Biomedical subjects

Simon M McCrea

Publications and source records attributed to Simon M McCrea.

2 recordsLinked to original sources

PubMed2006

A nonparametric study of the performance of cortical lesion patients on the Cognitive Assessment System.

Cortical lesion patients were tested on the Cognitive Assessment System (CAS) in the post-acute phase (median > or = 1 month) to determine the degree of sensitivity and specificity of the CAS subtests to neuropsychological impairment. Nonparametric ANOVA and subsequent Mann-Whitney statistics were used. Demographic variables of age, education, handedness, sex were controlled for Matching Numbers was sensitive to right-hemisphere lesions while Verbal-Spatial Relations was sensitive to anterior lesions. Receptive Attention and Figure Memory were sensitive to posterior lesions. Number Detection was sensitive to right anterior lesions. Nonverbal Matrices was sensitive right anterior lesions and the inclusion of a disproportionate number of left-handers within this specific group appeared to be partly moderating this effect. The magnitudes of the performance decrement for these subtests were substantial with Figure Memory demonstrating the largest effect. The results suggest that select CAS subtests could be useful for the multiple baseline assessment of neuropsychological functioning.

Adolescent↗

PubMed2006

Illusory conjunctions in simultanagnosia: coarse coding of visual feature location?

Simultanagnosia is a disorder characterized by an inability to see more than one object at a time. We report a simultanagnosic patient (ED) with bilateral posterior infarctions who produced frequent illusory conjunctions on tasks involving form and surface features (e.g., a red T) and form alone. ED also produced "blend" errors in which features of one familiar perceptual unit appeared to migrate to another familiar perceptual unit (e.g., "RO" read as "PQ"). ED often misread scrambled letter strings as a familiar word (e.g., "hmoe" read as "home"). Finally, ED's success in reporting two letters in an array was inversely related to the distance between the letters. These findings are consistent with the hypothesis that ED's illusory reflect coarse coding of visual feature location that is ameliorated in part by top-down information from object and word recognition systems; the findings are also consistent, however, with Treisman's Feature Integration Theory. Finally, the data provide additional support for the claim that the dorsal parieto-occipital cortex is implicated in the binding of visual feature information.

Aged↗