The aim of our study was to investigate the blood flow in middle cerebral arteries during the different forms of cognitive activity in dyslectic persons. Two group of subjects were tested. The first group consisted of 10 students with school difficulties, diagnosed neuropsychologically as having a particular form of dyslexia, i.e. dysgraphy or dysorthography. 6 of them were right lateralized and 4--left lateralized. The second contained 10 students without such problems. 7 of them were right lateralized and 3--left lateralized. We used four kinds of cognitive tasks, during which the blood flow velocity in MCA in left and right hemisphere was measured with the Transcranial Doppler method. The analysis of the results showed differences between the groups of blood flow velocity levels, without a difference in performance profile. The dysgraphic persons had significantly higher blood flow velocity in the right hemisphere compared to the reference group. The results suggest particularly important role of right hemisphere in dyslexic persons, which is consistent with results obtained by other authors. The analysis of lateralization showed that this factor influences significantly the blood flow velocity level--the left lateralized persons showed lower rise of blood flow velocity than the right lateralized, regardless of the kind of task and measured hemisphere.

Adolescent↗

PubMedDate not supplied

[Assessment of blood flow velocity during cognitive stimulation in persons with suspected hydrocephalus].

The aim of this work is to evaluate middle cerebral arteries (MCA) blood flow velocity changes during performance of linguistic and visuospatial cognitive tasks. Two groups were investigated: eight patients with suspected hydrocephalus without perceptible cognitive disturbances, and eight healthy persons. Blood flow velocity in left and right MCA was recorded with transcranial Doppler sonography while the examined patients were performing three different tasks. The analysis of the results showed differences between the groups concerning both increase of blood flow velocity values and performance patterns. Compared to healthy individuals less increase in blood flow velocity during performance of all tasks and no difference in haemodynamic changes between both hemispheres during task performance were observed in patients with hydrocephalus. The results obtained suggest, that the pattern of functional lateralization in brain in patients with suspected hydrocephalus is probably changed.

Adult↗

PubMedDate not supplied

[Cerebral functional asymmetry in face perception by the patients with focal brain damage].

The results are reported of the study of face perception in a group of 18 healthy subjects and 10 patients with lesions in the right or left cerebral hemisphere. The task given to these subjects included identification of a face photograph exposed for 20 msec in the right or left field of vision. The index of perception coefficient was the number of errors made while addressing the material to the left or right cerebral hemisphere. The results of the experiment confirmed the hypothesis of the dominant role of the right hemisphere for face perception. The results suggest also that face perception disturbances occur without respect to the site of lesion in the right hemisphere.

Brain Injuries↗

PubMedDate not supplied

[The hemispheric asymmetry of the brain during the processing of verbal material].

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Adult↗