COGNITIVE SCREENING OF NURSING-HOME RESIDENTS - FACTOR STRUCTURES OF THE MINI-MENTAL-STATE-EXAMINATION

OBJECTIVE: To examine factor structures of the Mini-Mental State Exami nation, attempting first to replicate any of previously proposed 2-fac tor solutions; and to explore, secondly, the presence of clinically mo re differentiated and statistically stable factor structures represent ing common neurocognitive dimensions. DESIGN: Factor analytic investig ation of descriptive dataset collected on nursing home residents. Two factor analyses were performed, one in which the number of factors was fixed at 2 in an effort to replicate previous studies, and one in whi ch the number of factors to retain was determined by the scree test. B oth factor analyses used established methods for judging the adequacy of the correlation matrix and the significance of factor loadings, and both applied principal components analysis for initial factor extract ion and the equamax criterion for orthogonal rotation. SETTING: Seven nursing homes with a total of 894 beds. PARTICIPANTS: 922 assessments on nursing home residents were performed, of which 892 were complete a nd entered into the factor analyses. The observation-to-variable ratio exceeded 81:1, assuring the statistical stability of factor solutions derived. MEASUREMENT: The Mini-Mental State Examination, with standar dization of words to be recalled and the inverted spelling of ''world' ' as the mental reversal task. MAIN RESULTS: Two factor structures wer e derived. A 2-factor solution, explaining 36.5% of the variance and s tatistically and conceptually different from those obtained in previou s studies, distinguished between Perceptual-Organizational and Psychom otor skills. A 4-factor solution, which explained 56.1% of the varianc e, included a factor named Executing Psychomotor Commands, while also further differentiating the perceptual-organizational processes into t he factors of Memory, Concentration, and Language. CONCLUSION: The 2-f actor solution shows that, notwithstanding previous claims to the cont rary, the MMSE can make stable and independent distinctions between ps ychomotor and perceptual-organizational processes. However, this solut ion is statistically and conceptually limited and, therefore, of limit ed clinical and scientific relevance. The 4-factor solution of the MMS E maps well onto commonly recognized dimensions of neurocognitive abil ity. It offers a stable, intuitively sound, and statistically supporte d framework for clinical differentiation of cognitive screening data i nto independent clinical dimensions of neurocognitive functioning. Thu s, it offers clinicians and researchers a 4-dimensional framework for interpreting data obtained by means of the MMSE. Studies with other po pulations of cognitively impaired and intact elderly are recommended t o validate and extend the present findings.