Sensory processing disorder (SPD)
Sensory Processing Disorder (SPD) is a neurological condition characterized by the brain's difficulty in properly processing sensory information, leading to atypical responses to sensory stimuli. Initially described in the 1970s, SPD has gained recognition as a distinct disorder rather than merely a symptom of other conditions, although its legitimacy remains debated among healthcare professionals. Individuals with SPD may experience a range of challenges, including oversensitivity, undersensitivity, or misinterpretation of sensory input, affecting one or multiple senses. Common manifestations include extreme reactions to sounds, textures, or movements, such as distress caused by certain noises or discomfort from clothing.
Research has suggested potential genetic factors and prenatal influences contributing to SPD, along with structural brain differences identified in affected children. Early diagnosis and intervention are crucial, as untreated SPD can lead to emotional difficulties, such as anxiety and low self-esteem, in adulthood. Effective management often involves creating a supportive sensory environment at home and in educational settings, emphasizing understanding and appropriate responses from caregivers and teachers. Support networks and resources are available for individuals with SPD, aiding their integration into personal and professional contexts.
Sensory processing disorder (SPD)
Sensory processing disorder (SPD) is a blanket term referring to a range of neurological disorders in which the brain is unable to properly process incoming sensory data, resulting in abnormal or inappropriate responses. Although SPD was first described in detail in the 1970s by psychologist Anna Jean Ayres, who, at the time, called it "sensory integration dysfunction," it only started to be accepted as a disorder in its own right rather than a symptom of other conditions, such as attention deficit hyperactivity disorder (ADHD) or autism, in the twenty-first century. The legitimacy of SPD as a diagnosis remained debated by the wider medical community. While this lack of recognition has made funding for research into SPD difficult to obtain, researchers have discovered evidence of a neurological basis for the disorder.
Background
An individual’s central nervous system is constantly receiving a flood of information provided by the senses—not just sight, sound, touch, smell, and taste, but also proprioception (the awareness of one’s muscle and joint position and movements), the vestibular sense (sense of balance and movement), and interoception (awareness of one’s internal physiological responses, such as hunger, thirst, and heart rate). A properly functioning nervous system will automatically categorize, organize, and integrate this information to provide a clear, comprehensive picture of one’s self and one’s surroundings. The brain works effectively and efficiently to process incoming data and provide a response.
In an individual with sensory processing difficulties, however, critical elements of the brain’s network of responses are blocked or ignored or misfire into unintentional processes that respond to other sorts of stimuli. Such individuals—who are usually, but not always, children—will exhibit abnormal responses to sensory stimuli, such as hearing a garbage truck outside and howling uncontrollably at the sound, vomiting when a shirt is pulled over their head, or touching a hot stove and not reacting until they are severely burned.
While SPD can be broadly described as an inability to properly process sensory input, as research into ADHD has revealed, the nature and extent of that inability can differ radically from one individual to another. Some individuals may be affected only in one sense, while others may have difficulty with multiple senses. In addition, SPD can manifest as either an oversensitivity or an undersensitivity to sensation, or even as an inability to correctly interpret sensation. While each case is different, SPD is broadly classified into three main categories: (1) sensory modulation disorder, a distortion in the degree to which a sensation is experienced, which encompasses sensory overresponsivity, sensory underresponsivity, and sensory craving; (2) sensory-based motor disorder, which involves difficulties with proprioception and the vestibular sense and encompasses dyspraxia and postural disorder; and (3) sensory discrimination disorder, in which sensation is incorrectly processed, resulting in an inability to identify or distinguish certain characteristics of stimuli, such as color, smell, or the experience of falling.
Sensory Processing Disorder Today
The causes of SPD remained unknown, but many researchers have believed it is most likely genetic, although some believe the condition may be tied to a variety of prenatal events. A 2013 study published by researchers at the University of California, San Francisco, revealed that children who have been diagnosed with SPD, but not with ADHD or autism spectrum disorders, show structural abnormalities in the white matter of their brains that are not present in those without SPD. While children with ADHD or autism spectrum disorders have similar white-matter abnormalities, those abnormalities tend to be in the front of the brain, while the ones observed in SPD cases are primarily in the back of the brain. The study was the first to find biological evidence that SPD is a distinct neurological disorder. By the 2020s, additional studies explored potential ties between environmental influences, particularly exposure to television and videos from a very young age, and development of atypical sensory processing.
If undiagnosed and hence untreated in childhood, SPD can prove emotionally debilitating for adults, many of whom struggle with poor self-esteem, anxiety over social interactions, depression, and an inability to respond to downtime. Because of this, researchers have worked to outline the condition and to begin to test protocols for treatment. Most agree that the most effective treatment is a modified approach to early education that would impact both home and school. Once a child is diagnosed with SPD, parents can provide a sensory-appropriate environment at home by modifying sounds, improving lighting schemes, or making other adjustments as applicable. Parents are encouraged to observe the child and note what situations create obvious hesitancy or inappropriate responses, to find patterns of response, and, of course, not to discipline the child for what may seem at first to be belligerency or intransigence. At school, teachers should be made aware of the condition so that they will not direct inappropriate punishment to the child. Researchers agree that there remained a lack of data indicating that SPD is of such severity that a child would need to be placed within a special education environment; with patience and understanding, the child can come to work effectively and cooperatively within a classroom. Counseling groups and websites, as well as research foundations, are dedicated to providing a support system for adults affected by SDP to help them adjust to personal and professional spheres.
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