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This study investigated sensory processing abnormalities in 32 individuals with Rett syndrome, a rare neurodevelopmental disorder caused by MECP2 gene mutations. Researchers found that both hypo-responsivity and hyper-responsivity to sensory stimuli were elevated and co-occurred in the same individuals, and that reduced inter-trial phase coherence (ITPC) - a measure of neural response consistency - was associated with diminished evoked potentials and increased sensory responsivity. The findings suggest that increased variability in the timing of neural responses may underlie sensory processing difficulties in Rett syndrome.
Why it matters
This research identifies ITPC as a potential functional biomarker for sensory dysfunction in Rett syndrome, which could aid in diagnosis and tracking treatment responses. Understanding that both sensory hypo- and hyper-responsivity stem from temporal inconsistency in neural responses provides a unifying framework that may extend to other neurodevelopmental disorders with similar sensory processing challenges.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Background: Rett syndrome (RTT), a rare neurodevelopmental disorder caused primarily by pathogenic variants in the MECP2 gene, is characterized by severe cognitive, motor, and autonomic impairments. Atypical sensory processing, including co-occurring hypo- and hyper-responsivity, is a core yet poorly understood feature. While evoked potentials (EPs) show delayed and attenuated sensory responses in RTT, the underlying mechanisms of these impairments remain unclear. Inter-trial phase coherence (ITPC), which quantifies trial-by-trial neural response consistency, offers a promising functional biomarker of variability in sensory processing. Methods: We characterized caregiver-reported sensory responsivity in 32 individuals with RTT (all female) and 28 typically developing controls (26 female, 2 male). EPs were then recorded during passive visual and auditory stimulation and ITPC was computed to assess whether variability in the timing of neural responses could account for reduced EP amplitudes and atypical sensory responsivity. Results: Hypo- and hyper-responsivity to sensory stimuli were both significantly elevated in RTT and were positively correlated, co-occurring within individuals. ITPC was significantly reduced in RTT across visual and auditory modalities and was associated with reduced EP amplitudes. Notably, reduced ITPC in visual-evoked potentials was further associated with elevated visual responsivity and greater behavioral symptom severity. Conclusions: Increased variability in neural response timing may contribute to both reduced EPs and atypical sensory responsivity in RTT, supporting ITPC as a functional biomarker. Decreased temporal precision of neural activity may explain the co-occurrence of hypo- and hyper-responsivity and provide a unifying framework for sensory dysfunction across neurodevelopmental disorders.
Source: Variability in sensory processing and evoked potentials in Rett syndrome