The analysis of drawing from memory performance in brain-damaged patients

The drawing from memory task is frequently used in cognitive neuropsychology to investigate visual processing impairments. However, in surprising contrast to most other neuropsychological tests, the analyses of results on this task are most often based solely on qualitative judgements about the normality of a patient's performance. In most case reports, these judgements are not made with reference to normative data and are not made by individuals who are impartial with respect to the study (that is, using a blind rating procedure). There are several grounds for arguing that such analyses are inadequate. First, seemingly abnormal drawings made by a patient may well be within the range of performance shown by control subjects. Second, judgments that are not based on a blind rating procedure are likely to be influenced by knowledge about the patient's performance on other tasks. We describe an alternative assessment procedure that addresses both of these concerns.