Hemispheric language organization after congenital left brain lesions: A comparison between functional transcranial Doppler and functional MRI

Abstract

This study investigated whether functional transcranial Doppler ultrasound (fTCD) is a suitable tool for studying hemispheric lateralization of language in patients with pre-perinatal left hemisphere (LH) lesions and right hemiparesis. Eighteen left-hemisphere-damaged children and young adults and 18 healthy controls were assessed by fTCD and fMRI to evaluate hemispheric activation during two language tasks: a fTCD animation description task and a fMRI covert rhyme generation task. Lateralization indices (LIs), measured by the two methods, differed significantly between the two groups, for a clear LH dominance in healthy participants and a prevalent activation of right hemisphere in more than 80% of brain-damaged patients. Distribution of participants in terms of left, right, and bilateral lateralization was highly concordant between fTCD and fMRI values. Moreover, right hemisphere language dominance in patients with left hemispheric lesions was significantly associated with severity of cortical and subcortical damage in LH. This study suggests that fTCD is an easily applicable tool that might be a valid alternative to fMRI for large-scale studies of patients with congenital brain lesions.

Task‐related fMRI in hemiplegic cerebral palsy—A systematic review

“…Reorganization of the language was studied in 130 UCP patients of 12 studies, almost all of them (128 cases) being left‐handed with right‐sided hemiparesis due to left hemispheric lesions (Table ) …”

“…The site and extent of a left hemispheric lesion determine the capacity for speech production reorganization. Right hemispheric language dominance is associated with severe damage of the cortical and subcortical structures (but not with white matter damage) in the left hemisphere . Staudt et al (2008) show that the degree of right hemispheric takeover of language production also depends on the degree of left hemispheric facial motor tract injury, explained by its role in speech articulation .…”

“…(Table 3). [27][28][29][30][31][32][33][34][35][36][37][38] The observed variants of fMRI activation during speech production were:…”

“…Right hemispheric language dominance is associated with severe damage of the cortical and subcortical structures (but not with white matter damage) in the left hemisphere. 38 Staudt et al (2008) show that the degree of right hemispheric takeover of language production also depends on the degree of left hemispheric facial motor tract injury, explained by its role in speech articulation. 33 Guzetta et al (2008) found that proximity of the lesion to the anterior language regions seems to evoke right hemispheric lateralization.…”

“…Continued) : uniPVL, unilateral periventricular leukomalacia; MCA, middle cerebral artery; LI, laterality index; IQ, intelligence quotient; PVL, periventricular leukomalacia; LH, left hemisphere; RH, right hemisphere; TMS, transcranial magnet stimulation; L-left, R-right; CSC, cortico-subcortical; CDGM-cortical and deep grey matter; PWM-periventricular white matter.primary regions in the dominant hemisphere become unavailable to exert inhibition 34,[36][37][38]. Guzzetta et al show substantial equipotentiality of the 2 hemispheres as to language function at term age 32.…”