Sensory Integration, Sensory Processing, and Sensory Modulation Disorders: Putative Functional Neuroanatomic Underpinnings

This paper examines conditions that have variously been called sensory integration disorder, sensory processing disorder, and sensory modulation disorder (SID/SPD/SMD). As these conditions lack readily and consistently agreed-upon operational definitions, there has been confusion as to how these disorders are conceptualized. Rather than addressing various diagnostic controversies, we will instead focus upon explaining the symptoms that are believed to characterize these disorders. First, to clarify the overall context within which to view symptoms, we summarize a paradigm of adaptation characterized by continuous sensorimotor interaction with the environment. Next, we review a dual-tiered, integrated model of brain function in order to establish neuroanatomic underpinnings with which to conceptualize the symptom presentations. Generally accepted functions of the neocortex, basal ganglia, and cerebellum are described to illustrate how interactions between these brain regions generate both adaptive and pathological symptoms and behaviors. We then examine the symptoms of SID/SPD/SMD within this interactive model and in relation to their impact upon the development of inhibitory control, working memory, academic skill development, and behavioral automation. We present likely etiologies for these symptoms, not only as they drive neurodevelopmental pathologies but also as they can be understood as variations in the development of neural networks.