This information is updated as scientists in the SPD Scientific Work Group inform the SPD Foundation about their new findings.
The SPD Scientific Work Group, initially founded in 2002, is a collaboration of researchers who have been conducting studies to further the understanding of SPD. Funded by the Wallace Research Foundation, these researchers have helped develop a blueprint for current and future research into SPD.
Information about the scientists is available by clicking on their names. Please visit the active member listing for biographical information and links to workgroup members’ websites.
What is the prevalence of SPD?
In a study of children born between July 1995 and September 1997 in the New Haven, CT area 16% of 7 to 11-year-olds had symptoms of SPD-SOR (Ben-Sasson et al., 2009). That is the same as 1 in 6 children. An earlier study in younger children (Ahn et al., 2004) found a prevalence of 5%, which is 1 in 20 children.
What are the risk factors for SPD?
Several groups (Ben- Sasson et al., 2009; Keuler et al., 2011; May-Benson et al., 2009; Schneider et al., 2007, 2008, 2009; Wickremasinghe et al. in press;) suggest the following are possible risk factors associated with SPD:
- Low birth weight (less than 2200 gram
- Prematurity (less than 36 weeks gestation)
- Prenatal complications
- Maternal stress
- Maternal illness
- Maternal use of medications
- Delivery complications
- Assisted delivery methods
- Ethnic minority
- Living with a single parent
- Lower socioeconomic status
Schneider’s group (Schneider et al., 2007, 2008, 2009; Moore et al., 2008) working with non-human primates provided corroborating evidence. They found that SPD-SOR was associated with maternal stress during gestation, drug and/or alcohol use by mothers during pregnancy, and postnatal lead exposure. PET scans revealed up-regulation of D2-receptor binding that correlated with increased behavioral withdrawal responses to tactile stimuli, supporting the hypothesis that neurophysiologic factors contribute to the expression of SOR behavior.
Studies also suggest a possible genetic susceptibility for tactile and auditory SOR (Goldsmith et al., 2006).
Is SPD a unique disorder, independent of other mental disorders?
SPD, like other DSM-IV recognized disorders such as ADHD and depression, can occur together with other mental disorders, but SPD quite often occurs alone, in the absence of other disorders.
Separate research groups, in different areas of the USA, have reported that many individuals with SPD-Sensory Over-Responsive (SOR) symptoms do not have other disorders:
- 75% of individuals with SPD-SOR were evaluated in CT (Carter et al., 2011)
- 58% of individuals with SPD-SOR were evaluated in WI (Van Hulle et al., 2012)
- 37 to 67% of preschoolers with SPD-SOR in IL (Gouze et al., 2009).
- 80% of those with SPD-SOR in CT do not meet DSM criteria for ADHD (Ben-Sasson et al., in preparation).
Do symptoms of SPD persist if untreated?
Studies have shown that characteristics of SPD-SOR are stable and most often continue from 1 to 8 years of age in children who are not treated.
- Atypical sensory characteristics of SPD-SOR observed in early childhood (1 to 3 years of age) are still present at 8 years of age (Ben-Sasson et al., 2010)
- 50% of twins who were over-responsive to auditory stimuli at age 2 were over-responsive at age 4-5 (Goldsmith et al., 2007)
- 48% of twins who were over-responsive to tactile stimuli at age 2 were over-responsive at age 4-5 (Goldsmith et al., 2007)
Are there symptoms/challenges that individuals with SPD face, in addition to sensory challenges?
Individuals with SPD-Sensory Over-Responsivity (SOR) have been reported to be 4 times more likely to also have internalizing problems (e.g., anxiety) and 3 times more likely to have externalizing problems (e.g., aggression; Ben-Sasson et al., 2009).
Children with SPD-SOR have been reported to have impaired participation in daily life activities (e.g., lower levels of activities, reduced frequency of activities, less enjoyment of activities) with a direct relationship between severity of sensory symptoms and degree of activity impairment (Bar-Shalita et al., 2008).
Additionally, adults with SPD demonstrate social-emotional difficulties and impairments in quality of life (e.g., increased symptoms of anxiety, decreased sense of vitality, decreased social functioning, decreased general health, and increased bodily pain; Kinnealey et al., 2011).
What physiologic evidence differentiates individuals with SPD from other conditions?
Several studies have shown that children with SPD- Sensory Over-Responsivity (SOR) have different physiological (i.e., electrodermal) responses to sensory stimuli compared to typically developing control children (McIntosh et al., 1999; Miller et al., 2012; Schoen et al., 2009) as well as children with autism spectrum disorders (Schoen et al., 2009) and ADHD (Miller et al., 2001).
In particular, children with SPD-SOR were reported to have an increased number of and larger electrodermal responses to sensory stimuli as well as slower rates of habituation compared to typically developing control children (McIntosh et al., 1999). Additionally, children with SPD-SOR had greater levels of baseline arousal and higher reactivity in response to sensory stimuli than children with autism spectrum disorders (Schoen et al., 2009).
What is the physiological basis of SPD?
Studies suggest that children with SPD-SOR have different neurophysiological (i.e., brain) responses to sensory stimuli than controls (Brett-Green et al., 2010; Davies & Gavin, 2007; Davies et al., 2009, 2010; Gavin et al., 2011).
- Initial studies demonstrated that multisensory integration (i.e., information from different sensory modalities combined in the nervous system) can be reliably measured in typically developing children and children with SPD (Brett-Green et al., 2008, 2010). Additional findings suggest that the Spatio-temporal pattern of both unisensory and multisensory nervous system processing of sensory stimuli is different in children with SPD-SOR than in typically developing children (Brett-Green et al., 2010).
- Neurophysiological studies suggest that children with SPD demonstrate less sensory gating and more within-group variability than typically developing control children (Davies, Chang, & Gavin, 2009; Davies & Gavin, 2007). Moreover, while sensory gating improves with age in typically developing children, the developmental trajectory in children with SPD is significantly different from the typically developing controls (Davies and Gavin, 2007; Davies et al., 2009, 2010). Children with SPD were also found to have decreased ability to regulate sensitivity to changes in frequency and loudness of auditory tones compared to typically developing control children (Davies et al., 2009, 2010). In this listening task measures of brain activity correctly classified children with SPD versus typically developing children with 77% accuracy when the sounds were presented while watching silent cartoons and 96% accuracy when no distraction was provided (Davies & Gavin, 2007; Davies et al., 2010; Gavin et al., 2011).
- Studies suggest that boys with SPD have decreased white matter connectivity, particularly in the parietal regions of the brain that distinguish them from typical boys (Owen J & Marco E, submitted).
- Research is also investigating neural mechanisms of normal and impaired sensory modulation and potential pharmacological therapeutic approaches using pre-pulse inhibition paradigms in rat models (Larrauri and Levin, 2010, 2012; Levin et al., 2007). Results suggest that sensory gating deficits may be related to activity of cholinergic, glutamatergic, and adrenergic receptors (Heath & Picciotto, 2009; Larrauri and Levin, 2010, 2012; Levin et al., 2007).
What are treatments for SPD?
Occupational therapy researchers and clinicians have developed effective behavioral treatments for SPD (Miller et al., 2007a, b, c). The most promising intervention that we know of is the STAR model. This model includes the following elements;
- Intensive model (3 to 5 times a week) for a set, relatively short time e.g., 20 to 40 sessions)
- Priority on parent education (~ 1 of every 5 or 6 sessions is parents only)
- Multi-disciplinary approach with pediatrician, psychologist, speech/language therapist and occupational therapist
- The intervention model focuses on arousal regulation first, relationships and engagement second, and sensory integration third. The overall goal of treatment is joie du vivre, (joy in life), not repairing sensory or motor functioning. Sensory and motor activities are a means to an end; the end is 1) social participation 2) self-regulation, and 3) self-esteem & self-confidence.For more information see SPDstar.org and
How does SPD affect the family?
SPD symptoms have been shown to affect individual relationships as well as family engagement in personal and social routines. Differences between families with a child who has SPD and those who have typically developing children include the following for families with SPD:
- Decreased frequency of taking a child with SPD to visit friends or family, to eat in a restaurant, to attend a community gathering
- Parent exhaustion and parenting stress
- Rates of family impairment are greater for families that have children with symptoms of SPD- Sensory Over-Responsivity (SOR) contributed to family life impairment above and beyond concurrent DSM-IV mental health diagnoses, and socioeconomic risk (Carter et al., 2011).
- Reduced feelings of competence in their parenting role (Cohen et al. 2011)
What are the characteristics of disorders that have comorbid SPD?
- Examining children with ADHD based on their response to sensory challenges, Lane and Reynolds (Reynolds, Lane & Gennings, 2009) found that cortisol responses to a sensory change differ. Children with ADHD and SOR respond in a manner commensurate with the response of typical children, whereas children with ADHD only showed a blunted response. This blunted cortisol response had been identified by other investigators for children with ADHD as a whole. This finding suggests that the larger group of children with ADHD might be better understood by also examining sensory responsivity; sensory responsivity influenced the cortisol or stress response (HPA activity) to sensory challenge in this population of children.
- Children with both ADHD and SOR more often exhibit anxiety than do children with ADHD, but not SOR, and their level of anxiety were more likely to reach clinically significant levels, as determined by total scores on the Revised Children’s Manifest Anxiety Scale (Reynolds & Lane 2009).
- Links between SOR and anxiety are apparent in children without another diagnosis. Electrodermal (sympathetic nervous system) recovery from the sensory challenges may be more difficult for typical children and children with ADHD if SOR is also apparent (Lane, Reynolds & Thacker, 2010).
- Examining participation in children with ASD, children demonstrating more frequent Sensory Sensitivity and Sensory Avoiding (Sensory Profile) had a significantly lower overall level of competence in activities, social, and school performance (Child Behavior Checklist). (Reynolds, Bendixen, Lawrence, & Lane, 2011).
- In examining the relationship between sleep and SOR in children with ASD and typical children, it was confirmed that children with ASD have a higher prevalence of atypical sensory behaviors and sleep disturbances than typical children. Overall, looking at all children in this study, behavioral and physiological measures were able to predict good sleepers versus poor sleepers with 85.7% accuracy, suggesting that atypical sensory behaviors are important to consider in relation to sleep deficits in children (Reynolds, Lane, & Thacker, 2011).
- The relationship between sensory over-responsivity (SOR) and anxiety was examined in children with ASD, ADHD, and typical development. Path analysis indicated that the magnitude of sensory responsivity mediates the relationship between baseline arousal and attention on one hand, and anxiety and physiologic recovery from sensory challenge on the other. Further, behavioral tools used to measure SOR were not reflective of physiological responsiveness, a mismatch that warrants further investigation (Lane, Reynolds, & Dumenci, 2012).
SPD Scientific Work Group research in progress
- Ben-Sasson, Carter, & Briggs-Gowan: Subgroups of children with elevated SPD-SOR and ADHD scores versus elevation in one domain are being studied to understand the distinct nature of SOR versus ADHD. They have found that girls who show both elevated SOR and ADHD have greater severity of SOR in the tactile domain relative to boys in that cluster compared to girls with only ADHD or only SOR.
- Dr. Shelly Lane and Dr. Stacey Reynolds long-term goal is to test the effectiveness of sensory-based arousal regulation activities, grounded in the theory of sensory integration, in improving attention and functional performance in children with neurodevelopmental disorders. Currently, we are working to test the short-term effects of select sensory-based tasks on measures of attention and performance in children ages 6-10 with typical development, ADHD and ASD.