The standardised copy of pentagons test

Area of Science:

• Neuropsychology
• Psychometrics
• Clinical Psychology

Background:

• The 'double-diamond copy' task, part of the Bender-Gestalt Test and Mini Mental State Examination (MMSE), has crude scoring and unknown psychometric properties.
• Existing methods for this cognitive assessment lack sensitivity and reliability.

Purpose of the Study:

• To develop a sensitive and reliable method for administering and scoring the 'double-diamond copy' task.
• To establish the psychometric properties of a standardized version of the task.

Main Methods:

• A sample of 93 healthy controls and 127 schizophrenia patients participated.
• A new scoring method was developed based on control group response frequencies.
• Factor analysis was used to derive indices and subscales for the Standardised Copy of Pentagons Test (SCPT).

Main Results:

• The SCPT demonstrated acceptable reliability (Cronbach's α=0.61, test-retest=0.41, inter-rater=0.52).
• Factor analysis yielded two indices and six subscales.
• The SCPT scores effectively distinguished between controls and schizophrenia patients, with a discriminant function achieving 63.44% correct classification for controls and 75.59% for patients.

Conclusions:

• The Standardised Copy of Pentagons Test (SCPT) is a satisfactory, reliable, and valid instrument for assessing non-organic psychiatric patients.
• The SCPT is easy to administer, requires minimal time, and shows potential as a neuropsychological test.
• Further research is needed to fully explore the psychometric properties and applications of the SCPT.