Dysfunctional auditory gamma oscillations in developmental dyslexia: A potential target for a tACS-based intervention

Area of Science:

• Neuroscience
• Developmental Psychology
• Speech and Hearing Science

Background:

• Developmental dyslexia interventions often focus on orthography-based training with limited efficacy.
• The core deficit and neurobiological underpinnings of dyslexia remain debated, with evidence for phonological and auditory temporal processing deficits.
• Cortical gamma oscillations in the auditory cortex are crucial for extracting linguistic information from acoustic signals.

Purpose of the Study:

• To investigate the relationship between auditory gamma oscillations, phonological awareness, and literacy skills in dyslexia.
• To explore the potential of gamma oscillations as a core deficit and therapeutic target in dyslexia.

Main Methods:

• Electroencephalography (EEG) was used to measure individual gamma frequencies in children and adolescents with dyslexia and a control group.
• Phonological awareness was assessed in both groups.
• Reading and writing performance were measured in dyslexic participants.

Main Results:

• Dyslexic participants showed significantly lower gamma peak frequencies compared to controls.
• Lower phonological awareness scores were observed in dyslexic participants.
• A positive correlation was found between individual gamma frequency and phonological awareness.

Conclusions:

• Altered gamma oscillations may represent a core deficit in dyslexia, impacting phonological awareness and literacy skills.
• Gamma oscillations present a potential target for future causal interventions in dyslexia.
• Transcranial alternating current stimulation is proposed as a promising technique to normalize dysfunctional oscillations in dyslexia.