[Clinical validity of two scales of instrumental activities in Alzheimer's disease].
BACKGROUND
Activities of daily living (ADL) are a major domain in the clinical assessment of Alzheimer's disease (AD) patients. However, ADL scales have not been sufficiently validated in Spain.


METHODS
Patients attending a neurology outpatient clinic were classified according to the global deterioration scale (GDS). Afterwards, an independent evaluator administers two scales of instrumental activities of daily living (IADL): Lawton and Brody's scale of IADL (SIADL) and Pfeffer's functional activities questionnaire (FAQ). The SIADL was scored in the original way (dichotomic) (SIADLd) and in an alternative way (ordinal) (SIADLo). Internal consistency (Cronbach alpha coefficient), test-retest reliability (intraclass correlation coefficient), diagnostic validity (sensitivity, specificity, number of patients correctly classified) and influence of different variables (regression analysis) were analyzed for the SIADLd, the SIADLo and the FAQ.


RESULTS
Ninety-eight patients were recruited. Internal consistency, reliability and diagnostic validity were good or excellent for the three scales. The SIADLo showed better diagnostic and scale features than the SIADLd, but the FAQ surpassed both in all the studied variables. No scale was able to make a proper distinction between patients with subjective complaints (GDS 2) and patients without complaints (GDS 1). Sex and age influenced the SIADL score, but not the FAQ score. The FAQ reached a sensitivity of 0.95 and a specificity of 0.88 in the screening of dementia.


CONCLUSIONS
The SIADL and the FAQ are useful, valid and reliable tools for the clinical assessment of AD patients. Ordinal scoring is more advantageous than dichotomic scoring in the SIADL, but the FAQ is preferable.
Olazarán
J
J
Consulta de Neurología, CEP Hermanos Sangro, Madrid. javier@mariawolff.es
Mouronte
P
P
Bermejo
F
F
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006801:Humans; D008609:Mental Status Schedule; D008875:Middle Aged; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013030:Spain; D011795:Surveys and Questionnaires