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Some Objective and Subjective Observations on the Vestibulo-Ocular System*
74
PAUL A. CHANDLER AND HARRY E. RRACONTER REFERENCES
1. Zimmerman, M. W.: Case of bilateral pigmental tumors probably cysts of the ciliary bodies. Ophth. Rev., 16:129, 1897. 2. Schieck, F.: Ueber pigmentierte Zysten an der Irishinterflache. Klin. Monatsbl. f. Augenth., 42:321, 1904. 3. Bickerton, T. H., and Clarke, E.: Cyst of iris. Tr. Ophth. Soc. U. Kingdom, 27 :83, 1907. 4. Coats, G.: An unusual form of cyst of the iris. Roy. Lond. Ophth. Hosp. Rep., 17:143, 1908. 5. Stephenson, S.: A cyst of the pigment epithelium of the iris. Tr. Ophth. Soc. U. Kingdom, 36:270, 1916. 6. Remky, E.: Spontane Zysten der Irishinterflache und des Corpus ciliare. Klin. Monatsbl. f. Augenh., 70:347, 1923. 7. Elschnig, H. H.: Ziliarkorperzyste. Klin. Monatsbl. f. Augenh., 74:476, 1925. 8. Wissman: Zur Klinik der Irisgeschwiilste. Klin. Monatsbl. f. Augenh., 79 :649, 1927. 9. Lindenmeyer: Klin. Monatsbl. f. Augenh., 79:650, 1927. 10. Meek, R. E.: Sarcoma of the iris. Arch. Ophth., 8 :864, 1932. 11. Vail, D., and Merz, E. H.: Embryonic intraepithelial cyst of the ciliary processes. Tr. Am. Ophth. Soc., 49:167, 1951. 12. Scheie, H. G.: Gonioscopy in diagnosis of tumors of the iris and ciliary body with emphasis on intraepithelial cysts. Tr. Am. Ophth. Soc, 51:313, 1953. 13. Bosteels: Observation d'un kyste de l'iris. Ann. Soc. med. d'Anvers, 25 :425, 1864. 14. Collins, T.: On the pathology of intraocular cysts. Roy. Lond. Ophth. Hosp. Rep., 13:41, 1893. 15. Mayou, M. S.: Cyst of the pigment epithelium of the iris. Tr. Ophth. Soc. U. Kingdom, 25 :86, 1905. 16. Wintersteiner: Ueber idiopathische Pigmentzysten der Iris. Klin. Monatsbl. f. Augenh., 44:297, 1906. 17. Pagenstecher, A. H.: Muftiple Cysten an der Irishinterflache und am Corpus ciliare. Arch. f. Ophth., 74:290, 1910. 18. Fisher, M. A.: Ein neuer Fall von einer spontanen pigmentierten Cyste der Irishinterflache. Klin. Monatsbl. f. Augenh., 65:876, 1920. 19. Bliedung, C.: Eine spontane intraepithelial Iriszyste. Klin. Monatsbl. f. Augenh., 67:401, 1921. 20. Vogt, A.: Zystenbildung des Pupillar pigmentsaumes. Klin. Monatsbl. f. Augenh., 67 :330, 1921. 21. Braunstein, E.: Multiple spontane pigmentierte Cysten der Irishinterflache. Arch. f. Ophth., 115:381, 1924-25. 22. Fillipow, N. A.: Zur Frage iiber die spontanen serosen Iriszysten. Klin. Monatsbl. f. Augenh., 84:247, 1930. 23. Town, A. E.: Cyst of the uveal layer of the iris. Am. J. Ophth., 16 :790, 1933. 24. Villard, H., and Dejean, C.: Les Kystes de l'iris. Arch. Ophtal., 50:91, 1933. 25. Francois, T.: Kystes de proces ciliaires, observes par la gonioscopie apres enclavement de l'iris. Ophthalmologica, 116:313, 1948. 26. Reese, A. B.: Spontaneous cysts of the ciliary bodv simulating neoplasms. Tr. Am. Ophth. Soc, 47:138,1949.
SOME OBJECTIVE AND SUBJECTIVE OBSERVATIONS ON THE VESTIBULO-OCULAR SYSTEM* DAVID G. COGAN, M.D. Boston, Massachusetts T h a t the vestibular apparatus, and par ticularly the labyrinths, plays an important role in the control of ocular movements is taken for granted. The violent nystagmus and illusory movement of the environment that occur with diseases of the peripheral labyrinth dramatically attest to this. More* From the Howe Laboratory of Ophthalmology, Harvard University Medical School, and the Massa chusetts Eye and Ear Infirmary.
over, this control can be quantitatively docu mented under normal conditions with vary ing degrees of acceleration and deceleration (Graybiel 1 ). Yet, with rare exception ( F o r d and W a l s h 2 ) , there appears to be little ap preciation of the essentiality of this labyrin thine control in stabilizing the eyes during small, seemingly trivial, movements of the head. The voluntary and opticokinetic move-
VESTIBULO-OCULAR SYSTEM merits mask the finer labyrinthine effects under normal conditions and few persons interested in ocular movements have had the opportunity—or misfortune—to study them subjectively from a pathologic point of view. A notable exception to this is the case of Crawford who described, with admirable clarity, the symptoms of his own loss of labyrinthine function following an overdosage of streptomycin.3 It was my contact with Dr. Crawford on several occasions and a personal encounter with what was called "labyrinthitis" that prompted my im mediate interest in the visual phenomena associated with labyrinthine disturbances and emphasized to me the important role the semicircular canals play in what are ordi narily considered minor activities of visuospatial orientation. It is the purpose of this report to point out some of these observa tions and to present a few other phenomena not generally recognized. This will be done through a description of two cases and an analysis of my own symptoms. C A S E REPORTS CASE 1
M. M. (12-62-29) was a 48-year-old nurse who was given a total of 21 gm. of streptomycin over a 12-day period for tuberculosis of one kidney. After receiving approximately 16 gm., she de veloped vertigo that increased over a period of several days to the point that she was unable to turn over in bed. In the meantime, she had had a nephrectomy and her symptoms were at first attributed to a postoperative disturbance. The streptomycin was therefore continued for several days after the onset of the vertigo. The vertigo continued to be relatively severe for about one week. It was acutely aggravated by movements of the head and was initially ac companied by moderate vomiting and illusory rota tion of the environment. In the subsequent two months it gradually improved. The patient has been followed a total of five months since the onset of the vertigo with little subjective change in the past three months. Two weeks after the onset, no nystagmus could be elicited by irrigation of either ear with ice water. Five months after the onset there was still no vestibular function that could be detected byrotation with a Barany chair. The patient's visual disturbances constituted a conspicuous part of her symptoms from the start. At first there was a violent illusory rotation of
75
the environment. As this resolved the patient ob served that she was unable to see clearly when her body was in motion. Specifically the environ ment appeared to oscillate up and down while she walked or as she rode in a car. This was, and has continued to be, so severe that she is unable to recognize people along the street unless she stops and remains immobile for a second or two. There has been only slight spontaneous improvement in this symptom but there is considerable symptomatic improvement on wearing a Thomas collar or hold ing her head rigid between her hands as she walks. In contrast to the up and down oscillations, no horizontal oscillations have been noted at any time. Reading was at first difficult. The lines of print ran together and drifted up and down unless her head were supported or unless she was able to lean it against a rigid support. Fatigue always made the reading more difficult. Reading on a train has been impossible. This difficulty in reading has improved considerably with time but is still present, one year after the onset, when the patient is fatigued. Examination of the eyes five months after the onset of the vertigo revealed little objective ab normality. Ocular movements were full without dissociation, dysmetria, or nystagmus. So long as the patient's head was motionless she could exercise full gaze movements in all directions without un toward symptoms. The opticokinetic response was normal and symmetric. The patient's visual acuity was 20/15 as long as she was immobile. Jogging on her heels, however, resulted in a reduction in her acuity during the movement to 20/200 or less and the print ap peared to oscillate up and down. Passive lateral movements of the head also resulted in a reduction in acuity to 20/200 or less but this was described as a blur and surprisingly not accompanied by any illusory movement of the environment. Several control observers showed no deterioration of vision with similar jogging on the heels or passive move ments of the head. As the patient's head was oscillated between the examiner's hands it was found that she was unable to hold fixation on the examiner as could normal subjects. Indeed, with relatively rapid oscillations of the head, the eyes moved with the head as though fixed in the orbits whereas normal subjects could hold their eyes fixed on an object despite compa rable oscillations of the head. Analogous observations were made on after-im ages induced with a flash of light from a discharge tube. Whereas, the after-image remained stationary for several control observers despite vigorous jogging on their heels or passive oscillations of their head, the patient observed that the after image made wide excursions up and down during the movement of her head. This, however, occurred only so long as there was light in the room to illuminate the background. In the dark or when the eyes were closed the after image did not appear to move. The after image (or the background?) moved in a vertical direction with up and down
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DAVID G. COGAN
movements of the head and in a horizontal direction with lateral movements of the head. Rotation in a Barany chair induced some move ment of the environment, although less than normal, but no postrotary oscillopsia. T h e patient's symptoms were typical of those which have been reported following streptomycin intoxication 4 ' 5 or loss of labyrinthine function from other causes. 8 T h e continued blurring of vision—not al ways recognized as illusory movement—with vertical movement of the head is particularly noteworthy. This was relieved by immobil ization of the head. It has continued with little improvement in the subsequent five months of observation. It may be demon strated with a measure of objectivity by testing visual acuity d u r i n g vertical move ment of the head or by observing an after image during vertical movements. T h e blur ring or illusory movement of the environ ment with horizontal movements was less conspicuous, but with passive horizontal movements of the head the patient was un able to maintain fixation as well as normally. CASE 2
J. C. (Dr. Crawford) was a 30-year-old phy sician who received a total of approximately 275 gm. of streptomycin over a two and one-half-month period for a presumed tuberculous arthritis. A de scription of the patient's early symptoms and reac tions has been presented in a superb autobiographi cal vignette published elsewhere.' Initially there was considerable vertigo and nausea evoked by movement of the head. Walking resulted in an ap parently up and down oscillation of the environment likened to a "yo-yo." Any movement of the body and head resulted in a marked reduction in vision so that the patient was unable to recognize people while he was walking or riding in a car. The joggle of a bicycle was particularly devastating to vision. Reading on the train was impossible. In deed, the slight movements of the head from arterial pulsation bothered his reading at first so much that it was necessary for him to hold his head still with his hands or to support it against some rigid object. All of these visual symptoms disappeared immediately as soon as he was stationary. With appropriate tests the patient was found to have complete loss of labyrinthine function. Dur ing the subsequent period he observed illusory movement of the environment whenever he moved his head but after the initial period no vertigo oc curred with movement so long as his eyes were closed. H e found the disorientation was somewhat
lessened as he learned to immobilize his head and to maintain his gaze on a distant object; holding onto a firm object also helped. Rapid bodily movements were accompanied by less visual disturb ance than slow movements. Examination of the patient five years after the loss of labyrinths showed no evident vestibular function with the conventional Barany test. Super ficial testing of eye movements showed nothing ab normal. There was a full range of movement in all directions without nystagmus. The following move ments were executed smoothly and the opticokinetic response was symmetric. There was a suggestion of ocular motor dysmetria but this was slight and inconstant. Visual acuity was 20/15 but jogging on the heels resulted in a reduction of the acuity during the movement to 20/70. Similar passive oscillations of the head resulted in a reduction in acuity propor tionate to the violence of the oscillations. These movements were accompanied by illusory movement of the environment and it was the patient's ob servation that the movement per se caused the blur. Illusory movement of the environment occurred equally in the horizontal or vertical plane accord ing to the direction of the head movements. The patient was unable to maintain his gaze on a near object during rapid turning of his head to the right and left, as can a normal person. As in the previous patient, the eyes tended to remain fixed in the orbit when the turning became sufficiently rapid. An after-image, induced by a flash of light, ap peared to move with passive movements of the head or with jogging on the heels. This was true for both the horizontal and vertical direction but occurred only when there was at least some il lumination of the room. When the room was com pletely dark or when the patient's eyes were closed the after-image did not appear to move. Under similar conditions the normal subject observed no movement of the after-image either in a lighted or darkened room. T h i s patient's early symptoms were also typical of those described with streptomycin intoxication.* As in the previous case, how ever, the prominent residual feature was blurring of vision with movements of the head and the blurring was evident with ex traordinarily slight movements. I t was de monstrable by the reduction in visual acuity * Two other patients with streptomycin intoxica tion are not included in this paper for lack of more adequate work up. They did, however, complain of incapacitating and persistent illusory movement of the environment with movement of the head. The one patient on whom visual acuity measurements were made showed a deterioration of vision from 20/20 to 20/70 with mild jogging on her heels.
VESTIBULO-OCULAR SYSTEM or by the oscillations of an after-image dur ing movement and had persisted for at least five years after the onset of the labyrinthine disease. It is presumably permanent. CASE 3
D. G. C. The following is a brief report of my own "labyrinthitis." Without prior warning or apparent etiology, I awoke to find that the room showed a continuous clockwise rotation whenever I opened my eyes. This was shortly followed by moderate vertigo, retching, tenesmus, and profound unsteadiness of gait. The gastrointestinal symp toms promptly abated but the spontaneous rotation of the environment continued with gradual improve ment for three days. It was worse on gaze to the right or on lying on my left side. It was of course accompanied by, or caused by, a horizontal rotary nystagmus which had a fast component to the right. The noteworthy feature of the nystagmus was that the environment always moved in one direction. This was to the right, repetitive, and synchronous with the slow component of the nystagmus. I was never aware of a movement to the left. Yet—and this seemed to me most surprising as I subsequently thought about it—there was no psychologic con flict in the fact that the environment should he back at the starting place again. In other words, I had I he seemingly paradoxical experience of seeing the environment continually moving in one direction over a defined arc and yet never being aware of how it got back to the beginning of the arc nor of being bothered particularly by the inherent con tradiction in this state of affairs. One further symptom which was apparent to me but rarely mentioned so far as I am aware, was the association of a blink, or tendency to blink at the end of the slow excursion, that is, concomitant with the onset of the fast phase of the nystagmus. As the nystagmus subsided in three days' time, and with it the vertigo, a new train of symptoms occurred characterized by illusory movement of the environment when the head was moved. This was in every way similar to that noted in the fore going two cases. It was much more evident for hori zontal than for vertical movements. There was also a definite lateralizing component for it was much more conspicuous on turning or tilting the head from right to left than from left to right. This illusory movement of the environment resulted in an annoying blur such that I was unable to recognize objects while walking or during movement. It was not always apparent that the blur was in fact due to the illusory movement. The effect might well be called simple dizziness by one not interested in analyzing it. It was accompanied by marked un steadiness of gait arid general (and spurious) sensa tion of inebriation. The unsteadiness of gait was not caused by the visual phenomena for it was present even with the eyes closed or in the dark. All these symptoms gradually subsided in the subsequent few weeks, but the left labyrinth gave
77
no caloric response when tested five weeks after the onset of symptoms and six months later it was still markedly hypoactive. There was no deafness at any time.
As a symptom of unilateral labyrinthitis, illusory movement of the environment was noted to occur with the slow phase of the nystagmus, and in the opposite direction. Curiously, it did not seem unnatural that the environment should be back at the startl ing point during each cycle without giving evidence of how it got back there. Of inci dental interest was the blink, or tendency to blink, of the lids synchronous with the fast phase of the nystagmus. Finally, the symp toms ensuing on the acute phase were similar to those described by persons who have lost their labyrinthine function through strepto mycin intoxication except in the present case there was evidence of lateralization and the symptoms were temporary only. DISCUSSION AND CONCLUSIONS
The inference is inescapable that the stabilizing effect of the labyrinths on the eyes is extraordinarily sensitive under nor mal conditions. It has of course been long known that the labyrinths exert positional effects on the eyes and may have well-nigh exclusive control of ocular motor function in such lower animals as the rabbit. But in man the labyrinthine control appears to play a role subordinate to that of voluntary and reflex mechanisms.8 From the present ob servations, however, on patients and from threshold measurements on normal subjects,8 it would appear that the labyrinthogenic stabilization of the eyes was of vital im portance for visual function in human beings during even slight movements of the head. The surprising feature is not the fact that the labyrinths exert an effect but rather the sensitivity of the mechanism and the magnitude of the visual deficit when the labyrinthine control is lost. Thus in both the foregoing patients who lost their laby rinths from streptomycin, jogging on the heels caused a reduction in visual acuity to
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DAVID G. COGAN
20/70 or less. T h e act of walking, riding in a car, or riding a bicycle so impaired vision that the patients were unable to recognize people on the street. Even the oscillations of the head from arterial pulsation so af fected one of the patients that he was unable to read unless he manually supported his head. It must be inferred, therefore, that under normal conditions the semicircular canals exert a significant stabilization for even these slight head movements. One of the curious features in these two patients was the predilection of the illusory movement of the environment for the verti cal direction. Oscillations of the head hori zontally induced an incapacitating blur but this was not necessarily interpreted as a movement of the environment. Somewhat similar visual phenomena were observed in the recovery stage of labyrinthitis as described in the third case. In addition it was noted during the early events of the labyrinthitis that the nystagmus re sulted in an illusory movement of the en
vironment in one direction only (opposite the slow phase) without revealing how the environment returned to the starting point. It is curious that this paradox did not seem unnatural at the time. A further and minor feature was the blink of the lids, or tendency to blink, that was synchronous with the fast phase. These correlatives of a labyrinthine deficit do not appear to be generally ap preciated, but may well be part of that vague dizziness of which patients with acute labyrinthine disturbance complain. SUMMARY
The visual phenomena are described in the cases of two patients who lost their labyrinthine function from streptomycin in toxication and in the case of one patient (the author) with so-called labyrinthitis. It is concluded that the semicircular canals have surprisingly important functions in stabilizing the eyes even with slight move ments of the head. 243 Charles Street (14).
REFERENCES
1. Graybiel, A., Kerr, W. A., and Bartley, S. H.: Stimulus thresholds of the semicircular canals as a function of angular acceleration. Am. J. Psychol., 59 :21, 1948. 2. Ford, F. R., and Walsh, F. B.: Clinical observations on the importance of the vestibular reflexes in ocular movements: The effects of section of one or both vestibular nerves. Bull. Johns Hopkins Hosp., 58:80-83, 1936. 3. Crawford, J.: Living without a balancing mechanism. New England J. Med., 246 :4S8, 1952. 4. Doucet, P. M. M., Behague, J., and Garderes, P. de: Troubles visuels chez les tuberculeux pulmonaires traites par des injections intra-musculaires de streptomycine. Soc. d'ophtal. Paris, 1948, pp. 63-64. 5. Sannella, L. S.: An early symptom of streptomycin neurotoxictty. Arch. Ophth., 50:331-332; 1953. 6. Ford, F. R., and Walsh, F. B.: Tonic deviation of eyes produced by movements of head. Arch. Ophth., 23:1274, 1940. 7. Crawford, J.: Living without a balancing mechanism. New England J. Med., 246:458, 1952. 8. Magnus, R.: Koerperstellung. Berlin, Springer, 1924. 9. Graybiel, A., Kerr, W. A., and Bartley, S. H.: Stimulus thresholds of the semicircular canals as a function of angular acceleration. Am. J. Psychol., 59 :21, 1948.
PAUL A. CHANDLER AND HARRY E. RRACONTER REFERENCES
1. Zimmerman, M. W.: Case of bilateral pigmental tumors probably cysts of the ciliary bodies. Ophth. Rev., 16:129, 1897. 2. Schieck, F.: Ueber pigmentierte Zysten an der Irishinterflache. Klin. Monatsbl. f. Augenth., 42:321, 1904. 3. Bickerton, T. H., and Clarke, E.: Cyst of iris. Tr. Ophth. Soc. U. Kingdom, 27 :83, 1907. 4. Coats, G.: An unusual form of cyst of the iris. Roy. Lond. Ophth. Hosp. Rep., 17:143, 1908. 5. Stephenson, S.: A cyst of the pigment epithelium of the iris. Tr. Ophth. Soc. U. Kingdom, 36:270, 1916. 6. Remky, E.: Spontane Zysten der Irishinterflache und des Corpus ciliare. Klin. Monatsbl. f. Augenh., 70:347, 1923. 7. Elschnig, H. H.: Ziliarkorperzyste. Klin. Monatsbl. f. Augenh., 74:476, 1925. 8. Wissman: Zur Klinik der Irisgeschwiilste. Klin. Monatsbl. f. Augenh., 79 :649, 1927. 9. Lindenmeyer: Klin. Monatsbl. f. Augenh., 79:650, 1927. 10. Meek, R. E.: Sarcoma of the iris. Arch. Ophth., 8 :864, 1932. 11. Vail, D., and Merz, E. H.: Embryonic intraepithelial cyst of the ciliary processes. Tr. Am. Ophth. Soc., 49:167, 1951. 12. Scheie, H. G.: Gonioscopy in diagnosis of tumors of the iris and ciliary body with emphasis on intraepithelial cysts. Tr. Am. Ophth. Soc, 51:313, 1953. 13. Bosteels: Observation d'un kyste de l'iris. Ann. Soc. med. d'Anvers, 25 :425, 1864. 14. Collins, T.: On the pathology of intraocular cysts. Roy. Lond. Ophth. Hosp. Rep., 13:41, 1893. 15. Mayou, M. S.: Cyst of the pigment epithelium of the iris. Tr. Ophth. Soc. U. Kingdom, 25 :86, 1905. 16. Wintersteiner: Ueber idiopathische Pigmentzysten der Iris. Klin. Monatsbl. f. Augenh., 44:297, 1906. 17. Pagenstecher, A. H.: Muftiple Cysten an der Irishinterflache und am Corpus ciliare. Arch. f. Ophth., 74:290, 1910. 18. Fisher, M. A.: Ein neuer Fall von einer spontanen pigmentierten Cyste der Irishinterflache. Klin. Monatsbl. f. Augenh., 65:876, 1920. 19. Bliedung, C.: Eine spontane intraepithelial Iriszyste. Klin. Monatsbl. f. Augenh., 67:401, 1921. 20. Vogt, A.: Zystenbildung des Pupillar pigmentsaumes. Klin. Monatsbl. f. Augenh., 67 :330, 1921. 21. Braunstein, E.: Multiple spontane pigmentierte Cysten der Irishinterflache. Arch. f. Ophth., 115:381, 1924-25. 22. Fillipow, N. A.: Zur Frage iiber die spontanen serosen Iriszysten. Klin. Monatsbl. f. Augenh., 84:247, 1930. 23. Town, A. E.: Cyst of the uveal layer of the iris. Am. J. Ophth., 16 :790, 1933. 24. Villard, H., and Dejean, C.: Les Kystes de l'iris. Arch. Ophtal., 50:91, 1933. 25. Francois, T.: Kystes de proces ciliaires, observes par la gonioscopie apres enclavement de l'iris. Ophthalmologica, 116:313, 1948. 26. Reese, A. B.: Spontaneous cysts of the ciliary bodv simulating neoplasms. Tr. Am. Ophth. Soc, 47:138,1949.
SOME OBJECTIVE AND SUBJECTIVE OBSERVATIONS ON THE VESTIBULO-OCULAR SYSTEM* DAVID G. COGAN, M.D. Boston, Massachusetts T h a t the vestibular apparatus, and par ticularly the labyrinths, plays an important role in the control of ocular movements is taken for granted. The violent nystagmus and illusory movement of the environment that occur with diseases of the peripheral labyrinth dramatically attest to this. More* From the Howe Laboratory of Ophthalmology, Harvard University Medical School, and the Massa chusetts Eye and Ear Infirmary.
over, this control can be quantitatively docu mented under normal conditions with vary ing degrees of acceleration and deceleration (Graybiel 1 ). Yet, with rare exception ( F o r d and W a l s h 2 ) , there appears to be little ap preciation of the essentiality of this labyrin thine control in stabilizing the eyes during small, seemingly trivial, movements of the head. The voluntary and opticokinetic move-
VESTIBULO-OCULAR SYSTEM merits mask the finer labyrinthine effects under normal conditions and few persons interested in ocular movements have had the opportunity—or misfortune—to study them subjectively from a pathologic point of view. A notable exception to this is the case of Crawford who described, with admirable clarity, the symptoms of his own loss of labyrinthine function following an overdosage of streptomycin.3 It was my contact with Dr. Crawford on several occasions and a personal encounter with what was called "labyrinthitis" that prompted my im mediate interest in the visual phenomena associated with labyrinthine disturbances and emphasized to me the important role the semicircular canals play in what are ordi narily considered minor activities of visuospatial orientation. It is the purpose of this report to point out some of these observa tions and to present a few other phenomena not generally recognized. This will be done through a description of two cases and an analysis of my own symptoms. C A S E REPORTS CASE 1
M. M. (12-62-29) was a 48-year-old nurse who was given a total of 21 gm. of streptomycin over a 12-day period for tuberculosis of one kidney. After receiving approximately 16 gm., she de veloped vertigo that increased over a period of several days to the point that she was unable to turn over in bed. In the meantime, she had had a nephrectomy and her symptoms were at first attributed to a postoperative disturbance. The streptomycin was therefore continued for several days after the onset of the vertigo. The vertigo continued to be relatively severe for about one week. It was acutely aggravated by movements of the head and was initially ac companied by moderate vomiting and illusory rota tion of the environment. In the subsequent two months it gradually improved. The patient has been followed a total of five months since the onset of the vertigo with little subjective change in the past three months. Two weeks after the onset, no nystagmus could be elicited by irrigation of either ear with ice water. Five months after the onset there was still no vestibular function that could be detected byrotation with a Barany chair. The patient's visual disturbances constituted a conspicuous part of her symptoms from the start. At first there was a violent illusory rotation of
75
the environment. As this resolved the patient ob served that she was unable to see clearly when her body was in motion. Specifically the environ ment appeared to oscillate up and down while she walked or as she rode in a car. This was, and has continued to be, so severe that she is unable to recognize people along the street unless she stops and remains immobile for a second or two. There has been only slight spontaneous improvement in this symptom but there is considerable symptomatic improvement on wearing a Thomas collar or hold ing her head rigid between her hands as she walks. In contrast to the up and down oscillations, no horizontal oscillations have been noted at any time. Reading was at first difficult. The lines of print ran together and drifted up and down unless her head were supported or unless she was able to lean it against a rigid support. Fatigue always made the reading more difficult. Reading on a train has been impossible. This difficulty in reading has improved considerably with time but is still present, one year after the onset, when the patient is fatigued. Examination of the eyes five months after the onset of the vertigo revealed little objective ab normality. Ocular movements were full without dissociation, dysmetria, or nystagmus. So long as the patient's head was motionless she could exercise full gaze movements in all directions without un toward symptoms. The opticokinetic response was normal and symmetric. The patient's visual acuity was 20/15 as long as she was immobile. Jogging on her heels, however, resulted in a reduction in her acuity during the movement to 20/200 or less and the print ap peared to oscillate up and down. Passive lateral movements of the head also resulted in a reduction in acuity to 20/200 or less but this was described as a blur and surprisingly not accompanied by any illusory movement of the environment. Several control observers showed no deterioration of vision with similar jogging on the heels or passive move ments of the head. As the patient's head was oscillated between the examiner's hands it was found that she was unable to hold fixation on the examiner as could normal subjects. Indeed, with relatively rapid oscillations of the head, the eyes moved with the head as though fixed in the orbits whereas normal subjects could hold their eyes fixed on an object despite compa rable oscillations of the head. Analogous observations were made on after-im ages induced with a flash of light from a discharge tube. Whereas, the after-image remained stationary for several control observers despite vigorous jogging on their heels or passive oscillations of their head, the patient observed that the after image made wide excursions up and down during the movement of her head. This, however, occurred only so long as there was light in the room to illuminate the background. In the dark or when the eyes were closed the after image did not appear to move. The after image (or the background?) moved in a vertical direction with up and down
76
DAVID G. COGAN
movements of the head and in a horizontal direction with lateral movements of the head. Rotation in a Barany chair induced some move ment of the environment, although less than normal, but no postrotary oscillopsia. T h e patient's symptoms were typical of those which have been reported following streptomycin intoxication 4 ' 5 or loss of labyrinthine function from other causes. 8 T h e continued blurring of vision—not al ways recognized as illusory movement—with vertical movement of the head is particularly noteworthy. This was relieved by immobil ization of the head. It has continued with little improvement in the subsequent five months of observation. It may be demon strated with a measure of objectivity by testing visual acuity d u r i n g vertical move ment of the head or by observing an after image during vertical movements. T h e blur ring or illusory movement of the environ ment with horizontal movements was less conspicuous, but with passive horizontal movements of the head the patient was un able to maintain fixation as well as normally. CASE 2
J. C. (Dr. Crawford) was a 30-year-old phy sician who received a total of approximately 275 gm. of streptomycin over a two and one-half-month period for a presumed tuberculous arthritis. A de scription of the patient's early symptoms and reac tions has been presented in a superb autobiographi cal vignette published elsewhere.' Initially there was considerable vertigo and nausea evoked by movement of the head. Walking resulted in an ap parently up and down oscillation of the environment likened to a "yo-yo." Any movement of the body and head resulted in a marked reduction in vision so that the patient was unable to recognize people while he was walking or riding in a car. The joggle of a bicycle was particularly devastating to vision. Reading on the train was impossible. In deed, the slight movements of the head from arterial pulsation bothered his reading at first so much that it was necessary for him to hold his head still with his hands or to support it against some rigid object. All of these visual symptoms disappeared immediately as soon as he was stationary. With appropriate tests the patient was found to have complete loss of labyrinthine function. Dur ing the subsequent period he observed illusory movement of the environment whenever he moved his head but after the initial period no vertigo oc curred with movement so long as his eyes were closed. H e found the disorientation was somewhat
lessened as he learned to immobilize his head and to maintain his gaze on a distant object; holding onto a firm object also helped. Rapid bodily movements were accompanied by less visual disturb ance than slow movements. Examination of the patient five years after the loss of labyrinths showed no evident vestibular function with the conventional Barany test. Super ficial testing of eye movements showed nothing ab normal. There was a full range of movement in all directions without nystagmus. The following move ments were executed smoothly and the opticokinetic response was symmetric. There was a suggestion of ocular motor dysmetria but this was slight and inconstant. Visual acuity was 20/15 but jogging on the heels resulted in a reduction of the acuity during the movement to 20/70. Similar passive oscillations of the head resulted in a reduction in acuity propor tionate to the violence of the oscillations. These movements were accompanied by illusory movement of the environment and it was the patient's ob servation that the movement per se caused the blur. Illusory movement of the environment occurred equally in the horizontal or vertical plane accord ing to the direction of the head movements. The patient was unable to maintain his gaze on a near object during rapid turning of his head to the right and left, as can a normal person. As in the previous patient, the eyes tended to remain fixed in the orbit when the turning became sufficiently rapid. An after-image, induced by a flash of light, ap peared to move with passive movements of the head or with jogging on the heels. This was true for both the horizontal and vertical direction but occurred only when there was at least some il lumination of the room. When the room was com pletely dark or when the patient's eyes were closed the after-image did not appear to move. Under similar conditions the normal subject observed no movement of the after-image either in a lighted or darkened room. T h i s patient's early symptoms were also typical of those described with streptomycin intoxication.* As in the previous case, how ever, the prominent residual feature was blurring of vision with movements of the head and the blurring was evident with ex traordinarily slight movements. I t was de monstrable by the reduction in visual acuity * Two other patients with streptomycin intoxica tion are not included in this paper for lack of more adequate work up. They did, however, complain of incapacitating and persistent illusory movement of the environment with movement of the head. The one patient on whom visual acuity measurements were made showed a deterioration of vision from 20/20 to 20/70 with mild jogging on her heels.
VESTIBULO-OCULAR SYSTEM or by the oscillations of an after-image dur ing movement and had persisted for at least five years after the onset of the labyrinthine disease. It is presumably permanent. CASE 3
D. G. C. The following is a brief report of my own "labyrinthitis." Without prior warning or apparent etiology, I awoke to find that the room showed a continuous clockwise rotation whenever I opened my eyes. This was shortly followed by moderate vertigo, retching, tenesmus, and profound unsteadiness of gait. The gastrointestinal symp toms promptly abated but the spontaneous rotation of the environment continued with gradual improve ment for three days. It was worse on gaze to the right or on lying on my left side. It was of course accompanied by, or caused by, a horizontal rotary nystagmus which had a fast component to the right. The noteworthy feature of the nystagmus was that the environment always moved in one direction. This was to the right, repetitive, and synchronous with the slow component of the nystagmus. I was never aware of a movement to the left. Yet—and this seemed to me most surprising as I subsequently thought about it—there was no psychologic con flict in the fact that the environment should he back at the starting place again. In other words, I had I he seemingly paradoxical experience of seeing the environment continually moving in one direction over a defined arc and yet never being aware of how it got back to the beginning of the arc nor of being bothered particularly by the inherent con tradiction in this state of affairs. One further symptom which was apparent to me but rarely mentioned so far as I am aware, was the association of a blink, or tendency to blink at the end of the slow excursion, that is, concomitant with the onset of the fast phase of the nystagmus. As the nystagmus subsided in three days' time, and with it the vertigo, a new train of symptoms occurred characterized by illusory movement of the environment when the head was moved. This was in every way similar to that noted in the fore going two cases. It was much more evident for hori zontal than for vertical movements. There was also a definite lateralizing component for it was much more conspicuous on turning or tilting the head from right to left than from left to right. This illusory movement of the environment resulted in an annoying blur such that I was unable to recognize objects while walking or during movement. It was not always apparent that the blur was in fact due to the illusory movement. The effect might well be called simple dizziness by one not interested in analyzing it. It was accompanied by marked un steadiness of gait arid general (and spurious) sensa tion of inebriation. The unsteadiness of gait was not caused by the visual phenomena for it was present even with the eyes closed or in the dark. All these symptoms gradually subsided in the subsequent few weeks, but the left labyrinth gave
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no caloric response when tested five weeks after the onset of symptoms and six months later it was still markedly hypoactive. There was no deafness at any time.
As a symptom of unilateral labyrinthitis, illusory movement of the environment was noted to occur with the slow phase of the nystagmus, and in the opposite direction. Curiously, it did not seem unnatural that the environment should be back at the startl ing point during each cycle without giving evidence of how it got back there. Of inci dental interest was the blink, or tendency to blink, of the lids synchronous with the fast phase of the nystagmus. Finally, the symp toms ensuing on the acute phase were similar to those described by persons who have lost their labyrinthine function through strepto mycin intoxication except in the present case there was evidence of lateralization and the symptoms were temporary only. DISCUSSION AND CONCLUSIONS
The inference is inescapable that the stabilizing effect of the labyrinths on the eyes is extraordinarily sensitive under nor mal conditions. It has of course been long known that the labyrinths exert positional effects on the eyes and may have well-nigh exclusive control of ocular motor function in such lower animals as the rabbit. But in man the labyrinthine control appears to play a role subordinate to that of voluntary and reflex mechanisms.8 From the present ob servations, however, on patients and from threshold measurements on normal subjects,8 it would appear that the labyrinthogenic stabilization of the eyes was of vital im portance for visual function in human beings during even slight movements of the head. The surprising feature is not the fact that the labyrinths exert an effect but rather the sensitivity of the mechanism and the magnitude of the visual deficit when the labyrinthine control is lost. Thus in both the foregoing patients who lost their laby rinths from streptomycin, jogging on the heels caused a reduction in visual acuity to
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20/70 or less. T h e act of walking, riding in a car, or riding a bicycle so impaired vision that the patients were unable to recognize people on the street. Even the oscillations of the head from arterial pulsation so af fected one of the patients that he was unable to read unless he manually supported his head. It must be inferred, therefore, that under normal conditions the semicircular canals exert a significant stabilization for even these slight head movements. One of the curious features in these two patients was the predilection of the illusory movement of the environment for the verti cal direction. Oscillations of the head hori zontally induced an incapacitating blur but this was not necessarily interpreted as a movement of the environment. Somewhat similar visual phenomena were observed in the recovery stage of labyrinthitis as described in the third case. In addition it was noted during the early events of the labyrinthitis that the nystagmus re sulted in an illusory movement of the en
vironment in one direction only (opposite the slow phase) without revealing how the environment returned to the starting point. It is curious that this paradox did not seem unnatural at the time. A further and minor feature was the blink of the lids, or tendency to blink, that was synchronous with the fast phase. These correlatives of a labyrinthine deficit do not appear to be generally ap preciated, but may well be part of that vague dizziness of which patients with acute labyrinthine disturbance complain. SUMMARY
The visual phenomena are described in the cases of two patients who lost their labyrinthine function from streptomycin in toxication and in the case of one patient (the author) with so-called labyrinthitis. It is concluded that the semicircular canals have surprisingly important functions in stabilizing the eyes even with slight move ments of the head. 243 Charles Street (14).
REFERENCES
1. Graybiel, A., Kerr, W. A., and Bartley, S. H.: Stimulus thresholds of the semicircular canals as a function of angular acceleration. Am. J. Psychol., 59 :21, 1948. 2. Ford, F. R., and Walsh, F. B.: Clinical observations on the importance of the vestibular reflexes in ocular movements: The effects of section of one or both vestibular nerves. Bull. Johns Hopkins Hosp., 58:80-83, 1936. 3. Crawford, J.: Living without a balancing mechanism. New England J. Med., 246 :4S8, 1952. 4. Doucet, P. M. M., Behague, J., and Garderes, P. de: Troubles visuels chez les tuberculeux pulmonaires traites par des injections intra-musculaires de streptomycine. Soc. d'ophtal. Paris, 1948, pp. 63-64. 5. Sannella, L. S.: An early symptom of streptomycin neurotoxictty. Arch. Ophth., 50:331-332; 1953. 6. Ford, F. R., and Walsh, F. B.: Tonic deviation of eyes produced by movements of head. Arch. Ophth., 23:1274, 1940. 7. Crawford, J.: Living without a balancing mechanism. New England J. Med., 246:458, 1952. 8. Magnus, R.: Koerperstellung. Berlin, Springer, 1924. 9. Graybiel, A., Kerr, W. A., and Bartley, S. H.: Stimulus thresholds of the semicircular canals as a function of angular acceleration. Am. J. Psychol., 59 :21, 1948.