Informant-Based Questionnaires in the Diagnostic Pathway for Screening of Cognitive Impairment.

Alzheimer's disease (AD) remains the most common form of dementia in elderly populations. Accurately diagnosing early forms of dementia and AD remains a significant clinical challenge, especially in fast-paced primary care settings. Informant-based questionnaires that rely on close caregivers of the patients, such as the Informant Questionnaire on Cognitive Decline in the Elderly, the Ascertain Dementia 8-Item, the Quick Dementia Rating System, and the Alzheimer's Questionnaire, have recently been shown to be a valuable supplement to current standards of diagnosis, such as performance-based tests. This review aimed to explore the key characteristics of various informant-based questionnaires and evaluate their efficacy in the medical setting. Analysis of each test demonstrated that informant-based assessments show a strong ability to detect cognitive impairment early on in its pathology and can highlight gradual decline over time, compared with the single-timeframe evaluations that performance-based tests provide. Informant-based questionnaires are also able to circumvent challenges associated with the patient's education level, language, and other cultural biases, thus making them useful in diverse populations. When used in conjunction with performance tests, informant-based tests can significantly streamline the diagnostic process for dementia and enhance management and treatment strategies. Further research is advised to effectively integrate these tests into routine clinical practice and establish a new standard of care.