# Neurobiological Convergence in SPDs and ADHD: Insights from a Narrative Review

## TL;DR

This review explores how sensory processing disorders and ADHD share similar brain patterns, aiming to improve diagnosis and treatment for sensory and attention issues.

## Contribution

The paper synthesizes neuroimaging and physiological evidence to clarify the neurobiological overlap and differences between SPDs and ADHD.

## Key findings

- SPDs and ADHD share sensory processing challenges and overlapping neural patterns.
- Current diagnostic boundaries between SPDs and ADHD remain unclear due to similar behavioral manifestations.
- Targeted interventions could benefit from a better understanding of shared and distinct neurobiological mechanisms.

## Abstract

People of all ages may experience differences in how they perceive and respond to sensory inputs such as sound, touch, movement, or other stimuli from their body and environment. These variations can be part of a sensory processing disorder (SPD), but they also occur in other neurodevelopmental or mental health conditions. Sensory challenges can affect emotional regulation, attention, learning, and social interaction. Although ADHD has distinct clinical features, many individuals with ADHD also show sensory difficulties, which can resemble those seen in SPD. This review examines how the brain processes sensory information in both conditions, drawing on evidence from neuroimaging and physiological studies. By comparing shared and distinct neural patterns, we aim to refine diagnostic understanding and support more targeted interventions for individuals facing sensory and attentional challenges in daily life.

The sensory system plays a critical role in development, as it enables the processing and integration of internal and external stimuli. Dysfunctions in this system lead to sensory processing disorders (SPDs), which affect approximately 5–13% of children aged 4–6 years, impacting not only sensory responsiveness but also social interaction, emotional regulation, motor coordination, learning, attention, communication, and sleep. Although SPDs have been extensively investigated from molecular to behavioral levels, their underlying neurobiological mechanisms remain debated, and reliable biomarkers are still lacking. Moreover, due to overlapping behavioral manifestations, SPDs are frequently misdiagnosed as attention deficit hyperactivity disorder (ADHD), leading to challenges in accurate diagnosis and treatment planning. This narrative review aims to synthesize current evidence on the neurofunctional and molecular underpinnings of SPDs in relation to ADHD, providing an integrated perspective on their converging and diverging pathways. By comparing neuroimaging and neurophysiological findings across the two conditions, we seek to deepen understanding of their shared mechanisms, clarify diagnostic boundaries, and inform the development of targeted, evidence-based interventions to address a critical gap in the field.