Relevance of 10-min delayed recall in dementia screening.

Within the context of early diagnosis of Alzheimer's disease (AD), there is a growing interest in neuropsychological screening tests. Amongst these tests, we focused on the largely used Memory Impairment Screen (MIS). The objective of the present work was to show that adding a 10-min delayed recall to the MIS, improves the test psychometric characteristics in order to detect dementia in the earliest stages. A prospective study was carried out on a cohort of 270 consecutive elderly ambulatory subjects attending the Broca Hospital Memory Clinic: normal controls (n = 67), mild cognitive impairment subjects (n = 98) and mildly demented patients [n = 105, Mini Mental State Examination (MMSE) = 23 +/- 4]. This study consisted in testing the advantage of the 10-min delayed recall entitled MIS-D compared with the MIS. At a cut-off score of 6, the MIS-D revealed satisfying psychometric characteristics with a sensitivity of 81% and a specificity of 91%, whilst the MIS alone indicated a sensitivity of 60% and a specificity of 88% in detecting dementia. In demented patients with MMSE score > or =26, MIS-D properties still remained satisfying (sensitivity: 75%, specificity: 92%). MIS-D is a more relevant screening test than MIS alone at very early stages of dementia.

Accidental MCI in healthy subjects: a prospective longitudinal study.

A study was realized on 130 healthy and autonomous volunteers (60-80 years old) who met specific medical and functional inclusion criteria. A comprehensive battery of neuropsychological tests was performed at baseline (M0), 6 and 12 months (M6, M12). At M0 the results indicated that 65% were cognitively normal on each of all the neuropsychological tests, whereas 35% presented a cognitive deficit on one or more tests. At M12, 52% of the subjects who had a cognitive deficit at M0 remained impaired, whereas 48% normalized their scores: they performed as well as the subjects classified normal at M0. The results also indicated that the subjects who remained impaired at M12, had at M0 low scores on three tests or more, whereas the ones who normalized their scores had one or two failed tests. This study focuses on the risk of false positive cases and shows that low scores can be accidental. The authors propose decision rules allowing to reduce the risk of false positive cases. The observation of accidental impairment invites to be cautious and makes this 1-year follow-up study particularly relevant, since a 1-year follow-up is generally needed to diagnose very mild dementia.