Maturation of Auditory Processing in Children With Dyslexia Compared to Average-reading Children

Hospices Civils de Lyon161 enrolled

Overview

The hypothesis of central auditory processing disorders has been advanced to explain the anomalies of the grapheme/phoneme combination in some dyslexia. These phonological disorders may be linked to abnormalities of the efferent (medial olivocochlear) system modulation and of cortical asymmetry. Indeed, the efferent system has an asymmetry in relation to handedness. Thus, in right-handed subject, it is predominant on the right side. In contrast, in the subject-handed dyslexic, the efferent system tends to be right-lateralized or non-lateralized. However, after an audio-visual training, normal lateralization can appear. This maturation of the efferent system lateralization during reading acquisition seems to have a particular profile in dyslexics with phonological disorder, especially if it is persistent. This finding allows to consider new prognostic evaluation and speech therapy rehabilitation in the dyslexic child.

Study Type

OBSERVATIONAL

Enrollment

161

Conditions

Dyslexia

Interventions

no interventionOTHER

Eligibility

Medical Language ↔ Plain English

Common inclusion criteria * Native French speaker and french education * No medical treatment for behavior or neurological disorders (as epilepsy) * Normal or corrected vision * Right-handed children (Edinburgh tets (Oldfield, 1971): \>+50%) * Normal ORL examination * No hearing loss : hearing thresholds not above 15 dB between 250 and 4 000 Hz * Presence of Otoacoustic Emissions (Total amplitude \< 5 dB or SNR \> 3dB for at least 3 frequency bands between 1 and 4 kHz) * Normal level of intellectual development * Regular school attendance For the normal reading children * Aged from 6 to less than 11 * Normal reading level For the dyslexic children * Aged from 8 to less than 11 * Diagnostic of dyslexia made by a complet check-up during the 6 last months before the inclusion Exclusion Criteria * Neurological or psychiatric disease incompatible with the testing procedure * Ear disease during more than 6 months * Normal reading children who have repeat a year * Previous speech therapy for normal reading children * Not corrected visual acuteness * Schooling in a foreign language * Foreign language spoken at home with both parents * Known hearing deficit * Invalid social security

Locations (3)

Centre Hospitzlier Le Vinatier

Bron, France

Service ORL CHU Montpied

Clermont-Ferrand, France

Service d'Audiologie et Explorations Orofaciales Centre de Référence des Troubles des Apprentissages

Lyon, France

Outcomes

Primary Outcomes

Change of The Asymmetry Index of the efferent system at 2 years interval

The change of the Asymmetry Index of the efferent system The Asymmetry Index is the difference between the equivalent attenuation measured on the right ear and the left ear. Evoked otoacoustic emissions were recorded monaurally at five stimulus intensities ranging from 57 to 69 dB SPL in 3 dB steps, in random presentation order, with and without contralateral acoustic stimulation consisting of 30 dBSPL continuous broadband noise (speech-like noise) produced by an audiometer

Time frame: Day 1 and then at least 2 years (± 4 weeks)

Secondary Outcomes

Change in the level of reading skill

Behavioral measure

Time frame: Day 1 and then at least 2 years (± 4 weeks)

Change in the percentage of correct answers obtained during a speech perception test in silence and noise.

Oral repetition of VCV

Time frame: Day 1 and then at least 2 years (± 4 weeks)

Change in percentage of correctly repeated stimuli which have been heard in both ears (binaural integration with divided attention) or in one indicated ear (binaural separation with selective attention)

Presentation of different speech material to both ears simultaneously

Time frame: Day 1 and then at least 2 years (± 4 weeks)