[Functional neuroimaging of the brain structures associated with language in healthy individuals and patients with post-stroke aphasia]

[Crossed aphasia in neurosurgical practice: case report and literature review]

BACKGROUND

Crossed aphasia in dexstral (CAD) is an extremely rare disorder. To date, about 200 cases have been described in the literature.

MATERIAL AND METHODS

The authors report 4 cases of CAD. Luria's neuropsychological examination was carried out. Functional asymmetry in the arm was analyzed using the Annett questionnaire. MRI and intraoperative findings confirmed localization of lesion in the right hemisphere in all patients.

RESULTS

A 59-year-old right-handed man developed frontotemporal aphasia after previous resection of right-sided glioblastoma of fronto-insular-temporal region. In a 31-year-old right-handed man, crossed aphasia occurred after extensive hemorrhage from arteriovenous malformation into the right frontotemporoparietal region. A 39-year-old right-handed man developed severe combined aphasia after resection of diffuse glioma of the right insular-temporal region. A 10-year-old right-handed boy developed aphasia with word forgetting after resection of a large tumor of the right temporal lobe. All patients had impaired dynamic praxis. Other cognitive functions were intact.

CONCLUSION

The authors discuss possible combinations of functions in one hemisphere for both right-handers and left-handers and emphasize diverse types of functional asymmetries described in the literature. Different localizations of functions in right-handers and left-handers indicate that local zones with different methods of information processing (successive or simultaneous) can coexist in one hemisphere. Therefore, the functions requiring different processing of information (for example, speech with praxis or spatial functions) can develop in one hemisphere. Cognitive impairment depends not only on the type of functional asymmetry, but also on localization of lesion. Crossed aphasia in right-handers indicates the rarest normal type of functional brain asymmetry with localization of speech functions in the right hemisphere. Possible aphasia in right-handers following damage to homologues of speech zones in the right hemisphere can require additional examination of these patients.

[The prognosis for post-stroke aphasia]

AIM

To determine risk factors and factors of favorable prognosis for regression of post-stroke aphasia in the early recovery period of ischemic stroke (IS).

MATERIAL AND METHODS

A cohort study was undertaken with 40 patients with different clinical forms of aphasia. The duration of study was 3-4 months of the disease. The regression of speech and non-speech cognitive impairment was assessed by the Method of a 10-point evaluation of higher mental functions. The method involves a comprehensive assessment of all mental functions with more than 90 subtests at the beginning and at the end of rehabilitation course and the calculation of the difference in the scoring of each mental function as a measure of treatment efficacy. Using logistic regression and odds ratio estimation, significance of the influence and the prognostic relationship of symptoms related to IS, and a number of biological and social factors (sex, age, and education) were studied.

RESULTS

An independent prognostic value for the aphasia regression on the third month of disease has the severity of neurologic symptomatology (NIHSS score) for the first day of stroke (OR 3,27 95% CI 1,02-9,77) and the third month of the disease (p=0,005, OR 4,6, 95% CI [1,39-15,11]) and the decrease in daily activity assessed by the total score of the Barthel index (p=0,004, OR 3,92, 95% CI [1,01-15,21]). A number of MRI signs (localization of post-stroke changes in the left angular gyrus, frontal-temporal region and focal volume) had a significant effect on the dynamics of non-verbal cognitive impairment. Neuropsychological examination revealed a significant improvement of speech in patients with initially severe forms of aphasias, in particular, sensory and sensorimotor. A direct relationship between age and certain clinical forms of aphasia as well as a significant positive effect of duration (β=1,91, p≤0,01) and level of education (β=1,68, p≤0,007) on aphasia regression were determined.

CONCLUSION

The severity of neurologic symptoms, in particular motor and sensory deficits, both in the acute and in the recovery period of the disease is one of the pathogenetic factors worsening the processes of functional reorganization of neuronal speech networks. The positive dynamics of the recovery of speech function is associated with the initial severity and clinical form of aphasia. The level and duration of education are related to factors positively affecting post-stroke neuroplasticity.