Visual evoked potentials detect cortical processing deficits in Rett syndrome.

Area of Science:

• Neuroscience
• Genetics
• Biomarker Development

Background:

• Rett syndrome (RTT) is a severe neurodevelopmental disorder caused by mutations in the MECP2 gene.
• Characterized by developmental regression, RTT significantly impacts brain function.
• There is a need for objective biomarkers to monitor disease progression and treatment efficacy in RTT.

Purpose of the Study:

• To investigate the utility of visual evoked potentials (VEPs) as an unbiased, quantitative biomarker for assessing brain function in Rett syndrome.
• To correlate VEP parameters with disease stage, clinical severity, and MECP2 mutation type in RTT patients.
• To evaluate VEPs as a tool for monitoring disease progression and treatment response in RTT.

Main Methods:

• Pattern-reversal VEPs were recorded in Mecp2 heterozygous female mice and 34 girls with RTT.
• VEP component amplitudes and latencies were quantified and analyzed in relation to clinical data.
• Visual acuity was assessed in both mice and patients by varying stimulus spatial frequency.

Main Results:

• Mice and RTT patients showed a comparable reduction in VEP amplitude, particularly in later disease stages.
• VEP response recovery time was prolonged in RTT patients and influenced by MECP2 mutation type.
• Both RTT patients and mice exhibited impaired visual spatial acuity, with deficits in discriminating smaller patterns at higher spatial frequencies.

Conclusions:

• Visual evoked potential (VEP) serves as a cross-species method to assess brain function, applicable to children with severe disabilities like RTT.
• Standardized VEP analysis can be implemented in clinical and research settings.
• VEP can probe neurobiological mechanisms of functional impairment and longitudinally monitor RTT progression and treatment response.