NOTE APHASIA DOES NOT ALWAYS FOLLOW LEFT THALAMIC HEMORRHAGE: A STUDY OF FIVE NEGATIVE CASES S.F. Cappa, C. Papagno, G. Vallar and L.A. Vignolo (Departments of Neurology, Universities of Milano and Brescia, Niguarda Hospital, Milano) INTRODUCTION Case reports on thalamic aphasia have consistently focused on positive cases. The occurrence of aphasia associated with an acute hemorrhagic or ischemic lesion of the left thalamus has been repeatedly stressed (see Mohr, 1983) all through neurologicalli terature, from the scattered clinical observations of earlier studies (for a review see Lecours and Lhermitte, 1979) to the welter of casereports of the last two decades. The clinical picture of this "thalamic aphasia" is not uniform, but in most cases a mixed transcortical picture, characterized by preserved repetition, with variable impairment of expression and auditory comprehension, has been described (see Cappa and Vignolo, 1983; Crosson, 1984). On the other hand, while left thalamic lesions unaccompanied by aphasia in right-handed subjects are an occurrence for the clinician, a surprisingly small number of such "negative" cases are found in literature and they are even fewer if well-studied cases, i.e. patients submitted to a formal language examination in the acute or "recent" period post stroke are considered. Graff-Radford, Damasio, Yamada et al. (1985) described ten cases in which Computerized Tomography (CT) - assessed ischemic lesions were confined to the left thalamus; language performance was investigated by the Multilingual Aphasia Examination (Benton and Hamsher, 1978). All three patients with antero-lateral thalamic infarctions were aphasic. Six patients had an infarction involving the lateral thalamus and the posterior limb of the internal capsule: of these, three, examined three to 15 days after stroke, had mild language difficulties, not conforming to any aphasic syndrome. The remaining three, tested at intervals of three days, one month and five months after stroke, did not show any aphasic disorder. One patient, with a posterior lateral thalamic infarction, associated with a posterior cerebral artery ischemic lesion, was not aphasic three months after stroke; On these grounds the authors suggest that intrathalamic localization of the ischemic lesion is a crucial factor for the occurrence of aphasia. Thalamic hematomas are less suited for Cortex (1986) 22, 639-647 640 S.F. Cappa, C. Papagno, G. Vallar and LA. Vignolo localization than infarcts, as they are usually large lesions which tend to involve, directly or due to mass effects, the whole thalamus and neighbouring structures. A few clinical series of thalamic hemorrhages (Miller Fisher, 1959; W alshe, Davis and Miller Fisher, 1977) suggest that aphasia is a frequent but not an invariable feature of left-sided lesions. No signs of aphasia following vascular thalamic lesions were found in a recent study (W allesch, Kornhuber, Brunner et al., 1983), but the patients, who had rather small ischemic or hemorrhagic thalamic lesions, were examined months to years post-stroke. These data suggest that the time interval between stroke and neuropsychological assessment is a crucial factor in anatomo-clinical correlation studies. In the present paper we describe five patients with thalamic hemorrhage, who did not display any sign of aphasia as assessed by a standard examination given within one month after stroke. MATERIAL AND METHODS Subjects Five right-handed patients (four men and one woman) were examined in the first month after a thalamic hemorrhage. Mean educational level was 10.2 years of schooling (range 5-17), mean age was 61.4 years (range 49-74). The lesion was documented by means of the CT scan and the site was checked by referring to the atlas by Matsui and Hirano (1978). Case! A 53 year old right-handed man with 13 years of schooling was hospitalized on December 17th, 1980. The day before he had suddenly noticed a loss of strength in his right limbs and difficulty in articulation of speech. On neurological examination he had a right hemiparesis, dysarthria and hypoesthesia in the area of the right fifth cranial nerve. The CT-scan showed a left hemorrhagic area with oedema involving the posterior thalamus (Figure 1). Fig. 1 -Case I. (a) CTperformed 12 days after stroke: hyperdense lesion, surrounded by an hypodense area, involving the posterior thalamus, the posterior limb of the internal capsule and encroaching on the posterior lateral lenticular nucleus. (b, c) CT performed 26 days after stroke: hypodense area involving the posterior thalamus. Left thalamic hemo"hage and aphasia 641 Fig. 2 - Case II. CT performed l days after stroke. Hyperdense area involving the posterior thalamus and the posterior limb of the internal capsule; limited extension to subcortical white matter. Fig. 3 - Case Ill. CT p erformed the same day of the stroke. Hyperdense area involving the posterior two thirds of the thalamus and the posterior limb of the internal capsule; limited ex tension to subcortical white matter. Case II A 49 year old right-handed man with 13 years of schooling was hospitalized on November 2nd, 1980. The night before, he had felt numbness and loss of strength in the right leg. On neurological examination he had a right hemiparesis more pronounced in the arm with increased deep tendon reflexes and Babinski sign. A somatosensory defect was present on the right side. The CT-scan showed an hyperdense area involving the posterior thalamus (Figure 2). Case III A 66 year old right-handed man with 17 years of schooling was hospitalized on March 23rd, 1984, when he suddenly noticed a loss of strength in the right limbs. Neurological examination revealed a right hemiparesis, less pronounced in the leg. The CT-scan showed a left hemorrhage involving the posterior two-thirds of the thalamus (Figure 3). 642 S.F. Cappa, C. Papagno, G. Vallar and LA. Vignolo Fig. 4 - Case IV. CT performed one day after stroke. Hyperdense area confined to the posterior thalamus and the posterior limb of the internal capsule. Fig. 5- Case V. CTperformed the same day of the stroke. Hyperdense area limited to the posterior thalamus and the posterior limb of the internal capsule. Case IV A 74 year old right-handed woman with 5 years of schooling was hospitalized on October 3rd, 1984. The day before she had suddenly noticed a loss of strength first in the right arm, then in the right leg. Neurological examination showed that the right arm was plegic, the right leg was paretic and there was a doubtful right homonymous hemianopia. The CT-scan showed a left posterior thalamic hemorrhage (Figure 4). Case V A 65 year old right-handed man with 8 years of schooling was hospitalized on September 24th, 1985. The day before, he had suddenly noticed a loss of strength in his right leg, followed by a similar sensation in the right arm. The neurological examination showed a right hemiplegia with hyperreflexia and hypoesthesia. He had severe dysprosodia and dysarthria. The CT-scan showed a left hemorrhage of the posterior thalamus and of the internal capsule. Language Examination The presence or absence of aphasia was assessed by means of a standard language examination carried out at our Aphasia Unit (Basso, Capitani and Left thalamic hemorrhage and aphasia 643 Vignolo, 1979), supplemented with the shortened version of the Token Test (De Renzi and Faglioni, 1978), which has a cut off score adju!;ted for educational level of 29 I 36. This language examination investigates oral expr