Abstract :
When assessing cognitive impairment and dementia, clinicians often seek information from informants to complement the findings from cognitive tests. In recent years, a number of standardized methods have been developed for collecting informant data, but these are not widely known. There are several advantages of using these methods including: everyday relevance, acceptability, useability with nontestable subjects, administration by telephone or mail, potential longitudinal perspective, and greater cross-cultural portability. This review identified 12 scales measuring cognitive impairment as a continuum, and four instruments for diagnosing dementia on the basis of informant data. Research on the psychometric properties of these instruments is reviewed. It is concluded that informant-based measures tap a global factor of cognitive impairment, are highly reliable, correlate with cognitive tests, and discriminate demented from nondemented subjects. Non-cognitive factors and informant characteristics are also likely to influence informantsʹ ratings, but less is known about these influences. Although informant-based methods are a comparatively recent development, existing findings support their use as a complement to cognitive testing, particularly in assessment of dementia.
