Development
In the early development phase, an initial pool of items was generated, based on the World Health Organisation International Classification of Functioning, Disability and Health (WHO-ICF), which was further refined by a content analysis of semi-structured interviews with relatives of individuals with acquired brain injury.
Thus, SASNOS differs from existing NBD tools because it was designed specifically for ABI, is aligned with contemporary models of neurorehabilitation, and is focused on the objective measurement of a person’s behaviour.
As the SASNOS does not require highly specialised experts (a neuropsychologist/neurologist) for administration, a multidisciplinary mix of professionals then rated patients with ABI on the refined item set. Comprehensive statistical methods were then applied, including Rasch analysis – a novel approach that had not been applied to NBD previously.
A normative data set was also created to aid clinical diagnosis and to allow clinicians to produce a meaningful profile of strengths/weaknesses – an essential feature present in fewer than 40% of existing NBD tools.
Utilising 336 sets of ratings, multiple indicators of validity demonstrated that SASNOS ratings recorded perceived symptoms of NBD and could reliably distinguish between individuals with and without ABI. Norm-referenced interpretation of ratings was also undertaken by converting ratings to T-scores to enable comparison for diagnostic purposes with a neurologically healthy control group and for clinicians to construct a meaningful profile of strengths and weaknesses.
The stability and consistency of ratings over time was also evidenced via multiple indices – inter-rater reliability, test-re-test reliability and Rasch analysis. Thus, two critical psychometric properties of the tool, namely, its validity and reliability, were established.
The SASNOS was then further strengthened by adding a supplementary scoring system to convey the impact of support received on ratings of NBD, and by fulfilling the final component of the triumvirate of psychometric properties; responsiveness.
Description
Behaviours and symptoms of NBD are rated on 49 items which measure five major domains of NBD – interpersonal behaviour, cognition, aggression, inhibition and communication; each has 2-3 subdomains.
Each item consists of a statement regarding a behaviour or other symptom of NBD whose perceived prevalence is rated using a seven point scale (‘never’ to ‘always’).
An Excel spreadsheet is used to calculate a range of standardised scores based on ratings of a neurologically healthy sample. Scoring is constructive, so higher ratings equate to a greater perception of ability.
The profile of NBD can be used to determine needs, track recovery and response to rehabilitation, and for research purposes.
Benefits
To find out more about the benefits of SASNOS, you can explore our Why Choose SASNOS page and read testimonials from professionals who use SASNOS in practice.