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Show I Gin. Neuro-ophthalmol. 3: 147-151, 1983. Illusion of Tilting of the Visual Environment Report of Five Cases ALLAN H. ROPPER, M.D. Abstract The symptom of sudden tilting of the visual surroundings is described in detail based on experience with five patients. Patients perceive the visual fields as suddenly turning through a variable are, most frequently 90-180°, usually associated with dizziness. In three patients with vertebral-basilar artery disease, visual tilting was more closely related to local pontomedullary ischemia than to posterior cortical ischemia. It is suggested that most instances of this illusion are due to disorders of the vestibular-otolithic apparatus or its central connections, most frequently from vertebral- basilar ischemia. The illusion of tilting of the visual surroundings is reported in patients with the lateral medullary syndrome,I-4 labyrinthine disorders,"·6 and less well-studied instances apparently related to cerebral' or cerebellar lesions." H The author reports on five carefully questioned patients in order to give a detailed description of this symptom, since experience with it is limited. Previous reports are reviewed in an attempt to clarify its pathophysiology. Illustrative Cases Visual Tilting Associated with Vertebral-Basilar Artery Disease Patient 1. A 65-year-old man had a 5-7-minute episode typical of transient global amnesia. The following day he leaned over to change television channels and noted that for 1 second the entire room tilted down on the left, counterclockwise about 45 0. Over the subsequent 5-8 seconds it tilted back slowly to the horizontal and continued turning 10° clockwise and then suddenly returned to 45° counterclockwise (Fig. 1 A). He dropped back into a chair and felt as if he was turning in the frontal plane. The entire episode lasted 30-45 From the Department of Neurology. Neurological/Neurosurgical Intensive Care Unit. Massachusetts General Hospital. Boston. Massachusetts. June 1983 seconds. There was no distortion of shapes, sizes, or colors. Three days later, a 20-second episode of 30° counterclockwise visual rotation occurred. Simultaneously he became diaphoretic, nauseated ("like seasickness"), and developed a right supraorbital headache. One week later there was a brief episode of vertigo with a sensation of the bed sinking on the left, and some brief dimming of the right visual field, but no visual tilting. He denied diplopia, dysarthria, weakness, ataxia, hearing loss, tinnitus, or facial numbness. Examination between episodes showed only nystagmus on left gaze. Digital subtraction angiography demonstrated a small right vertebral artery with opacification of the basilar artery but no opacification of the left vertebral artery. After the angiogram he transiently developed vertigo, vomiting, diplopia, and nystagmus. He had no further symptoms on Coumadin. Comment. This patient had transient global amnesia followed by probable left vertebral artery occlusion. Visual tilting was temporally associated with vertigo and was the most dramatic symptom related to vertebral-basilar ischemia. Patient 2. A 74-year-old man with metastatic prostatic carcinoma awoke at 6 A.M. and called to his wife that he was extremely "dizzy" but denied any sense of movement. He repeatedly told her that "everything is turned around 90° and the ceiling is off to the left" (Fig. 1 B). There were no other visual distortions reported. Several minutes later he began retching and complained of feeling very hot, then cold. His speech, mentation, and vision were unimpaired according to his physician daughter and the dizziness was never vertiginous. The patient denied tinnitus, hearing loss, diplopia, dysarthria, or numbness. The visual tilting stopped sometime within 1 hour after onset. Six hours after onset, he was drowsy but arousable for 30 seconds and then would drop off to sleep for several minutes. His speech was severely dysarthric and there was a right homonymous hemianopia. The globes rested dyscongugately with a left hypertropia and esotropia. On right gaze the right eye abducted to within 6 mm of the outer canthus and the left eye stayed to the left of the midline adducting to only 9 mm from the inner 147 Tilting of Visual Environment A-----' ---_A••• • ~'; ---7 '~V,. ~ " Visual Tilting Unassociated with Other Syndromes Patient 4. A 30-year-old woman had 1 year of virtually daily stereotyped spells of visual blurring as if "out of focus," followed by momentary minimal horizontal diplopia and then bright yellow pinpoints of light through the visual field, distortion of hues (blue became a more intense "electric blue" and red became orange), as well as waviness of outlines as if "looking through water." During the latter part of the episode the surroundings momentarily tilted upwards on the left, clockwise, for a variable distance, sometimes to slightly less than 90° (Fig. 10). The point about which turning occurred was in the right lower quadrant. On at least one occasion she had blurring which she attributed to diplopia and binocular tilting simul- Comment. Visual tilting was the first sign of pontine infarction in this patient. As with pati~nt I, there were signs of ischemia in the postenor cerebral artery territory separated temporally from the basilar artery syndrome. Patient 3. A 71-year-old woman awakened and began retching. She could not stand but co~ld lift her legs off the bed. There was no vertigo or dizziness while in bed. That evening she awakened and immediately saw everything upside down, the room seeming to turn exactly 1800 for 5 minutes. (Fig. 1 C). The light normally above her bed seemed to be shining up from the floor. Furniture appeared on the ceiling with usual interrelationships preserved. Most striking to her was a tumbler on her night table which stood upside down without water spilling. Upon awakening in the morning she noted diplopia, mostly vertical, and could walk only with assistance, but visual tilting was absent. Initial examination showed atrial fibrillation, horizontal left beating nystagmus on left gaze, and clumsiness of the left arm. There was no ophthalmoparesis, dysarthria, facial, or limb weakness. One week later there was left hemiataxia, a 2mm left hypotropia, and rotary and left beating nystagmus predominantly evoked by left gaze. A CT scan showed an enhancing area in the left cerebellar hemisphere. Two weeks later there was a small, nonenhancing low-density lesion in the same areas. An angiogram was normal without basilar artery atherosclerosis or branch occlusion. The left posterior cerebral artery arose predominantly from the left internal carotid artery and there was a large right posterior communicating artery with flow derived from both the basilar and carotid arteries. All symptoms and signs cleared. Comment. It was thought that this patient had an embolus that traversed the vertebral, then basilar artery. Visual tilting occurred early in the syndrome with retching and there were no signs of posterior cerebral artery infarction. E '.0--- Figure 1. Schematic representation of the illusions of visual tilting experienced by five patients. (A) Patient 1; Sudden tilting of the entire room counterclockwise 45° for 1 second, then slow return to normal position over 5-8 seconds overshooting 10° clockwise, followed by sudden return to 45° counterclockwise. (8) Patient 2; Tilting precisely 00° counterclockwise persisting for less than 1 hour. (C) Patient 3: Upon awakening, all objects were perceived as turned upside down for 5 minutes. (0) Patient 4; Variable sudden clockwise tilting of objects in separate episodes. Turning occurred about a point in the right lower quadrant. (E) Patient 5; Most episodes were abrupt clockwise tilting to almost or exactly 00° with one episode of upsidedown vision. Turning occurred about a point in the left lower quadrant. B ,- o canthus. Left gaze was full. Convergence was symmetric but unsustained. There was limitation of ocular depression, worse in the right eye. Nystagmus was absent. He could hear whispering in both ears. The right corneal response was diminished. Bulbar movements and tongue protrusion were normal. There was a right hemiparesis and right hemiataxia but the right limbs could be raised from the bed briefly. The right biceps tendon jerk was exaggerated and there was a right Babinski sign. Responses to pinprick and vibration were similar on both sides. On the second day he was abulic and responded only in whispers. He wrote the alphabet with two errors but took 3 minutes. Mild right facial weakness, right hemiataxia, and a right Babinski sign remained. EEG, CT scan, and brain stem auditoryevoked responses were normal. There was no change 6 months later on Coumadin. 148 Journal of Clinical Neuro-ophthalmology taneously. The episodes lasted 5-20 seconds and were accompanied by dizziness but not vertigo. After listening to loud music she reported tinnitus predominantly from the left side but no dizziness or visual tilting. On two occasions visual tilting occurred while driving a car and caused her to turn the car on to the right shoulder of the road. Vertigo, nausea, weakness, parethesias, dysarthria, or headache were denied. There was no family history of migraine. Two observed episodes lasted 4-6 seconds each, associated with visual blurring and minimal visual tilting. There was tonic convergence, 1-2 mm left hypotropia, but no cyclorotation as judged from scleral vessels, and no nystagmus. She was unable to perform versions during the spells. The pupils remained approximately 4 mm. An EEG during the episodes was normal. Neurological examination between episodes was normal including headhanging maneuvers. An audiogram, brain stem auditory-evoked responses, ENG, and CT scan were normal. Dilantin or Tegretol had no effect on the daily spells. Comment. The repetitive nature of this patient's complaint was interesting; some features suggested conversion, but she also had migrainous symptoms. Patient 5. A 21-year-old woman had episodes of abrupt tilting of vision 45-900 clockwise for 1 second (Fig. 1 f). The tilting was "as if on a door hinge" with the point about which turning occurred located in the left lower quadrant. She then felt unsteady for 15 minutes, feeling as if she might fall to the left, but was able to walk. Four episodes occurred in a year, then none for a year. A fifth episode occurred in which the visual field turned upside down, precisely 1800 for 1 second or less. With some episodes she could perceive the actual turning motion so that the illusion was not immediate. One episode while driving caused her to swerve to the side opposite the tilting. On that occasion she felt unbalanced for 15 minutes and vaguely unwell, "spacey" for 21/2 hours. There was no vertigo, nausea, weakness, paresthesias, diplopia, dysarthria, tinnitus, toppling, or headache. On the day following the last attack, neurological examination, EEG, and CT scan were normal. An ENG and audiogram done after the first four episodes demonstrated right beating nystagmus but a diminished caloric response on the right. The episodes ceased for 18 months at the time of last follow-up. Comment. Associated symptoms and the ENG suggested a labyrinthine disorder in this woman. Discussion The descriptive nature of tilting of the visual surrounding is similar in all cases. The visual fields of both eyes are turned through a variable arc in June 1983 Ropper the frontal plane most frequently to 90 or 1800. Some patients perceive the dynamic circular motion of the field but more often the illusion is instantaneous and static. An individual patient can experience varying degrees of rotation on different occasions. There are no other distortions in visual perception and objects maintain their normal interrelations. Episodes are brief, usually 1-5 seconds, and the return to normal orientation also tends to be instantaneous. However, persistent visual tilting for 1 or 2 days has been reported after lateral medullary infarction. 4 Turning occurs about a fulcrum usually at the center of vision but it may be eccentric. The pivotal point is consistent between multiple spells, as in patients 4 and 5, suggesting that it is a part of the symptom complex rather than related to the visual fixation point. Except in patient 1 turning was exclusively undirectional. In patient 1, counterclockwise turning was followed by a slight clockwise rotation, and then counterclockwise again. It is possible that the first return to normal position was mistaken for a small clockwise rotation since it is a known optical illusion that a vertical line appears deviated to the opposite side when the head is tilted.9 Mild over correction has been reported with the oculogravic illusion (see below). All patients reported dizziness with visual tilting; however, simultaneous vertigo, specifically defined to the patient as the sensation of bodily or environmental movement, was present in only one. Most patients linked a sense of imbalance to visual tilting, suggesting perhaps an altered sense of verticality was part of the illusion. Diplopia occurred after the tilting ceased in patients with vascular disease. Retching or vomiting was common at sometime during the illness in the vascular cases. Labyrinthine6 and lateral medullary disease may cause illusory visual tilting.s As with vertigo, most cases of visual tilting seem to be due to disease of the vestibular-otolithic apparatus or its brain stem connections. However, a small number of reported cases may be related to hemispheral lesions.5 . 12 Our patients with vascular disease seemingly offer an opportunity to determine if pontomedullary or cortical lesions are primarily responsible for the illusion of visual tilting. The temporal association of visual tilting and lateral medullary signs suggests a brain stem origin. Patient 1 typifies the difficulties in drawing definite conclusions, since prior transient global amnesia and right homonymous visual blurring suggested posterior cerebral artery territory ischemia in addition to lateral medullary symptoms. Patient 2 had a similar transient hemianopia but this occurred well after brain stem symptoms. Parietooccipital lesions have been said to produce visual tilting, in addition to other visuospatial distortions,lo but analysis of reported cases fails to establish this with certainty. Vertigo of apparent cortical origin has been reported in 149 Tilting of Visudl Environment association with homonymous metamorphopsia due to a parietooccipital tumor, I I (although not specifically with visual tilting). Monocular tilting of the visual environment unrelated to local ocular disease, has been reported with ipsilateral brain stem lesions'; however, a mechanism for this is obscure, and none of our patients had this complaint. There was no consistent relation between the direction of visual turning and the side of an associated brain stem lesion in our cases. Patient 2 had counterclockwise tilting, but other brain stem signs were bilateral, perhaps more severe on the right. Patient 3 had left brain stem signs but the visual field instantly turned 1800 , so that a rotational direction could not be assigned to the symptom. Previous cases do little to indicate that there is a laterality to brain stem visual tilting. Hagstrom's second patient had 90° clockwise rotation with a right lateral medullary syndrome, 1 while Silverskiold's patient had 90° counterclockwise rotation with stroke on the same side.:l Homsten reported three patients with unilateral lateral medullary infarctions by clinical signs, but two of them (patients 6 and 9) had 1800 visual rotation.~ Similarly, a patient with bilateral but asymmetric labyrinthine disease had clockwise tilting; however, counterclockwise turning could be induced by negative pressure in the external auditory meatus.~ This suggests that an asymmetry in function of the vestibular-otolithic apparatus or its connections causes visual tilting, but the direction of rotation is inconsistent. The possibility cannot be excluded that clockwise rotation represents extreme degrees of counterclockwise rotation and vice versa (e.g., 45 0 clockwise could theoretically result from a 225 0 counterclockwise movement). Patients were generally unable to observe the actual direction of turning but those who did, failed to report turning beyond 1800 Visual tilting in labyrinthine disease has been linked to ocular torsion'; The eyes normally have a maximum cyclorotation of approximately 8 0 which comes into playas ocular counterrolling compensating for head tilt. Pathologically induced cyclorotation of approximately 15° may occur with extreme labyrinthine stimulation.'; The magnitude of illusory tilting in neurological disease far exceeds IS°, indicating that ocular torsion and tilting of the retinal image does not explain most instances. Several ocular syndromes should be distinguished from visual tilting. The ocular tilt reaction 1:1 is associated with ocular torsion, skew deviation, and head tilting. It may occur in frequent repeated attacks; however, patients may not report associated visual tilting. Alternating skew l1 and superior oblique myokimia are also associated with torsion of the globes, but do not generally cause visual tilting. The "oculogravic illusion," produced by a sudden change in the direction of rotation of a subject, causes an apparent shift in the position of viewed objects. I'> The application of an additional centripetal force while revolving about an axis in front of the subject causes the illusion of tilting of objects in the frontal plane that is indistinguishable from the symptom reported here. Tonic ocular torsion in response to static tilt, mediated by stimulation of otolith receptors, is not associated with nystagmus. It is likely that the otolith organs or their central connections are responsible for illusory visual tilting possibly by communicating oculostatic information that is mismatched to visual information. Patient 5 with recurrent tilting and an ENG suggesting labyrinthine disease is of interest because of a benign course despite her recurrent symptoms. Patient 4 may have had tilting as part of a conversion complex. Their only complaint besides annoyance at the episodes was swerving to correct for the illusion while driving. The term "tortopia" may be useful to describe the symptom complex of tilting of the visual environment. References I. Hdgstron, I., Hornstenm, G., dnd Silfverskiold, B. P.: OCUloStdtiC dnd visudl phenomend occuring in dSsocidtion with Wallenberg's syndrome. Acta. Neurol. Scand. 45: 5b8-582, 1979. 2. Hornsten, G.: Wallenberg's syndrome. Pdrt I. Cenerdl symptomdtology with specidl reference to visudl disturbances dnd imbdldnce. ActJ. Neurol. Scand. 50: 434-44b, 1974. 3. Silfverskiold, B. P: Skew deviation in Wdllenberg's syndrome. Acta. Neural. Scand. 41: 381-38b, 1%5. 4. Bjerver, K., dnd Silfverskiold, B. P.: Ldteropulsion dnd imbdl.lnce in Wdllenberg's syndrome. ActJ. Neurol. ScanJ. 44: 91-100, 19b8. 5. Spiegel. E. A., dnd Sommer, I. B.: Neurology of the Ear, Nose Jnd Throat. Crune & Strdtton, New York. 194-1, p. 12t,. b. Deecke, L., Mergner, T., dnd Plester, D.: Tullio phenomenon with torsion Llf the eyes dnd subjective tilt of the visual surround. Ann. N. Y ACJd. Sci. 374: b50-t'55, 10 81. 7. Wilder, J.: Uben Schief-und Verkehrtsehn. Dtsch. Z. Ncn'enh. 104: 222-25b, 1928. 8. Cloning, K., and Hoff, H.: Cerebrdl locdliution of disorders of higher nervous system activity. In H.lIldboo/... of Clinical Neurology, Vol. III, P. J. Vinken .lnd G. W. Bruyn, Eds. North Holldnd Publishing, Amsterdam, 1969, Chdp. 3, p. 28. o Closter, J.: LlCtors influencing the ViSUdl judgement of the vertical direction. Trdl1s. Ophthalmol. Soc. U.K 73: 421-433,1953. 10. Hec.len, H.: Interhemispheric Relations dl1d CerebrJI Dominance, V. B. Mountcdstle. Ed. Johns Hopkins Press, B.lltimore, 1962. 11. Geyer, K.: Zentrdle Storungen des Formensehns: Zur Journdl of Clinicdl Neuro-ophthalmology Pathogenese der Metamorphopsic. Dtsch. Z. Nervehn. 184: 378-387, 1963. 12. Schnieder, R., Calhoun, H., and Crosby, E.: Vertigo and rotational movement in cortical and subcortical lesions. ]. Neural. Sci. 6: 493-516, 1968. 13. Rabinovitch, H., Sharpe, J., and Sylvester, T.: The ocular tilt reaction. Arch. Ophthalmol. 95: 13951398, 1977. 14. Corbett, J., Schatz, N., Shults, W. T., Behrens, M., and Berry, R.: Slowly alternating skew deviation: Description of a pretectal syndrome in three patients. Ann. Neural. 10: 540-546, 1981. June 1983 Ropper 15. Graybiel, A.: Oculogravic illusion. Arch. OphthaJmol. 48: 605-615, 1952. Acknowledgment The author thanks Drs. Stephen Parker and Shirley Wray for their helpful advice. Write for reprints to: Allan H. Rapper, M.D., Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114. 151 |
