Introduction: The objective is to establish the existence of possible correlations between cognitive measures using the a-BT, and functional measures in a population of normal to moderately severe demented subjects.
Methods: A sample of 107 subjects (42 healthy controls, 19 subjects with mild cognitive impairment and 46 patients with probable Alzheimer's disease) were included in the present study. The instruments of the cognitive measure used was the abbreviated Barcelona Test (a-BT), a test of general cognitive function. Apart from that, the following functional scales, evaluating activities of daily living, were used: Rapid Disability Rating Scale-2 (RDRS-2), Blessed Dementia Rating Scale (BDRS), and Interview for Deterioration in Daily living in Dementia (IDDD). The statistical procedures were the correlations between cognitive and functional measures using Pearson's correlation coefficient.
Results: The correlations obtained between the cognitive and all functional measures were all highly significant (p < 0.0001) and consistently high, with correlations ranging between 0.72 and 0.80. Correlations between the a-BT and functional measures of more basic activities of daily living (RDRS-2, BDRS) were lower than those that included instrumental and some advanced activities of daily living (IDDD).
Discussion: The present paper establishes the existence of satisfactory correlations between the functional measures studied and the global scores of the a-BT. These correlations are applicable for groups of subjects with cognitive impairment that does not reach the threshold of a diagnosis of dementia as well as subjects suffering from Alzheimer's disease, at least up to moderately severe cases. The global score of the a-BT allows for some degree of prediction of the functional status of a subject with suspected Alzheimer's disease pathology evaluated.