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Research Highlight | 6 July 2020

The ABCs of dementia

A scale could evaluate degrees of dementia, and plot the condition’s development more accurately.

An alternative scale for evaluating the severity of dementia is more accurate than the standard scale, researchers in Japan have revealed1. This finding could help to more accurately identify people who have the onset of dementia and trace its development.

More than 4.6 million people in Japan suffer from dementia. As the proportion of the population older than 65 increases, the condition will significantly strain the country’s healthcare system. To manage this risk, scientists in Japan have been seeking a way to dynamically monitor the development of symptoms from mild cognitive impairment (MCI) to severe dementia.

The global standard for diagnosing MCI is a score of 0.5 in the Clinical Dementia Rating (CDR), a rating from 0 to 3, where 1, 2, and 3 correspond to mild, moderate, and severe dementia, respectively. The rating is calculated based on five areas: memory, orientation, judgment and problem solving, home and hobbies performance, and community affairs.

However, there may be a better indicator of MCI, a study led by Kenji Wada-Isoe, a professor at Kawasaki Medical School’s Department of Dementia Research, and Takashi Kikuchi, a medical statistician at TRI, has suggested.

Wada-Isoe and colleagues across Japan conducted a cluster analysis that compared the use of CDR to the ABC Dementia Scale (ABC-DS), which measures changes in activities for behavioural and psychological symptoms of dementia, and cognitive function.

“Our previous studies had shown that the ABC-DS may be useful in diagnosing dementia and assessing its severity,” says Wada-Isoe. “However, it was unknown whether the ABC-DS could evaluate symptoms of MCI patients.”

The team’s cluster analysis revealed that not only could the ABC-DS assess symptoms of MCI patients; it was also more accurate than CDR at identifying those with MCI1.

“While a modified form of CDR called CDR-SOB (sum of boxes) is useful for more accurate determination of MCI in clinical research, the determination is time-consuming and complicated,” says Wada-Isoe. “The ABC-DS, by comparison, can evaluate MCI easily and is more useful in general practice.”

In a subsequent study, the team evaluated the ABC-DS for tracking the development from MCI to severe dementia2.

“By repeatedly evaluating the symptoms of dementia patients using ABC-DS, it is possible to grasp the changes of clinical symptoms longitudinally,” says Wada-Isoe. Understanding the changes in these symptoms is useful for selecting therapeutic agents, understanding their effects, and estimating a patient’s prognosis.

“Our cross-sectional analysis of patients with mild to severe dementia revealed that the ABC-DS might indicate the trajectory of symptoms related to activities for daily living, behavioural and psychological symptoms of dementia, and cognitive function,” says Wada-Isoe.

Researchers can download the ABC-DS questionnaire in English, French, Chinese, and Korean here under the terms and conditions specified.

The next step is to demonstrate the utility of the ABC-DS in clinical practice by conducting a longitudinal study, Wada-Isoe says.


  1. Wada-Isoe, K., Kikuchi, T., Umeda-Kameyama, Y., Mori, T., Akishita, M. & Nakamura, Y. Global clinical dementia rating score of 0.5 may not be an accurate criterion to identify individuals with mild cognitive impairment. Journal of Alzheimer’s Disease Reports 3, 233–239 (2019). | article
  2. Wada-Isoe, K., Kikuchi, T., Umeda-Kameyama, Y. & Mori, T. ABC dementia scale classifies Alzheimer’s Disease patients into subgroups characterized by activities of daily living, behavioral and psychological symptoms of dementia, and cognitive function. Journal of Alzheimer’s Disease 73, 383–392 (2020) | article

About the Researcher

Kenji Wada-Isoe, Professor, Department of Dementia Research at Kawasaki Medical School

Kawasaki Medical School

Takashi Kikuchi, PhD, DPhil, Translational Research Center for Medical Innovation, Foundation for Biomedical Research and Innovation at Kobe

Translational Research Center for Medical Innovation

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