Neuropsychological study in patients with thalamic and putaminal hemorrhage

Abstract

Language and visuo-spatial memory as well as general intellectual abilities were evaluated in forty-two right-handed patients with localized chronic thalamic hemorrhage. The lesions were localized in the left hemisphere in twenty-three patients and in the right in nineteen patients. Aphasia was identified in twenty-one right-handed patients with putaminal hemorrhage and compared with that caused by thalamic hemorrhage. Thalamic aphasia appears to be different from the aphasia caused by a cortical lesion, because of its short duration and its overall mildness. It is suggested that the integrity of the thalamus is necessary for language behavior, although symptoms following a thalamic lesion are not as specific as to warrant a specific label such as thalamic aphasia. Indeed, symptoms were very similar to those in patients with putaminal hemorrhage. Aphasia due to a thalamic lesion is considered to be caused by a secondary cortical dysfunction. Neuropsychological symptoms and signs were observed mainly in the patients with lesions in the pulvinar and posterior portions of the thalamus. However, their prognoses were fairly good except for auditory functions. On the other hand, it is suggested that the putamen itself does not participate in language behavior, and that aphasia caused by putaminal hemorrhage is essentially due to destruction of the structures surrounding the putamen. The type of aphasia and prognosis vary with the site of the lesion and the hematoma volume. It is also suggested that the thalamus is related to language behavior as part of a thalamus-cortical language area-thalamus loop. Aphasia caused by putaminal or thalamic hemorrhage was observed to be different from classical cortical aphasia. However, there was no significant difference between aphasia caused by putaminal lesions and that due to thalamic lesions.