Atypical conduction aphasia and the right hemisphere: Cross-hemispheric plasticity of phonology in a developmentally dyslexic and dysgraphic patient with early left frontal damage

Abstract

We report the rare case of a patient, JNR, with history of mixed handedness, developmental dyslexia, dysgraphia, and attentional deficits associated with a Klippel-Trenaunay syndrome and a small subcortical frontal lesion involving the left arcuate fasciculus. In adulthood, he suffered a large right perisylvian stroke and developed atypical conduction aphasia with deficits in input and output phonological processing and poor auditory-verbal short-term memory. Lexical-semantic processing for single words was intact, but he was unable to access meaning in sentence comprehension and repetition. Reading and writing deficits worsened after the stroke and he presented a combination of developmental and acquired dysgraphia and dyslexia with mixed lexical and phonological processing deficits. This case suggest that a small lesion sustained prenatally or early in life could induce a selective rightward shift of phonology sparing the standard left hemisphere lateralisation of lexical-semantic functions.

Repeating with the right hemisphere: reduced interactions between phonological and lexical-semantic systems in crossed aphasia?

“…We also examined for the first time the role of right white matter pathways involvement in repetition processes in crossed aphasia. Our results replicate findings from previous similar cases (Berndt et al, 1991; Berthier et al, 2011) showing that repetition deficits have atypical features in more demanding tasks (sentence repetition) reflecting limited reliance on lexical-semantic processing as has been reported in typical CA associated to left hemisphere damage. Further, our neuroimaging findings suggest that subcortical lesions in the right hemisphere lesioning perisylvian and commissural pathways may account for the observed language deficits by altering the interaction between right and left hemispheres.…”

“…Evaluation in patient JNR replicated the results obtained in EDE (except for abnormal phonological input processing), but patient ORL had repetition deficits similar to the ones described in cases with CA and left hemisphere involvement (see further details in Berthier et al, 2011; McCarthy and Warrington, 1984). In light of the limited data available and mixed results on the pattern of repetition in patients with crossed CA, analysis of further cases is clearly needed.…”

“…Interestingly, the association of CA with an atypical location is more commonly encountered with right hemisphere lesions (35%) than after left hemisphere involvement (13%) (Basso et al, 1985; Alexander et al, 1989a; Dewarrat et al, 2009). Despite the relatively frequent occurrence of CA in cases of both “mirror image” (Henderson, 1983; Bartha et al, 2004) and “anomalous” crossed aphasia (Alexander et al, 1989a) comprehensive analyses of its main deficits (repetition, short-term memory, sentence comprehension) have been described in only three cases (patient ORL, McCarthy and Warrington, 1984; patient EDE, Berndt et al, 1991; and patient JNR, Berthier et al, 2011). Below, a brief summary of the main findings from patient EDE are described.…”

The modern approaches to the prognostication of rehabilitation of the patients after stroke on an individual basis: a review of the literature and the results of original investigations

“…Некоторые ав-торы предлагают классификацию когнитивных на-рушений, основанную только на результатах реги-страции электроэнцефалограммы и ВП, а именно на оценке амплитуды и латентности компонентов ВП и расчете индекса тета-ритма [13][14][15][16][17][18][19][20][21].…”

Analysis of the cerebral mechanisms underlying rehabilitation of the patients after stroke

“…Авторы предположили, что нару-шения в когнитивной и двигательной сферах могут быть обусловлены снижением скорости кодирова-ния информации для хранения в памяти (что кли-нически проявляется снижением объема оператив-ной памяти) или связаны с «повреждением» на эта-пе принятия решения, когда новый стимул сравни-вается с уже известным из прежнего опыта. Подоб-ные изменения могут лежать в основе нарушения выработки двигательных навыков при реабилита-ции больных с инсультом правополушарной лока-лизации, нарушающим функциональные связи пре-фронтальной коры [2,24,27].…”