Left hemisphere enhancement of auditory activation in language impaired children

Abstract

Specific language impairment (SLI) is a developmental disorder linked to deficient auditory processing. In this magnetoencephalography (MEG) study we investigated a specific prolonged auditory response (N250m) that has been reported predominantly in children and is associated with level of language skills. We recorded auditory responses evoked by sine-wave tones presented alternately to the right and left ear of 9–10-year-old children with SLI (n = 10) and children with typical language development (n = 10). Source analysis was used to isolate the N250m response in the left and right hemisphere. In children with language impairment left-hemisphere N250m responses were enhanced compared to those of controls, while no group difference was found in the right hemisphere. Consequently, language impaired children lacked the typical right-ward asymmetry that was found in control children. Furthermore, left but not right hemisphere N250m responses correlated positively with performance on a phonological processing task in the SLI group exclusively, possibly signifying a compensatory mechanism for delayed maturation of language processing. These results suggest that enhanced left-hemisphere auditory activation reflects a core neurophysiological manifestation of developmental language disorders, and emphasize the relevance of this developmentally specific activation pattern for competent language development.

Auditory deficits in infants at risk for dyslexia during a linguistic sensitive period predict future language

“…At-risk infants did not show a pattern of increased neural efficiency over time, but instead a shift to atypical larger and longer activations to simple sounds in the auditory cortex. This was especially pronounced in the left hemisphere – a result that agrees with prior research in children with SLI showing atypical larger and longer-lasting auditory evoked responses only in the left hemisphere ( van Bijnen et al, 2019 ). Also, auditory processing in at-risk infants was compromised early in time (starting at 100 ms after stimulus onset, Fig.…”

“…Furthermore, whereas prior research linked left temporal deficits primarily to phonological processing problems ( Hoeft et al, 2007 , Temple et al, 2003 ), our findings suggest that risk for dyslexia involves a general impairment of this region for processing acoustic stimuli unrelated to language. This is supported by studies in TD and SLI children showing a link between less efficient neural sound processing and poorer reading speed ( Parviainen et al, 2011 , van Bijnen et al, 2019 ). Worth noting is that we observed over activation in 12-month-old at-risk infants in contrast to prior findings of under activation in this region in children and adults with dyslexia.…”

“…In contrast, we expected that at-risk infants would start out with deficiencies in auditory processing and demonstrate continued aberrant neural efficiency by the end of the first year indicated by delayed and/or larger neural responses to white noise compared to the TD infant group. We further expected to find more pronounced deficiencies in the left hemisphere based on prior MEG research in children with specific language impairment SLI (suggested to share some genetic etiology with dyslexia) that reported atypical larger and longer-lasting auditory evoked responses only in left hemisphere ( van Bijnen et al, 2019 ).…”

Child specific activation in left auditory cortex predicts behavioral performance in inhibition tasks

“…Indeed, children show an auditory evoked response (i.e. N250m) that is reported even by passive stimulation, using different sound types, and under different attentional conditions (van Bijnen et al, 2019; Parviainen et al, 2019; Albrecht et al, 2000; Takeshita et al, 2002; Johnstone et al, 1996). This response is typically absent in adults.…”

Magnetic Source Imaging and Infant MEG: Current Trends and Technical Advances

“…With the increasing popularity of MEG, there have been a series of comprehensive scientific review papers [6,7,8,9,10,11] and textbooks/edited volumes [12,13,14,15,16,17,18] to introduce MEG to the scientific community, the medical field, and the wider audience in general. There have also been summary reports of MEG studies on special populations with various clinical conditions such as autism [19,20,21], epilepsy [22,23], schizophrenia [24,25,26], language impairment [27], dementia [28], dystonia [29,30], major depression disorder [31], obsessive-compulsive disorder [32], fibromyalgia syndrome [33], and other neurological and psychiatric disorders [8,34]. A guideline by Schwartz et al [35] on pediatric MEG studies provides a detailed overview and some successful examples, reassuring the feasibility of using MEG to explore cognitive development in both typical and clinical populations.…”