The primary aim of this research was to investigate the nature of tactile modulation dysfunction as it applies to children with cerebral palsy and to use this information to develop an assessment of tactile modulation dysfunction. A further aim was to commence the process of investigating the psychometric properties of the assessment. Tactile modulation, and sensory modulation in general, have recently been the focus of research attention in other populations of children, however our understanding of these constructs as they apply to children with cerebral palsy is limited. When children have difficulties responding to tactile information, it is believed to have broader implications for their development, learning and their interaction with people and their environment. Consequently, occupational therapists are interested in minimising these difficulties to improve children's functional skills and the quality of life for both children and families.
An inductive exploratory study was conducted to investigate the responses of children with cerebral palsy to tactile stimuli. In-depth interviews were conducted with the mothers, occupational therapists and teachers of 5 children with cerebral palsy and observations were made of the children at home, in an occupational therapy session and at school where possible. The data underwent an inductive thematic analysis. The results of this study identified a range of issues that were important for the development of an assessment of tactile modulation, the primary one being the need to focus on behavioural responses rather than developing a trait based assessment.
The results of the exploratory study were then used along with current theory, empirical literature, and the clinical experience of the researcher to develop the Tactile Behaviour Observation System (TBOS). The TBOS is a direct observation behavioural assessment that measures the responses of children with cerebral palsy to tactile stimuli in selected activities. Content validity of the TBOS was evaluated by an expert panel review. Six experts rated all aspects of the TBOS highly and their comments resulted in some minor modifications to the TBOS. A caregiver report version of the assessment, the Tactile Behaviour Caregiver Report (TBCR), was developed at this point in time as a possible alternative method of assessment.
Accuracy of the TBOS coding system was investigated via the use of a script as an incontrovertible index, against which data obtained with the TBOS was compared. The TBOS coding system was found to be accurate for all behaviours, with the exception of one, withdrawal, which did not meet the minimum requirement of 80% accuracy. A preliminary study of interobserver agreement was also conducted in which three therapists observed six children performing 41 activities. Two behaviours, withdrawal and bilateral hand use, had fair to good interobserver agreement for frequency (k = 0.53 and k = 0.56), with all other behaviours having good to excellent (k = > 0.7) interobserver agreement. There was limited evidence to support the convergent validity of the TBOS with the TBCR and it was concluded that direct observation is a more suitable method than caregiver report for collecting detailed information regarding behavioural responses to tactile stimuli for children with cerebral palsy.
The treatment utility of the TBOS was investigated by two case studies. Two occupational therapists administered the TBOS to a child with cerebral palsy and used their assessment results to plan and carry out a 12 week intervention program. Data sources included questionnaires completed by the therapists, the researcher's field notes, videotaped observations of the sessions, and informal interviews with the therapists. The results indicated that the TBOS positively affected the therapists' conceptualisation of the children's tactile difficulties, their clinical decision making and the children's outcomes.
This research has begun the process of understanding tactile modulation dysfunction in children with cerebral palsy, leading to the development of the TBOS and evaluation of its psychometric properties. Future work to be done in the area of psychometric evaluation is outlined. The TBOS has the potential to be used in clinical and research environments and in particular can be used to commence investigation of the effectiveness of intervention programs, and to further develop theoretical knowledge of tactile modulation in cerebral palsy. The results of this research are discussed in relation to the application of sensory modulation theory to cerebral palsy.