Neural biomarkers for dyslexia, ADHD and ADD in the auditory cortex of children

• Main Authors: Bettina Serrallach, Christine Gross, Valdis Bernhofs, Dorte Engelmann, Jan Benner, Nadine Gündert, Maria Blatow, Martina Wengenroth, Angelika Seitz, Monika Brunner, Stefan Seither, Richard Parncutt, Peter Schneider, Annemarie Seither-Preisler
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2016-07-01
• Series: Frontiers in Neuroscience
• Subjects: Auditory Cortex; Magnetic Resonance Imaging; synchronization; developmental disorders; auditory evoked fields; Hemispheric asymmetries
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fnins.2016.00324/full

Dyslexia, attention deficit hyperactivity disorder (ADHD), and attention deficit disorder (ADD) show distinct clinical profiles that may include auditory and language-related impairments. Currently, an objective brain-based diagnosis of these developmental disorders is still unavailable. We investigated the neuro-auditory systems of dyslexic, ADHD, ADD, and age-matched control children (N=147) using neuroimaging, magnet-encephalography and psychoacoustics. All disorder subgroups exhibited an oversized left planum temporale and an abnormal interhemispheric asynchrony (10-40 ms) of the primary auditory evoked P1-response. Considering right auditory cortex morphology, bilateral P1 source waveform shapes, and auditory performance, the three disorder subgroups could be reliably differentiated with outstanding accuracies of 89-98%. We therefore for the first time provide differential biomarkers for a brain-based diagnosis of dyslexia, ADHD, and ADD. The method allowed not only a clear discrimination between two subtypes of attentional disorders (ADHD and ADD), a topic controversially discussed for decades in the scientific community, but also revealed the potential for objectively identifying comorbid cases. Noteworthy, in children playing a musical instrument, after three and a half years of training the observed interhemispheric asynchronies were reduced by about 2/3, thus suggesting a strong beneficial influence of music experience on brain development. These findings might have far-reaching implications for both research and practice and enable a profound understanding of the brain-related etiology, diagnosis, and musically based therapy of common auditory-related developmental disorders and learning disabilities.