The LICA consists of a story recall test, a word list recall test, stick construction, a visuospatial span test, the Digit Stroop test, a money calculation test, a visual recognition test, an animal fluency test, confrontation naming, and the Color and Object Recognition Test (CORT). The LICA was divided into two clearly separated factors in the validation study.3 The first factor included "tests for other cognitive domains except verbal memory" and comprised stick construction, the visuospatial span test, the Digit Stroop test, the money calculation test, the visual recognition test, the animal fluency test, confrontation naming, and the CORT. The second factor included "verbal memory tests" and comprised the story recall test and the word list recall test. We excluded the story recall test of the LICA in the S-LICA because it showed lower test-retest reliability compared to the word list recall test in the validation study.3 When some shy individuals were unable to remember verbs but remembered nouns in the sentences of the story recall test, they refused to say the words that they remembered. A previous study found that the word list learning test was a more useful tool for examining verbal memory function for older adults in Korea than the story recall test.7 The visuospatial span test and the money calculation test were also excluded because very low scores were obtained by some illiterate controls. Therefore, the finally developed S-LICA comprised eight subtests with total scores ranging from 0 to 100 (Table 1). We were able to evaluate verbal and visual memory, language, visuoconstruction, executive function, and semantics of objects with the S-LICA.

The S-LICA, K-MMSE, and CDR were administered to 108 patients with dementia (41 males and 67 females) and 188 normal controls (46 males and 142 females). One illiterate patient with dementia could not perform the Digit Stroop test because she was not able to read the numerals '1', '2', and '3'. Two illiterate patients with dementia received scores of less than 10 points on the K-MMSE and a CDR score of 3 points. Three of the normal subjects and four of the dementia patients were aged <60 years. After excluding 10 subjects, 101 patients with dementia and 185 normal controls were included in this study (Fig. 1). The severity of dementia was assessed using the CDR Scale. Twelve patients (1 illiterate and 11 literate) were rated as CDR stage 0.5, 68 (25 illiterate and 43 literate) as stage 1, and 21 as stage 2.

The patients with dementia fulfilled the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.8 They were recruited consecutively among outpatients from the memory clinics of four university hospitals. The normal controls consisted of community-dwelling elderly individuals and the spouses of patients. The controls were aged ≥60 years, did not have subjective memory complaints or any of 28 diseases, and did not have a history suggestive of a decrease in cognitive function (stroke or transient ischemic attack, seizures, Parkinson's disease, multiple sclerosis, cerebral palsy, Huntington's disease, encephalitis, meningitis, brain surgery, vascular surgery of the brain, diabetes requiring insulin control, improperly managed hypertension, cancer diagnosed within the previous 3 years excluding skin cancer, shortness of breath while sitting still, use of oxygen at home, heart attack with changes in memory, walking, or solving problems lasting at least 24 hours afterwards, kidney dialysis, liver disease, hospitalization for mental or emotional problems in the previous 5 years, current use of medications for mental or emotional problems, alcohol consumption greater than 3 drinks daily, drug abuse in the previous 5 years, treatment for alcohol abuse in the previous 5 years, unconsciousness for more than 1 hour other than during surgery, overnight hospitalization due to head injury, illness causing a permanent decrease in memory or other mental functions, trouble with vision that prevents reading ordinary print even with glasses, or difficulty understanding conversations because of hearing even with a hearing aid).9 The controls also had scores that were at least one standard deviation above the mean scores of the respective age- and education-matched population on the K-MMSE and an average score of 0.42 or less on the Korean Instrumental Activities of Daily Living (K-IADL).5,10 It has been demonstrated that this score discriminates dementia from cognitively healthy elderly subjects. The K-IADL score ranges from 0 to 3, with lower scores indicating better function.

Subjects were asked to read aloud two sentences: "Young-Hee was thirsty due to physical exercise. She opened a refrigerator". They were then asked to write what would happen next. Subjects who could read the sentences and write an appropriate response were judged to be literate. Demented patients were stratified into a literate or illiterate group according to caregiver reports of their premorbid reading and writing ability. Subjects who were illiterate due to learning and developmental difficulties were excluded.

The K-MMSE was administered to all of the participants to evaluate its concurrent validity with the S-LICA. The S-LICA and K-MMSE were administered on the same day. The test administrators were blinded to the dementia diagnosis of the participants when administering the two questionnaires. Using a random sampling method, 116 controls were matched with 97 demented patients by age, gender, and education. This method permitted evaluation of the sensitivity and specificity of diagnosing dementia using receiver operating characteristic (ROC) curve analysis. The association between the S-LICA and the original LICA was evaluated by administering the S-LICA to 41 normal elderly subjects 1 month after administration of the LICA. To evaluate test-retest reliability, the S-LICA was administered twice with an interval of 28±4 days (mean±SD) to 37 subjects (6 illiterate and 15 literate normal elderly subjects, and 3 illiterate and 13 literate subjects with dementia). The study protocol and informed consent form were approved by the institutional review board. Literate subjects gave written informed consent to participate in the study, and illiterate subjects gave verbal consent.

Student's t-test was used to test for differences in age and education between the control group and the dementia group. The difference in the gender ratio between the two groups was evaluated using the chi-square test. Cronbach's coefficient alphas and item-total correlation coefficients were generated to examine the internal consistency of the S-LICA. Pearson correlation coefficients were generated to evaluate test-retest reliability. To evaluate concurrent validity, S-LICA total scores were compared with the K-MMSE scores and the LICA using Pearson's correlation coefficients. An ROC curve was used to examine the sensitivity and specificity of the S-LICA. Statistical analyses were performed with SPSS 18.0 for Windows (SPSS, Chicago, IL, USA), and the level of statistical significance was set at p<0.05 for all analyses.

This study was conducted between March 2009 and October 2009. The demographic characteristics of the subjects are listed in Table 2. The years of education did not differ significantly between the subjects with dementia and the normal subjects. However, the proportion of men was lower among the normal subjects (25%) than among those with dementia (39%, p<.001).

The Cronbach's coefficient alpha was 0.92 for illiterate subjects and 0.94 for literate subjects. The item-total correlation ranged from 0.63 to 0.81 and was statistically significant (p<0.01) (Table 3). The test-retest reliability of the S-LICA total score was high (r=0.94, p<.001), and the subtests had high test-retest reliabilities (r=0.68-0.87, p<.01) (Table 3).

The correlation between the total scores of the shortened version and the original version of the LICA was very strong (r=0.99, p<.001). The linear correlation between the K-MMSE and S-LICA total scores was substantial for both the illiterate (r=0.84, p<.001) and literate (r=0.80, p<.001) subjects.

The normal controls were matched to the dementia patients to evaluate the sensitivity and specificity of the diagnosis of dementia; there were no significant differences in age, education, or gender ratio between patients with dementia and controls for either literacy group (Table 2).

The ROC curve was used to determine the degree to which the S-LICA screened dementia. The area under the curve (AUC) of the ROC curve was 0.999 (95% confidence interval=0.980-0.999, SE=0.005) for the literate subjects and 0.985 (95% confidence interval=0.975-0.994, SE=0.007) for the illiterate subjects. The sensitivity and specificity of the S-LICA for a diagnosis of dementia were 97% and 96%, respectively, with a cutoff of 72 for the literate subjects, and 96% and 93%, respectively, with a cutoff of 68 for the illiterate subjects (Fig. 2).

The total application time of the S-LICA was 18.1±9.5 minutes for the literate normal controls (n=24), 18.6±8.7 minutes for the illiterate normal controls (n=22), 21.2±15.4 minutes for the literate dementia patients (n=33), and 22±17.5 minutes for individuals who were illiterate with dementia (n=19).

This study was subject several limitations. First, the small numbers of subjects could have introduced selection or other bias. Second, only a clinic-based patient population was included, as in the LICA study. Third, the analysis was not conducted according to subtypes of dementia. Future studies should compare aspects of cognitive impairment among various subtypes of dementia using the S-LICA. Finally, patients with a CDR rating of >stage 3 were not included in this study, and hence future studies should also be conducted with patients in these stages of dementia. In addition, the illiterate female group was larger than the illiterate male group. However, data from the United Nations Educational, Scientific, and Cultural Organization show that worldwide, the prevalence of illiteracy is also greater for women than for men.1

The findings of this study show that the S-LICA is a valid and reliable instrument for detecting dementia in both illiterate and literate elderly individuals. Its diagnostic accuracy appears to be comparable to that of the LICA, while its test-retest reliability and concurrent validity are superior. The S-LICA also has the strengths of a shorter application time and easier interpretation of the total score compared to the LICA.