Ординатура / Офтальмология / Английские материалы / The Neurology of Eye Movements_Leigh, Zee_2006

610 The Diagnosis of Disorders of Eye Movements

horizontal gaze. Ann Neurol 1984; 16:495-

504.

1520. Zak TA. Infantile convergence-evoked nystagmus. Ann Ophthalmol 1983; 15:368-9.

1521. Zangemeister WH, Meienberg O, Stark L, Hoyt WE Eye-head coordination in homonymous hemianopia. J Neurol 1982;226:24354.

1522. Zangemeister WH, Mueller-Jensen A. The coordination of gaze movements in Huntington's disease. Neuro-ophthalmology 1985; 5:193-206.

1523. Zasorin NL, Baloh RW Downbeat nystagmus with alcoholic cerebellar degeneration. Arch Neurol 1984;41:1301-2.

1524. Zasorin NL, Baloh RW, Myers LB. Acetazo- lamide-responsive episodic ataxia syndrome. Neurology 1983;33:1212-4.

1525. Zauel D, Carlow TJ. Internuclear ophthalmoplegia following cervical manipulation. Ann Neurol 1977;1:308.

1526. Zee DS. Ophthalmoscopy in examination of patients with vestibular disorders. Ann Neurol 1978;3:373-4.

1527. Zee DS. Considerations on the mechanisms of alternating skew deviation in patients with cerebellar lesions. J Vestibul Res 1996;6:l-7.

1528. Zee DS, Chu FC, Leigh RJ, Savino PJ, Schatz NJ, Reingold DR, Cogan DG. Blink-saccade synkinesis. Neurology 1983;33:1233-6.

1529. Zee DS, FitzGibbon EJ, Optican LM. Saccadevergence interactions in humans. J Neurophysiol 1992;68:1624-41.

1530. Zee DS, Fletcher W. Bedside evaluation of the dizzy patient. In Baloh RW, Halmagyi GM, editors. Disorders of the vestibular system. New York: Oxford; 1996; p. 178-91.

1531. Zee DS, Freeman JM, Holtzman NA. Ophthalmoplegia in maple syrup urine disease. J Pediatr 1974;84:113-5.

1532. Zee DS, Friendlich AR, Robinson DA. The mechanism of downbeat nystagmus. Arch Neurol 1974;30:227-37.

1533. Zee DS, Hain TC, Carl JR. Abduction nystagmus in internuclear ophthalmoplegia. Ann Neurol 1987;21:383-8.

1534. Zee DS, Leigh RJ, Mathieu-Millaire F. Cerebellar control of ocular gaze stability. Ann Neurol 1980;7:37-40.

1535. Zee DS, Optican LM, Cook JD, Robinson DA, Engel WK. Slow saccades in spinocerebellar degeneration. Arch Neurol 1976;33:243-51.

1536. Zee DS, Robinson DA. A hypothetical explanation of saccadic oscillations. Ann Neurol 1979;5:405-14.

1537. Zee DS, Tusa RJ, Herdman SJ, Butler PH, Giicer G. Effects of occipital lobectomy upon eye movements in primate. J Neurophysiol 1987;58:883-907.

1538. Zee DS, Yamazaki A, Butler PH, Gucer G. Effects of ablation of flocculus and paraflocculus on eye movements in primate. J Neurophysiol 1981;46:878-99.

1539. Zee DS, Yee RD, Cogan DG, Robinson DA, Engel WK. Ocular motor abnormalities in hereditary cerebellar ataxia. Brain 1976;99: 207-34.

1540. Zee DS, Yee RD, Singer HS. Congenital ocular motor apraxia. Brain 1977; 100:581-99.

1541. Zegers de Beyl D, Flament-Durand J, Boren-

1542. Zeviani M, Bertagnolio B, Uziel G. Neurological presentations of mitchondrial diseases. J Inherit Metab Dis 1996; 19:504-20.

1543. Ziffer AJ, Rosenbaum AL, Demer JL, Yee RD. Congenital double elevator palsy: vertical saccadic velocity utilizing the scleral search coil technique. J Pediatr Ophthalmol Strabismus 1992;29:142-9.

1544. Zihl J. Eye movement patterns in hemianopic dyslexia. Brain 1995;! 18:891-912.

1545. Zihl J, Hebel N. Patterns of oculomotor scanning in patients with unilateral posterior parietal or frontal lobe damage. Neuropsychologia 1997;35:893-906.

1546. Zihl J, Von Crammon D. The contribution of the "second" visual system to directed visual attention in man. Brain 1979; 102:835-56.

1547. Zimmerman CF, Roach ES, Troost BT See-

saw nystagmus associated with Chiari malformation. Arch Neurol 1986;43:299-300.

1548. Zoghbi HY. GAG repeats in SCA6. Anticipating new clues. Neurology 1997;49:1196-9.

1548a. Zubcov AA, Reinecke RD, CalhounJH, Asymmetric horizontal tropias, DVD, and manifest latent nystagmus: an explanation of dissociated horizontal deviation. J Pediatr Ophthalmol Strab 1990;27:59-64.

1549. Zubcov AA, Stark N, Weber A, Wizov SS, Reinecke RD. Improvement of visual acuity after surgery for nystagmus. Ophthalmology 1993; 100:1488-97.

1550. Zumstein H, Meienberg O. Upbeat nystagmus and visual system disorder in Wernicke's encephalopathy due to starvation. Neuroophthalmology 1982;2:157-62.

Although the order and specific details of testing may be modified according to the nature of the clinical problem, systematic examination of each ocular motor subsystem is worthwhile, particularly in evaluating signs such as nystagmus. Here we outline a scheme for examining eye movements, providing video examples of abnormal findings for certain tests. The technical details of each step in the ocular motor examination are described in the respective chapters. The reader should note that ocular motor signs are rarely diagnostic touchstones; they require interpretation in the context of the history and full examination.

1.General Features:

a.Look for abnormal head postures, such as turns or tilts (see VIDEO: "Skew deviation"), abnormal patterns of eye-head coordination—such as the head thrusts of ocular motor apraxia (see VIDEOS: "Acquired ocular motor apraxia," "Congenital ocular motor apraxia"), and head tremors (see VIDEO: "Spasmus Nutans").

b.Look for abnormalities of the lids including ptosis, lid-opening apraxia (see VIDEO: "Lid-opening apraxia"), retraction, and aberrant regeneration.

2.Visual Examination:

a.Measure corrected visual acuity and perform confrontation visual fields with each eye viewing.

b.Check color vision (Ishihara or Hardy-Rand-Rittler plates), to screen for optic neuropathy e.g., in patients with monocular pendular nystagmus.

c.Test stereopsis (e.g., Titmus Optical or Randot stimuli), especially when ocular misalignment is thought to be of early onset.

d.Test pupillary reflexes.

3.Range of Movement and Alignment of the VisualAxes:

a.Establish range of motion with ductions (one eye viewing) and versions (both eyes viewing) (see VIDEO: "Abducens nerve palsy").

b.Test ocular misalignment (in patients with diplopia or strabismus).

•Confirm that diplopia is only present during binocular viewing

•Subjective tests, such as the red

glass, and Maddox rod (Fig. 9-11)

•The cover test (Fig. 9-12) (see VIDEO: "Oculomotor nerve palsy") for tropias

•The alternate cover test (Fig. 9-13) (see VIDEOS: "Oculomotor nerve palsy") for phorias. Measure deviation at both near and far, and in the cardinal positions of gaze

•Quantify with prisms by nullifying the deviation as measured with alternate cover test (Fig. 9-13) or Maddox rod (Fig. 9-11)

•For vertical deviations, use the Bielschowsky head-tilt test (Fig. 9-14) (see VIDEOS: "Trochlear nerve palsy"), to diagnose superior oblique muscle paresis

4.Fixation (using simple visual inspection, the ophthalmoscope, and Frenzel goggles:

a. In primary position: Look for extra-

neous saccades (see VIDEOS: "Macrosaccadic oscillations," "Square-wave jerks") and nystagmus (see VIDEO: "Acquired nystagmus impairing vision").

b.In eccentric gaze: Look for gazeevoked and then rebound nystagmus (see VIDEOS: "Gaze-evoked, rebound, and downbeat nystagmus").

c.Determine the position of the eyes under closed lids by noting corrective movements when the patients open their eyes (e.g. steady-state deviation of the eyes toward the side of the lesion in Wallenberg's syndrome) (see VIDEOS: "Wallenberg's syndrome").

d.In patients with nystagmus, the time in the cycle when the image of the target is brought to the fovea can be determined during ophthalmoscopy by having the patient fix upon the center of the ophthalmoscope cross hairs.

5.Vestibular:

a.Measure visual acuity (Snellen chart) before and during head shaking (horizontal and vertical) at a frequency of greater than 1cycle/sec.

b.Look for corrective saccades during sinusoidal head oscillations at about

1Hz and following brief but high acceleration head thrusts, while the patient is required to fix upon a target straight ahead (see VIDEO: "Anterior inferior cerebellar artery (AICA) distribution infarction").

c.Using Frenzel goggles,* after 10 to

15seconds of brisk head shaking, first in the horizontal, then in the

vertical plane, look for nystagmus (see VIDEO: "Head-shaking nystagmus"). In cases of suspected bilateral vestibular loss, look for nystagmus following circular head-shaking.

*Frenzel goggles consist of 10to 20-diopter spherical convex lenses that defocus the pa-

tient's vision (so preventing fixation of objects) and also provide the examiner with a magnified, illuminated view of the patient's eyes. An alternative is +20 diopter lenses mounted in a spectacle frame and fitted with side-blinkers. The room lights should be turned off and either the lights of the goggles or a pen light used to illuminate the eyes.

d.Using the ophthalmoscope, watch for abnormal movement of the retinal vessels or optic nerve head with the head still. Recall that the direction of horizontal or vertical motion of the retina is opposite to that of the front of the eye. Alternately cover and uncover the other eye to see if any drift of the retina is brought out or exacerbated by the removal of fixation. Watch for oscillation of the optic disc during small-amplitude head shaking at a frequency of greater than 1 cycle/sec to see if the gain of the VOR is correct. If the gain is too high, the disc appears to move with the head, if too low, opposite the head.

e.Use positional maneuvers to elicit nystagmus. First use the DixHallpike maneuver: The head is turned 45°to the right or left. Then the patient is brought to a supine position with the head just below the horizontal (Fig. 10-19); observe any nystagmus, preferably behind Frenzel goggles (see VIDEO: "Nystagmus with benign paroxysmal positional vertigo"). The patient is then brought back to the upright position; look again for nystagmus. The same maneuver is then repeated with the head turned 45° in the opposite direction. Second, with the patient lying supine, rotate the head to the right ear down, then straight back, then left ear down positions.

f.With Frenzel goggles or using the ophthalmoscope to observe for nystagmus, use small amounts of ice water (less than 1 ml) to elicit the minimal ice water caloric test.

g.Rotate the patient in a swivel chair to elicit perrotational nystagmus; when the chair stops, look for postrotational nystagmus. Test responses in each plane of head rotation: horizontal (head upright), vertical (head tilted over 90°, ear-to-shoulder), or torsional (head looking to the ceiling).

h.Use the Valsalva maneuver (against a closed glottis and pinched nostrils), tragal compression, and mastoid vibration to elicit nystagmus.

6.Saccades:

a.Observe spontaneous saccades, saccades to visual or auditory targets, and saccades to command. Note latency, velocity (see VIDEO: "Slow horizontal saccades"), trajectory (see VIDEO: "Niemann-Pick type C

disease"), accuracy (see VIDEO: "Saccadic hypermetria"), and conjugacy (see VIDEO: "Unilateral internuclear ophthalmoplegia").

b.Assess quick phases induced by vestibular rotation or caloric stimuli, and a hand-held optokinetic drum or tape. During vertical stimulation, with stripes moving down, check for retraction nystagmus (see VIDEO: "Convergence-re- traction nystagmus").

7.Smooth Pursuit:

a.Instruct the patient to track a small moving target smoothly, horizontally and vertically. Look for corrective saccades that indicate an inappropriate smooth-pursuit gain. If the gain is low, saccades will be catch-up; if the gain is too high, saccades will be back-up.

b.Use a small optokinetic drum, tape, or mirror to bring out pursuit asymmetries, or "inverted"

optokinetic nystagmus, as occurs with congenital nystagmus.

8.Eye-Head Coordination:

a.Assess head and eye movements (latency, accuracy, velocity) during combined eye-head rapid (saccadic) refixations (see VIDEOS: "Acquired ocular motor apraxia").

b.Test cancellation of the vestibuloocular reflex by asking the patient to fixate a target moving with the head. Look for corrective saccades.

9.Vergence:

a.Test vergence to disparity stimuli (place a prism in front of one eye).

b.Test vergence to accommodative stimuli: With one eye covered, the other eye alternately fixes upon the near and distant targets (Fig. 8-1).

c.Test vergence to combined disparity and accommodative stimuli by asking the patient to fixate a target brought in along the midsagittal plane toward the nose (see VIDEO: "Bilateral internuclear ophthalmoplegia").

d.Note pupillary changes during vergence movements.

Disadvantages

No "record" to analyze. May be difficult to distinguish different types of oscillations or to judge eyevelocity

Electrical and electromyographic noise, lid artifact; unstable baseline, requiring repeat calibration and adaptation to level of ambient lighting. Unreliable for vertical eye movements. Cost depends mainly on amplifiers selected, but usually not very expensive

Limited range (±20°horizontally and ±10°vertically). Intermediate cost

Lens motion artifact.Subject's head must be immobilized on bite bar. Expensive to buy and maintain

Subject required to wear headgear, which may be bulky;velocity noise of system may limit analysisof slow eye movements. May be expensive

Subject required to wear scleral annulus on eye; topical anesthetic drops required. Large (2 m) field coils are expensive; scleral annulus for measuring 3-D rotations is expensive

Uncomfortable; technically difficult. With a few exceptions (prior to strabismus surgery) probably onlyjustifiable for research

The table summarizes techniques currently available to measure rotations of the eyes, each methodology having its strengths and limitations.3'6'13 At present, the magnetic search coil technique (Fig. 1-1) is generally regarded as the most reliable and versatile method,12 and it is used widely to measure eye movements in humans and many animal species. It allows measurement of eye rotations around all three axes,2'7 with a sensitivity of greater than 5 minutes of arc (the standard deviation of system noise is typically less than 0.02°), a potential linear range of 360°, a bandwidth of 0 to 500 Hz, minimal drift, insensitivity to translation of the eye, and an unlimited field of view. One disadvantage is that the subject must wear a "contact lens" (a Silastic annulus in which are imbedded coils of fine wire); this annulus is placed after applying topical anesthetic eyedrops. Our experience, based on studying over 500 patients, is that the scleral search coil is well tolerated for periods of up to 60 minutes, even by those with advanced neurological disease. A disad-

vantage is the potential for corneal abrasion, but the incidence in our laboratories is less than 1 in 500. It is especially valuable for measuring eye movements in patients who cannot reliably point their eyes at calibration targets (e.g., due to nystagmus), since the scleral annulus that the patient wears can be precalibrated on a pro-

tractor device.

Electro-oculography (EOG) is widely used for clinical testing because it allows measurement of a large range of movement and is relatively inexpensive. However, it suffers from a number of limitations including inability to reliably measure vertical eye movements,1 low sensitivity (due to muscle artifact and other noise sources), baseline drift, and limited bandwidth due to the filtering required to remove noise from the signal.

Photoelectric methods that track the limbus (scleral-iris edge) of the eye by measuring the amount of scattered light from infrared sources are generally more sensitive and reliable than EOG9 but provide a limited linear range, especially vertically. In addition, most photoelectric systems use photodetectors that must be

Appendix B 615

mounted close to the eyes, so they may restrict the field of view. Photoelectric methods also suffer from potentially large errors if there is lateral motion of the sensors relative to the eye.

Another approach has been to measure movement of images reflected by the eye as it rotates; a stationary source of infrared light can be used. Because the center of curvature of the corneal bulge differs from the center of rotation of the globe, eye movements cause displacement of the corneal, or first Purkinje, image. Alternatively, the video image of the pupil can be tracked. However, measurement of movement of one such image suffers from the disadvantage that movement of the transducer relative to the subject's head will be interpreted as eye rotation. In systems that measure eye rotation by tracking only corneal reflections, 1 mm of lateral motion of the sensor relative to the eyes introduces errors of approximately 10°.13 For systems that measure eye rotations by tracking only the center of the pupil, the errors are approximately 5° per 1 mm of lateral motion. Since it is very difficult to eliminate this lateral motion completely, an alternative approach is to measure movement of reflected light from one surface of the eye (e.g., the cornea) in conjunction with another reflected image (e.g., the pupil, or the fourth Purkinje image from the posterior surface of the lens).

Such an approach allows measurement of horizontal and vertical eye movements that is insensitive to translation of the eye with respect to the transducer. The latter

is the case because the circumferences of rotation of the two images differ, and hence the two images move relative to one another during rotation but not during translation.

One such method that has been used mainly as a research tool is the double Purkinje image tracker, which uses the first and fourth Purkinje images.4 This tracker suffers from disadvantages that limit its usefulness,especially in evaluating patients; failure to detect the rather dim fourth image of certain subjects; the presence of an artifact due to lens movement during saccades; the requirement that the subject's head be fixed on a bite-bar, and

616 AppendixB

substantial expense to purchase and maintain. An alternative has been to measure the first Purkinje image and the pupil, and this approach, which is technically easier, has been incorporated in a number of recently developed video-based oculography systems.5'6'8'11 The conventional video camera has a bandwidth of 0 to 30 Hz (imposed by its frame rate 60 Hz), which suffices for smooth-pursuit eye movements but is inadequate toaccurately measure saccades. However, the current development of faster, smaller, and more sensitive cameras may make video-based systems the method of choice in the next few years.

REFERENCES

1.Barry W, Melvill Jones G. Influence of eyelid movement upon electro-oculographic recordings of vertical eye movements. Aerospace Med 1965;36:855-8.

2.Bartl K, Siebold C, Glasauer S, Helmchen C, Biittner U. Mathematical methods for three-di-

mensional eye movement recordings using search coils. In Fetter M, Haslwanter T, Misslisch H, Tweed D, editors. Three-Dimensional Kinematics of Eye, Head and Limb Movements. Amsterdam: Harwood; 1997;p. 413-21.

3.Carpenter RHS. Movements of the Eyes. Second ed. London: Pion; 1988; p. 405-426.

4.Cornsweet TN, Crane HD. Accurate two-dimen- sional eye tracker using first and fourth Purkinje images. J Opt SocAm 1973;63:921-8.

5.Das VE, Thomas CW, Zivotofsky AZ, Leigh RJ. Measuring eye movements during locomotion. Filtering techniques for obtaining velocity signals

from a video-based eye monitor. J Vestibul Res 1996;6:455-61.

6.DiScenna AO, Das VE, Zivotofsky AZ, Seidman SH, Leigh RJ. Evaluation of a video tracking device for measurement of horizontal and vertical eye rotations during locomotion. J Neurosci Methods 1995;58:89-94.

7.Ferman L, Collewijn H, Jansen TC, Van Den Berg A. Human gaze stability in the horizontal, vertical and torsional direction during voluntary head movements, evaluated with a three dimensional scleral induction coil technique. Vision Res 1987;27:811-28.

8.Haslwanter T. Measurement and analysis techniques for three-dimensional eye movements. In Fetter M, Haslwanter T, Misslisch H, Tweed D, editors. Three-Dimensional Kinematics of Eye, Head and Limb Movements. Amsterdam: Harwood; 1997; p. 401-12.

9.Hess CW, Miiri R, Meienberg O. Recording of horizontal saccadic eye movements. Methodological comparison between electro-oculography and infrared reflection oculography. Neuroophthalmology 1986;6:189-98.

10.Jampolsky A. What can electromyography do for the ophthalmologist? Invest Opnthalmol Vis Sci 1970;9:570-99.

11.Moore ST, Curthoys IS, Haslwanter T, Halmagyi GM. Measuring three-dimensional eye position using image processing—the VTM system. In Fetter M, Haslwanter T, Misslisch H, Tweed D, editors. Three-Dimensional Kinematics of Eye, Head and Limb Movements. Amsterdam: Harwood; 1997; p.445-450.

12.Robinson DA.A method of measuring eye movement using a scleral search coil in a magnetic field. IEEE Trans Biomed Electron 1963;10: 137-45.

13.Young LR, Sheena D. Survey of eye movement recording methods. Behav Res Methods Instrument 1975;7:397-429.

14.Zee DS. Ophthalmoscopy in examination of patients with vestibular disorders. Ann Neurol 1978;3:373-4.

Abducens fascicles, disorders affecting, 352t, 355 Abducens internuclear neurons, 216, 216f

vergence eye movements and, 297-298 Abducens nerve, anatomy of, 331, 332f Abducens nerve disorders

affecting cavernous portion, 352t, 355-356 affecting orbital portion, 352t

affecting petrous portion, 352t, 355 affecting subarachnoid portion, 352t, 355 affecting superior orbital fissure, 352t

Abducens nerve palsy, 348f-349f bilateral, 356

in children, 356 clinical features of, 351

divergence paralysis and, 309 etiology of, 351, 352t laboratory evaluation of, 35It management of, 356

partial, saccadic adaptation after, 124-125 pseudo-, 518

Abducens nucleus, 217d anatomy of, 216f, 331,333f

disorders affecting, 352-355, 352t horizontal conjugate eye movements and,

216-220, 216f, 218f

lesions of, 220-221, 352-353, 497-498, 497d combined, 509-510

vergence eye movements and, 296 Abetalipoproteinemia, 558t, 560 AC/A ratio, 292

abnormalities of, 307-310 defined,288t

environmental modification of, 303 in internuclear ophthalmoplegia, 298 measurement of, 306

Accessory optic system, smooth pursuit and, 172, 173

Accommodation

adaptive mechanism for, 302-303, 303f convergence-linked, 288t, 292 defined, 288t

measurement of, 291 near triad and, 290-291

vergence and, interactions between, 291-292, 302-303, 303f

Accommodative vergence, 12, 290, 291f, 306 Accommodative-linked convergence, 288t Acetazolamide, 459

Acetylcholine gaze-holding and, 203

myasthenia gravis and, 375-377 vestibular eye movements and, 457

Acoustic schwannoma (acoustic neuroma) Bruns' nystagmus and, 431 flocculo-nodular syndrome and, 497

hyperventilation-induced nystagmusand, 414 Acquired immune deficiency syndrome. See

HIV/AIDS

Acquired pendular nystagmus See Pendular nystagmus, acquired

Acquired ocular motor apraxia, 542-544, 544f-545f ACTH (adrenocorticotropic hormone), for opso-

clonus, 459 Acupuncture, for nystagmus, 463 Adaptation

central, in myasthenia gravis, 377-378 disconjugate, 304-306, 305f

prism. See Phoria saccadic, 124-126 smooth pursuit, 160

vestibulo-ocular reflex 48-53 Adduction, upshoot in, 350

Adduction lag, in internuclear ophthalmoplegia, 503, 504, 506, 506f

Adrenocorticotropic hormone, for opsoclonus, 459 Adult-onset hexosaminidase A deficiency, 558t,

559

Aerobics, vertigo and, 468 Afferents

otolith, 29

vestibular, 28-31,32-33

After-nystagmus, optokinetic. See Optokinetic afternystagmus

Age. See also Children; Infant(s)

smooth pursuit and, 160, 163-164, 178 square-wave jerks and, 180

vergence eye movements and, 290 vestibulo-ocular reflex and, 42

AICA. SeeAnterior inferior cerebellar artery AIDS. SeeHIV/AIDS

Albinism, congenital nystagmus and, 445 Alcohol

gaze-evoked nystagmusand, 430, 563t positional nystagmusand, 477, 479 treatment for seesaw nystagmus, 459 vertigo and, 469-470

Alexander's law, 209, 412

ALS (amyotrophic lateral sclerosis), 526 ophthalmoplegia and, 369

Alternate cover test, 341, 34If, 342 Alternating sursumduction, 350 Alzheimer's disease

eye movement abnormalities in, 549 saccadic abnormalities in, 133

618 Index

Amblyopia

nystagmus and, 435, 445 strabismus and, 350

Amino acid disorders, branch-chain, 558t Aminoglycosides

ototoxicity of, 481 vertigo and, 470

Amphetamines, 459, 563t

Amyloid, restrictive ophthalmopathy in, 383 Amyotrophic lateral sclerosis, 526

ophthalmoplegia and, 369 Anderson-Kestenbaum operation, for congenital

nystagmus, 462 Aneurysm(s)

basilar artery, oculomotor nerve and, 362t, 364 carotid artery

abducens nerve palsy and, 355 oculomotor nerve palsy and, 365 trochlear nerve palsy and, 359

intracavernous, oculomotor nerve palsy and, 365 posterior communicating, oculomotor nerve palsy

and,365

Angular vestibulo-ocular reflex, see Rotational vestibulo-ocular reflex

Anisometropia, adaptation to, 304-306, 305f Annulus of Zinn, 323, 325f

Anterior semicircular canal BPPV, 476 Anterior inferior cerebellar artery, 24

infarction in the distribution of, 486f, 487, 496 Anterior vestibular artery, 25

Anti-acetycholine receptor antibodies, in myasthenia gravis, 376-377

Anticholinergic agents, treatment of nystagmus and, 458

Anticipatory eye movements, smooth pursuit and, 158-159

Anticonvulsants, gaze-evoked nystagmus and, 430

Anti-GQlb antibody, 372 Antidepressants, 561, 562t Anti-Hu antibody, 454, 496 Anti-Ri antibody, 454 Anti-Yo antibody, 496 Antisaccade task, 532f

Alzheimer's disease and, 549 in clinical examination, 96-97 frontal lobe lesions and, 542

Huntington's disease and, 532-533, 532f Apogeotropic nystagmus, 475, 476 Apoplexy, pituitary, 365, 366f-367f

Apraxia, ocular motor. SeeOcular motor apraxia Area 7a, gaze control and, 236f, 238-239 Arnold-Chiari malformation, 421, 423f, 491-492,

493f

convergence nystagmus and, 441-442 diagnosis of, 62

divergence nystagmus and, 441 eye movement disturbances in, 492t oscillopsia and, 481

treatment of, 463

Arterial aneurysms. See Aneurysm(s)

Arteritis, giant-cell, restrictive ophthalmopathy in, 383

Ascending tract of Deiters, 31 Ataxia(s)

familial episodic vertigo and, 430, 459, 472, 493, 495t

hereditary, ocular motor findings in, 492-496, 494t-495t

spinocerebellar, 493, 494t-495t, 510 Ataxia telangiectasia, 495t, 558t

Auditory stimuli, treatment for nystagmus, 463

Baclofen, 563t

for nystagmus, 458

for periodic alternating nystagmus, 458 vestibular eye movements and, 457

Balint's syndrome, 117-118, 240, 540, 543 Barbecue-spit rotation, 67

Barbiturates, 459, 562t

Bardet-Biedl syndrome, horizontal saccade failure and, 547

Basal ganglia

caudate nucleus of, 120, 248, 533

disease of, ocular motor abnormalities and, 528-534

saccade generation and, 119-121, 248 substantia nigra pars reticulata, 120-121, 533 in voluntary control of eye movements, 14

Basilar artery

aneurysm of, oculomotor nerve palsy and, 362t, 364

dolichoectasia of, 483 Bassen-Kornzweig disease, 560 Bechterew's phenomenon, 69 Becker's dystrophy, 379-380 Benedikt's syndrome, 364

Benign paroxysmal positional vertigo (BPPV) anterior-canal variant, 476

bilateral, 476 canalolithiasis, 473, 476, 477 clinical features of, 473-476

diagnosis of, 61, 473-476, 474f-475f lateral-canal, 475-476

nystagmus with, 68, 412, 473-474 pathophysiology of, 476-477 treatment of, 457, 474f-475f, 479

Benign paroxysmal vertigo of childhood, 471 Benzodiazepines, 561, 562t

Benztropine, treatment for acquired pendular nystagmus, 458

Beta blockers, 563t

Bickerstaff's brain stem encephalitis, 372 Bielschowsky head-tilt test, 342-344, 343f Binocular vision, latent nystagmus and, 446-

447

Biofeedback, for treatment of nystagmus, 463 Bismuth intoxication, 549

Blepharospasm, 533 Blindness. See Vision, loss of Blinks

frequency of, 127 saccadesand, 127-128, 127f

Blowout fracture of orbit, 371 Bobbing, ocular, 552t, 553, 553f

Bode plot, of vestibulo-ocular reflex, 39, 39f Botulinum toxin, 373

for nystagmus, 460f-461f, 462 Bow-tie nystagmus, 417, 419f

BPPV. See Benign paroxysmal positional vertigo

Brain stem

conjugate eye movements and horizontal,

215-221, 216f,218f

vertical and torsional, 220f, 221-228, 224f-225f lesions of, ophthalmoplegia and, 369, 369t saccadic intrusions and, 455

saccadic pulse generator in, 103-104, 110, 11 If in vertical smooth pursuit, 226-228

VOR elaboration by, 29-35, 30t, 32f Brain stem encephalitis, 372, 453 Brain stem ischemia

horizontal gaze palsy and, 502 positional vertigo and, 477 vertical gaze palsy and, 519t

Branch-chain amino acid disorders, 558t

Brodman area 40, lesions of, smooth pursuit and, 169 Brown's syndrome, 359

Bruns' nystagmus, 431 Builup neurons, collicular, 114 Burst neurons, 103

collicular, 113 excitatory, 104-105 inhibitory, 104

for horizontal saccades, 103-104 long-lead, 105-106, 121 midbrain, 104-105 pontomedullary, 104

premotor, 104-105

saccadic oscillations and, 133-134 vergence, 297, 297f, 301

for vertical and torsional saccades, 104-105 Burst-position neurons, 31

Burst-tonic cells, vergence, 297, 301

CA/C ratio, 292 defined,288t modification of, 303

Cajal, interstitial nucleus of. See Interstitial nucleus of Cajal

Calcium channel blockers, treatment for familial episodic vertigo and ataxia type 2, 459

Caloric testing

acute peripheral vestibulopathy and, 466-467 bedside, 63

nystagmus and, 64-65 quantitative, 64-65

in unconscious patients, 555-556 Campylobacter jejuni infection, Guillain-Barre syn-

drome and,371

Canalolithiasis, 473, 476, 477. Seealso BPPV Carbamazepine, 457t, 562t

Carotid artery aneurysm abducens nerve palsy and, 355 oculomotor nerve palsy and, 365 trochlear nerve palsy and, 359

Carotid cavernous fistula

multiple ocular motor nerve palsies and, 370 restrictive ophthalmopathy in, 383

Caudate nucleus hemorrhage of, 533

Huntington's disease and, 533 saccade generation and, 120, 248

Cavernous sinus syndromes, multiple ocular motor nerve palsies and, 369-370, 369t

Index 619

Central adaptation, in myasthenia gravis, 377-378 Central eye position, defined, 322t

Central mesencephalic reticular formation, 227, 228d

eye-head saccades and, 270

lesions of, 106, 227, 522d. Seealso Progressive supranuclear palsy

long-lead burst neurons in, 105-106 Central nucleus

anatomy of, 333

nuclear oculomotor palsy and, 361 Central otolith connections, lesions of, 71 Central vestibular nystagmus, 415-424

clinical features of, 415-421, 4l7f-419f, 423f etiology of, 415t, 420t, 422t

horizontal, 421, 423f pathogenesis of, 421-422, 424 perverted, 421

Centripetal drift

clinical evaluation of, 208-209 correction of, 202-203 myasthenia gravis and, 375

Centripetal nystagmus, 210, 429, 429d, 431 Centronuclear myopathy, 380

Cerebellar arteries, infarction in the territories of, 487, 487f, 496-497

Cerebellar eye signs, 487-497 Cerebellar syndromes, 487-490

Cerebellar tonsils, displacement of, in Arnold-Chiari malformation, 492, 493f

Cerebellar vermis, 23Id

vergence eye movements and, 299 Cerebellectomy, total, 124, 126, 171

Cerebellum 23Id, 232d. Seealso Vestibulocerebellum adaptive control of eye movements and, 13, 491 anatomy of, 229f

conjugate eye movements and, 228-233, 229f degeneration of, paraneoplastic, 496 developmental anomalies of. See Arnold-Chiari

malformation

dorsal vermis of, see Dorsal vermis

downbeat nystagmus and, 422, 424, 496 fastigial nucleus of. See Fastigial nucleus

fixation and, 181, 491 flocculus of. See Flocculus(i)

gaze holding and, 206-207, 206f gaze-evoked nystagmus and, 430, 496 hemorrhage of, 497

lesions of mass, 497

ocular bobbing and, 553, 553f

ocular motor syndromes caused by, 487-497, 490f, 492t, 493f, 494t-495t

neural integration and, deficient, 206-207, 206f nodulus of. See Nodulus

opsoclonus and, 455-456 paraflocculus of. See Paraflocculus(i)

periodic alternating nystagmus and, 425 positional nystagmus and, 479 positional vertigo and, 477

recurrent vertigo and, 471-472

saccade generation and, 121-124, 121f, 123f saccadic adaptation and, 126

skew deviation and, 465 smooth pursuit and, 171-172 tumors of, 497