1445 Evidence of Somatotopic Organization of the Sensory Thalamus Based on Infarction in the Nucleus Ventralis Posterior Onofre Combarros, MD; Jose M. Polo, MD; Julio Pascual, MD; and Jose Berciano, MD Background: This is to describe a restricted sensory syndrome of unique distribution due to thalamic infarct. Case Description: We report a case of pure sensory disturbance involving the left intraoral and perioral regions and the tips of the thumb and forefinger of the left hand. Magnetic resonance imaging revealed a small infarct in the contralateral thalamus, presumably affecting the nucleus ventralis posterior. Conclusions: This patient provides an excellent correlation between clinical findings and thalamic representation of body surface as established during stereotactic procedures. (Stroke 1991;22:1445-1447) T he cheiro-oral syndrome (from the Greek "cheiros" meaning "hand") is a sensory disturbance affecting both the hand and the corner of the mouth on the same side, but without motor impairment. Pure sensory deficit with a cheirooral topography usually occurs as a result of a vascular lesion, either hemorrhage or infarction, in the region of the ventralis posterior nucleus of the thalamus1-7 and in the brain stem sensory pathways projecting to this nucleus.7-11 In a large survey of pure sensory stroke, Fisher12 analyzed the patterns of distribution of paresthesias and suggested that selective involvement of some, rather than all, fingers indicated a cortical localization, whereas a thalamic lesion typically caused involvement of all fingers indiscriminately. We report a case of small thalamic infarction showing a contralateral cheiro-oral syndrome with sensory impairment restricted to the tips of the thumb and forefinger. No previous cheiro-oral syndrome case has been associated with such a sensory distribution, which is consistent with the current view concerning the somatotopic representation on the human sensory thalamus. Case Report A 54-year-old hypertensive woman suddenly developed burning paresthesia, as if stung by nettles, in the From the Service of Neurology, University Hospital "Marques de Valdecilla," Faculty of Medicine, Santander, Spain. Address for correspondence: Jose Berciano, MD, Service of Neurology, University Hospital "Marques de Valdecilla," 39008 Santander, Spain. Received April 12, 1991; accepted July 17, 1991. tongue, oral cavity, lips, cheek, and the tips of the thumb and forefinger, all on the left side. General physical examination was unremarkable except for a blood pressure of 165/110 mmHg. Neurological examination in the emergency room revealed no significant abnormalities, and no sensory deficit was evident. Routine blood and urine examinations, x-rays of the chest, and electrocardiogram were normal. Brain computed tomography with and without contrast was normal. Three months after its onset, she continued to complain of persistent burning in the left oral cavity and tongue. These dysesthetic sensations were aggravated by exposure to extremes of temperature, especially hot liquids and food. Taste was unaffected. Pins-and-needles paresthesia affected the left upper and lower lips, adjacent face, and the tips of the two medial fingers, and touching over these areas caused electriclike sensations. Sensory examination revealed decreased left intraoral pain and light touch sensation. Sensation to pinprick was diminished in the left perioral structures and in the tips of the first and second fingers of the left hand, but these areas were hyperesthetic to light touch. Propioceptive sensation, however, was preserved. Magnetic resonance imaging (MRI) at this time showed an area of increased signal on the T2weighted scan in the right inferolateral thalamus (Figure 1). The somatosensory evoked potentials elicited by left median nerve stimulation showed absent N20 and subsequent responses on the contralateral sensory cortex. Two years later, moderate to severe distress from unpleasant paresthesia had not significantly changed. Downloaded from http://stroke.ahajournals.org/ by guest on May 14, 2015 1446 Stroke Vol 22, No 11 November 1991 bance limited to the peribuccal area and palm of the hand and fingers. In fact, most previously reported cases showed this stereotyped pattern (Table 1). Paresthesia or numbness referable to the face occurred in one half of the patients, and sensory defect localized within the mouth was encountered in only one third. An unusual cheiro-oral syndrome with bilateral oral involvement has been described in one case of small pontine hemorrhage.11 Characteristically, all the fingers were equally affected. In a detailed clinical study of pure sensory stroke, Fisher12 proposed patterns of sensory deficit to predict the localization, thalamic or cortical, of the vascular lesion. Patients with occlusive disease of a penetrating thalamic branch artery had paresthesia of the face, arm, and leg on one side, and all fingers of that side were affected. However, in occlusion of the internal carotid and middle cerebral arteries, paresthesias were usually restricted to a faciobrachial or brachial topography, with some fingers more impaired than others. A similar pattern was described in a patient with a small cortical infarction affecting the parietal region, accompanied by sudden onset of pure sensory deficit in the three medial fingers of the right hand and in the right foot.13 The limited sensory deficit in the tips of the thumb and forefinger, as described in our case, is extremely unusual in cheiro-oral syndrome caused by a thalamic infarct. In this respect, our case is similar to that reported by Garcin and Lapresle,2 who described numbness in the right peribuccal region, the radial edge of the forearm, and the first to third fingers of the right hand; at autopsy a lacune was found in the ventralis posterior nucleus of the contralateral thalamus. In our patient MRI revealed a FIGURE 1. T^weighted magnetic resonance imaging revealing lacunar infarction in the area corresponding to ventralis posterior nucleus (arrow). Treatment with carbamazepine, imipramine, amitriptyline, and mexilitine had produced no effect. Reexamination showed that sensory signs remained confined to the same distribution. Discussion The traditional view has held that the cheiro-oral syndrome is a combined unilateral sensory disturTABLE 1. Summary of Previous Reports of Cheiro-Oral Syndrome Reference Garcin and Lapresle1 Garcin and Lapresle2 Fisher,3 Case 9 Fisher,4 Case 1 Case 2 Ono and Inoue8 Valzellis Araga et al,9 Case 1 Case 2 Awada6 Kawakami et al,7 Case 1 Case 2 Case 3 Case 4 Iwasaki et al10 Matsumoto et al," Case 1 Case 2 IO + + + + + + PO + + + + + + + + + + + + + + + + + Distribution F D + + + + + + + + + + + + + + + + + + + + + H + + + + + + + + + + + + FA + + + + + IO, intraoral; PO, perioral; F, face; D, digits; H, hand; FA, forearm; ' magnetic resonance imaging. > Lesion location Identification VP thalamic infarct VP thalamic infarct VP thalamic infarct VP thalamic infarct VP thalamic infarct Midbrain hemorrhage Thalamic infarct Dorsolateral pontine hemorrhage Dorsolateral pontine hemorrhage Thalamic infarct Pontine infarct Thalamic hemorrhage Thalamic infarct Pontine hemorrhage Thalamic hemorrhage Pontine hemorrhage Pontine hemorrhage Autopsy Autopsy Autopsy Autopsy Autopsy CT CT CT CT MRI MRI CT MRI CT CT CT/MRI CT/MRI posterior nucleus; CT, computed tomography; MRI, Downloaded from http://stroke.ahajournals.org/ by guest on May 14, 2015 Combarros et al Thalamic Infarct 1447 as that of our patient, can be produced by a small infarction in this thalamic area. Acknowledgments The authors thank Dr. Maria Teresa Berciano for the redrawing of Figure 2 and Mrs. Marta de la Fuente for secretarial assistance. FIGURE 2. Homunculus representation in the ventralis posterior nucleus in its coronal section. Adapted from Ohye.14 FX, fornix; LD, nucleus lateral dorsal; MD, nucleus medial dorsal; CM, nucleus centrum medianum; LP, nucleus lateral posterior; VP, nucleus ventralis posterior. small inferolateral thalamic infarct that presumably involved that nucleus. The particular topography of sensory deficit in our patient exactly conforms to the representation of body surface in the ventralis posterior nucleus, as obtained from microelectrode mapping techniques during stereotactic thalamotomy for treatment of involuntary motor disturbances.14 These studies indicate that in the ventralis posterior nucleus, the principal rule of the somatotopic representation is face, upper limb, and lower limb, progressing to its dorsolateral pole. The tongue extrudes most medially, and the fingers, especially the thumb, are located adjacent to the former, as shown in the homunculus proposed by Ohye14 (Figure 2). An organization comparable to that existing in human sensory thalamus has been described in primates by Kaas et al,15 who emphasized that the representation of tips of the digits occupies a relatively large portion of the ventralis posterior nucleus. These cases help to explain how a limited sensory disturbance, such References 1. Garcin R, Lapresle J: Syndrome sensitif de type thalamique et a topographie cheiro-orale par lesion localisee du thalamus. Rev Neurol 1954;90:124-129 2. Garcin R, Lapresle J: Deuxieme observation personelle de syndrome sensitif de type thalamique et a topographie cheiroorale par lesion localisee du thalamus. Rev Neurol 1960;103: 474-481 3. Fisher CM: Pure sensory stroke involving face, arm and leg. Neurology 1965;15:76-80 4. Fisher CM: Thalamic pure sensory stroke: A pathologic study. Neurology 1978;28:1141-1144 5. Valzelli L: About the cheiro-oral syndrome. Neurology 1987; 37:1564-1565 6. Awada A: Fourmillements cheiro-faciaux isoles par hematome thalamique. Rev Neurol 1989;145:861-862 7. Kawakami Y, Chikama M, Tanimoto T, Shimamura Y: Radiological studies of the cheiro-oral syndrome. / Neurol 1989;236: 177-181 8. Ono S, Inoue K: Cheiro-oral syndrome following midbrain haemorrhage. J Neurol 1985;232:304-306 9. Araga S, Fukada M, Kagimoto H, Takahashi K: Pure sensory stroke due to pontine haemorrhage. / Neurol 1987;235: 116-117 10. Iwasaki Y, Kinoshita M, Ikeda K, Takamiya K, Shiojima T: Pure sensory stroke and cheiro-oral syndrome. J Neurol 1989; 236:186-187 11. Matsumoto S, Kaku S, Yamasaki M, Imai T, Nabatame H, Kameyama M: Cheiro-oral syndrome with bilateral oral involvement: A study of pontine lesions by high-resolution magnetic resonance imaging. / Neurol Neurosurg Psychiatry 1989;52:792-794 12. Fisher CM: Pure sensory stroke and allied conditions. Stroke 1982;13:434-447 13. Derouesne C, Mas JL, Bolgert F, Castaigne P: Pure sensory stroke caused by a small cortical infarct in the middle cerebral artery territory. Stroke 1984;15:660-662 14. Ohye C: Thalamus, in Paxinos G (ed): The Human Nervous System. San Diego, Calif, Academic Press, Inc, 1990, pp 439-468 15. Kaas JH, Nelson RJ, Sur M, Dykes RW, Merzenich MM: The somatotopic organization of the ventroposterior thalamus of the squirrel monkey, Saimiri sciureus. J Comp Neurol 1984; 226:111-140 KEY WORDS • cerebral infarction • hypesthesia • thalamus Downloaded from http://stroke.ahajournals.org/ by guest on May 14, 2015 Evidence of somatotopic organization of the sensory thalamus based on infarction in the nucleus ventralis posterior. O Combarros, J M Polo, J Pascual and J Berciano Stroke. 1991;22:1445-1447 doi: 10.1161/01.STR.22.11.1445 Stroke is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1991 American Heart Association, Inc. All rights reserved. Print ISSN: 0039-2499. Online ISSN: 1524-4628 The online version of this article, along with updated information and services, is located on the World Wide Web at: http://stroke.ahajournals.org/content/22/11/1445 Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Stroke can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. 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