lesion ◽  
Black And White ◽  
Slow Phase Velocity ◽  
Unilateral Labyrinthectomy ◽  
The Difference

Optokinetic nystagmus was recorded and measured in 101 subjects comprising six diagnostic categories: 1) normal, screened for otologic disease, 2) chronic unilateral labyrinthectomy, 3) unilateral Menière's disease, 4) neurologically confirmed focal brainstem lesion, 5) brainstem-cerebellar syndrome, and 6) focal unilateral supratentorial lesion. For the OKN test, each subject looked at a translucent screen onto which a field of parallel black and white bars was back-projected. The array of bars could be projected vertically or horizontally to allow for study of nystagmus beating right and left or up and down. The speed of movement of the bars varied over a range from 20 to 140°/sec of visual angle, in each axis for both directions. An analysis of the slow phase velocity of OKN indicated that patients with brainstem disease produced significantly lower eye speeds than did normal subjects or patients with chronic peripheral vestibular disease. The latter groups could not be distinguished. The responses of patients with cortical lesions fell midway between these two extremes and were significantly different from those of the brainstem group. Directional preponderance of nystagmus proved to be significantly related to the side of lesion for both the labyrinthine and cortical groups. However, the absolute value of the difference in slow phase velocity for nystagmus beating toward or away from the side of lesion was no greater than the difference between right and left-beating nystagmus in normal subjects. While the results provide statistical confirmation for the findings of earlier investigations, it is noted that for purposes of clinical diagnosis, the test is of value only in the context of the otoneurological test battery. Distribution of results for individuals in the various groups overlap considerably. The designation of a numerical cutoff for differential diagnosis leads to error rates far in excess of what may be confidently attributed to chance.

Comparison of Vestibular Function Between Right and Left Handed Normal Population

2018 ◽  
Vol 16 (1) ◽  
pp. 28-31
Author(s):  
Sharma Bhandari ◽  
Sagun Shrestha ◽  
R.K. Saxena
Keyword(s):  
Normal Population ◽  
Vestibular Function ◽  
Hand Preference ◽  
Normal Subjects ◽  
Slow Phase ◽  
Canal Paresis ◽  
Slow Phase Velocity ◽  
Left Handed ◽  
Left And Right ◽  
The Right

Objective To identify the side of vestibular dominance in right handed & left handed people. Method A total of 50 normal subjects, aged between 15 - 45 years were included as Left handers (n = 25) and Right handers (n = 25). Handedness was confirmed by the Annett Hand Preference Questionnaire. Bithermal caloric testing was done which was recorded by Electronystagmography (ENG). Maximum Slow Phase Velocity (MSPV) was taken as the parameter of choice. Directional Preponderance (DP) and Canal Paresis (CP) were calculated in each group. Results Out of the 25 Left handed subjects, 8 had DP towards Left whereas 7 had DP towards the Right and the remaining 10 showed no DP to any side (normal) (p<0.001). Out of the 25 Right handed subjects, 4 had DP towards Right and none had DP towards the Left, remaining 21 showed no DP to any side (normal) (p<0.001). For CP, out of 25 Left handed subjects, 2 showed CP towards the Left and 1 towards the Right, the remaining 22 showed no CP (normal) at all. Similarly out of the 25 Right handed subjects, 2 showed CP towards the Left and 1 towards the Right, the remaining 22 showed no CP (normal) at all. Out of 25 Right handers, it was found that Right handers showed Right vestibular preference whereas vestibular preference was almost equally distributed to Left and Right side in Left handers. Conclusion On considering DP, it was found that Right handers showed Right vestibular preference whereas vestibular preference was almost equally distributed toLeft and Right side in Left handers (p<0.001).

Vestibular Function and Motion Sickness Susceptibility: Videonystagmographic Evidence From Oculomotor and Caloric Tests

2020 ◽  
Vol 29 (2) ◽  
pp. 188-198
Author(s):  
Cynthia G. Fowler ◽  
Margaret Dallapiazza ◽  
Kathleen Talbot Hadsell
Keyword(s):  
Phase Velocity ◽  
Motion Sickness ◽  
Repeated Measures ◽  
Short Form ◽  
Vestibular Function ◽  
Slow Phase ◽  
Test Results ◽  
Normal Range ◽  
Slow Phase Velocity ◽  
Caloric Tests

Purpose Motion sickness (MS) is a common condition that affects millions of individuals. Although the condition is common and can be debilitating, little research has focused on the vestibular function associated with susceptibility to MS. One causal theory of MS is an asymmetry of vestibular function within or between ears. The purposes of this study, therefore, were (a) to determine if the vestibular system (oculomotor and caloric tests) in videonystagmography (VNG) is associated with susceptibility to MS and (b) to determine if these tests support the theory of an asymmetry between ears associated with MS susceptibility. Method VNG was used to measure oculomotor and caloric responses. Fifty young adults were recruited; 50 completed the oculomotor tests, and 31 completed the four caloric irrigations. MS susceptibility was evaluated with the Motion Sickness Susceptibility Questionnaire–Short Form; in this study, percent susceptibility ranged from 0% to 100% in the participants. Participants were divided into three susceptibility groups (Low, Mid, and High). Repeated-measures analyses of variance and pairwise comparisons determined significance among the groups on the VNG test results. Results Oculomotor test results revealed no significant differences among the MS susceptibility groups. Caloric stimuli elicited responses that were correlated positively with susceptibility to MS. Slow-phase velocity was slowest in the Low MS group compared to the Mid and High groups. There was no significant asymmetry between ears in any of the groups. Conclusions MS susceptibility was significantly and positively correlated with caloric slow-phase velocity. Although asymmetries between ears are purported to be associated with MS, asymmetries were not evident. Susceptibility to MS may contribute to interindividual variability of caloric responses within the normal range.

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