The revised French version of the Hierarchic Dementia Scale (HDS) was assessed in 88 DAT patients (30 men, 58 women, mean age: 70, MMS from 0 to 26). The HDS consisted of 20 subtests which covered the entire range of cognitive functions; each subtest was hierarchically organized. This scale has been validated by the authors in 149 control subjects (Démonet et al., 1990). The goals of the present study were to validate this scale in DAT patients in comparison with the MMS scores and to specify the cognitive impairments of our pathologic population. Results showed that the scores on the HDS were highly correlated with the MMS scores (p < .0001). Some subtests of the HDS (memory subtests and mental control) allow good discrimination between mild demented patients and controls (sensibility = 80.8 p. 100, specificity = 96 p. 100). Conversely some subtests allowed a cognitive follow-up of patients for whom the MMS was no longer useful (MMS scores from 0 to 10). In conclusion, it appears that this scale is useful for drawing cognitive profile of DAT patients and to approach the heterogeneity of dementia.