Screening of cognitive functions: analysis and development of neuropsychological test instruments

INTRODUCTION: Cognitive impairments are common after stroke, particularly those involving the executive functioning, which is a complex cognitive construct encompassing a collection of interrelated functions (or set of processes) that are responsible for controlled goal-directed behaviours to novel or complex situations (Gioa, Isquith, & Guy, 2001). Therefore, deficits in executive processes can affect an individual profoundly. There are numerous executive measures currently available, however they are mostly language-laden, and therefore not ideal for stroke patients who are present with aphasia and neglect. Accordingly, in this thesis we aimed to develop unbiased measures of planning/organisation (the 'systematicity' index) using performance-based, language reduced, nonverbal tasks that are suitable for use in a stroke population. METHOD: Initially, we examined the cognitive variation in stroke profile, across various stages, using the Birmingham Cognitive Screen (BCoS: Humphreys, Bickerton, Samson, & Riddoch, 2012). Subsequently, we developed three novel scoring measures, on two key tests: 1) the Broken Hearts test (from the Oxford Cognitive Screen (OCS): Demeyere, Riddoch, Slavkova, Bickerton, & Humphreys, 2015) and 2) the Complex Figure test (from the BCoS/OCS). RESULTS: Measures include: I) The 'Nearest Neighbour' measure - validated against the subjective ratings provided by experienced neuropsychologists (of how systematic a patient is during cancellation) and a measure of executive function (EF); 2) the 'Global - Local Scoring System' - a qualitative scoring system that provides an index of executive measure for the BCoS Complex Figure which was validated against subjective ratings from experienced neuropsychologists and other measures of EF; 3) the 'automated Global-Local Scoring System'- validated against the 'Nearest Neighbour' measure on the overall cancellation performance. CONCLUSION: We conclude that these measures would be beneficial to clinicians in terms of measuring planning/organisation abilities of stroke survivors and freeing them from time consuming and tedious tasks