versión On-line ISSN 0038-2337
S. Afr. j. occup. ther. vol.43 no.3 Pretoria mar. 2013
Janine van der LindeI; Denise FranzsenII; Paula Barnard-AshtonIII
IB occ tier (UFS), MSc oT (Wits). Postgraduate Student, Department of Occupational Therapy, School of Therapeutic Sciences, Faculty of Health Sciences, University of Witwatersrand
IIBSc OT (Wits), MSc OT (Wits). Senior Lecturer, Department of Occupational Therapy, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand
IIIBSc OT (Wits), MSc OT (Wits). E Learning Co-ordinator, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand
The Sensory Profile is useful in assisting with diagnosis of certain conditions which present with different sensory processing patterns.
The purpose of this study was to compare the Sensory Profile for children with Specific Language Impairment (SU) (n=22) to a typical pattern, as well as the reported profiles of samples with autism and Attention Deficit/Hyperactive Disorder (ADHD). The SU sample had significantly more sensory processing difficulties than the typical population in all aspects. The Sensory Profile for both the autism and ADHD samples differed significantly from that of the SLI sample for H. Modulation Related to Body Position and Movement and Factor 6: Poor Registration. The SU sample showed fewer sensory processing problems except for J. Modulation of Sensory Input Affecting Emotional Responses, M. Behavioural Outcomes of Sensory Processing and Factor 9: Fine motor/perceptual indicating that this small sample of children with SLI did present with a unique Sensory Profile pattern.
The Sensory Profile developed by Winnie Dunn is a measure of sensory processing and has been widely used both clinically and in research to gain information on how children process sensory information from the body and the environment1. The information gained from the Sensory Profile provides information on the contribution of sensory processing to a child's daily performance. It provides information regarding behavioural tendencies in response to stimuli and identifies which sensory systems are likely to contribute to, or create barriers during functional activities2. Studies using the Sensory Profile propose that children with certain dysfunctions respond differently to sensory stimuli than children without dysfunctions2-5. It is assumed that children with certain dysfunctions process sensory information differently.
Research indicates that there are specific patterns of sensory processing consistent with the diagnostic criteria for children with autism and children with Attention Deficit Hyperactivity Disorder (ADHD)2,3,6,7. It is however not known whether a similar consistent pattern of sensory processing is present in other dysfunctions, like Specific Language Impairment (SLI), where behaviours similar to those associated with autism and ADHD are also observed8,9.
The development of the Sensory Profile progressed from the ground breaking work that was initially done by Jean Ayres on sensory integration10. Sensory integration results from the brain's ability to process and integrate sensory information received from the environment and from the body10. The main contributors to sensory integration as described in the work of Ayres are the tactile, vestibular and proprioceptive systems, but does not exclude the visual, auditory, olfactory and taste senses10. There is an ongoing debate on the use of terminology but this article describes sensory processing according to Dunn's research and published work on this concept11.
Thus for the purposes of this research the processing of sensory input refers to the functions the nervous system used to receive, regulate, and organise sensory input according to the neurological threshold of a child12. Sensory modulation is the ability to regulate sensory information and to generate an appropriate response that matches the demands and expectations of the environment12. It further plays a role in regulating the habituation and sensitisation of the person's responses to sensory information from the body and the environment13. Dunn further proposed that, in order to produce functional behaviour, modulation of information needs to create an interchange along a continuum of habituation and sensitisation1. When a child has difficulty modulating between habituation and sensitization, they present with maladaptive behaviours, for e.g. they can present as being over excitable, hyperactive or overly lethargic10. However when the impact of neurological thresholds on the behavioural responses is considered, a range of possible interpretations of these behaviours emerge, depending on the effect of the high or low thresholds on performances1. Children with a low neurological threshold often display the over excitable or hyperactive behaviours while over habituation can occur when a high neurological threshold is present resulting in overly lethargic and inattentive behaviour. The conceptual model developed by Dunn considers the relationship between neurological thresholds and behavioural (self-regulation) strategies1,11. Four basic patterns of responding to sensory events in everyday life were identified: low registration, sensation seeking, sensory sensitive and sensation avoiding1,11. These patterns are identified through the use of the Sensory Profile, a 125 item, behavioural questionnaire that is completed by a child's caregiver11.
Various studies have been done to determine if the Sensory Profile could discriminate between different diagnostic groups2-4,6,7,13,14. In a study by Dunn and Bennett3 the researchers evaluated 70 children with ADHD to compare their sensory processing patterns to that of typically developing children, using the Sensory Profile. Multivariate analyses of variance (MANOVA) indicated that the children with ADHD showed differences in all 14 sections of the Sensory Profile. The Sensory Profile was found to discriminate best between the high incidence factors like sensory seeking behaviours, inattention and distractibility and low incidence factors like oral sensory sensitivity and fine motor perceptual behaviour in children with ADHD3. This led them to believe that the Sensory Profile can be useful in discriminating between ADHD and typical children3.
Kientz and Dunn4 found that children from the autistic population showed different responses to the typically developing children population in 84 of the 99 items on the Sensory profile4. Similar findings in studies by Brown, Leo and Austin7, Ermer and Dunn,2 Provost et. al.6, Tomchek and Dunn15, Watling, Deitz and White16 confirmed that there are significant differences in the way that children with autism process sensory input. Ermer and Dunn2 further states that factor analytic studies indicated that children from the autistic population have a low incidence of behaviours on Factor: 1 Sensory seeking. This however was disputed by the findings by Tomchek and Dunn15 who found that 90% of the their sample of children with autism had a high incidence of sensory seeking behaviours.
In New Zealand a study by Provost et.al.6, found that children with autism experienced more difficulties with oral sensory sensitivity and obtained more definite different scores on all 14 sections than typical children. Provost et. al.6 and Dunn et. al.14 found similar results with Dunn et. al.14 also showing that visual processing proved to be a strength for these children. Further studies by Brown et.al.7 in Australia and Watling et. al.16 also found that children with ASD more frequently have hypersensitivity to tactile processing and auditory input and they are hyposensitive to movement input.
Although there is a lack of consistency in the research studies in regards to the sample sizes, the use of the Sensory Profile or the Short Sensory Profile, the findings were very similar and confirm that children with autism all scored definite differences in patterns of sensory processing on the Sensory Profile on almost all items. No studies have been published on the Sensory Profile for children in other diagnostic groups such as Specific Language Impairment (SLI).
Specific Language Impairment
Specific Language Impairment (SLI) is a common neuro-develop-mental disorder, diagnosed when children present with expressive or receptive language impairment which is not due to intellectual disability, physical disability, hearing loss, emotional problems or environmental deprivation16-18. It is among one of the most commonly occurring communication disorders or developmental problems in children between the ages of 5-10 years in England and the United States where it is estimated that 5 - 7% of typically developing children experience speech and language difficulties19. Children with SLI present with a specific or primary speech and language impairment and although clinical identification of these impairments is based on the absence of other contributing factors the diagnosis needs to be confirmed by a speech and language therapist following a full assessment17.
According to Tomblin9 SLI is diagnosed when the achievement of age appropriate language levels fall at least -1 Standard Deviation (SD) below the norm. The International classification of disease version 10 (ICD-10) further states that a disorder or delay in developmental speech and language is strongly related to biological maturation of the central nervous system and in most cases the functions affected are language, visio-spatial skills and motor coordination18.
Although a number of studies on SLI deal with controversies about language acquisition and use, such as difficulties in auditory processing, learning the rules of language and registering the different contexts for language, research has also reported other characteristics common to children with SLI19,20. These characteristics, which are non-linguistic, include poor social skills, a lack of attention21, difficulty with fine and gross motor skills22 and poor short term memory21. Difficulties with planning, organising and sequencing of thoughts and problems with beginning and completing tasks are also features of this condition23.
Sensory processing and language
Hulslander et. al.8, found a possible association between speech and language disorders and sensory processing difficulties in some children and proposed that there could be a link between chronic disorganisation in terms of behaviour and difficulties with vestibular, tactile and auditory processing in children with SLI8. This connection was supported by Ayres who described how the CNS mediates language development and that speech and language are seen as an end product of sensory integration10.
The difficulties children with SLI experience particularly in modulating the amount of sensory input they receive and their disturbed auditory processing have been identified as a potential risk for the development of speech and language disorders24. A problem in this type of processing presents as inconsistent awareness of sound and is commonly found in conjunction with other dysfunctions that manifest as attention seeking, temper tantrums, hyperactivity, impulsivity and oppositional behaviours25.
Owens26 also described a possible the link between poor auditory processing and poor self-regulation which results in behaviours like daydreaming, problems in sitting still, completing assignments and increased anxiety. Other research has also suggested that there could be a link between chronic disorganisation in terms of behaviour and speech and language and that children with SLI may also have vestibular and tactile processing problems17.
Problem statement: Research studies indicated that children with certain specified dysfunction respond differently from children without dysfunction on the Sensory Profile, suggesting underlying sensory processing and modulation difficulties which are reflected in their behavioural and emotional responses9. This then raised the question as to whether children with speech and language disorders, specifically SLI will also demonstrate differences on the Sensory Profile and if there are certain characteristics or patterns that are commonly associated with this condition?
The purpose of this study was therefore to determine the Sensory Profile for a group of children with SLI and to compare their profile to children with and without dysfunction.
The following research question was addressed:
♣ Does a significant difference exist between the Sensory Profile scores of children with SLI and those profiles published for children who are typically developing, children who have autism and children with ADHD?
A quantitative, descriptive cross sectional research design was used in that children in the study were assessed at one time using the Sensory Profile. The study was conducted over the period of a year in Greater London and the South of England. To ensure that no ethical issues were raised regarding service delivery following assessment, parents were provided with an electronic report to give to their local therapist and referrals were made to OT services if the Sensory Profile indicated definite difficulties.
Ethical clearance was obtained from the Ethics committee for Research on Human Subjects at the University of the Witwa-tersrand. Further permissions were obtained from the schools and the participants.
Criteria for participant selection
The criteria for inclusion were that the children should be English speaking and between the ages of 5 years and 10 years 11 months. This age criterion was used as the Sensory Profile is standardised on an English speaking population of children aged 5 years to 10 years 11 months. A primary speech and language disorder (SLI), as identified by a speech and language therapist, had to be present as well as a statement of special educational needs (this is a formal document that describes a child's learning difficulties and the educational input that will be needed. It also includes details of the therapeutic input and type of school placement required). This criterion was important in order to ensure that the children identified for this study were also known to the special needs educators and therapists.
Exclusion criteria included children diagnosed by a paediatrician as having autism, Autistic Spectrum Disorder, ADHD, epilepsy, a cognitive disorder, Cerebral Palsy or developmental delay as these children may have sensory processing difficulties2-4,7.
Data collection: Through the Department of Education in the UK, special schools for children with speech and language disorders and mainstream schools with a language unit/base in Greater London and the South of England were identified for participation. The sample of children was identified by the speech and language therapist and occupational therapist within each school and all children meeting the inclusion criteria in these schools were invited to participate. Letters requesting participation in the study were sent out to the parents. On receipt of consent from the parents the Sensory Profile questionnaires, as well as the Developmental profile II (DP-II), were sent to parents for completion. The parents had the option of contacting the researcher by phone or e-mail for assistance in completing the forms. A total of 260 questionnaires were sent out, but only 1 6 questionnaires (6%) were returned to the researcher, despite parents being reminded via e-mail twice during the process. As this sample was too small, a second request for participation was sent out and another eight of this group responded. Therefore only 24 out of a total of 320 (7.5% return rate) of the Sensory Profile questionnaires were used for data analysis. This small sample is a limitation in this study and may well have affected the internal validity as well as the external validity of the study and therefore results cannot be generalised to the population.
Instruments used: The Sensory Profile is a judgment based caregiver questionnaire consisting of 14 sections (total of 125 items), that reports the frequency of behavioural occurrences that are used to measure the patterns of performance indicative of difficulties experienced in sensory processing11.
The DPII includes 186 items that assesses the development of the child in five areas; physical age, self-help age, social age, academic age and communication age. This test was used to determine if the children selected had any pervasive developmental delays27. Background information (chronological age, developmental age, gender, grade, diagnosis and type of speech and language impairment) of each participant was collected from the demographic information section on the Sensory profile scoring sheet.
Data Analysis: The data from the questionnaires were placed onto an Excel spread sheet and then analysed, using descriptive statistics and the t-test. The raw scores from the Sensory Profile were determined through adding all scores for a section. The mean and standard deviation values were then determined per group for each section total on the profile11. Scores that fell within the probable difference (below - 1 SD), as well as the definite difference range (below - 2SD) were considered to be indicative of a problem11.
The percentage of children who fell in a specific group (typical, probable difference and definite difference) was then determined for comparison between the groups.
The raw scores for the typically developing children, children with ADHD and children with autism were obtained from the literature in order to compare them to this study sample3,4,11. Parametric testing (t-test analysis) was used to establish if there were significant differences between the mean raw scores of the SLI group and those of typically developing children1, those with ADHD in studies carried out by Dunn and Bennet3 and those with autism in the study by Kientz and Dunn4.
Only 24 questionnaires were returned from the SLI children and the scores of two participants could not be used as the Developmental Profile II indicated that they had developmental disorders. This poor return rate of 20% was below the accepted level of 60% for a mail survey and affected the external validity and the internal validity of the study28. The sample size is in line with previous research done to identify unique sensory profiles for different diagnostic categories the results of this study must however be viewed with caution2,4,6,7. The larger standard deviations obtained for all aspects of the Sensory Profile when compared to the other groups indicate larger variations in the sample of children with SLI than those obtained in the other studies and further confirmation of these findings on a larger sample is needed.
Demographic information indicated that eight children were females and 14 were males with an age range of 5 years 1 month to 10 years 8 months and a mean age of 8 years 2 months. More than half of all the children had received occupational therapy and all were being treated by a speech and language therapist.
Sensory profile results
Data analysis revealed that the sample of children with SLI had unique patterns of sensory responsivity with the raw scores of all scores patterns on the Sensory Profile being significantly lower (p<0.00) than those reported for the typically developing child, indicating possible sensory processing difficulties in children with SLI for all components measured on the Sensory Profile4(Table 1 on page 37).
Considering the score patterns pertaining to the percentage of the sample of children with SLI that scored within the probable difference or significant difference ranges (indicating difficulties) on the Sensory Profile, the statistical analysis did indicate that the sample of children with SLI had difficulty with all areas of sensory processing (multi-sensory processing (81.82%) and auditory processing (68.1%), as well as vestibular, touch and oral processing (54.44%). Visual processing proved to be an area of strength for the sample (only 45.45% experienced difficulties) (see Table II).
In the modulation score pattern, these children had lower raw scores on all modulation scores than the typical sample and 54.45% had difficulty with modulation of sensory input affecting emotional response and 81.82% of the sample had difficulty with modulation of movement affecting activity levels (see Table II).
Behaviour and emotional response patterns on the Sensory Profile proved to be problematic for the sample of children with SLI with all raw scores falling below that of the sample of typically developing children and more than 50% of the sample presenting with difficulties in terms of behavioural and emotional responses.
Responsiveness score patterns as seen in the factor scores indicated that these children also experienced difficulties with Factor 5: Inattention and distractibility (81.82%), Factor 9: Fine motor/perceptual (72.73%), Factor 2: Emotionally reactive (63.64%) and Factor 1: Sensory seeking (54.54%) (see Table II).
A comparison of Sensory Profile of the sample of children with SLI to other samples of children with autism and children with ADHD disclosed differences in performance between the these samples and children with SLI in the reported patterns on the Sensory Profile3.
Results indicated that the raw scores for SLI, autism and ADHD fell below those of typically developing children and that children with autism had the lowest scores in all of items on the Sensory Profile.
Table 1 indicates that the scores for the sample of children with SLI were significantly higher under the sensory processing section for D. Touch Processing (p<0.00), F. Oral Processing (p<0.03) than the sample of children with autism's scores.
The modulation score patterns of the sample of children with SLI are similar or less dysfunctional than those of the sample of children with ADHD except for J. Modulation of Sensory input Affecting Emotional responses where the scores for the sample of children with SLI were significantly (p<0.0l) lower (Figure 2). The scores for H. Modulation related to body position and movement compared to the sample of children with autism's profile (p<0.02) and the sample of children with ADHD's profile (p<0.04) were significantly lower than the sample of children with SLI.
A similar trend for behavioural scores was observed. The sample of children with SLI had higher raw scores than the sample of children with ADHD except for the scores for M. Behavioural outcomes of Sensory Processing (p<0.02) and L. Emotional and behavioural Responses when compared to the sample of children with autism (p<0.03).
On all factor scores the sample of children with SLI scored higher scores except for Factor 9: Fine motor/perceptual which was significantly lower (p<0.00) than the sample of children with ADHD. The factor scores that were significantly higher for the sample of children with SLI were Factor!: Sensory seeking (p<0.04) and Factor 2: Emotionally reactive (p<0.05) for those of children with ADHD and autism respectively (Figure 2). Similar results were found for the scores for Factor 6: Poor Registration (p<0.00 and p<0.01).
In the study by Brown et. al.7 the researchers suggested that the Sensory Profile is able to discriminate between groups of children with disabilities and typically developing children. This study investigated the differences in raw scores between samples of children with SLI, children with autism and children with ADHD on the items of the Sensory Profile.
Children with Specific Language Impairment compared to Typically developing children
The results of this study suggest that the participants with SLI show a significant difference on all items of the Sensory Profile when compared to typically developing children. As a lower raw score is an indication of difficulties it is possible to say that there is a significant difference between the sample of children with SLI and typically developing children. Thus for the sample of children with SLI in this study it can be presumed that they present with sensory processing dysfunction.
Children with Specific Language Impairment compared to children with Attention Deficit Hyperactivity Disorder
In light of the many similar problems described in relation to children with SLI and children with ADHD, it had been expected that the sample of children with SLI would have a Sensory Profile similar to that found for the children with ADHD29,30. The results of this study indicated that overall the sample of children with SLI and children with ADHD have similar patterns of processing sensory information; but however indicated that there were some areas with significant differences in raw scores between the sample of children with SLI and children with ADHD (Table 1).
The raw scores for H. Modulation Related to Body Position and Movement were found to be lower in the sample of children with ADHD indicating that they engage in this behaviour (take movement risks, excessive movement, seeks opportunity to fall etc.) more often than the sample of children with SLI. A possible explanation could be that children with ADHD are not registering sensory input effectively and are therefore constantly seeking more sensory input in order to generate responses for movement3. The lower raw scores on Factor 6: Poor registration could possibly be proof of their difficulty with registering information from the environment. Dunn proposed that children with poor registration may have inadequate neural activation, which can result in sensory seeking behaviour9,13, and that children with ADHD use sensory seeking behaviour to enable their learning. Further confirmation of this could be that factor scores indicated that the sample of children with ADHD had significantly lower scores for Factor I: Sensory seeking, indicating that they are engaging more in sensory seeking behaviour.
Children with ADHD often have difficulties with behaviour due to their inability to focus, high activity levels and impulsivity29. It was thus expected that differences in items scoring behaviour would be lower than that of the sample of children with SLI. The raw scores on M. Behavioural outcomes of sensory processing were however significantly lower in the sample of children with SLI than in the sample of children with ADHD. The sample of children with SLI also had significantly lower scores on J. Modulation of sensory input affecting emotional responses. This may be explained by the fact that speech and language are an end product of sensory integration and it is therefore proposed that the children with SLI who experience difficulties with sensory processing will find it more difficult to meet the demands set by the environment which will then result in more emotional responses such as frustration and emotional outbursts10.
The significantly lower scores found in the sample of children with SLI for Factor 9: Fine motor/perceptual is also congruent with the reported characteristics of children with SLI25. This agrees with the findings of Kruger et al. that children with language disorders have problems with fine motor skills, whereas children with ADHD tend to experience more visuo-motor and perceptual difficulties3,15.
Children with Specific Language Impairment compared to children with Autism
As children with autism also have severe speech and language difficulties it is very important to distinguish between children with autism and children with SLI when establishing a diagnosis17,31. Research indicated that children with autism process sensory information in a different way to typically developing children4-7.
Factor analytic studies indicated that they have a low incidence of behaviours on Factor: I Sensory seeking, and a high incidence of oral processing and behaviours on Factor 4: Oral sensory sensitivity, Factor 5: Inattention and Factor 9: Fine motor/ perceptual, that contributed to the differences found in children with autism from typically developing children2.
Dunn et. al.14 described children with autism as having more difficulties with oral sensory processing and that visual processing proved to be a strength for this sample. According to the literature, oral processing was found to be the most discriminating for children with autism14 and they are described as experiencing oral sensitivity to particular tastes, textures and smells.
The sample of children with SLI presented with significantly better mean raw scores for both oral processing and oral sensory sensitivity than the autistic group, although they scored lower than the typical group. It had been expected that the sample of children with SLI might have difficulties with oral processing, as oral processing also plays a role in the development of speech (the production of sound, placement of the tongue and lips, pressure of the lips etc. when producing words)32 . Their problems however appear to differ from and are not as severe as those found in children with autism which means this item can be used to differentiate children with SLI from those with autism.
Touch processing was found to be dysfunctional in children with autism and in a study by Baranek, Foster and Berkson33 it was found that these children tend to experience more difficulties with tactile defensiveness. Thus not unexpectedly the sample of children with autism appear to be much more sensitive to touch input resulting in more rigid and inflexible behaviour related to dependence on a specific routine10. The significantly higher scores for D. Touch processing in the sample of children with SLI means they have less sensitivity to touch input resulting in less rigid and inflexible behaviour. This is another item which can be used to discriminate between children with SLI and autism as can H. Modulation Related to Body Position and Movement scores which were also significantly lower for the sample of children with autism than the sample of children with SLI. This aspect of sensory processing is manifest in children with autism when they display repetitive motor movements like whole body rocking or jumping in one place10.
The emotional/social section of the Sensory Profile measures the child's psychosocial coping strategies. Significant differences in raw scores on L: Emotional/social responses and Factor 2: Emotional reactive indicated that the sample of children with autism found emotional responses more difficult to control. This was not unexpected as children with autism are expected to have more problems in this aspect as one of the difficulties they experience is transitioning from one activity to the next. They further experience frustration, which can lead to subsequent emotional outbursts. The raw scores for Factor 6: Poor registration was significantly lower for the sample of children with autism than the samples of children with ADHD and SLI. This can probably be explained by what literature describes as children with autism "being in their own world", not aware of what is going on around them, especially when they are over focused on an object or part thereof4,31.
Even though this study was limited by a poor response rate, lower than the accepted 60%, the results suggest that significant differences were found between the sample of children with SLI and typically developing children and that the SLI sample do have a specific sensory profile.
The pattern of performance of the sample of children with SLI on the Sensory Profile showed significant differences to that of typically developing children with several differences being found when compared to the a sample of children with autism and a sample of children with ADHD. The children with autism had more difficulties than the children with SLI on all sections of the Sensory Profile whereas the differences between the children with SLI and the children with ADHD varied.
Although the small sample size was a limitation, the study did provide provisional information to indicate differences between these populations. Therefore further research with a larger sample size will be of value to confirm the results of this study. The literature indicates that identifying the differences between dysfunction on the Sensory Profile can assist in discriminating between different groups and can therefore assist in the process of obtaining a diagnosis. This will be helpful in determining a differential diagnosis for children with SLI, autism and ADHD as all three groups have difficulties with speech and language, but have different sensory processing issues.
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Janine van der Linde