Sensory Processing Disorder (SPD) is a neurological condition where the brain struggles to organize the vast amount of information it receives from the senses, leading to difficulties in responding appropriately to the environment. This challenge is not a behavioral problem but a difference in how the nervous system processes sensory input from the world and the body. The resulting difficulty in regulating and interpreting sensations can significantly impact a person’s daily life, affecting learning, social interactions, and emotional regulation. SPD affects between 5% and 16% of children in the United States. The disorder is categorized into three main patterns, which describe how the sensory system struggles to manage incoming information.
Sensory Modulation Patterns
Sensory Modulation Disorder involves challenges with regulating the intensity and nature of sensory messages, leading to responses that are either too much or too little for the stimulus received. This pattern breaks down into three distinct subtypes, each reflecting a different way the brain handles the flow of sensory input.
Sensory Over-Responsiveness (SOR) is characterized by an intense, often “fight or flight” reaction to ordinary stimuli. A person with SOR may find common sounds painfully loud, react strongly to a light touch, or be overwhelmed by bright lights or certain fabric textures. The brain perceives these sensations as a threat, which can lead to distress, avoidance, or emotional meltdowns.
In contrast, Sensory Under-Responsiveness (SUR) is when an individual appears lethargic, passive, or fails to notice stimuli. They may not register pain or temperature extremes, seem unaware of their surroundings, or be slow to respond when their name is called. Since sensory messages are not adequately registered, the person often seems sluggish or oblivious.
The third subtype, Sensory Seeking or Craving, involves constantly searching for intense sensory input to satisfy a nervous system that needs more stimulation. This person might crash into objects, touch everything, move excessively, or make loud noises. While they actively seek stimulation, they often become disorganized once they receive it, leading to a continuous, unsatisfied desire for more input.
Sensory Discrimination Patterns
Sensory Discrimination Disorder (SDD) focuses on the brain’s ability to interpret and define the subtle qualities of a sensation, addressing the “what” and “where” of the input rather than its intensity. Here, the person registers the input, but their brain struggles to process the fine details necessary to make sense of the sensation. This difficulty can occur across any of the sensory systems, including touch, hearing, vision, and body awareness.
For example, a person with tactile discrimination challenges may be unable to identify an object in their pocket, like a coin, by touch alone, requiring them to use vision instead. Auditory discrimination difficulties can make it hard to distinguish between similar-sounding words, such as “cap” and “pack,” or to locate the source of a sound in a noisy room. Similarly, poor proprioceptive discrimination, which relates to body awareness, can lead to difficulty knowing how much force to use, such as how hard to push a pencil or how tightly to squeeze a hug.
This pattern is distinct from modulation because the problem lies in the brain’s analytical processing, not the initial reaction or regulation of the input. The inability to accurately process sensory details can impact everyday skills, such as reading, following complex instructions, or performing fine motor tasks that rely on precise sensory feedback.
Sensory-Based Motor Patterns
Sensory-Based Motor Disorder (SBMD) occurs when poor sensory processing directly impairs motor skills and coordination. The difficulty stems from the brain’s inefficient use of sensory information, particularly input from the vestibular system (balance and movement) and the proprioceptive system (body position and muscle sense). This inefficiency prevents the brain from planning and executing movements. This pattern includes two specific subtypes.
Postural Disorder involves difficulty maintaining stability, balance, and endurance, resulting from poor control over the body’s position against gravity. Individuals often have low muscle tone and may appear weak or tire quickly, frequently slumping in their chair or leaning against furniture. The body struggles to automatically coordinate the muscles needed for core stability, making simple tasks like sitting upright or standing still a conscious, fatiguing effort.
The second subtype is Dyspraxia, also known as Developmental Coordination Disorder, which involves significant difficulty with motor planning, or praxis. Praxis is the process of generating an idea for a novel movement, planning the sequence of actions, and then executing that plan. People with dyspraxia may appear clumsy, struggle to learn new physical skills like riding a bike or tying shoes, and have trouble with tasks that require sequencing movements. Their motor output is often awkward because the brain is not effectively organizing the necessary sensory input to guide the action.
Identifying Need and Seeking Support
Recognizing the signs of Sensory Processing Disorder is the first step toward finding appropriate help when challenges interfere with daily life. If a person exhibits persistent difficulties in regulating, discriminating, or using sensory information for movement, a thorough evaluation is warranted. These evaluations are typically conducted by an Occupational Therapist (OT) who specializes in sensory integration.
The OT will use a combination of standardized testing, clinical observations, and detailed reports from parents or the individual to determine the specific patterns of sensory processing that are affected. While other professionals may screen for sensory issues, the occupational therapist provides the detailed assessment necessary for a diagnosis. The primary intervention is Occupational Therapy utilizing a Sensory Integration approach, which involves engaging the person in play-based activities that challenge the nervous system in a controlled, therapeutic environment.