A Three-Stage Algorithm for Quantification of the MMSE Interlocking Pentagon Areas

ABSTRACT The Mini-Mental State Examination (MMSE) is a widely employed assessment tool for measuring the severity of cognitive impairment. Among the MMSE items, the pentagon copying test (PCT) requires participants to accurately replicate a sample of two interlocking pentagons. While the PCT are traditionally scored on a binary scale, there has been limited developments of granular scoring scale to assess task performance. In this paper, we present a novel three-stage algorithm, called Quantification of Interlocking Pentagons (QIP), which quantifies PCT performance by computing the areas of individual pentagons and their intersection areas, and a balance ratio between the areas of the two individual pentagons. The three stages of the QIP algorithm include: (1) detection of line segments, (2) unraveling of the interlocking pentagons, and (3) quantification of areas. The QIP algorithm was applied to 497 cases from 84 participants. Analysis of the quantified data revealed a significant inverse relationship between age and balance ratio between two pentagon areas (beta = -0.49, p = 0.0033), indicating that older age was associated with a smaller balance ratio. The QIP algorithm enhanced the scoring of performance in the PCT. It can serve as a useful tool for granular level scoring of PCT.