How do cognitively impaired elderly patients define "testament": Reliability and validity of the testament definition scale

The testament definition scale (TDS) is a specifically designed six-item sc ale aimed at measuring the respondent's capacity to define "testament." We assessed the reliability and validity of this new short scale in 31 communi ty-dwelling cognitively impaired elderly patients. Interrater reliability f or the six items ranged from .87 to .97. The interrater reliability for the total score was .77. Significant correlations were found between the TDS s core and the Mini-Mental State Examination (MMSE) and the Cambridge Cogniti ve Examination scores (r=.71 and .72 respectively, p=.001). Criterion valid ity yielded significantly different means for subjects with MMSE scores of 24-30 and 0-23: mean 3.9 and 1.6 respectively (t(20)=4.7, p=.001). Using a cutoff point of 0-2 vs. 3+, 79% of the subjects were correctly classified a s severely cognitively impaired, with only 8.3% false positives, and a posi tive predictive value of 94%. Thus, TDS was found both reliable and valid. This scale, however, is not synonymous with testamentary capacity. The disc ussion deals with the methodological limitations of this study, and highlig hts the practical as well as the theoretical relevance of TDS. Future studi es are warranted to elucidate the relationships between TDS and existing le gal requirements of testamentary capacity.