Validation of brief cognitive tests in mild cognitive impairment, Alzheimer's disease and dementia with Lewy bodies

Abstract: Background
It is estimated that 34 million people suffer from dementia, costing society US$422 billion each year. Alzheimer’s disease (AD) is the most common dementia and the global prevalence is predicted to increase to over 100 million people by the year 2050, with the greatest increase in developing countries. Therefore, inexpensive and efficient instruments are required for investigation and evaluation.

Aim
To evaluate the brief cognitive tests cube copying, clock drawing, the Mini-Mental State Examination (MMSE) and A Quick Test of Cognitive Speed (AQT) in the early diagnosis, treatment evaluation and differential diagnosis of dementias.

Populations
I. 85 patients with AD.
II. 33 patients with dementia with Lewy bodies (DLB) and 66 with AD.
III. 75 patients with AD.
IV. 99 patients with mild cognitive impairment (MCI).

Findings
I. Cube copying was found useful for evaluating treatment with acetylcholinesterase inhibitors (AChEI) in patients with AD.
II. Easy and quick interpretations of the MMSE, clock drawing and cube copying differentiated patients with DLB from patients with AD.
III. AQT was twice as sensitive as the MMSE in detecting treatment response to AChEI in patients with AD.
IV. The MMSE, AQT and clock drawing were as accurate as cerebrospinal fluid biomarkers (tau, Aβ42 and P-tau) in predicting development of AD and dementia in mild cognitive impairment during an average of five years.

Conclusion
This thesis has improved the validity of brief cognitive tests and contributed with results that can be clinically relevant for evaluating treatment of AD, differentiating DLB from AD, and predicting development of AD and other dementias.