16 Development of a Systematic Scoring System to Measure Adherence to a Temporal-Spatial Heuristic when Completing the Rey Complex Figure Task

Objective:It has been established that capturing how an individual draws the Rey Complex Figure Task (RCF) is as important as assessing what is drawn (Rey, 1941, Osterrieth, 1944). Despite the development of multiple systems that have been designed to measure these qualitative characteristics there are still no systematic means to measure adherence to the temporal-spatial heuristic that represents a typical drawing practice in healthy, neurotypical adults (Visser, 1973; Hamby et al, 1993).This study sought to develop a system for scoring temporal-spatial adherence when drawing the figure to provide objective, continuous data.Participants and Methods:Fifty-three English-speaking adults (mean age 44.61 yrs, SD 12.48; 44 female) were recruited. Exclusion criteria included vision and hearing impairment not corrected by aids; neurodivergent, neurological or psychiatric diagnosis, cancer or brain injury history. Participants completed the RCF copy phase as part of an extended neuropsychological battery. The RCF drawing process was recorded via video and a ball-point pen that digitally recorded drawing. Order data for the 18 RCF elements (Osterrieth, 1944,Taylor, 1959) was recorded by two scorers and analysed via Principal Component Analysis (PCA) with an equimax rotation to identify elements typically drawn together by a healthy, neurotypical adult. Using scoring methodology adapted from Geary et al (2011), the extent to which participants drew consecutively the member elements of each factor or 'strategy cluster’ was calculated and recorded. Strategy Cluster Scores across the population sample were examined to understand normative performance.Results:Order data was examined for interrater reliability via Pearson’s correlation coefficient and was considered good (r2 = 0.78, p < 0.001). PCA identified four factors or 'strategy clusters’ that were statistically robust and accounted for 67.34% of total variation. The strategy clusters were Core Structure (rectangle, diagonal, horizontal, vertical); Triangular Structure (triangle, horizontal in triangle, vertical in triangle, diamond); Internal Left-Hand Side (four horizontal lines, smaller rectangle, horizontal in top-left quad); and Internal Right-Hand Side (five lines, circle, vertical top-right quad, small triangle). The mean RCF Strategy Cluster Score was 6.23 (SD 1.94; possible range: 2.75 to 10). Population data spread indicated that healthy neurotypical adults only partially observed a temporal-spatial heuristic, rather than strict, absolute adherence.Conclusions:Four strategy clusters were identified where cluster members were typically drawn consecutively. RCF Cluster Strategy scoring was shown to measure the temporal-spatial heuristic objectively, providing continuous data that lends itself to clinical standardisation. Further, the study demonstrated that whilst healthy, neurotypical adults copy the RCF using a temporal-spatial heuristic, it is only partially adhered to. Traditionally deviation from strict adherence to the four strategy clusters during drawing was deemed to be indicative of cognitive dysregulation, however our findings demonstrate a normal distribution of typical population performance. These findings have important implications for interpreting how RCF drawing strategy informs clinical assessment and diagnosis as both very strict and very weak adherence to a temporal-spatial heuristic can be indicative of atypical function. The study supports this novel scoring system as a fast and reliable means to systematically measure RCF Cluster Strategy that with further validation could be adopted within clinical practice.