Brixton Test Research Articles

Further investigation of the Supervisory Attentional System in schizophrenia: Planning, inhibition, and rule abstraction

Introduction. This study investigated Supervisory Attentional System (SAS) functions in schizophrenic patients. Method. Fifteen schizophrenic patients and 15 normal controls matched for age, gender, and educational level were compared. Three tasks (Tower of London, Hayling, and Brixton tests) were used to examine three executive processes (planning, inhibition, and rule detection). Results. Schizophrenic patients performed significantly worse than normal controls on all three tasks. In addition, patients' performances on selected measures of the three tests were correlated, even when age and medication were partialled out. Conclusion. Patients are impaired on all SAS functions. The possible role of a general impairment (processing speed or cognitive resources) is discussed.

Supervisory Attentional System in Patients with Focal Frontal Lesions

The aim of this study was to re-examine the hypothesis of a link between frontal cortex and the Supervisory Attentional System (SAS; Shallice, 1988). Contrary to previous studies that examined patients with lesions extending beyond the frontal lobes (Shallice, 1982; Burgess Shallice, 1996a, 1996b), SAS or executive functions were evaluated in a group of patients with strict frontal lesions. Three tasks (Tower of London -TOL-, Hayling and Brixton tests) designed to assess specific SAS processes (planning, inhibition and ion of logical rules respectively) were administered. In the TOL test, although frontal patients were slower than control participants, the two groups did not differ in their ability to solve problems. Furthermore, the two groups did not differ in terms of performance in the Hayling and Brixton tests either. These results are discussed in terms of the SAS model and are compared to those observed by Shallice (1982) and Burgess Shallice (1996a, 1996b). Additionally, the issue of the neural subtract of executive functions is addressed.

Late event related potentials in schizophrenia : K.P. Ebmeier∗, A.R. Mackenzie∗, D. Potter∗∗, J.R. Crawford, J.A.O. Besson∗ and E. Salzen∗∗ ∗Department of Mental Health and ∗∗Department of Psychology, University of Aberdeen, Aberdeen, UK

This case series describes the cognitive functioning of 10 individuals who were briefly exposed to a mixture of organic solvents as a result of an industrial accident. Data were obtained 10 years after the exposure on measures of intellect, memory, attention, and executive functioning, using standardised neuropsychological measures including WAIS III, WMS III, Hayling and Brixton Tests, The Trail Making Test, Controlled Oral Word Association, Rey–Osterrieth Complex Figure Test, and The Speed and Capacity of Language-Processing Test. The group performed in the average range across the majority of measures but deficits (z > 1.0 S.D.) were observed on tests that measure speed of information processing, memory, attention, and verbal fluency. Discrepancy scores between the NART and the WAIS suggest subtle but statistically significant decline in performance IQ following solvent exposure.