Eur. Neurol. 27: 227-230 (1987) © 1987S. Karger AG, Basel 0014-3022/87/0274-0227$2.75/0 Unilateral Pseudobulbar Syndrome with Limited Capsulothalamic Infarction M. Rousseaux, F. Lesoin, S. Quint Service des Convalescents and Service de Neurochirurgie, CHU, Lille, France Key Words. Cerebral infarction - Internal capsule - Thalamus - Pyramidal tracts Abstract. A unilateral pseudobulbar syndrome consequent to unilateral capsulothalamic infarction is described. Motor deficit of the face was associated with marked velar and pharyngeal unilateral palsy; paresis of limbs was mild. ACT scan revealed a circumscribed infarction of the genu of the internal capsule. This raised the problem of unilateral supra- nuclear pharyngeal palsies and of the precise anatomy of the genicular tract in the genu of the internal capsule. A unilateral glossopharyngeal and laryn- geal palsy, ipsilateral to hemiplegia, must evoke the opercular syndrome [1, 2], but it has been recently shown that an isolated lesion of the internal capsule may give rise to the same symptoms. In the following case, a unilateral pseudo- bulbar syndrome with velar and pharyngeal palsy was the result of a limited capsular infarction. Case Report A 71-year-old man presented at the end of 1984 with left-sided, transient ischemic attacks. Angiogra- phy revealed an aneurysm of the cervical internal carotid artery, which was operated on December 13th, 1984. Immediate postoperative evolution was good, but 4 days later, a left hemiparesis and an important phonation and deglutition deficit arose. Examination showed a mild left-sided pyramidal deficit. The left facial deficit was important, involv- ing the inferior and upper territories. The masseteric muscle was weak. Swallowing was impossible and this induced a right-sided pneumopathy. Dysphonia was marked. A complete left-sided velar and pharyngeal palsy was noted. Velar and pharyngeal reflexes were initially weak, but recovered in a few weeks, while the pharyngeal palsy remained unchanged. Tongue pro- traction was weak, without lateral deviation. Facial, lingual, velar and pharyngeal sensibilities were nor- mal. An oculomotor examination showed a mild defi- cit of leftward gaze command. On EEG bilateral theta waves were recorded from the temporal and parietal areas. A CT scan (fig. 1) showed a circumscribed Rousseaux/Lesoin/Quint Fig. 1. CT scan. Right-sided capsular (genu) and antero-exter- nal thalamic infarction (arrow). hypodensity of the right anterior and external thala- mus, which also involved the genu (inner part) and posterior limb (anterior part) of the internal cap- sule. In a few weeks, the left-sided paresis resolved. When standing up was possible, a left-sided body deviation was found. The swallowing deficit slowly recovered, oral feeding and later drinking became possible. The voice returned nearly to normal, with mild nasal emission, but the left-sided velar palsy per- sisted (fig. 2). The patient was discharged in February, 1985, after a 7 weeks’ reeducation time. Reinsertion was good, with complete recovery of functional abilities. Four months later, examination still showed a left- sided paresis of the velum and pharynx. Discussion In our patient, a unilateral pseudobulbar syndrome was the result of a limited infarc- tion of the genu and posterior limb of the internal capsule and adjacent anterior thala- mus. The clinical symptons were very simi- lar to the descriptions of unilateral opercular Fig. 2. Left-sided velar palsy (arrows). syndromes of Alajouanine et al. [1], Pertui- set and Perrier [3], Boudin et al. [4], Schott et al. [5], Rebucci et al. [6] and Bruyn and Gathier [2] in cortico-subcortical lesions. In this syndrome, destruction of the upper part of the rolandic operculum gives rise to a pure motor deficit, with predominant involve- ment of the territories of the cranial nerves V, VII, IX, X, XI and XII. The upper-limb palsy is mild and sometimes absent. Velo- pharyngeal reflexes are often weak at the beginning but recover rapidly. Bilateral lacunar infarctions of internal capsule may be associated with similar but bilateral symptoms. Patient No. 7 of Fisher [7] presented with dysphagia and aphemia. In another case (No. 5), complete speechless- ness was associated with paralysis of the lips and tongue. Mohr [8] described a patient which ‘yielded virtual anarthria, severe dys- phonia and dysphagia, but only a mild right arm weakness’. A similar case was presented by Leys et al. [9]. Unilateral Pseudobulbar Syndrome in Capsulothalamic Infarction 229 Even if dysphagia and dysarthria caused by unilateral cerebral lesions may be much commoner than most recognize [10], we found only one case with unilateral capsule involvement and documented unilateral buccolingual palsy: Bogousslawsky et al, [11] described a patient with dysarthria and right-sided lingual paresis related, as in our case, to a limited lesion in the genu of the internal capsule. This raised the prob- lem of the precise topography of the fron- tobulbar motor tracts. In older studies, Brissaud [12] placed the geniculate fascicu- lus going to the medulla oblongata in the capsular genu. Dejerine [13] situated the tract comming from the rolandic opercu- lum and F3 foot at the same level. In an anatomicoclinical case (patient ‘Schweigof- fer’), secondary degeneration after opercu- lar lesions was found in the capsular genu and anterior thalamus, in the area of our patient’s infarction. According to Brion and Guiot [14], the frontopontine tract is at the level of the genu and the frontobul- bar tract behind it in the anterior part of the posterior limb of internal capsule. Fur- thermore, pedunculopontine fibers have a superoinferior and anteroposterior trajecto- ry. Ross [15] confirmed this posterior shift- ing of the pyramidal tract. The blood supply of the anterior thala- mus comes predominantly from the polar thalamic artery branch of the posterior com- municating artery [16], but the adjacent genu of the internal capsule receives branches form the carotid bifurcation [17]. The vascular lesion of our patient was situ- ated in one of these two contiguous territo- ries. In conclusion, if the unilateral glossopha- ryngeal supranuclear palsy was classically re- lated to cortico-subcortical structures at the level of the rolandic operculum, a restricted infarction near the genu of internal capsule may give rise to the same symptoms. 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