Developmental conduction aphasia after neonatal stroke

Abstract

Objective: Impairment of speech repetition following injury to the dorsal language stream is a feature of conduction aphasia, a well-described "disconnection syndrome" in adults. The impact of similar lesions sustained in infancy has not been established. Methods: We compared language outcomes in term-born individuals with confirmed neonatal stroke (n 5 30, age 5 7-18 years, left-sided lesions in 21 cases) to matched controls (n 5 40). Injury to the dorsal and/or ventral language streams was assessed using T 1 -and T 2 -weighted magnetic resonance imaging (MRI) and diffusion tractography. Language lateralization was determined using functional MRI. Results: At the group level, left dorsal language stream injury was associated with selective speech repetition impairment for nonwords (p 5 0.021) and sentences (p < 0.0001). The majority of children with significant repetition impairment had retained left hemisphere language representation, but right hemisphere dominance was correlated with minimal or absent repetition deficits. Post hoc analysis of the repetition-impaired group revealed additional language-associated deficits, but these were more subtle and variable. Interpretation: We conclude that (1) despite the considerable plasticity of the infant brain, early dorsal language stream injury can result in specific and long-lasting problems with speech repetition that are similar to the syndrome of conduction aphasia seen in adults; and (2) language reorganization to the contralateral hemisphere has a protective effect.

Cortical Reorganization after Rehabilitation in a Patient with Conduction Aphasia Using High-Density EEG

“…These results confirmed that language expression is associated with multiple brain areas [12]. To date, literature studies investigated the neural reorganizations in patients with conduction aphasia in terms of diagnosis and neuroimaging evidence [13][14][15][16]. Few studies provided evidence in terms of brain plasticity after an intensive rehabilitative process in patients with conduction aphasia, in fact it was demonstrated that early aphasia rehabilitation is associated with a more recruitment of brain areas, particularly the left inferior frontal gyrus [17].…”

Contributions of nonhuman primate research to understanding the consequences of human brain injury during development

“…Early theories of the ontogeny underpinning brain organization have swayed between the extremes of early specialization (8,9) and equipotentiality/age-dependent plasticity (10), with both positions surviving the test of time with help from the application of neuroimaging techniques (e.g., refs. [11][12][13]. Recognizing the undeniable fact that in the absence of early brain damage the vast majority of adult individuals exhibit hemispheric specialization, most notably for speech and language, and cognizant of the need for compatibility between neuronal plasticity and early hemispheric equipotentiality, a number of researchers have argued for a middle ground between the 2 extremes 14, with the view that "constrained plasticity" (15), or "ontogenetic specialization" (16) progressively unfolds during brain maturation.…”

Pharmacotherapy of Traumatic Childhood Aphasia: Beneficial Effects of Donepezil Alone and Combined With Intensive Naming Therapy

“…For instance, studies of children with brain injury have shown that early damage to the AF may be succesfully compensated through recruitment of ipsilateral and contralateral brain areas and tracts, resulting in an average performance on multiple language tasks (Rauschecker et al, 2009;Asaridou et al, 2020), although some deficits may persist (Yeatman and Feldman, 2013). In this line, after early brain damage, functional and structural rightward lateralization of the dorsal pathway is associated with better language outcomes (Northam et al, 2018;Francois et al, 2019). Despite this evidence, spontaneous readjustment of the language system after brain lesion seems to be limited as evidenced by the frequent persistence of language deficits (Tavano et al, 2009;Turkstra et al, 2015;Francois et al, 2016).…”