Bilateral thalamic damage, cortical hypometabolism and behavioural disturbances.

Thalamic damage could be responsible for reduced metabolism in anterior cortical areas. In order to investigate an anatomical lesion and impairment of regional blood flow (rCBF) in distant cortical areas, we studied by magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) a patient with bilateral thalamic infarction, who presented with sudden consciousness impairment, drowsiness, gaze paralysis, dysphagia and bilateral Babinski sign. Three weeks later the neurological symptoms disappeared, but a severe mental deterioration was evident MRI showed thalamic bilateral damage of posterior and medial areas, involving part of the pulvinar, more evident for the right thalamus. A (99m) Tc-HMPAO SPECT showed a decrease of rCBF over frontal and parietal regions, more evident for the right hemisphere. Six months later a severe memory impairment was still evident and MRI and SPECT picture were unchanged. The persistent memory defect could be related to a loss of cortical activation following the thalamic damage. The absence of primary lesions of cortical regions on CT scan and MRI and the neuroanatomical considerations on the diffuse projections running from medial nuclei and pulvinar to large parts of anterior neocortex supported this hypothesis.

Semantic paralexias facilitated by tachistoscopic reading in a patient with impairment of phonological recoding.

This study of a dyslexic patient supports the view that the level of impairment of the phonological route plays a role in the production of semantic paralexias. The patient's reading was based on a defective phoneme-to-grapheme transcoding, in spite of evidence that semantic information was available through non phonological routes. The hypothesis that the residual ability to carry out phonological recoding could block the production of semantic paralexias was confirmed by tachistoscopic reading, assumed to interfere with phonological recoding in this patient, that provoked a definite rise of this type of error. The relationship between the degree of damage of phonological route and the clinical expression of the syndromes of phonological dyslexia and deep dyslexia is also discussed.

On the different roles of the cerebral hemispheres in mental imagery: the "o'Clock Test" in two clinical cases.

This paper develops the hypothesis of different roles of the two hemispheres in imaginal processes. A test designated the "o'Clock Test" is proposed, which contains closely confrontable perceptual and imaginal tasks. It enables examination of the abilities both to generate mental images and to explore them in their right and left halves (R + L Condition). This test was used to examine two patients, one severely affected by hemi-inattention resulting from a right posterior lesion, and the other with a selective deficit of imagery due to a left occipital lesion. The former demonstrated left neglect in both perceptive and imaginal capacities, while the latter was able to perform correctly only the perceptive tasks. These results suggest that the right hemisphere has functions of organization and spatial exploration at both perceptive and imaginal levels, and that the left hemisphere's role is to generate mental images.

Glycosaminoglycan polysulfate (Ateroid) in old-age dementias: effects upon depressive symptomatology in geriatric patients.

1. Glycosaminoglycan polysulfate is a mixture of sulfo-muco-polysaccharides with hypolipidemic activity. A number of clinical studies have indicated that it is effective in improving psychopathology in patients with cardiac and/or cerebral disease associated with arteriosclerosis. 2. A multicenter clinical trial was performed to compare the effects of two different dosages of glycosaminoglycan polysulfate upon depressive symptomatology in patients with multi-infarct dementia and primary degenerative dementia. 3. A total of 39 patients were treated in an 18-week clinical trial which followed a single-blind parallel design. 4. Results indicated that patients with both diagnoses improved significantly in depressive symptomatology over the course of treatment, with particular improvement noted in cognitive disturbance. Drug dosage was not a significant determinant of treatment response for either diagnostic group.

Glycosaminoglycan polysulfate in old-age dementias: a factor-analytic study of change in psychopathologic symptoms.

In a multicenter clinical trial, two dosages of glycosaminoglycan polysulfate were compared in patients with primary degenerative dementia and multi-infarct dementia. Psychopathologic symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). A factor analysis of this scale revealed four factors in this population. During the clinical trial, significant improvements were noted on the primary BPRS factor (i.e. depressive withdrawal), as well as on total BPRS score. There was a tendency for greater improvement in the primary degenerative dementia group than in the multi-infarct dementia group.

Visuoimaginal constructional apraxia: on a case of selective deficit of imagery.

We report a case of a patient with a left occipital lesion who presented a peculiar behavioral dissociation. He was able to copy pictures but not to draw a simple object without a visual model; the relationship among the component parts was altered in drawings produced under the guidance of his mental representations. We have called this disturbance "visuoimaginal constructional apraxia." The mechanisms underlying visuoimaginal constructional apraxia are investigated in an attempt to contribute to studies on the nature of mental imagery.