At present, one in every 10 people aged ≥65 years has dementia and dementia is regarded as a ‘common disease’.1,2 In addition, the initial symptoms of dementia, such as forgetfulness, tend to be overlooked because people consider that ‘it cannot be helped due to aging’. Patients often visit a hospital after developing behavioral problems, such as wandering and violence, which is not early detection because the symptoms have already progressed. Thus, difficulties with the early detection of dementia are major problem in its treatment. Alzheimer-type dementia, as the main type of dementia at present, can be treated with donepezil hydrochloride (Aricept; Eisai, Tokyo, Japan) and early detection is necessary. The possibility of preventing dementia by early detection has also been demonstrated5–7 and dementia screening has attracted attention. Herein, I describe the present status of dementia screening, although there is a lack of convincing data because this type of screening has just started. The main difference among the different screening procedures that have been used until now is the method used at the first-stage screening. Therefore, the present status of screening is discussed according to the first-stage screening method.
SCREENING METHOD USING A QUESTIONNAIRE
The screening method using a questionnaire can be readily performed. This method is often used in screenings led by medical associations and performed in Morioka City, Iwate Prefecture, Gunma Prefecture, and Tokushima City, Tokushima Prefecture. In Morioka City, Iwate Prefecture, this screening was initiated in 2002 and a questionnaire developed by the medical society is used in both the first- and second-stage screenings. In 45 medical institutions, mainly institutions with which the examinees' primary care physicians are affiliated, a forgetfulness test was performed. In the first-stage screening, examinees who could not answer at least three of 15 questions (such as ‘presence/absence of a spouse’, ‘presence/absence of a family living with the examinee’, ‘cannot remember all contents of breakfast’, and ‘cannot describe five kinds of vegetable’) were required to undergo second-stage screening. In the second-stage screening, examinees who gave the wrong answer to two or more of the 10 items (such as ‘What month of the year is it now?’ or ‘What is your date of birth?’) were referred to medical institutions with specialists. In 2002, Alzheimer-type dementia was detected in 17 of 473 examinees, cerebrovascular dementia was detected in seven and depression and other diseases were detected in three subjects. In 2003, 95 institutions participated and there were 2336 examinees in the first-stage screening, of whom 1037 underwent the second-stage screening and 117 required third-stage screening. After exclusion of 42 examinees who have either not yet undergone or refused third-stage screening, 75 underwent the third-stage screening and Alzheimer-type dementia was detected in 26 examinees, cerebrovascular dementia in six, other types of dementia in six, mild cognitive impairment (MCI) in 17, depression in four and no abnormalities in 16. Thus, of the examinees in the first-stage screening, 2.1% had dementia or MCI.
In Tokushima City, Tokushima Prefecture, of 53 290 inhabitants aged ≥40 years who were invited to a basic health examination given in 2005 by the Tokushima City Medical Association, 3643 underwent a forgetfulness test. In the first-stage screening, a questionnaire was used and detailed examination was considered to be necessary in the case of 1061 examinees, of whom 755 underwent second-stage screening. The second-stage screening was performed by physicians using the Mini Mental State Examination (MMSE). As a result, dementia was suspected in 210 of 755 examinees. After detailed examination, Alzheimer-type dementia was detected in 97 examinees and cerebrovascular dementia was detected in 31 (total 128). Of all examinees, 3.5% showed dementia.
The screening in Gunma Prefecture is performed on inhabitants aged ≥60 years. As the first-stage screening, a self-administered questionnaire consisting of 20 items is distributed and examinees check applicable items and return the questionnaire to the place of the basic health examination. Examinees who check less than five items are considered normal, whereas those who check five or more items are required to undergo the MMSE as the second-stage screening, which is performed by specialists, such as health nurses. An MMSE score ≥25 indicates no abnormality. Examinees with an MMSE score ≤24 are referred to their primary care physicians or specialists. In 2003, this screening was performed in Shin-machi, Myogi-machi, Kitatachibana-mura, Kasukawa-mura, Kurohone-mura and Haruna-cho, Gunma Prefecture. There were 5139 examinees in the first-stage screening, of whom 1633 (31.8%) who checked five or more items underwent the second-stage screening. The MMSE score was ≤24 in 281 examinees (5.5%). No abnormality was observed by detailed examination in 111 subjects (2.2%), patients were referred back to their primary care physicians for observation and drug treatment in 119 cases (2.3%) and detailed examination was performed by specialists in 53 subjects (1.0%). In 2004, this screening was performed in Shin-machi, Myogi-machi, Kitatachibana-mura, Kasukawa-mura, Kurohone-mura, Haruna-cho, and Oomama-mura. There were 6921 examinees in the first-stage screening, of whom 1429 (20.6%) checked five or more items and underwent the second screening. The MMSE score was ≤24 in 228 examinees (3.3%). No abnormality was observed by detailed examination in 88 examinees (1.3%), patients were referred back to their primary care physicians for observation and drug treatment in 70 cases (1.0%) and detailed examination was performed by specialists of 70 subjects (1.0%).3
METHOD USING THE FIVE-COG
In approximately 3000 inhabitants aged ≥65 years in Tone-cho, Ibaragi Prefecture, assessment of the mood state (Geriatric Depression Scale; GDS), activities of daily living/instrumental activities of daily living (ADL/IADL) and a cognitive function test (Five-Cog) are performed as the first-stage screening process. The Five-Cog is a cognition test specified for the diagnosis of the prodromal condition (memory, attention, inference, language and visuospatial perception). The test is displayed using a projector and can be performed in a group (maximum 50 examinees). The time required for this test is 30 min. As the second-stage screening, a structured interview and individual test are performed. Cognitive function and the mental state are evaluated in all examinees with suspected depression indicated by GDS and randomly selected examinees by psychiatric physicians. Of the inhabitants invited to the screening, 70% participated and door-to-door visits, an institution survey and a survey using care insurance applications were performed in addition to group tests. As a result, the incidence of dementia was estimated to be 10% in inhabitants aged ≥65 years (cf. previous national surveys that indicated an incidence of only 6%). The incidence of prodromal conditions was 3% for MCI (constant in each 5-year age group) and 7% for age-associated cognitive decline 1 (AACD1) memory.4
METHOD INVOLVING A SCREENING SYSTEM USING A TOUCH-PANEL COMPUTER
The subjects who were screened using this method comprised 49 patients with Alzheimer-type dementia and 30 healthy controls. The touch-panel computer uses a dialog form consisting of sounds and images, and subjects can undergo examination while answering questions as if they were playing a game. There is a total of five questions, including those concerning words, time and date, and cube distinction, and the examination is completed within 5 min, including the time for the printing of results. Most patients with Alzheimer-type dementia showed a score ≤12 (perfect score 15), requiring examination by specialists (Fig. 1). The sensitivity (positive results in the presence of disease) of this screening method was 96% and the specificity (negative results in the absence of disease) was 97%, showing high reliability.5 In addition to reliability, this method excludes any examiner-related differences, induces only minimum psychological and physical stress, and can be readily performed anywhere. This screening system using a touch-panel computer is available commercially (Forgetfulness Consultation Program; Nihon Kohden, Tokyo, Japan) and can be used generally (Fig. 2). At present, periodical examination using this system allows the early and accurate detection of dementia. Examinations performed using this system have been introduced in Japan as described below.
Screening in Oshima-cho Suo, Yamaguchi Prefecture
Oshima-cho in Suo, Yamaguchi Prefecture, is a town on the Seto Inland Sea with a population of 22 000. The subjects of screening in this town are all inhabitants aged ≥65 years. As the first-stage screening, examination using the Forgetfulness Consultation Program is performed. Examinees with a score <13 (perfect score 15) are required to undergo second-stage screening. In the second-stage screening, MMSE, instrumental activity of daily living (IADL) assessment and a health and lifestyle survey are performed. Examinees with an MMSE score ≤24 are considered to require detailed examination and are referred to medical institutions with specialists. In 2004, 979 inhabitants underwent the first-stage screening and 237 (24.2%) who had a score <13 underwent the second-stage screening. As a result, 29 inhabitants (13.8%) were determined to require detailed examination. In 2005, there were 724 examinees in the first-stage screening, of whom 163 (22.5%) had a score <13 and underwent second-stage screening, with 56 (35.6%) requiring detailed examination. In 2005, because the MMSE cut-off value in the second-stage screening was changed to ≤26 so as not to overlook MCI, the number of examinees requiring detailed examination increased to 56 (35.6%). Using either cut-off value, overlooking patients with dementia at this stage may be infrequent if the Forgetfulness Consultation Program is used as the first-stage screening.
Screening in Kotoura-cho in Tohaku-gun, Tottori Prefecture
On 1 September 2004, Tohaku-cho and Akasaki-cho merged to become Kotoura-cho, which has a population of 20 119 and an aged population (≥65 years) of 5782 (28.7%). As the first-stage screening test, the Forgetfulness Consultation Program was used. Examinees with a score <13 (perfect score 15) were required to undergo second-stage screening. In the second-stage screening, assessment on the Alzheimer's Disease Assessment Scale (ADAS) using a touch-panel computer (TDAS) was performed.6 In 2004 (former Tohaku area), 558 of 2767 inhabitants (20%) invited to the screening underwent first-stage screening, 208 examinees (37.3%) underwent second-stage screening and 93 of the original sample subjected to first-stage screening (16.7%) were considered to have MCI or mild dementia.
Screening in Goshogawara City, Aomori Prefecture
In the first-stage screening for dementia, brain health assessment and examination using the Forgetfulness Consultation Program were performed. In the second-stage screening, MMSE and TDAS assessment were performed, and their usefulness was compared. In addition, a questionnaire was completed by the examinees and examiners. In the first-stage screening, examinees who checked five or more items on the brain health check table and those with a score <13 using the Forgetfulness Consultation Program were required to undergo second-stage screening. In the second-stage screening, examinees with an MMSE score ≤24 and those with a TDAS score ≥7 were considered to have signs of dementia. Examinees requiring detailed examination were referred to medical institutions with specialists. As a result, of 302 examinees in the basic health examination, 154 (51%) underwent first-stage screening. As the second-stage screening, 21 (13.6%) and 32 (20.8%) examinees underwent MMSE and TDAS assessment, respectively, and seven and six examinees, respectively, were determined to show positive results in the dementia tests. Of the examinees determined to be positive, six underwent detailed examination in medical institutions with specialists, and five and one patient were diagnosed as having dementia and mental retardation, respectively (correct screening rate 85%). The questionnaire showed favorable comments regarding the the Forgetfulness Consultation Program, such as ‘enjoyable’, ‘like a game’ or ‘I would like to do it more’.7
Screening in Haruna-cho, Takasaki City, Gunma Prefecture
All 73 inhabitants invited to the screening underwent a brain health check assessment and 66 underwent examination using the Forgetfulness Consultation Program as the first-stage screening procedure. As the second-stage screening, 16 of 73 subjects who underwent the brain health check assessment required and underwent MMSE, and five were regarded as positive. Of the 66 who underwent examination using the Forgetfulness Consultation Program, 11 required TDAS assessment and 10 subjects took it. Positive results were observed in five examinees, of whom three consulted with their primary care physician and one was referred to a specialist. The questionnaire showed very favorable comments regardng the Forgetfulness Consultation Program, such as ‘enjoyable’, ‘simple’ and ‘modern and good’, as well as favorable comments regarding the TDAS, with ‘good’ and ‘fairly good’ accounting for more than 80%, although ‘slightly difficult’ was also given as a response.7
DISCUSSION ON SCREENING METHODS FOR DEMENTIA
The use of a questionnaire is inexpensive and only slightly burdens examinees, but the detection rate appears to be low. Because patients with dementia have no self-awareness of their disease, they became unaware of forgetfulness when the disease progresses. Therefore, they may not answer parts of the questionnaire. In the early stage of dementia, patients may not apply checks deliberately, even though they are aware of their forgetfulness. In our area, in examinees without abnormalities at the questionnaire stage of screening, assessment using the Forgetfulness Consultation Program, which is a dementia-screening system using a touch-panel computer, frequently revealed abnormalities. The Five-Cog is a direct examination method, and therefore better than the questionnaire, and is considered to be excellent due to the high detection rate of dementia based on data. The problems associated with the use of the Five-Cog are group examination and the long examination time (30 min). Assessment using the Forgetfulness Consultation Program allows individual examination in a relatively short time (approximately 3 min) and it may be the most effective method. Its disadvantage is its high cost.
In the future, the prevention of dementia will be a very important issue and the establishment of simpler and more accurate methods of detection, as well as the acquisition of evidence, are necessary.
DEMENTIA-PREVENTION CLASSES AND THEIR EFFECTS
The effects of a dementia-prevention class in Kotoura-cho, Tohaku-gun, Tottori Prefecture is described. A dementia-prevention class was given to examinees with a score of <13 (perfect score 15) and MCI but not dementia. This 2-h class was given once a week for approximately 3 months (total 12 classes) and assessment using the TDAS was performed before the start and after the completion of the classes. Approximately 70% of participants showed significant improvement, with not only short-term effects over the 3-month period, but also long-term effects for approximately 3 years (Fig. 3). Dementia-prevention classes using a similar method have also been given in other areas of Tottori Prefecture and Omuta City, Fukuoka Prefecture, and have led to similar improvements.