***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Forty eight elderly Thai patients , 12 demented , 36 non-demented who consecutively attended a geriatric clinic , at Chulalongkorn University Hospital , with a memory problem were recruited in the study which aim ed to determine the validity of the clock-drawing test ( CDT ) and Chula mental test ( CMT ) . Subjects took the Chula Mental Test ( CMT ) and were asked to draw a clock on a preprinted 12 centimeters circle showing the time of 11:10 . Clocks were scored using the Chula Clock-drawing Scoring System ( CCSS )  . Ten subjects voluntarily participated and completed the WAIS test . The best cutoff score of the CMT and the CDT using diagnosis of dementia as a gold st and ard were 15 and 7 respectively . Sensitivity and specificity for detecting dementia by the CDT were 100 per cent and 94.1 per cent respectively . Sensitivity and specificity for detecting dementia by the CMT were 83.3 per cent 91.7 per cent . The likelihood ratio ( 95 % confidence interval ) of the CMT and the CDT were 10 ( 3.3 - 30.4 ) and 17 ( 4.4 - 65.2 ) respectively . There was a good correlation of the CDT score and the CMT score with the WAIS score . Although the CDT was better than the CMT in literate patients , the CDT had limitation of use among illiterate patients but not the CMT . The benefits of simultaneously application on dementia screening was shown . This study showed that the CDT was a valuable , brief method of dementia screening in elderly Thai patients with memory problems BACKGROUND Subjects with a mild cognitive impairment ( MCI ) have a memory impairment beyond that expected for age and education yet are not demented . These subjects are becoming the focus of many prediction studies and early intervention trials . OBJECTIVE To characterize clinical ly subjects with MCI  cross-sectionally and longitudinally . DESIGN A prospect i ve , longitudinal inception cohort . SETTING General community clinic . PARTICIPANTS A sample of 76 consecutively evaluated subjects with MCI were compared with 234 healthy control subjects and 106 patients with mild Alzheimer disease ( AD ) , all from a community setting as part of the Mayo Clinic Alzheimer 's Disease Center/Alzheimer 's Disease Patient Registry , Rochester , Minn. MAIN OUTCOME MEASURES The 3 groups of individuals were compared on demographic factors and measures of cognitive function including the  Mini-Mental State Examination , Wechsler Adult Intelligence Scale-Revised , Wechsler Memory Scale-Revised , Dementia Rating Scale , Free and Cued Selective Reminding Test , and Auditory Verbal Learning Test .  Clinical classifications of dementia and AD were determined according to the Diagnostic and Statistical Manual of Mental Disorders , Revised Third Edition and the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer 's Disease and Related Disorders Association criteria , respectively . RESULTS The primary distinction between control subjects and subjects with MCI was in the area of memory , while other cognitive functions were comparable . However , when the subjects with MCI were compared with the patients with very mild AD , memory performance was similar , but patients with AD were more impaired in other cognitive domains as well . Longitudinal performance demonstrated that the subjects with MCI declined at a rate greater than that of the controls but less rapidly than the patients with mild AD . CONCLUSIONS Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD . They appear to constitute a clinical entity that can be characterized for treatment interventions OBJECTIVES To assess the usefulness , relative ease of administration , and patient acceptance of the clock drawing test as well as the time and change test for detecting dementia in Chinese elderly adults . DESIGN Prospect i ve case-controlled study . SETTING Memory clinic and geriatric clinic of a district hospital , Hong Kong . PARTICIPANTS A convenient sample of 85 subjects aged 65 years or older attending the two clinics during the period from September 2002 to June 2003 . MAIN OUTCOME MEASURES The  clock drawing test scored according to Lam 's method ; the time and change test with modification to the making change task ;  and the Chinese version of the Mini-Mental State Examination .  RESULTS Demented subjects were matched with non-demented ones with respect to age , sex , educational level , and co-morbidity status . The clock drawing test had a comparable sensitivity ( 89.4 % ) but a lower specificity ( 47.1 % ) when compared with that of the Chinese version of the  Mini-Mental State Examination  ( 96.0 and 76.5 % , respectively ) . In contrast , the time and change test had a lower sensitivity ( 62.7 % ) but higher specificity ( 94.1 % ) . Both tests took significantly less time to complete than the Chinese version of the Mini-Mental State Examination . All except four subjects completed the clock drawing test while all subjects accepted the time and change test well . CONCLUSIONS The Chinese version of the Mini-Mental State Examination is still the best among the three tests despite the longer time to completion . The clock drawing test may be a good alternative to the Mini-Mental State Examination as an effective screening test for dementia when time does not permit . The time and change test , although time-saving , is not suitable to be used alone because of its low sensitivity BACKGROUND As elderly population s grow , dementia detection in the community is increasingly needed . Existing screens are largely unused because of time and training requirements . We developed the Mini-Cog , a brief dementia screen with high sensitivity , specificity , and acceptability . Here we describe the development of its scoring algorithm , its receiver operating characteristics ( ROC ) , and the generalizability of its clock drawing scoring system . SAMPLE AND METHODS A total of 249 multi-lingual older adults were examined . Scores on the three-item recall task and the clock drawing task ( CDT-CERAD version ) were combined to create an optimal algorithm . Receiver operating characteristics for seven alternatives were compared with those of the MMSE and the CASI using expert raters . To assess the CDT scoring generalizability , 20 naïve raters , without explicit instructions or prior CDT exposure , scored 80 r and omly selected clocks as " normal " or " abnormal " ( 20 from each of four CERAD categories ) . RESULTS An algorithm maximizing sensitivity and correct diagnosis was defined . Its ROC compared favorably with those of the MMSE and CASI . CDT concordance between naïve and trained raters was > 98 % for normal , moderately and severely impaired clocks , but lower ( 60 % ) for mildly impaired clocks . Recalculation of the Mini-Cog 's performance , assuming that naïve raters would score all mildly impaired CDTs in the full sample as normal , retained high sensitivity ( 97 % ) and specificity ( 95 % ) . CONCLUSION The Mini-Cog algorithm performs well with simple clock scoring techniques . The results suggest that the Mini-Cog may be used successfully by relatively untrained raters as a first-stage dementia screen . Further research is needed to characterize the Mini-Cog 's utility when population dementia prevalences are low The ten‐point clock test is administered by tracing an 11·4 cm ( 4 1/2 inch ) diameter circle on a piece of paper and asking the patient to ‘ Write the numbers in the face of a clock ’ . The patient is then asked to ‘ Make the clock say 10 minutes after 11 ’ . The spacing of the numbers and the positions of the h and s are used to score the test . A score of less than eight points identified 71 % of patients with Alzheimer 's disease who had a Mini‐Mental State Examination score of greater than 23 . The specificity measured in elderly controls was 82 % . The test may prove useful in screening for early stage Alzheimer 's disease . Copyright © 1999 John Wiley & Sons , OBJECTIVE To assess the accuracy of clock drawing for detecting dementia in a multicultural , non-English-speaking- background population . DESIGN A prospect i ve cohort study . SETTING A general geriatric medical outpatient clinic in southwest Sydney , Australia . PARTICIPANTS Ninety-three consecutive new patients to the clinic who had a non-English-speaking- background country of birth ( mean age 78.0 years ) . MEASUREMENTS The clock drawing test was conducted at the beginning of each clinic visit by a blinded investigator . Each patient was then assessed by a geriatrician who collected demographic data , administered the Modified Barthel Index , the Geriatric Depression Scale , and the Folstein Mini-Mental State Examination , and categorized each patient as normal or demented , according to DSM-IV criteria . Interpreters were used for participants who spoke a language other than English or who requested them . Each clock drawing was scored according to the 4-point CERAD scale and the previously published methods of Mendez , Shulman , Sunderl and , Watson , and Wolf-Klein . Scoring was evaluated for reliability and predictive accuracy , using receiver operating characteristic ( ROC ) curve analysis . Logistic regression analysis was used to assess the potential interaction between level of education and each of the clock scoring methods . RESULTS Using ROC curve analysis , there was no significant difference between the clock scoring methods ( area under the curve varied from 0.60 to 0.72 ) . The most sensitive was the Mendez scoring method ( 98 % ) , with a specificity of 16 % . Specificity above 50 % was found only for the Wolf-Klein method , with an intermediate sensitivity of 78 % . CONCLUSIONS There were no significant differences in the clock scoring methods used to detect dementia . Performance of the clock drawing test was modest at best with low levels of specificity across all methods . Scored according to these methods , clock drawing was not a useful predictor of dementia in our multicultural population INTRODUCTION The Clock Drawing Test ( CDT ) has been used in recent years as a simple neuropsychological instrument to assess cognitive deterioration associated with dementia , even though uniform operative criteria with respect to its application and scoring have not been established . OBJECTIVE To present application normatives and establish the most relevant psychometric criteria of the CDT in a sample of healthy subjects ( HS ) and patients with Alzheimer 's disease ( AD ) . PATIENTS AND METHODS 56 patients were selected of which 35 were female and 21 were male . The patients ' mean age was 72.7 with a st and ard deviation of 7.64 . All of whom where probable AD patients according to the NINCDS-ADRDA criteria at stage 1 CDR . The group of HS was made up of 56 control subjects ( 34 female , 22 male ) with a mean age of 72.14 and a st and ard deviation of 7.2 . The CDT was applied in both its comm and ( COM ) and copy ( COP ) experimental conditions . RESULTS The main psychometric parameters analysed in the studied series showed the following values : internal consistency ( Cronbach 's alpha coefficient 0.9029 ) ; cut off point CT COM 6 with 92.80 , sensitivity ; false negatives ( FN ) 7.2 with a specificity rating 93.48 ; false positive ( FP ) 6.52 with 93.16 efficacy ; cut off point CT COP 8 with 73.11 sensitivity ; FN 26.89 with 90.58 specificity ; FP 9.42 with 82.49 efficacy . CONCLUSION The CDT can be used to discriminate between HS and those in the initial stages of AD in the given sample using the established application and scoring criteria OBJECTIVE To develop a simple , readily administered and scored screening test for dementia utilizing the clock-drawing task . DESIGN Retrospective analysis of clock-drawing errors and prospect i ve validations . SETTING Hospital-based outpatient geriatric assessment clinic , rehabilitation service , apartment building for older adults , and long-term care facility . PARTICIPANTS Convenience sample of patients attending the geriatric assessment clinic , patients on the rehabilitation service , or residents of the above sites . MEASUREMENTS Sensitivity and specificity of a clock-scoring system  in identifying patients with dementia and the comparison of this system with the  Short Blessed Test ( SBT )  in the diagnosis of dementia and in the prospect i ve validation of the test . RESULTS Of the 10 clock-drawing errors evaluated , placement of digits in a pre-drawn circle had the greatest sensitivity and specificity in distinguishing patients with irreversible dementia from patients with other disorders who did not meet NINCDS-ADRDA criteria for probable dementia . The derived scoring system had a sensitivity of 87 % and a specificity of 82 % , compared with a sensitivity of 82 % and a specificity of 88 % for the SBT in identifying dementia . Test-retest reliability for the distinction between demented and non-demented was 82 % , with a Kappa of 0.63 for the clock completion , and 82 % , with a Kappa of 0.62 for the SBT . Inter-rater reliability for clock completion was 0.90 to 0.93 . CONCLUSION A simple , completely objective scoring system for a  clock completion test  has been developed which involves only the number of digits placed in the fourth quadrant of a pre-drawn circle . This readily administered test is as effective in screening for dementia as the longer six-item SBT Causes of cognitive impairment in the elderly include dementia , delirium , toxic effects of medications , trauma , and psychiatric illness . Dementia is the most common cause , and it implies a decline in cognitive function severe enough to interfere with social functioning . The estimated prevalence of dementia is  
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The correlation with other st and ard screening tests was statistically significant in most studies , but the results were influenced by age , education and language .
In studies that included patients with mild or question able dementia , the CDT had a low sensitivity and variable specificity .
Conclusion : The CDT has the characteristics of a good screening method for moderate and severe dementia .