Epidemiological dementia index: a screening instrument for Alzheimer's disease and other types of dementia suitable for use in populations with low education level.

INTRODUCTION

MMSE and CAMCOG are neuropsychological scales developed for use in everyday clinical practice and epidemiological surveys.

MATERIAL AND METHODS

These two instruments were used as part of the assessment during an epidemiological survey in the municipality of Pylaia, Greece. The project was based on the World Health Organization Program for Research on Aging and Age-Associated Dementias (1992). It had two phases. During phase I, nursing students collected demographic data, risk factors, personal and family history data and they applied MMSE, CAMCOG and scales of everyday life functioning. During phase II, 4 physicians examined all subjects that manifested possible cognitive deterioration (MMSE<27), in order to reach a final diagnosis. The final diagnosis was made according to DSM-IV and NINCDS-ADRDA criteria. MMSE and CAMCOG were not taken into consideration in the diagnostic process. Three hundred and eighty subjects were initially screened. All were aged over 70 years. After the exclusion of subjects who were illiterate, blind, etc., the results of 277 subjects were finally analyzed. Subjects with 6 years of education or less accounted for 92.42% of the total study sample. Twelve of them (5.33%) suffered from Alzheimer's disease, 7 from vascular dementia (2.52%) and 1 suffered from secondary dementia (0.36%).

RESULTS

MMSE exceeded 90% sensitivity at the level 22/23 and specificity at 14/15. The levels for CAMCOG were 56/57 and 43/44, respectively. This low performance of both tests is to a large extent due to the functional illiteracy of elderly individuals in Greece, to possible coexistence of mood disorders or simply to lack of cooperation. The analysis of data led to the development of an Epidemiological Dementia Index (EDI), with a scale ranging from 0 to 7. Nondemented subjects had a mean EDI of 5.12 (SD = 1.67) and demented patients had a mean EDI of 1.6 (SD = 1. 92). At the level 4/5 sensitivity was 93.33. Specificity was 93.56 at the level 2/3.