A standardized scoring method for the copy of cube test, developed to be suitable for use in psychiatric populations

The study sample included 93 healthy control subjects (53 women and 40 men) aged 35.87 ± 12.62 and 127 patients suffering from schizophrenia (54 women and 73 men) aged 34.07 ± 9.83 years. The psychometric assessment included the Positive and Negative Symptoms Scale (PANSS) the Young Mania Rating Scale (YMRS), and the Montgomery-？sberg Depression Rating Scale (MADRS).A scoring method was developed based on the frequencies of responses of healthy controls. Cronbach's α was equal to 0.75 and inter-rater reliability was 0.90. Three indices and five subscales of the Standardized Copy of the Cube Test (SCCT) were eventually developed. They included the Deficit Index (DcI), which includes the Missing Elements (ME) Mirror Image (M) subscales, the Deformation Index (DfI) which includes the Deformation (D) and the Rotation (R) subscales and the Closing-In Index (CiI).The SCCT seems to be a reliable, valid and sensitive to change instrument for the testing of psychiatric patients. The great advantage of this instrument is the fact that it only requires paper and a pencil, and is this easily administered and brief. Further research is necessary to test its usefulness as a neuropsychological test.The copy of cube task is a well known, simple paper and pencil test which is part of the Short Test of Mental Status (STMS) [1,2]. Additionally, patterns of blocks of cubes are incorporated in the Bender Gestalt Test [3-11]. This simple test demands the copy of a Necker cube. This shape is an optical illusion first published in 1832 by the Swiss crystallographer Louis Albert Necker, and it is an ambiguous line drawing. In essence, it is a wireframe drawing of a cube in isometric perspective. This means that parallel edges of the cube are drawn as parallel lines in the picture. The ambiguity lies in the fact that when two lines cross, the picture does not show which is in front and which is behind. This leads to what is called multistable perception, since sometimes the observer might ex