Correlation between cognitive impairment and the Rey auditory-verbal learning test in a population with Alzheimer disease.

Abstract

Patients affected by Alzheimer disease (AD) need an accurate diagnosis, to the extent allowing us to find the best therapy or polytherapy, in order to take under control their cognitive impairment. In our Alzheimer Evaluation Units (from the Italian name abbreviated: UVA), the patients undergo a multidimensional evaluation, which can address us towards a proper diagnosis and of other weakening, or even dementia-related diseases. The patients are also subject to neuropsychometric and neuropsychological evaluations, allowing a more focused analysis on cognitive impairments. Among the tests, we use the Rey auditory-verbal learning test (RAVLT), evaluating the patient's verbal memory. A list of 15 words is read to each patient. N the first part of the test, the clinician repeats 5 times such a list. the patient is hen asked, at the end of every repetition, to tell all words he/she remembers. This part is useful to evaluate the immediate recall (IR) ability. The score, i.e., the total number of recalled words, ranges from 0 to 75. After 15 minutes, the delayed recall (DR) ability is evaluated: the patient is newly asked to repeat as many words as he can recall from the list. The score for this part ranges from 0 to 15 minutes. The score is corrected of rage and education, with a cut-off of 28.5 for IR and 4.7 for DR. We made a survey with the purpose of deciding if there was a correlation between cognitive impairment and verbal memory lack, whose deficiency appears earlier in AD. To this aim, we selected several patients with AD, diagnosed during the period between September 2002 and February 2003. We only considered those patients whose AD was not associated with other weakening diseases, and whose clinical dementia rating scale (CDR) score was between 0.5-2.0. A sample of 35 individuals (11 men and 24 women) could be obtained. A meaningful correlation was observed between CDR and IR (r = -0.725, p < 0.01), as well as between CDR and DR (r = -0.470; p < 0.05). Such a result confirms the importance of evaluating immediate and long-term memories, for the early diagnosis of AD, because it is the only symptom of clinically not yet diagnosed dementia, as proven also by other studies.