Informant Questionnaires in Dedicated Memory Clinics: How Much Do They Contribute?

Area of Science:

• Neurology
• Geriatrics
• Psychiatry

Background:

• Memory clinic diagnoses rely heavily on cognitive testing.
• Informant input via interviews or questionnaires can significantly influence diagnostic accuracy.
• The study evaluated the added value of informant questionnaires in diagnosing neurodegenerative disorders.

Purpose of the Study:

• To assess if informant questionnaires improve diagnostic predictability for neurodegenerative disorders.
• To compare the effectiveness of informant questionnaires against standard cognitive tests (CERAD, MMSE).
• To determine the impact of questionnaires on differentiating conditions like MCI, dementia, and depression.

Main Methods:

• Retrospective analysis of 394 patients with dementia, MCI, depression, or subjective cognitive impairment.
• Utilized logit models to predict diagnoses based on cognitive scores alone and in combination with informant questionnaires.
• Employed validated questionnaires including the Bristol Activities of Daily Living Scale and the Informant Questionnaire on Cognitive Decline in the Elderly.

Main Results:

• Informant questionnaires showed high correlations with each other.
• Adding questionnaires statistically improved diagnostic predictability between MCI and dementia, and dementia and depression.
• The reduction in misprediction rates was modest (up to 6 percentage points).
• Using multiple questionnaires or all CERAD subtests did not yield clinically relevant improvements.

Conclusions:

• Informant questionnaires contribute to statistically better diagnostic predictions for certain differential diagnoses.
• The clinical pertinence of these questionnaires may be limited when routine interviews are conducted by trained staff.
• Standardized, longitudinal assessment using questionnaires should not be underestimated.