Practitioner Review: Effective management of functional difficulties associated with sensory symptoms in children and adolescents
First published:13 March 2020
Conflict of interest statement: No conflicts declared.
Abstract
Background
Sensory symptoms are defined as atypical behavioral responses to daily sensory stimuli that impact on the performance of everyday routines. Sensory symptoms have been observed in young people with and without developmental concerns. There is uncertainty, however, regarding the best way to identify and manage sensory symptoms. The aim of this paper is to provide a review of current best evidence regarding measurement of and interventions for sensory symptoms.
Methods
A narrative review methodology is adopted to address the aims of this paper. First, sensory symptoms are defined, and then, an overview of the evidence for the relationship between sensory symptoms and childhood function is provided. Second, commonly used sensory assessment tools are summarized and evaluated. Finally, an overview and critique of the evidence for sensory and nonsensory‐based interventions addressing sensory symptoms are given.
Results
The terminology used to describe sensory symptoms varies by discipline, and several conceptual taxonomies including sensory subtypes have been proposed. There is ample evidence to support the association of sensory symptoms with childhood function including social engagement, repetitive behaviors, anxiety, and participation in self‐care routines. Measurement of sensory symptoms is dominated by proxy‐report instruments, and few single instruments assess the entire domain of sensory symptomatology. The evidence for interventions for sensory symptoms is emerging but still limited by low quantity and methodological concerns.
Conclusions
Effective management of sensory symptoms may mitigate the burden of neurodevelopmental disability and mental illness in young people. Identification of sensory symptoms should be conducted by a skilled practitioner utilizing multiple measurement methods. Intervention protocols for sensory symptoms should be informed by current best evidence which is strongest for Ayres Sensory Integration®, Qigong massage, the Alert Program®, and Social Stories. To make significant progress in this field, however, new intervention studies must address the question of ‘what intervention works for whom?’.
Introduction
Sensory symptoms have been described and observed in young people with and without developmental and mental health concerns. As many as 10%–55% of children without and 40%–80% of young people with developmental concerns may experience functional impacts related to sensory symptoms (Pfeiffer, May‐Benson, & Bodison, 2017). Functional difficulties in emotion and mood regulation, making transitions between activities, motor coordination, fussy eating, and sleep habits have been attributed to sensory symptoms (Critz, Blake, & Nogueira, 2015). Subsequently, sensory and nonsensory‐based interventions have been developed and applied to support young people and their families in this area. There is debate, however, as to the actual benefits of these therapies and the method by which sensory symptoms are identified and classified.
The aim of this paper is to provide practitioners with guidance pertaining to the management of functional difficulties associated with sensory symptoms in children and adolescents. To do this, the paper will: (a) define sensory symptoms and other terminology used to describe these symptoms, (b) overview the evidence for the relationship between sensory symptoms and childhood function, (c) provide an evaluation of commonly used sensory assessment tools, and (d) overview the evidence for sensory and nonsensory‐based interventions addressing sensory symptoms.
What are sensory symptoms?
Sensory symptoms refer to observable behaviors that indicate unusual or dysfunctional responses to daily sensory stimuli. Examples of sensory symptoms include the following: a child who covers their ears and shows extreme distress to an unexpected but nonthreatening auditory stimulus (e.g. vacuum cleaner turned on in the next room); an intolerance of the feeling of clothing tags to the point where the clothing cannot be worn or the tag needs to be removed; and the failure to respond with distress to a painful stimulus of sufficient intensity that distress would be expected. Although less described in the literature and case reports, sensory symptoms can also include postural and motor coordination difficulties. In all cases, the behavior cannot be attributed to sensory loss, for example, hearing or visual impairment or an identifiable central nervous system lesion. Sensory symptoms are also only clinically relevant when they result in significant disruption to daily routines and function (Miller, Anzalone, Lane, Cermak, & Osten, 2007). Behaviors that indicate sensory preferences but do not impact on function, therefore, are not considered clinically pertinent, while they may be captured in general measures of sensory symptoms used in research. For example, a child who refuses to eat pumpkin because of an aversion to its smell but eats a good variety of other vegetables in a balanced diet is not considered to have clinically significant sensory symptoms.
Etiology of sensory symptoms
The etiology of sensory symptoms is largely unknown. Symptoms are observed behaviorally rather than identified using biomedical testing. There is emerging evidence, however, that sensory symptoms are associated with subtle differences in central nervous system function. For example, in a functional magnetic resonance imaging study of 9 to 17‐year‐olds with autism, Green et al. (2015) observed an association between stronger activation (measured by blood oxygen level‐dependent signal change) in primary sensory cortices and the amygdala and parent‐reported sensory symptoms (specifically, sensory over‐responsivity). These authors concluded that participants with autism and sensory over‐responsivity showed decreased neural habituation to mildly aversive auditory and tactile stimuli. In a follow‐up study, Green, Hernandez, Bookheimer, & Dapretto (2016) reported a further association between parent‐reported sensory over‐responsivity and resting‐state salience network connectivity in children with autism. Increased sensory over‐responsivity was associated with increased functional connectivity. Green, Chandler, Charman, Simonoff, & Baird (2016) and Green, Hernandez, et al. (2016) hypothesize that individuals with autism and sensory over‐responsivity may attend disproportionately to sensory stimuli resulting in some of the functional difficulties observed with this group.
In a nonautism group, Chang et al. (2016) reported group differences in a number of measures of white matter microstructure integrity between typically developing children and those with parent‐reported sensory symptoms. These anatomical differences were focused in regions containing primary sensory projection pathways and connecting key sensory centers. In addition, reduced fractional anisotropy, measured in a diffusor tension imaging study, was associated with both parent reports and direct measures of tactile and auditory sensory symptoms (Chang et al., 2016).
In a summary of neurophysiological studies of sensory symptoms in autism using EEG, fMRI, and MEG technologies, Schauder and Bennetto (2016) concluded that there was ample neural evidence supporting impairments in sensory processing in individuals with autism. Impairments were characterized by variance in: (a) response – at both early and late stages of neural processing, (b) spatial patterns of neural activation in response to sensation, and (c) maturation and lateralization of sensory responding. Schauder and Bennetto (2016), however, identify that, unlike the studies from Green and Chang outlined previously, most neural studies do not consider the relationship of neural sensory processing to behavioral and clinical observations of sensory symptoms. Therefore, at this juncture, it is difficult to determine either the mechanism or etiology of sensory symptoms in children and adolescents. Definitive conclusions are further limited by the lack of neurophysiological research pertaining to sensory symptoms in young people without autism. While it is acknowledged that the sensory symptoms observed clinically have a neurophysiological base, our level of knowledge about how symptoms are directly impacted by neurological processes is in its infancy. Much of the extant literature regarding sensory symptoms, therefore, is based on clinical observation and/or proxy‐report measures.
Conceptual taxonomies
There have been several frameworks proposed for the classification of sensory symptoms into a clinically meaningful nosology. For the most part, these frameworks have been developed in the field of occupational therapy and are designed to assist clinicians to isolate specific behaviors indicative of sensory dysfunction, plan treatments to address sensory symptoms, and provide a platform from which to understand the impact of sensory symptoms on function. Three of the most commonly cited of these are by Ayres (1972), Dunn (1997, 1999, 2014), and Miller et al. (2007). Ayres' (1972) is credited as the founding theorist linking difficulties in the integration of daily sensory stimuli with adaptive behavior and functional limitations. Ayres' work underpins much of contemporary occupational therapy practice in this area and is the supporting framework for Ayres' Sensory Integration®, one of the principal intervention approaches utilized. Dunn's conceptual framework provides a basis for sensory assessment and provides some theoretical commentary on the mechanisms by which sensory symptoms emerge. Miller et al. (2007) proposed a sensory diagnostic taxonomy. A summary of each framework is provided below.
Ayres' sensory integration theory
Ayres' (1972) was the first to theorize that the process of neurological organization of sensation (both from the body and the environment) was integral to the ability of the individual to perform adaptively in daily life situations (Bundy & Lane, 2020). Ayres' theory of sensory integration is built around three core postulates:
- Learning is dependent on the ability to process and integrate sensory information which is then subsequently used to organize behavior.
- Difficulties in processing and integrating sensory information will result in functional syndromes that impact learning and behavior.
- Sensory experiences can be applied within treatment paradigms to improve sensory integration thereby advancing adaptive learning and behavior (Bundy & Lane, 2020).
In recent updates to Ayres' original theory, sensory dysfunction is conceptualized within two broad categories – sensory modulation dysfunction and dyspraxia (Bundy & Lane, 2020). Sensory modulation dysfunction is manifested by behaviors suggestive of difficulty with aligning response to stimuli such that responses are either too intense or insufficiently intense. Examples of these behaviors include defensiveness or aversion to light touch (sensory over‐responsiveness) or failure to respond to a stimulus (sensory under‐responsiveness). Ayres' hypothesized that sensory modulation difficulties were related to autonomic nervous system functions directing fight, flight, and fear responses (Bundy & Lane, 2020).
Dyspraxia, in Ayres' theory, is manifested as high‐level difficulties in planning new motor actions and is thought to be associated with sensory discrimination difficulties in vestibular, proprioceptive, and tactile systems (Bundy & Lane, 2020). Clinically, individuals with sensory‐based dyspraxia may present with clumsiness, postural control difficulties, and visual‐motor coordination deficits. It is well‐documented that postural and motor functions are dependent on the integration of vestibular (balance, head righting, postural reflexes), proprioception (body scheme), and tactile (force modulation) systems (Fong, Tsang, & Ng, 2012). Dyspraxia, therefore, is hypothesized to be mediated by the integrity of sensory‐dependent feedforward and feedback motor control mechanisms located in motor, parietal, and cerebellar centers (Bundy & Lane, 2020).
Dunn's conceptual framework
Dunn's model of sensory function (1997, 2014) is perhaps the most well‐known of the sensory frameworks due to the popularity of the Sensory Profile® (Dunn, 2014) family of sensory assessments that are based on Dunn's schema. Dunn's work is informed by that of Ayres' (1972), however, is primarily concerned with sensory modulation dysfunction rather than dyspraxia.
Central to Dunn's model is the notion that an individual's response to sensation can be understood in terms of a neurological threshold continuum and a behavioral response continuum (Dunn, 1997). The neurological threshold continuum refers to neurophysiological modulation of sensation; a ‘high’ threshold indicates a propensity for early habituation, whereas a ‘low’ threshold indicates sensitization. Individuals with a ‘high’ neurological threshold may be observed to respond initially to a stimulus but then quickly accommodate this new information and cease responding to the stimulus. Individuals with a ‘low’ neurological threshold, on the other hand, are noted to be sensitive to sensory information and may continue to respond to the stimulus beyond the point when habituation would be expected (Dunn, 1997).
The behavioral response continuum refers to the typical behavioral response style observed in the individual. This concept is akin to temperament, and Dunn acknowledges that behavioral style is influenced strongly by factors such as environmental context, opportunity, motivation, and preference (1997). At one end of the behavioral response continuum are behaviors that appear to be in accordance with the individual's neurological threshold and at the other behaviors that appear to counteract the individual's neurological threshold. For example, an individual with a ‘high’ neurological threshold who is acting in accordance with that threshold may appear to ignore or be nonresponsive to sensory stimuli. That same individual, however, who is acting to counteract his/her ‘high’ neurological threshold may present with sensation‐seeking behaviors which are hypothesized to support increased behavioral organization through the increase of overall sensory stimulation.
Based on these core concepts, Dunn (1997) proposed the quadrant model of sensory dysfunction. Four patterns of sensory dysfunction are described based on the individual's neurological threshold (high or low) and behavioral response style (in accordance or to counteract). The four patterns are described as follows:
- Poor registration (Bystander) – high threshold, acting in accordance.
- Sensation seeking (Seeker) – high threshold, acting to counteract.
- Sensory sensitive (Sensor) – low threshold, acting in accordance.
- Sensory avoiding (Avoider) – low threshold, acting to counteract
In 2014, Dunn revised her theory to integrate a strengths‐based perspective to the conceptual model. Dunn argued that the four sensory patterns described in her original work are not always ‘dysfunctional’ and can support functional performance in certain conditions. Subsequently, the labels applied to each sensory pattern have been updated and are indicated in parentheses.
Miller et al.'s diagnostic taxonomy
Miller et al. (2007) proposed a diagnostic taxonomy based on three core patterns of sensory symptoms. In doing so, they attempted to provide clinically useful detail to Ayres' broad categories of sensory modulation dysfunction and dyspraxia. Miller's et al. sensory patterns are as follows:
- Sensory Modulation Disorder – where the primary difficulty relates to the appropriate modulation or grading of a response aligned to the characteristics of the stimulus. This pattern is further subdivided into sensory over‐responsivity (the response to the stimulus is too intense), sensory under‐responsivity (the response to the stimulus is insufficiently intense or absent), and sensory seeking (the response to the stimulus indicates a craving for the stimulus).
- Sensory‐Based Motor Disorder – where the primary difficulty relates to the use and integration of visual, vestibular, proprioceptive, and tactile stimuli for movement planning, movement coordination, and postural control.
- Sensory Discrimination Disorder – where the primary difficulty relates to the accurate perception and interpretation of sensory stimuli that may result in learning difficulties, for example, auditory processing or visual perceptual disorders.
It is also important to note that while Miller and colleagues use the term ‘disorder’ to describe these patterns and despite attempts to have ‘sensory processing disorder’ included in the DSM‐5, there is currently no formal diagnostic category dedicated to sensory concerns for children aged over five years. At the time of the development of the DSM‐5, evidence to support the existence of a disorder focused on sensory symptoms independent of other diagnoses, such as attention‐deficit hyperactivity disorder, autism spectrum disorder, and anxiety disorder, was considered insufficient (APA, 2013).
For younger children aged 0–5 years, however, a diagnosis category of sensory processing disorders is established in the DC:0–5, Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood (ZERO‐TO‐THREE, 2016). In this age group, the sensory symptoms of over‐responsivity and under‐responsivity are considered to be a pivotal component of the expression of regulatory disorders affecting mood, impulse, and internal state regulation. The development of these features through early childhood, late childhood, and adolescence is currently insufficiently understood. It is evident, however, that functional difficulties associated with sensory symptoms are observable through the life span and are transdiagnostic phenomena, expressed across a number of neurodevelopmental and mental health diagnoses. As such, it is becoming increasingly important to precisely characterize sensory symptoms in childhood.
Limitations of current taxonomies
Each of the current sensory taxonomies offers a clinically useful framework from which to identify the potential functional impacts of sensory symptoms. All three taxonomies are currently used to guide occupational therapy practice in the treatment of sensory symptoms. Dunn's model, however, is the most limited in scope as it focuses only on sensory modulation dysfunction. Miller's taxonomy has arguably the broadest scope incorporating sensory modulation, sensory‐based movement (dyspraxia), and sensory perception difficulties. A limitation of all frameworks proposed is that while each proposes theoretical links to neurological sensory symptoms, empirical evidence to support these links has not yet been established. A further limitation is that each framework utilizes varying terms to describe similar sensory phenomena.
Sensory symptoms terminology
It has been noted that the terminology used to describe sensory symptoms is highly variable, dependent on discipline and framework used, and at times confusing (Cascio, Woynaroski, Baranek & Wallace, 2016; Schauder & Bennetto, 2016). Schaaf and Lane (2015) attempted to disentangle sensory terminology particularly in relation to its use in the autism field. These authors concluded that core sensory symptoms could be captured using the following terms:
- Sensory Reactivity – difficulties associated with sensory reactivity are expressed as a misalignment of the intensity of the child's response (either too intense or insufficiently intense) to a sensory stimulus. These types of difficulties are well documented in accounts of sensory symptoms impacting autism, anxiety, and ‘sensory processing disorder’. They include heightened and negative reactions to sensory input as described by terms such as sensory over‐responsiveness (SOR), sensory hyper‐reactivity, sensory sensitivity, low threshold, sensory defensiveness, and sensory avoidance (Schauder & Bennetto, 2016). Sensory reactive symptoms also include absent or attenuated responses to sensory input described as sensory under‐responsiveness (SUR), sensory hyporeactivity, high threshold, and poor registration (Schauder & Bennetto, 2016).
- Unusual Sensory Interests – are commonly observed in autism but are less prevalent in other childhood disorders. These symptoms consist of behaviors where it appears that sensory input is being actively sought or enhanced by the young person, for example, spinning self repeatedly in a desk chair, rocking self backwards, and forwards persistently. The term ‘unusual sensory interests’ is synonymous with sensory seeking and sensory craving (Schauder & Bennetto, 2016).
- Sensory Perception – difficulties in sensory perception in young people manifest in specific learning difficulties, for example, dyslexia and auditory processing disorder. These symptoms are observable impairments in the accurate interpretation of sensory stimuli and are generally measurable using standardized neuropsychological assessments or psychophysiological testing. Impairments may impact any sensory modality such as vision, for example, figure‐ground or spatial orientation difficulties; audition for example, difficulties in isolating speech in noise; tactile, for example, poor texture or temperature discrimination; or proprioception, for example, poor body awareness or right/left discrimination.
- Sensory Integration – difficulties in sensory integration can result in the breakdown of complex functions reliant on sensory inputs from multiple sensory modalities, for example dysgraphia and developmental coordination disorder. Impairments of motor planning, posture, and complex motor coordination can be considered as impairments in the integration of vestibular, tactile, and proprioceptive sensory inputs (Fong et al., 2012). The term ‘sensory integration’ is synonymous with others such as multisensory integration and sensory filtering (Schauder & Bennetto, 2016).
Sensory subtyping in autism
More recently, empirical efforts have been made to identify sensory phenomena at a subgroup rather than symptom level. The identification of distinct patterns or clusters of sensory symptoms within subgroups of children is a process referred to as ‘sensory subtyping’ (DeBoth & Reynolds, 2017; Hand, Dennis, & Lane, 2017). This is an important development in the field as it has been long recognized that individual sensory symptoms such as sensory hyper‐responsiveness or hyporesponsiveness and sensory seeking may co‐occur within individuals. Intervention protocols targeted at the symptom‐level, therefore, may conflict. For example, interventions to increase the responsiveness of an individual who displays hyporeactivity may confound efforts to manage co‐existing hyper‐reactivity symptoms. If sensory subtypes could be identified, then clinical protocols could be customized to subtype rather than individual sensory symptoms. This approach is thought to be advantageous in that individual children with sensory challenges rarely present with a single sensory symptom meaning that clinical protocols need to address sets of symptoms rather than individual behaviors. Further, from a research perspective, identification of commonly co‐occurring sets of sensory symptoms in sensory subtypes may provide insights into the mechanisms underlying sensory disruption which will then inform the development of better targeted intervention protocols. To date, several sensory subtype models have been proposed in the literature including one with a focus on typically developing children (discussed in further detail later in the article). Most subtype models, however, relate to children and adolescents with autism. All are based on parent‐report measures. A brief overview of the subtype models in autism is presented in Table 1.
| Subtype model |
Age
group
| Measurement | Analysis approach | Description | Strength of evidence |
|---|---|---|---|---|---|
| Lane, Young, Baker, and Angley (2010, Lane, Dennis, and Geraghty (2011), Lane et al. ( 2014) | 2–10 years |
| Model‐based cluster analysis |
Four subtypes:
|
|
| Ausderau, Furlong, et al. (2014) and Ausderau et al. (2016) | 2–12 years |
| Latent profile analysis |
Four subtypes:
| |
| Tomchek et al. (2018) | 3–6 years |
| Latent profile analysis |
|
|
| Simpson et al. (2019) | 4–11 years |
| Dirichlet process mixture model |
Two subtypes:
|
|
| Uljarević et al. (2016) | 11–17 years |
| Model‐based cluster analysis |
Three subtypes:
|
|
| Ben‐Sasson et al. (2008) | 18–33 months |
| Ward's minimum variance hierarchical cluster analysis |
Three subtypes:
|
|
| Philpott‐Robinson et al. (2016) | 12–24 months |
| Model‐based cluster analysis |
Two subtypes:
|
|
As can be seen, most of the subtype models are based on versions of Dunn's Sensory Profile, both old (1999) and new (2014) editions. Cluster (Bayesian and traditional forms) and latent profile analysis approaches were used. There are some evident similarities between models. First, many models indicate that some children with autism do not experience clinically significant sensory symptoms. This sensory subtype is described as ‘sensory adaptive’ (Lane, Molloy, & Bishop, 2014; Philpott‐Robinson, Lane, & Harpster, 2016; Uljarević, Lane, Kelly, & Leekam, 2016), ‘mild’ (Ausderau, Furlong, et al., 2014; Ausderau et al., 2016), ‘low frequency’ (Ben‐Sasson et al., 2008), or ‘perceptive–adaptable’ (Tomchek, Little, Myers, & Dunn, 2018). Second, many of the subtype models identify a subtype characterized by extreme or wide‐ranging sensory symptoms – ‘generalized’ (Lane et al., 2014), ‘extreme‐mixed’(Ausderau, Furlong, et al., 2014; Ausderau et al., 2016), ‘sensorimotor’ (Tomchek et al., 2018), ‘uniformly elevated’ (Simpson, Adams, Alston‐Knox, Heussler, & Keen, 2019), ‘sensory severe’ (Uljarević et al., 2016), and ‘high frequency’ (Ben‐Sasson et al., 2008). Differences in the sensory characteristics of the remaining subtypes across models are likely due to the variance between the measures used to capture sensory symptoms. Of the published subtype models, those proposed by Lane et al. and Ausderau et al. are the best validated through multiple studies. The Ausderau et al. model has been developed on the largest sample size and utilized a measurement tool with a validated factor structure for children with autism. The limitations of the currently available subtype models are their restriction to autism clinical groups and exclusive reliance on data from parent‐report measures, which are prone to bias and do not uniformly distinguish between variances in sensory symptoms based on sensory modality which may further discriminate between individuals (Tavassoli et al., 2019). Parent‐report measures, however, are the current standard for use in clinical practice.
Measurement of sensory symptoms
There are numerous measures available to identify sensory symptoms in children and adolescents (see Table 2; Eeles et al., 2013; Jorquera‐Cabrera, Romero‐Ayuso, Rodriguez‐Gil, & Triviño‐Juárez, 2017; Persch et al., 2017). The majority of these measures are parent‐ or proxy‐report instruments (Jorquera‐Cabrera et al., 2017) and are intended for use with a range of clinical groups. These tools generally consist of a series of prompts relating to child sensory‐related behaviors in which the parent/proxy is asked to rate according to the frequency of occurrence of these behaviors in daily contexts. Performance‐based measures are also available for the assessment of sensory symptoms. Examples include the: Sensory Integration and Praxis Test (Ayres, 1989), the Evaluation in Ayres Sensory Integration® (Mailloux, Parham, Roley, Ruzzano, & Schaaf, 2017), the Sensory Processing Assessment (Baranek, 1999), the Sensory Assessment for Neurodevelopmental Disorders (Piper et al., 2017), and the Sensory Processing Three‐Dimensions Scale (Mulligan et al., 2019). Typically, these measures are administered by occupational therapists and involve engaging the child in a range of sensory and sensorimotor games, for example, playing cymbals to a music track, trying different tastes, completing a visual puzzle, and spinning on a chair. Scoring of sensory performance on these assessments is dependent on the task being administered but ranges from the therapist rating their ‘global clinical impression’ of the child's responsiveness to the task, for example, hyper‐responsive, hyporesponsive, or seeking, through to scoring the precision and timing of a completed perceptual task. In research settings, psychophysical and imaging tools have additionally been utilized to further quantify sensory function in children and adolescents but these are rarely incorporated into clinical assessment protocols (see Marco, Hinkley, Hill, & Nagarajan, 2011; Schauder & Bennetto, 2016 for a review of these). Further, there are only a handful of studies that have investigated the links between proxy‐report and neurophysiological measures of sensory function (see earlier discussion).
| Sensory assessment | Author/s | Age range | Target population | Mode of administration | Sensory symptoms assessed | Psychometric summary | Availability |
|---|---|---|---|---|---|---|---|
| Sensory Profile 2 | Dunn (2014) | Alternate forms for different age‐groups from birth to adolescence and in home and school settings | All children | Parent/proxy report | Sensory hyporeactivity, sensory hyper‐reactivity, and sensory seeking. |
Varies by form.
Internal consistency: moderate–strong
Test–retest reliability: moderate–strong
Inter‐rater reliability: weak–strong; some forms are not tested
Convergent validity: moderate–strong
Evidence of known groups validation.
| Commercially available |
| Short Sensory Profile | McIntosh et al. (1999) | 3–10 years | All children | Parent/proxy report | Sensory hyporeactivity, sensory hyper‐reactivity, sensory seeking; sensorimotor, movement, and posture responses |
Internal consistency: moderate–strong
Evidence of known groups validation.
| Commercially available. Superseded by Short Sensory Profile 2 (Dunn, 2014) |
| Sensory Experiences Questionnaire (3.0) | Baranek, David, Poe, Stone, and Watson (2006) and Ausderau, Sideris, et al. (2014) | 2–12 years | Autism | Parent/proxy report | Sensory hyporeactivity, sensory hyper‐reactivity, and sensory seeking. |
Validated on autism groups only.
Content domain confirmed via factor analysis.
Internal consistency: strong
Test–retest reliability: strong
Inter‐rater reliability: not reported
Convergent validity: moderate
Evidence of known groups validation
| Research only |
| Sensory Processing Measure | Parham et al. (2007) | Alternate forms for preschool and school‐age groups | All children | Parent/proxy report | Sensory hyporeactivity, sensory hyper‐reactivity, sensory seeking; sensorimotor, movement, and posture responses |
Varies by form.
Internal consistency: strong
Test–retest reliability: strong
Inter‐rater reliability: not reported
Confirmatory factor analysis did not confirm factor structure in school‐age form.
Evidence of known groups validation
| Commercially available |
| Sensory Integration and Praxis Test | Ayres (1989) | 4–8 years, 11 months | All children | Performance‐based | Sensorimotor, sensory perception, sensory integration, and sensory discrimination |
Internal consistency: not reported
Intrarater reliability: moderate to strong
Inter‐rater reliability: strong
| Commercially available. Requires extensive postgraduate training. |
| Sensory Processing Assessment | Baranek (1999) | 3–5 years | Autism | Performance‐based | Sensory hyporeactivity, sensory hyper‐reactivity, and sensory seeking. |
Internal consistency: moderate
Test–retest reliability: strong
Inter‐rater reliability: strong
Convergent validity: weak to moderate
Evidence of known groups validation.
| Research only |
There is no standardized guideline or best practice clinical consensus for the measurement of sensory symptoms in either research or clinical settings. There have been three published critical reviews of sensory measures for use with children and adolescents, however, that provide some insight into the quality of existing tools (Eeles et al., 2013; Jorquera‐Cabrera et al., 2017; Persch et al., 2017). Eeles et al. reviewed available tools for infants and toddlers with sensory symptoms. These authors concluded that direct comparisons between available measures were unable to be made as each tool measured a slightly different aspect of sensory function. Persch et al. in their review of sensory tools for preschool and school‐aged children reached a similar conclusion. Available measures differed in their assessment of the broader construct of sensory function with some tools, generally parent‐report questionnaires, focusing exclusively on sensory reactivity, while others were aimed at evaluating sensory perception or sensorimotor skills. Further, psychometric data for the available tools were inconsistently reported and variable in standard (Eeles et al., 2013; Persch et al., 2017). Many tools report acceptable levels of reliability; however, suggesting that once established, the available sensory tools are able to be used consistently by multiple raters to identify common sensory concerns. The outcomes of validation studies have been less consistent, however, largely due to the varying nature of the types of sensory symptoms assessed by each instrument.
The clinical utility of each of the tools was also variable. Persch et al. (2017) observed that some of the tools with the best psychometric qualities were not available for general clinical use. The popularity of parent‐report tools is also noted to be related to the ease of administration in a clinical setting with some performance measures, for example Sensory Integration and Praxis Tests requiring substantial postgraduate clinician training, clinician time, and client expense (Persch et al., 2017). Performance‐based measures are also generally administered within controlled, clinical settings and are not always sensitive to contextual factors that may impact on sensory symptom presentation. Schaaf and Lane (2015) in their review of best practice sensory assessment principles for children with autism concluded that a comprehensive sensory assessment should include both parent‐report and performance‐based measures. A number of authors have also recommended the continued development of new tools and assessment processes that include systematic and comprehensive assessment of the entire domain of sensory function, that is, sensory reactivity, sensory integration, and sensory perception (Eeles et al., 2013; Persch et al., 2017; Schaaf & Lane, 2015).
Sensory symptoms and functional difficulties in normal development, neurodisability, and mental health
Sensory symptoms are observable across the spectrum of typical and atypical childhood development although there has been relatively little study of sensory symptoms in nonclinical groups. Recently, Little, Dean, Tomchek and Dunn (2017) described sensory subtypes in a large community sample of children with and without developmental conditions (n = 1,132; age range = 3–14 years). Using the Sensory Profile 2 (Dunn, 2014), five distinct sensory subtypes were identified. The subtypes were described as follows: (a) ‘balanced’ – low frequency of sensory symptoms, (b) ‘intense’ – high frequency of sensory symptoms across all areas, (c) ‘vigilant’ – high levels of sensory sensitivity and avoidance, (d) ‘interested’ – increased sensory seeking, and (e) ‘mellow until …..’ – poor sensory registration (hyporeactive) and avoiding. Eighty‐eight percent of the children in the study without developmental conditions fell into the ‘balanced’ subtype indicating few sensory symptoms. However, typically developing children were also represented in the interested (6%), intense (2%), mellow until… (2%), and vigilant (1%) subtypes suggesting that sensory symptoms are not uniquely associated with neurodevelopmental conditions. Further, younger children (mean age = 6.2 years) were over‐represented in the ‘interested’ subtype suggesting that specific patterns of sensory behavior may be developmentally driven.
In other studies of children without developmental concerns, sensory symptoms were further observed to relate to key functional behaviors. For example, Schulz and Stevenson (2019) reported that sensory hyper‐reactivity was strongly associated with repetitive behaviors in both children with autism and children who were typically developing. In fact, parent report of sensory hyper‐reactivity was noted to be a stronger predictor of all forms of repetitive behaviors (e.g. repetitive motor movements, rigidity, adherence to routine, and preoccupations) than diagnosis of autism (Schulz & Stevenson, 2019). Other authors have reported a strong association between sensory hyper‐reactivity in taste, smell, tactile, auditory and visual modalities, and anxiety and selective eating in a representative sample of children aged 5–10 years (n = 95) from a local school district (Farrow & Coulthard, 2012). In this study, parents completed questionnaires about their child's eating behaviors, anxiety, and sensory hyper‐reactivity symptoms. A ‘sensory sensitivity’ subtotal was derived from the Short Sensory Profile (McIntosh, Miller, & Shyu, 1999) consisting of four of the seven subscales determined by the authors to pertain to sensory sensitivity. Correlation analysis revealed that selective eating habits were moderately and significantly associated with sensory sensitivity, particularly taste sensitivity. Follow‐up mediation analysis further revealed that sensory hyper‐reactivity fully mediated the relationship between anxiety and patterns of selective eating leading the authors to conclude that sensory sensitivity explains why anxious children are more prone to be picky eaters (Farrow & Coulthard, 2012).
There is strong evidence for the role of sensory symptoms in the functional difficulties experienced by many young people with neurodevelopmental disabilities and mental illness (Green, Chandler, et al., 2016; Robertson & Baron‐Cohen, 2017). Green et al. note that sensory symptoms are prevalent in both children with autism and other, nonautism developmental concerns such as intellectual disability, language impairment, and conduct disorder. In autism, the severity of sensory symptoms has been linked with parent‐reported emotional difficulties, repetitive and problem behaviors, anxiety, and gastrointestinal issues. There is mixed evidence, however, for the association between sensory symptoms and IQ and autism symptom severity (Green, Chandler, et al., 2016; Lane et al., 2014; Mazurek et al., 2013; Wigham, Rodgers, South, McConachie, & Freeston, 2015). Sensory hyper‐reactivity in the form of sensory avoiding has also been proposed to mediate the relationship between insistence on sameness and anxiety in children with autism (Lidstone et al., 2014). Insistence on sameness behaviors is hypothesized to function to reduce or constrain sensory input from the environment thereby modulating over‐arousal and feelings of anxiety (Lidstone et al., 2014).
Links between sensory hyper‐reactivity and anxiety in autism have been investigated by a number of authors (Green & Ben‐Sasson, 2010; Uljarević et al., 2016). Green and Ben‐Sasson (2010) proposed two theoretical causal models explaining the relationship between sensory hyper‐reactivity and anxiety. In the first, anxiety is cast as the primary factor contributing to sensory hyper‐reactivity via generalized hyperarousal and hypervigilance. In the second, sensory hyper‐reactivity is proposed as the primary contributor to anxiety whereby over‐reaction to environmental stimuli results in context conditioning leading to generalized anxiety. In follow‐up work, Green and colleagues reported than in toddlers with autism, sensory hyper‐reactivity emerged prior to anxiety and was predictive of the later development of anxiety lending support for the second theoretical causal model (Green et al., 2012). Further research is required, however, to determine which of the models is best supported by evidence.
Much of the literature pertaining to sensory symptoms in young people has been focused on their presentation in autism. A recent meta‐analysis of autism‐related sensory literature concluded that symptoms of sensory hyper‐reactivity distinguish individuals from autism from all other groups including typically developing, other developmental disabilities, intellectual disability, sensory processing difficulties, and ADHD (Ben‐Sasson, Gal, Fluss, Katz‐Zetler & Cermak, 2019). In each case, sensory hyper‐reactivity was more functionally limiting in autism than in other groups. Symptoms of sensory hyporeactivity and sensory seeking also discriminated between autism and typically developing groups although seeking differences were moderated by age, IQ, and self vs proxy report (Ben‐Sasson et al., 2019). The findings of this review suggest that analysis of patterns of sensory symptoms in children and adolescents with neurodisability may be a useful method of isolating specific functional vulnerabilities within diagnostic groups and may support differential diagnosis processes (Ben‐Sasson et al., 2019).
Following a comprehensive scoping review of the literature published between 2005 and 2014 (261 articles), Dunn et al. (2016) concluded that there is ample evidence linking sensory symptoms in children with and without developmental conditions to social engagement, temperament, cognition, and participation. For example, Dunn et al. (2016) report that auditory and visual processing have been found to be associated with school performance. Further, proprioceptive processing has been associated with preferences for sedentary versus physical activities. Poor compliance with self‐care routines such as oral care, toileting, and sleep has also been linked with sensory sensitivity (Bellefeuille, Schaaf, & Polo, 2013; Stein, Polido, & Cermak, 2012; Stein, Polido, & Cermak, 2013; Wengel, Hanlon‐Dearman, & Fjeldsted, 2011). Children with more sensory symptoms have also been observed to require greater supports with social interactions (Cosbey, Johnston, & Dunn, 2010). In infancy, sensory sensitivity has been associated with greater negative mood and more difficult self‐regulation (DeSantis, Harkins, Tronick, Kaplan, & Beeghly, 2011). Dunn et al. (2016) conclude that there is sufficient evidence to establish the association between sensory symptoms and functional difficulties and that these symptoms are present in approximately 15% of typically developing children. In general, however, sensory symptoms are more prevalent in children with developmental conditions and the extant literature has focused on these groups rather than on studying methods of managing sensory symptoms in the general population (Dunn et al., 2016). There has also been less attention given to understanding the effectiveness of interventions targeting sensory symptoms, which would inform best practice in the support of children with sensory symptoms and their families (Dunn et al., 2016).
Interventions addressing sensory symptoms
Interventions to address the functional challenges experienced by children and adolescents with sensory symptoms are varied. In general, occupational therapy has been the lead profession in identifying and addressing sensory symptoms in therapy. The most common occupational therapy approach in this area is sensory intervention. Sensory interventions are those that make use of targeted sensory experiences in therapy. These interventions are based on the assumption that sensory systems can be directly impacted through intervention thus resulting in ‘up‐stream’ behavioral change. Sensory interventions take a number of different forms as discussed below.
Sensory interventions
Ayres' sensory integration
Ayres' sensory integration (ASI®) is based on the principles of Ayres' theory of sensory integration (Ayres, 1979), which proposes that adaptive childhood behavior is dependent on the accurate perception and integration of environmental sensory inputs. Ayres' work is considered foundational to both the identification of sensory symptoms as a substantive contributor to functional differences in children and in contemporary occupational therapy practice for children with sensory challenges (Parham et al., 2007). A published, manualized approach to ASI® with companion fidelity measure is available (Parham et al., 2011). The principles of ASI® include the following: an individualized approach targeting sensorimotor skills linked with functional performance deficits, play‐based, provision of a ‘just‐right’ challenge and a child‐directed, collaborative therapeutic process (Parham et al., 2011; Schaaf, Dumont, Arbesman, & May‐Benson, 2017; Schoen et al., 2019). Further, ASI® should be conducted in a clinical environment that enables the safe exposure of the child to various sensorimotor experiences, for example, suspension equipment, mats, rolls, and ball pits, and should be facilitated by an appropriately trained therapist with certification in sensory integration intervention or assessment (Parham et al., 2007).
There is emerging evidence supporting the effectiveness of ASI® for children with sensory symptoms. Systematic reviews that have focused exclusively on studies, where ASI® has been provided in a manner consistent with the published fidelity guidelines, have concluded that strong evidence exists for the positive impact of ASI® on functional performance (Schaaf et al., 2017; Schoen et al., 2019). Further, there is moderate‐level evidence supporting the efficacy of ASI® in reducing caregiver burden in relation to supporting children's self‐care performance (Schaaf et al., 2017). The evidence supporting the impact of ASI® on children's sensorimotor and social skills is, however, weak. While the quality of the evidence included in these recent reviews is generally high (RCTs), the quantity of evidence is small (n = 3 and n = 4 studies in each review) and studies only included children with autism limiting the generalizability of the findings to other client groups.
Specific unimodal sensory strategies
Sensory interventions of this type tend to target a single sensory modality, for example, touch, proprioception, or audition, are adult‐directed and require passive acceptance by the child rather than active participation (e.g. brushing, massage, swinging). Manualized protocols for unimodal sensory strategies are inconsistently available.
The evidence for the effectiveness of unimodal sensory strategies is mixed. Strong evidence supports the use of Qigong massage for children with autism with positive outcomes observed in self‐regulatory behaviors, parental stress, and task engagement (Bodison & Parham, 2017; Wan Yunus, Liu, Bissett, & Penkala, 2015). The evidence for a commonly used brushing protocol, the Wilbarger protocol, is insufficient, however (Weeks, Boshoff, & Stewart, 2012). Only a small number of low‐level studies (e.g. case series) of the Wilbarger protocol are available for critique with mixed findings reported (Weeks et al., 2012). Additionally, there is insufficient evidence to determine the impact of weighted vests on the task engagement or stereotyped behaviors of children with autism or ADHD (Bodison & Parham, 2017; Case‐Smith, Weaver, & Fristad, 2014). Studies investigating weighted vest interventions generally use low‐level designs or are vulnerable to significant threats to internal validity (Bodison & Parham, 2017). Case‐Smith et al. (2014) reported that of seven single‐subject studies of weighted vests in autism, only one reported positive effects on attention. Neither Wan Yunus et al. (2015) nor Bodison and Parham (2017) found sufficient evidence for other vestibular/proprioceptive sensory strategies such as slow linear swinging, and Case‐Smith et al. (2014) reported limited evidence for therapy ball seating interventions. In summary, the evidence for unimodal sensory strategies is characterized by poor methodological quality, nonmanualized treatment protocols, and substantial variation in both the characteristics of the participants in the studies and the outcomes evaluated. Subsequently, it is currently impossible to determine the likely value of unimodal sensory strategies for children and adolescents with sensory symptoms.
Sensory environmental modifications
A third type of sensory intervention involves modifications to the child's sensory environment such as wearing headphones to reduce ambient noise, reducing visual clutter in a classroom, or changing the color or intensity of light sources. These approaches are highly customized dependent on the child characteristics and the environmental context. Published standardized approaches in this intervention category, therefore, are rare.
Published studies examining the use of sensory environmental modifications, which are commonly used in practice, are scarce. In fact, in a recent systematic review, only one study reporting on a sensory environmental adaptation was found to meet inclusion criteria (Bodison & Parham, 2017). This lone study provided moderate‐level evidence of the efficacy of an intervention altering the auditory and visual environment of a dental clinic along with the provision of a decorated weighted blanket on the participation of children in dental procedures. This sensory intervention succeeded in reducing child anxiety, stress, and self‐reported pain and was effective for both children with autism and those who were typically developing.
Multisensory environments
There has been a recent re‐emergence of interest in the use of multisensory environments or Snoezelen rooms to reduce challenging behaviors in individuals with neurodevelopmental disability. Snoezelen rooms are purpose‐built sensory spaces in which the aim is to explore multisensory experiences and provide relaxation. In one study of older adolescents and adults with autism and intellectual disability, 36 × 30‐minute sessions of Snoezelen therapy provided in a small group setting resulted in reduced autism symptom severity in the treatment group (Novakovic et al., 2019). Other studies utilizing case series methodologies have reported improved visual, tactile, and auditory functioning along with increased following instructions and environmental awareness following 12 months of Snoezelen therapy (Mey, Cheng, & Ching, 2015). Overall, however, there is limited evidence reporting on the efficacy of multisensory environment approaches for children and adolescents with sensory symptoms. Therefore, it is premature to determine the value of this treatment approach for young people with sensory symptoms.
Nonsensory interventions
Interventions that are nonsensory in nature are also utilized in addressing sensory symptoms in children and adolescents. Some examples of nonsensory intervention approaches include the following: cognitive, task‐based, and parent/teacher training or coaching. Cognitive approaches utilize techniques to improve executive function, emotion regulation, attention, and memory (e.g. cognitive behavior therapy, Alert Program®, mindfulness). Task‐based approaches include participation in leisure or recreational activities, for example, horseback riding, yoga, sports, or club participation. Parent/teacher training or coaching techniques have a primary focus in educating relevant caregivers in the nature of sensory symptoms and principles for managing these at home and school.
There is moderate‐level evidence to support the use of cognitive strategies such as the Alert Program® and Social Stories to improve self‐regulation skills in children and adolescents with sensory symptoms (Pfeiffer, Clark, & Arbesman, 2017) although the studies tend to be conducted on small sample sizes without randomization. The Alert Program® aims to teach children to identify and monitor their internal regulatory states and to use sensory strategies to moderate their internal state as required. Social Stories are customized narratives in either textual or graphic form that teaches children how to respond in various challenging social and sensory scenarios. There is also promising evidence for iPad‐based perceptual discrimination and visuomotor training, EVO™, on parent and EEG measures of attention in children with both sensory and attention difficulties (Anguera et al., 2017). Similarly, preliminary findings indicate that a group‐based cognitive intervention focusing on a combination of psychoeducation, cognitive behavioral strategies and sensory coping techniques for adolescents with autism and sensory symptoms, is both feasible and effective (Edgington, Hill, & Pellicano, 2016). Using qualitative methodologies, authors reported improvements in participant meta‐conscious awareness and self‐regulation (Edgington et al., 2016). Previous studies have also reported the effectiveness of the Cognitive Orientation to Occupational Performance (CO‐OP) approach for children with diagnoses such as autism and developmental coordination disorder (Anderson, Wilson, & Williams, 2017) where comorbid sensory symptoms are likely. CO‐OP utilizes a structured goal‐setting framework to assist children and adolescents to identify and work toward functional goals (Missiuna, Mandich, Polatajko, & Malloy‐Miller, 2001). None of the CO‐OP studies, however, provided detail regarding the sensory symptoms of the participants, and so, the efficacy of this approach specifically for children and adolescents with sensory challenges is unknown.
Available literature examining the effectiveness of task‐based interventions for children and adolescents with sensory symptoms is more limited. Pfeiffer et al. (2017) in a systematic review of task‐based interventions reported moderate‐level evidence for therapeutic horseback riding for children with autism and sensory symptoms. Two studies reported positive effects of horseback riding on social interaction, sensory symptoms, and autism symptoms. Pfeiffer et al. (2017) found only a single study examining the effectiveness of yoga for adolescents with mental health needs and sensory concerns. The study reported positive outcomes of yoga for emotion regulation and self‐soothing for this group (Pfeiffer, Clark, et al., 2017). Yoga and other mindfulness techniques have garnered increased attention in the literature as potentially useful tools to support the mental health of young people (Kallapiran, Koo, Kirubakaran, & Hancock, 2015). As yet, however, few studies have identified their specific impact on the functional performance of young people with sensory symptoms.
Similarly, there is limited available evidence for the effectiveness of parent/teacher training and coaching interventions for children and adolescents with sensory symptoms. Miller‐Kuhaneck and Watling (2017) reported on four studies in a systematic review of pertinent literature. Techniques adopted in these studies included parental coaching and parental training and instruction. None of the studies evaluated programs targeted at teachers. Positive outcomes were reported by the studies on measures including parental stress and self‐efficacy and child behavior. All studies were focused on parents of children with autism.
Limitations of the intervention literature
Overall, while there are increasing attempts to document and quantify the impact of sensory and nonsensory interventions for children and adolescents with sensory symptoms, there are still significant limitations of the literature. First, there are fundamental methodological flaws in many of the studies that threaten internal validity including a failure to explicitly identify whether the participants experienced sensory symptoms. In the studies that do identify sensory symptoms, the nature of these symptoms is generally not specified. A pressing question for next‐generation research in this area is ‘what interventions will work best for whom?’. Integration of high‐quality intervention research with detailed participant characterization at baseline including sensory subtyping is required. Second, much of the higher‐level literature is focused on autism rather than children with sensory challenges more broadly. Generalization of the findings of these studies to other client groups, therefore, is difficult. Third, many systematic reviews and meta‐analyses of sensory interventions have failed to adequately discriminate between types of sensory interventions. Schoen et al. (2019) highlight that this has led to the potential for misinterpretation of the literature in regard to the effectiveness of sensory interventions. Going forward, research examining the efficacy of both sensory and nonsensory interventions for children and adolescents with sensory symptoms must provide evidence of a replicable intervention process and ensure the validity of the approach used via explicit measurement of intervention fidelity.
Conclusion
Sensory symptoms are recognized as an important aspect of the clinical presentation of children and adolescents with various neurodevelopmental and mental health disorders. There is evidence that sensory symptoms impact substantially on the daily functional difficulties of young people. Effective management of sensory symptoms may mitigate the burden of neurodevelopmental disability and mental illness for the individual child, family, and surrounding communities. To date, there is no consensus regarding best practice assessment and treatment of sensory symptoms in childhood. Research in this area has, however, increased over the last decade. Based on current evidence, sensory symptoms should be identified by a skilled practitioner, generally an occupational therapist, utilizing appropriate measures including parent report, performance assessment, and clinical judgement. In terms of treatment efficacy, the evidence is mixed. At this stage, there appears to be good support for the use of ASI® for children with autism and sensory challenges. Sensory interventions that are unimodal, adult‐directed, and noncollaborative, however, are not well supported in the literature with the exception of Qigong massage. There is insufficient evidence to determine the efficacy of sensory environmental interventions. With regard to nonsensory interventions, best evidence is available for cognitive interventions, many of which incorporate a sensory component.
Future research must address the many significant limitations of the extant literature. These include issues of methodological rigor but also phenotyping. To make significant progress in this field, new intervention studies must address the question of ‘what intervention works for whom?’ To do this, careful characterization of the sensory symptoms of clients regardless of diagnosis must be conducted through the development of consensus protocols for sensory assessment and the examination of differential outcomes based on sensory subtypes.
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