Neuropsychological deficits after bithalamic hemorrhages.

Strategic lesions of the thalamus interfere with cognitive functions and produce complex neuropsychological symptoms. Bilateral, simultaneous thalamic hemorrhages are unusual causes of thalamic dementia. We present clinical, neuropsychological and structural neuroimaging data of a 12-month follow-up period of a patient with bilateral thalamic hemorrhages. After the operation of pancreatitis acuta hemorrhagico-necroticans, the patient developed coma. Computed tomography (CT) and magnetic resonance (MR) of the brain showed medially situated bithalamic hematomas. During the follow-up period, patient's level of consciousness has improved. Moderate dementia (MMSE 20/30) was found with severe temporal and spatial disorientation. Neuropsychological tests showed that attention and concentration were prominently impaired; there were severe verbal and less prominent, visual memory deficits, with anterograde and retrograde amnesia, accompanied by confabulations. Loss of cognitive flexibility and dysexecutive syndrome were also demonstrated. Dynamic apraxia, visual organization and visual construction deficit and impairment of categorial and phonemic fluency were noted. Language was only moderately impaired (anomia). A year later, neuropsychological profile was similar with moderate improvement of retrograde amnesia, whereas anterograde deficits persisted. Neuropsychological syndrome in our patient with bilateral thalamic hemorrhages was characteristic for subcortico-cortical cognitive deficit and was caused by disruption of the cortico-thalamic circuitry.

Subcortical aphasia: three different language disorder syndromes?

The study analyses clinical presentation of language functions of 32 patients with subcortical aphasia induced by stroke. The patients have been divided into three groups according to neuroanatomic localization of the lesion, defined by CT and MRI examination (striato-capsular aphasia, aphasia associated with white matter paraventricular lesions and thalamic aphasia). The following batteries and tests were used: the neurologic examination, CT scan, MRI, Doppler ultrasound, Mini Mental State Examination, Boston Diagnostic Aphasia Examination (BDAE), Boston Naming Test (BNT), Token Test and Verbal Fluency Test. Clinical presentation of subcortical aphasias is characterized with preserved repetition, however, some groups differ by certain specific features of language impairment. Striato-capsular aphasia and aphasia associated with white matter paraventricular lesions are characterized with lack of speech fluency, occurrence of literary paraphasias, mainly preserved comprehension and naming. Thalamic aphasia, however, is characterized with fluent output, impaired comprehension and naming with predominant verbal paraphasias. The specific features of language impairment suggest that subcortical structures contribute to language organization. Considering the results of language tests we presume that the most prominent feature in striato-capsular aphasia is phonetic impairment of language, opposite to thalamic aphasia where lexical-sematic processing seems to be affected.