Sensory processing disorder (SPD also known as sensory integration dysfunction) is a condition where multisensory integration is not adequately processed in order to provide appropriate responses to the demands of the environment.
Sensory Processing Disorder or SPD (originally called Sensory Integration Dysfunction) is a neurological disorder in which the sensory information that the individual perceives results in abnormal responses.
Sensory integration was defined as “the neurological process that organizes sensation from one’s own body and from the environment and makes it possible to use the body effectively within the environment”. Sensory processing disorder has been characterized as the source of significant problems in organizing sensation coming from the body and the environment and is manifested by difficulties in the performance in one or more of the main areas of life: productivity, leisure and play or activities of daily living.
Sources debate whether SPD is an independent disorder or represents the observed symptoms of various other, more well-established, disorders. SPD is not recognized by the Diagnostic and Statistical Manual of the American Psychiatric Association and the American Academy of Pediatrics has recommended that pediatricians not use SPD as a diagnosis.
Signs and symptoms
Symptoms may vary according to the disorder’s type and subtype present. SPD can affect one sense or multiple senses. While many people can present one or two symptoms, sensory processing disorder has to have a clear functional impact on the person’s life:
Signs of over-responsivity, including, for example, dislike of textures such as those found in fabrics, foods, grooming products or other materials found in daily living, to which most people would not react, and serious discomfort, sickness or threat induced by normal sounds, lights, movements, smells, tastes, or even inner sensations such as heartbeat.
Signs of under-responsivity, including sluggishness and lack of responsiveness; and Sensory cravings, including, for example, fidgeting, impulsiveness, and/or seeking or making loud, disturbing noises; Sensorimotor-based problems, including slow and uncoordinated movements or poor handwriting.
Sensory discrimination problems, that might manifest themselves in behaviors such as things constantly dropped.
Critics have noted that what proponents claim are symptoms of SPD are both broad and, in some cases, represent very common, and not necessarily abnormal or atypical, childhood characteristics. The checklist of symptoms on the website of the SPD Foundation, for example, includes such warning signs as “My infant/toddler has problems eating,” “My child has difficulty being toilet trained,” “My child is in constant motion,” and “My child gets in everyone else’s space and/or touches everything around him.” — “symptoms” which read much like the day-to-day complaints of an average parent.
Sensory processing issues represent a feature of a number of disorders, including anxiety problems, ADHD, food intolerances, behavioral disorders, and particularly, autism spectrum disorders. This pattern of comorbidities poses a significant challenge to those who claim that SPD is an identifiable specific disorder, rather than simply a term given to a set of symptoms common to other disorders.] Dr. Catherine Lord, a leading autism expert and the director of the Center for Autism and the Developing Brain at New York-Presbyterian Hospital, argues that sensory issues are an important concern, but not a diagnosis in themselves. “I do think there’s a value in attending to how a child is perceiving sensations, thinking about whether he could be uncomfortable. Where I get concerned is labeling that as a separate disorder.”
Two studies have provided preliminary evidence suggesting that there may be measurable neurological differences between children diagnosed with SPD and control children classified as neurotypical or children diagnosed with autism. Despite this evidence, the fact that SPD researchers have yet to agree on a proven, standardized diagnostic tool undermines researchers’ ability to define the boundaries of the disease and makes correlational studies, like the ones about structural brain abnormalities, less convincing.
Sensory processing disorder may affect one sense, like hearing, touch, or taste. Or it may affect multiple senses. And people can be over- or under-responsive to the things they have difficulties with.
Like many illnesses, the symptoms of sensory processing disorder exist on a spectrum.
In some children, for example, the sound of a leaf blower outside the window may cause them to vomit or dive under the table. They may scream when touched. They may recoil from the textures of certain foods.
But others seem unresponsive to anything around them. They may fail to respond to extreme heat or cold or even pain.
Many children with sensory processing disorder start out as fussy babies who become anxious as they grow older. These kids often don’t handle change well. They may frequently throw tantrums or have meltdowns.
Many children have symptoms like these from time to time. But therapists consider a diagnosis of sensory processing disorder when the symptoms become severe enough to affect normal functioning and disrupt everyday life.
____ My infant/toddler has problems eating. ?
____ My infant/toddler refused to go to anyone but me.
____ My infant/toddler has trouble falling asleep or staying asleep?
____ My infant/toddler is extremely irritable when I dress him/her; seems to be uncomfortable in clothes.?
____ My infant/toddler rarely plays with toys, especially those requiring dexterity.?
____ My infant/toddler has difficulty shifting focus from one object/activity to another. ?
____ My infant/toddler does not notice pain or is slow to respond when hurt. ?
____ My infant/toddler resists cuddling, arches back away from the person holding him.?
____ My infant/toddler can not calm self by sucking on a pacifier, looking at toys, or listening to my voice.?
____ My infant/toddler has a “floppy” body, bumps into things and has poor balance. ?
____ My infant/toddler does little or no babbling, vocalizing. ?
____ My infant/toddler is easily startled. ?
____ My infant/toddler is extremely active and is constantly moving body/limbs or runs endlessly.?
____ My infant/toddler seems to be delayed in crawling, standing, walking or running.
____ My child has difficulty being toilet trained.?
____ My child is overly sensitive to stimulation, overreacts to or does not like touch, noise, smells, etc.?
____ My child is unaware of being touched/bumped unless done with extreme force/intensity.?
____ My child has difficulty learning and/or avoids performing fine motor tasks such as using crayons and fasteners on clothing.?
____ My child seems unsure how to move his/her body in space, is clumsy and awkward.?
____ My child has difficulty learning new motor tasks.?
____ My child is in constant motion.?
____ My child gets in everyone else’s space and/or touches everything around him.?
____ My child has difficulty making friends (overly aggressive or passive/ withdrawn).?
____ My child is intense, demanding or hard to calm and has difficulty with transitions.?
____ My child has sudden mood changes and temper tantrums that are unexpected.?
____ My child seems weak, slumps when sitting/standing; prefers sedentary activities.?
____ It is hard to understand my child’s speech.?
____ My child does not seem to understand verbal instructions.
School Age: ?
___ My child is overly sensitive to stimulation, overreacts to or does not like touch, noise, smells, etc.?
___ My child is easily distracted in the classroom, often out of his/her seat, fidgety.?
___ My child is easily overwhelmed at the playground, during recess and in class.?
___ My child is slow to perform tasks.?
___ My child has difficulty performing or avoids fine motor tasks such as handwriting. ?
___ My child appears clumsy and stumbles often, slouches in chair. ?
___ My child craves rough housing, tackling/wrestling games. ?
___ My child is slow to learn new activities.?
___ My child is in constant motion.?
___ My child has difficulty learning new motor tasks and prefers sedentary activities. ?
___ My child has difficulty making friends (overly aggressive or passive/ withdrawn).?
___ My child ‘gets stuck’ on tasks and has difficulty changing to another task.?
___ My child confuses similar sounding words, misinterprets questions or requests.?
___ My child has difficulty reading, especially aloud.?
___ My child stumbles over words; speech lacks fluency, and rhythm is hesitant.
___ I am over-sensitive to environmental stimulation: I do not like being touched. ?
___ I avoid visually stimulating environments and/or I am sensitive to sounds.?
___ I often feel lethargic and slow in starting my day.?
___ I often begin new tasks simultaneously and leave many of them uncompleted.?
___ I use an inappropriate amount of force when handling objects.?
___ I often bump into things or develop bruises that I cannot recall. ?
___ I have difficulty learning new motor tasks, or sequencing steps of a task.?
___ I need physical activities to help me maintain my focus throughout the day.?
___ I have difficulty staying focused at work and in meetings.?
___ I misinterpret questions and requests, requiring more clarification than usual.?
___ I have difficulty reading, especially aloud.?
___ My speech lacks fluency, I stumble over words.?
___ I must read material several times to absorb the content.
___ I have trouble forming thoughts and ideas in oral presentations.
___ I have trouble thinking up ideas for essays or written tasks at school.
The exact cause of SPD is not known. However, it is known that the mid-brain and brain stem regions of the central nervous system are early centers in the processing pathway for multisensory integration; these brain regions are involved in processes including coordination, attention, arousal, and autonomic function. After sensory information passes through these centers, it is then routed to brain regions responsible for emotions, memory, and higher level cognitive functions. Damage in any part of the brain involved in multisensory processing can cause difficulties in adequately processing stimuli in a functional way.
Studies using event-related potentials (ERPs) in children with the sensory over-responsivity subtype found atypical neural integration of sensory input. Different neural generators could be activated at an earlier stage of sensory information processing in people with SOR than in typically developing individuals. The automatic association of causally related sensory inputs that occurs at this early sensory-perceptual stage may not function properly in children with SOR. One hypothesis is that multisensory stimulation may activate a higher-level system in the frontal cortex that involves attention and cognitive processing, rather than the automatic integration of multisensory stimuli observed in typically developing adults in auditory cortex.
Recent research found an abnormal white matter microstructure in children with SPD, compared with typical children and those with other developmental disorders such as autism and ADHD.
The exact cause of sensory processing problems has not been identified. But a 2006 study of twins found that hypersensitivity to light and sound may have a strong genetic component.
Other experiments have shown that children with sensory processing problems have abnormal brain activity when they are simultaneously exposed to light and sound.
Still other experiments have shown that children with sensory processing problems will continue to respond strongly to a stroke on the hand or a loud sound, while other children quickly get used to the sensations.
Although sensory processing disorder is accepted in the Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood (DC:0-3R), it is not recognized as a mental disorder in medical manuals such as the ICD-10 or the DSM-5.
Diagnosis is primarily arrived at by the use of standardized tests, standardized questionnaires, expert observational scales, and free play observation at an occupational therapy gym. Observation of functional activities might be carried at school and home as well.
Depending on the country, diagnosis is made by different professionals, such as occupational therapists, psychologists, learning specialists, physiotherapists and/or speech and language therapists. In some countries it is recommended to have a full psychological and neurological evaluation if symptoms are too severe.
Sensory Integration and Praxis Test (SIPT)
DeGangi-Berk Test of Sensory Integration (TSI)
Test of Sensory Functions in Infants (TSFI)
Sensory Profile, (SP)
Infant/Toddler Sensory Profile
Adolescent/Adult Sensory Profile
Sensory Profile School Companion
Indicators of Developmental Risk Signals (INDIPCD-R)
Sensory Processing Measure (SPM)
Sensory Processing Measure Preeschool (SPM-P)
Clinical Observations of Motor and Postural Skills (COMPS)
Developmental Test of Visual Perception: Second Edition (DTVP-2)
Beery–Buktenica Developmental Test of Visual-Motor Integration, 6th Edition (BEERY VMI)
Miller Function & Participation Scales
Bruininks–Oseretsky Test of Motor Proficiency, Second Edition (BOT-2)
Behavior Rating Inventory of Executive Function (BRIEF)
The large number of different forms and tools of assessment listed here reflects what critics have argued is a fundamental problem with the diagnosis process: SPD researchers have yet to agree on a proven, standardized diagnostic tool, a problem that undermines the ability of researchers to define the boundaries of the disorder.
Sensory processing disorders have been classified by proponents into three categories: sensory modulation disorder, sensory-based motor disorders and sensory discrimination disorders  (as defined in the Diagnostic Classification of Mental Health and Developmental Disorders in Infancy and Early Childhood).
Sensory modulation disorder (SMD) Sensory modulation refers to a complex central nervous system process by which neural messages that convey information about the intensity, frequency, duration, complexity, and novelty of sensory stimuli are adjusted.
SMD consists of three subtypes:
Sensory-based motor disorder (SBMD) According to proponents, sensory-based motor disorder shows motor output that is disorganized as a result of incorrect processing of sensory information affecting postural control challenges, resulting in postural disorder, or developmental coordination disorder.
The SBMD subtypes are:
Sensory discrimination disorder (SDD)
Sensory discrimination disorder involves the incorrect processing of sensory information. The SDD subtypes are:
1. Visual 2. Auditory 3. Tactile 4. Gustatory (taste) 5. Olfactory (smell) 6. Vestibular (balance) 7. Proprioceptive (feeling of where parts of the body are located in space)
Many families with an affected child find that it is hard to get help. That’s because sensory processing disorder isn’t a recognized medical diagnosis at this time.
Despite the lack of widely accepted diagnostic criteria, occupational therapists commonly see and treat children and adults with sensory processing problems.
Treatment depends on a child’s individual needs. But in general, it involves helping children do better at activities they’re normally not good at and helping them get used to things they can’t tolerate.
Sensory integration therapy
Vestibular system is stimulated through hanging equipment such as tire swings
The main form of sensory integration therapy is a type of occupational therapy that places a child in a room specifically designed to stimulate and challenge all of the senses.
During the session, the therapist works closely with the child to provide a level of sensory stimulation that the child can cope with, and encourage movement within the room. Sensory integration therapy is driven by four main principles:
Just right challenge (the child must be able to successfully meet the challenges that are presented through playful activities)
Adaptive response (the child adapts his behavior with new and useful strategies in response to the challenges presented)
Active engagement (the child will want to participate because the activities are fun)
Child directed (the child’s preferences are used to initiate therapeutic experiences within the session)
Sensory processing therapy
This therapy retains all of the above-mentioned four principles and adds:
Intensity (person attends therapy daily for a prolonged period of time)
Developmental approach (therapist adapts to the developmental age of the person, against actual age)
Test-retest systematic evaluation (all clients are evaluated before and after)
Process driven vs. activity driven (therapist focuses on the “Just right” emotional connection and the process that reinforces the relationship)
Parent education (parent education sessions are scheduled into the therapy process)
“joie de vivre” (happiness of life is therapy’s main goal, attained through social participation, self-regulation, and self-esteem)
Combination of best practice interventions (is often accompanied by integrated listening system therapy, floor time, and electronic media such as Xbox Kinect, Nintendo Wii, Makoto II machine training and others)
The treatments themselves may involve a variety of activities and interventions (for example, prism lenses). Children with hypo-reactivity may be exposed to strong sensations such as stroking with a brush, vibrations or rubbing. Play may involve a range of materials to stimulate the senses such as play dough or finger painting. Children with hyper-reactivity, on the other hand, may be exposed to peaceful activities including quiet music and gentle rocking in a softly lit room. Treats and rewards may be used to encourage children to tolerate activities they would normally avoid. While occupational therapists using a sensory integration frame of reference work on increasing a child’s ability to adequately process sensory input, other OTs may focus on environmental accommodations that parents and school staff can use to enhance the child’s function at home, school, and in the community. These may include selecting soft, tag-free clothing, avoiding fluorescent lighting, and providing ear plugs for “emergency” use (such as for fire drills).
Evaluation of treatment effectiveness
Some of these treatments (for example, sensorimotor handling) have a questionable rationale and no empirical evidence. Other treatments (for example, prism lenses, physical exercise, and auditory integration training) have had studies with small positive outcomes, but few conclusions can be made about them due to methodological problems with the studies.   In its overall review of the treatment effectiveness literature, AETNA concluded that “The effectiveness of these therapies is unproven.”, while the American Academy of Pediatrics concluded that “parents should be informed that the amount of research regarding the effectiveness of sensory integration therapy is limited and inconclusive.” A 2015 review concluded that SIT techniques exist “outside the bounds of established evidence-based practice” and that SIT is “quite possibly a misuse of limited resources.”