112616ournal ofNeurology, Neurosurgery, and Psychiatry 1993;56:1126-1128 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.10.1126 on 1 October 1993. Downloaded from SHORT REPORT

Upbeat nystagmus in a patient with a small medullary infarct

N A R Munro, B Gaymard, S Rivaud, A Majdalani, Ch Pierrot-Deseilligny

Abstract Romberg's test showed a tendency to fall to A 43 year old man presented with the left. There were no cerebellar signs. decreased sensitivity in the left side of the face and both upper limbs, and with MRI upbeat nystagmus and skew deviation. A small left sided medullary infarct extending MRI demonstrated a welil defined lesion 4 mm in its rostrocaudal length was demon- compatible with an infarct in the left side strated 5 mm caudal to the pontomedullary of the medulla, caudal and ventral to the junction (fig 1A,B). The infarct was ovoid, , possibly involving the sparing both ventral and dorsal medulla but most caudal of the perihypoglossal probably involved the central nuclei of the nuclei, the nucleus intercalatus. Ocular , the medullary part of the motor studies, using an infrared system, fifth nerve nucleus, the inferior tip of the showed that the nystagmus slow phase , and the spinothalamic decayed exponentially, suggesting a fail- tract. Ventrally, the caudal tip of the inferior ure of integration for vertical eye move- olive and the pyramids were spared. Dorsally, ments. Vertical integration might, the medial part of the cuneate nucleus therefore, be performed partly in the appeared to be affected, while its lateral part nucleus intercalatus. and the gracile nucleus were spared. Medially, the lesion extended to the nucleus (T Neurol Neurosurg Psychiatry 1993;56:1126-1128) and tractus solitarius and the nucleus interca- latus and was close to the 12th nerve nucleus (fig 1 C). The rostral tip of this lesion was Upbeat nystagmus is an uncommon clinical caudal to the caudal tip of both the vestibular finding usually associated with lesions affect- nuclei and the nucleus prepositus hypoglossi. ing the pontomesencephalic junction,' or the

rostral medulla or caudal ." Less com- recordings http://jnnp.bmj.com/ monly, it has been associated with cerebellar Recordings were made 5 days after the initial or midbrain lesions, where its association with symptoms. The patient was seated, with head internuclear ophthalmoplegia is well recog- fixed, 80 cm in front of a semicircular array of nised.78 We report a case with upbeat nystag- closely spaced light emitting diodes. mus and a skew deviation related to a small Recordings were made from the right eye medullary infarct. using infrared oculography (Skalar "IRIS" system) and were sampled at 250 Hz. There was an upbeat nystagmus in the pri- on September 26, 2021 by guest. Protected copyright. Case report mary position which was increased on looking A 43 year old man suffered a mild headache upwards (fig 2), persisting even with pro- and a strange sensation in the left side of his longed eccentricity of gaze. The character of Department of Clinical face and in his left hand. Subsequently, he the slow phase was clearly exponentially Neurology, Radcliffe vomited, though there was no vertigo. He dis- decaying. There was a horizontal gaze nystag- Infirmary, Woodstock covered that he was veering to the left. On mus on looking to the right which was just Road, Oxford OX2 at of per- in the There was no 6HE arrival the hospital, he complained present primary position. N A R Munro sistent hiccoughs and double vision. rebound nystagmus. Vertical smooth pursuit Laboratoire INSERM Examination showed an upbeat nystagmus in of a target moving sinusoidally with amplitude 289, Hopital de la both eyes, barely visible in the primary posi- of 100 and frequencies of 0-25 and 0 5 Hz Salpetriere, 47 Bvd de tion, but more marked on upward gaze. A were symmetrical. The gain of horizontal l'Hopital, 75653 Paris cedex 13, France mild horizontal gaze nystagmus was also pre- smooth pursuit was slightly reduced towards B Gaymard sent. He had an intermittent skew deviation the left. Lateral and-vertical saccades were S Rivaud with hypotropia of the left eye, without evi- normal. A Majdalani Ch Pierrot-Deseilligny dence of a torsional component. There was a slight increase of the right sided reflexes. Correspondence to: N A R Munro Sensitivity to light touch in the left side of the Discussion Received 10 July 1992 face and in the left hand was decreased, as This patient suffered from a postural imbal- and in revised form was to and temperature on the ance in 11 September 1992. sensitivity pain the absence of symptoms of rotational Accepted 30 September 1992 right side of the body, sparing the face. vertigo, an upbeat nystagmus, with an expo- Upbeat nystagmus in a patient with a small medullary infarct 1127 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.10.1126 on 1 October 1993. Downloaded from Figure 1 Lateral (A), dorsal (B), and cross sectional (C) Magnetic resonance images of the pons and medulla. Left sided structures are demonstrated on the left. 1 vestibular nuclei: (a) superior, (b) lateral, (c) inferior, (d) medial; 2 nucleus prepositus hypoglossi; 3 nucleus of Roller; 4 nucleus intercalatus (hatched area); 5 XII nerve nucleus; 6 nucleus and tractus solitarius; 7 gracilis and cuneate nuclei; 8 nucleus and tractus of V nerve; 9 spinothalamic tract; 10 inferior olive; 11 nucleus ambiguus; 12 pyramids. The lesion is demonstrated by light shading and is shown involving the nucleus intercalatus (hatched area).

6 http://jnnp.bmj.com/ on September 26, 2021 by guest. Protected copyright.

nentially decaying waveform, and an intermit- which had bled several times.25 The vestibu- tent skew deviation. lar system has been implicated in upbeat nys- Upbeat nystagmus has not so far been tagmus,"16 but in our patient the lesion was reported with a small infarct affecting the located more ventrally and caudally to the caudal dorsolateral medulla. Upbeat nystag- vestibular nuclei. The clear demonstration of mus is not a usual finding in a pure lateral exponential decay in the slow phase is strong medullary syndrome (Wallenberg's syn- evidence of impaired integration.9 The nucle- drome). However, upbeat nystagmus has us prepositus hypoglossi, the largest of the been reported in two cases involving the perihypoglossal nuclei, is thought, with the medial medulla and in a patient with a medial vestibular nucleus, to be the integrator haematoma affecting the central medulla, for horizontal eye movements.9 This nucleus 128 Munro, Gaymard, Rivaud, Majdalani, Pierrot-Deseilaigny J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.10.1126 on 1 October 1993. Downloaded from hypoglossi.JI It receives afferents from the 16 - medial and inferior vestibular nuclei and has numerous projections including the cerebel- lum and the ocular motor nuclei.'" This case cn) suggests that a vertical integrator exists in the a) caudal medulla and could be located near the 0, 15- midline. The most likely structure appears to be the nucleus intercalatus. A unilateral 0 l,,, lesion of this nucleus could result in upbeat co in both because of its bilateral 0 nystagmus eyes 0. connections with other brainstem structures. (D 14-

0 1 Fisher A, Gresty M, Chambers B, Rudge P. Pimary posi- 1-- tion upbeating nystagmus. A variety of central positional nystagmus. Brain 1983;106:949-64. 2 Baloh RW, Yee RD. Spontaneous vertical nystagmus. Rev Neurol (Paris) 1989;145:527-32. 3 Daroff RB, Troost BT. Upbeat nystagnus. J Am Med 13 - Assoc 1973;225:312. , 4 Hirose G, Kawada J, Tsukada K, et al. Primary position T.. I .... . 5 6 upbeat nystagmus. Clinicopathologic study of four 0 1 2 3 4 patients. Acta Otolaryngol (Stockh) 1991;111:357-60. Time (seconds) 5 Keane JR, Itabashi HH. Upbeat nystagmus: clinicopatho- logic study oftwo patients. Neurology 1987;37:491-4. Figure 2 Vertical eye movement recording demonstrating upbeait nystagmus. The patient 6 Ranalli PJ, Sharpe JA. Upbeat nystagmus and the ventral isfixating a point 15° above the horizontal. Thefastphases are Xupward and show an tegmental pathway of the upward vestibulo-ocular amplitude ofapproximately 0.50. The slow phases show an expotzentialy decaying reflex. Neurology 1988;38:1329-30. 7 Pawl R. Upbeat nystagmus. J Am Med Assoc 1973; waveform. 225-312. 8 Kirkham TH, Katsarkas A. An electrographic study of internuclear ophthanmoplegia. Ann Neurol 1977;25: 385-92. or other perihypoglossal inuclei could also be 9 Cannon SC, Robinson DA. Loss of the neural integrator involved in integration of vertical velocity sig- monkey.of the oculomotorJ Neurophysiolsystem1987;57:from1383-409.brain stem lesions in nals, a function probabily shared with the 1o Fukushima K, Fukushima J, Harada C, et al. Neuronal activity related to vertical eye movement in the region of nucleus of Cajal'0 in the nnidbrain. The nucle- the interstitial nucleus of Cajal in alert cats. Exp Brain us intercalatus, the most ccaudal of the perihy- Res 1990;79:43-64. poglossal nuclei, has strong reciprocal 11 McCreaof the RA,perihypoglossalBaker R. Cytologynuclei inandtheintrinsiccat. J ComporganizationNeurol connections with the nucleus prepositus 1985;237:360-76. http://jnnp.bmj.com/ on September 26, 2021 by guest. Protected copyright.