A Short Test of Mental Status: Description and Preliminary Results

Transcription

1 Short Test of Mental Status: Description and Preliminary Results EMRE KOKMEN, M.D., Department of Neurology; JMES M. NESSENS, M.P.H., KENNETH P. OFFORD, M.S., Department of Medical Statistics and Epidemiology short test of mental status (encompassing about 5 minutes) was administered to 93 consecutive neurologic outpatients without dementia, 67 outpatients with lzheimertype dementia, and 2 outpatients with dementia of miscellaneous causes. The mean scores for patients with lzheimer-type dementia were lower than those for the nondemented patients in the total scoring and on all subtests (P). When a total score of 29 or less (maximal attainable score, 38) was used as a screen for dementia, a sensitivity of 92% and a specificity of 9% were reached. For patients older than 6 years of age, a score of 29 or less resulted in a sensitivity of 95% and a specificity of 88%. Thus, in general, this easily administered test distinguishes demented from nondemented patients, but it should not be used as the sole means of diagnosing dementia. n analysis of the mental status of a patient is often revealing in any medical examination. In many situations, because of time limitations, completion of a full and detailed mental status examination is impractical. In this report, we describe a short test of mental status that can be performed in about 5 minutes in an outpatient setting. The sensitivity and specificity were assessed by studying a group of nondemented and a group of demented outpatients. The test had a high degree of specificity and sensitivity in screening for dementia. SELECTION OF PTIENTS In a period of weeks, during routine consultative neurologic practice, a short test of mental status was administered by one of us (E.K.) to all patients, regardless of the reason for consultation or the diagnosis. Of the 5 patients who underwent evaluation, 2 were excluded from the study for various causes: 7 were rejected from final ddress reprint requests to Dr. Emre Kokmen, Department of Neurology, Mayo Clinic, Rochester, MN consideration because their primary language was not English, 2 had severe pain and pain behavior that made the examination impossible, was not testable because of severe pseudobulbar speech, was demented by clinical criteria, and was mentally retarded. Thus, 93 nondemented patients (8 women and 5 men) completed the short test of mental status and were considered in the final analysis. In this group of 93 nondemented patients, 9 underwent examination for signs and symptoms referable potentially to a central nervous system disorder such as stroke, migraine, or epilepsy. The other patients underwent assessment for signs and symptoms that were potentially attributable to a peripheral nervous system disorder (including conditions of the spinal cord) such as peripheral neuropathy, radiculopathy, or mechanical back pain. The patients had no difficulties related to progressive memory, cognition, or intellect, and they were able to continue their usual and customary activities at home and at work. In addition to other data, handedness (8 right-handed and 9 left-handed patients), age, and highest educational level (number of years of formal schooling) were recorded. Mayo Clin Proc 62:28-288,987 28

2 282 SHORT TEST OF MENTL STTUS Mayo Clin Proc, pril 987, Vol 62 The short test of mental status was also administered by the senior author (E.K.) to 87 demented outpatients during a period of approximately 2 years. The demented patients were in mild to moderate stages of dementia; they all lived at home and required various degrees of supervision by family members. The diagnosis of dementia was based on customary criteria derived from the Diagnostic & Statistical Manual of the merican Psychiatric ssociation, third edition (DSM-III). 2 lzheimer-type dementia was diagnosed only after complete neurologic and general medical examinations had been performed; the diagnosis was based on criteria derived from the DSM-III and the criteria suggested by the National Institute of Neurological and Communicative Disorders and Stroke and the lzheimer's Disease and Related Disorders ssociation Work Group. 3 Of the 87 demented patients, 56 (6%) had psychometric testing with recorded IQ and memory quotient values derived from the Wechsler dult Intelligence and Memory Scales. mong the 87 patients in this group, 67 had lzheimer-type dementia and 2 had dementia from miscellaneous causes, including dementia of unknown cause and mechanism. The duration of disease was defined as the time since diagnosis of dementia in the demented patients. PROCEDURES In each patient, the neurologic history was elicited and review of systems was performed in the customary manner. Immediately after the completion of the history-taking process and before any other part of the neurologic examination was conducted, the short test of mental status was performed. Usually, the test was introduced to the patient with a statement such as, "I would now like to examine your memory and related items. Please relax, pay attention to the questions I am asking, and answer them as best as you can." SHORT TEST OF MENTL STTUS Orientation. The patient was asked to give his or her () full name, (2) address, current location that is, (3) building, () city, and (5) state and the current date (6) either the day of the week or the day of the month, (7) the month, and (8) the year. Each correct response was worth point. The maximal score was 8. ttention. The second subtest was forward digit span. The patient was told, "I will give you a series of numbers. Please pay close attention to them, wait until I am finished, and then repeat the numbers back to me in the same order as I have given them." Usually a span of five digits was given to the patient. If the patient responded correctly, the span was increased to six and then to seven. The patient's best performance was then recorded. If the patient was able to repeat seven digits forward, the test was terminated. The number of digits correctly repeated was the score; the maximal score was 7, and the minimal score was. Learning. The patient was told, "I shall now give you four words. I would like you to learn them, keep them in mind, and repeat them to me from time to time when I ask you to do so." The four words were always "apple," "Mr. Johnson," "charity," and "tunnel." The patient was asked to repeat the words. If he or she learned the words on the first trial, then the next subtest was given. If the patient was unable to learn all four words, the investigator repeated them for a maximum of four trials and recorded the number of trials that the patient required to learn all four words. If the patient was unable to learn all four words by the end of the fourth trial, the patient's best performance was recorded (the number of words learned and the number of trials required). Learning was scored in two parts. point was earned for each word learned (a maximum of points). One less than the number of trials (a maximum of ) required to learn the words was subtracted from the score. Thus, the values that were subtracted were between and 3. rithmetic Calculation. -The patient was asked to multiply 5 by 3, to subtract 7 from 65, to divide 58 by 2, and to add and 29. Each correct answer earned point, and the maximal score was. bstraction. Interpretation of similarities was used as a test of abstraction. The word pairs were as follows: orange/banana, horse/dog, and table/bookcase. One point for each word pair was given only for definitely abstract interpretations (for example, horse/dog = animal). Concrete interpretations or inability to see a similarity earned points for that word pair. The maximal score was 3.

3 Mayo Clin Proc, pril 987, Vol 62 SHORT TEST OF MENTL STTUS 283 Information. The patient was asked to name the current president and the first president of the United States, to state the number of weeks per year, and to define an island. Each correct answer earned point, and the maximal score was. Construction. The patient was asked to draw the face of a clock showing :5 and also to copy a three-dimensional cube (Fig. ). The patient was able to view the diagram of a cube, as shown in Figure, while drawing his or her own version. For each construction, an adequate conceptual drawing was scored as 2, a less than complete drawing earned a seore of, and inability to perform the task earned a score of. The maximal score for the construction task was. Recall. t the end of the test, the patient was asked to recall the four words from the learning subtest apple, Mr. Johnson, charity, and tunnel. No cues or reminders were provided. The patient earned point for each word recalled, and the maximal score was. Total Score. The total score for each patient was the sum of the scores on the eight subtests. The highest possible score on the test was 38. The short test of mental status is summarized in Table. Table. Summary of Short Test of Mental Status Subtest Orientation ttention Learning Number of words learned (maximum of ) Number of trials (maximum of ) for acquisition - rithmetic calculation bstraction Information Construction Recall Total score* Maximal possible score *Total score = sum of subtest scores - (number of trials for acquisition - ). For example, if a patient learned all four words on the first trial, nothing was subtracted from the sum of the subtest scores. If a patient required four trials to learn some or all four words, then 3 was subtracted from the sum of the subtest scores. STTISTICL METHODS ssociations between test scores and age, education, and duration of disease were assessed by use of the linear correlation coefficient and the rank correlation coefficient. Only the linear correlation coefficients are reported because the results were consistent with both techniques. ll comparisons of means between patient groups were assessed with two-sample t tests, Wilcoxon rank sum tests, and analysis of covariance, after adjustment for age and education. Sensitivity (true positive/[true positive + false negative] x ) and specificity (true negative/[true negative + false positive] x ) for the diagnosis of dementia are reported for the various test scores. Fig.. Three-dimensional cube that patients are asked to copy in construction component of short test of mental status. RESULTS The short test of mental status took approximately 5 minutes to administer. No time limits were imposed for performance of any subtest. Of the 93 nondemented patients, 9 (%) had 8 years or less of formal education, 38 (%) had 9 to 2 years, and 6 (9%) had 3 or more years of education. mong the 67 patients with lzheimertype dementia, (7%) had 8 years or less of education, 27 (%) had 9 to 2 years, and 29 (3%) had 3 or more years. Of the other 2 patients with dementia, 2 (%) had 8 years or less of education, (5%) had 9 to 2 years, and 8 (%) had 3 or more years.

4 28 SHORT TEST OF MENTL STTUS Mayo Clin Proc, pril 987, Vol 62 The mean age of the 93 patients without dementia was 5.5 years, and the mean years of education in this group was 2.9. In the 67 patients with lzheimer-type dementia, the mean age was 7. years, and the mean years of education was 2.8. The older age of the patients with dementia reflects the fact that dementia from all causes and especially from lzheimer's disease afflicts older persons much more frequently than younger persons. subset of demented and nondemented patients 6 years of age or older was identified, and the sensitivity and specificity of the short test of mental status were determined in these restricted case and control groups. In the 2 patients with dementia of miscellaneous causes, the mean age was 66.2 years, and the mean years of education was 3.3. The duration of dementia in 87 demented patients ranged from ( were diagnosed at the time of testing) to.3 years (mean, 2.96 years; standard deviation, 2.6 years). In the 67 patients with lzheimer-type dementia, the range was ( diagnosed at testing) to 8.7 (mean, 2.87 years; standard deviation,.88 years). In the 2 patients with non-lzheimer dementia, the duration of dementia ranged from (3 diagnosed at time of testing) to.3 years (mean, 3.26 years; standard deviation, 2.6 years). The patients with lzheimer-type dementia included women (66%), whereas the patients without dementia included 6 women (9%). There were seven women (35%) among the other patients with dementia. The effects of gender among the nondemented patients were measured by comparing the scores on the short test of mental status for men with those for women. No significant difference was found in mean scores between the sexes for either total scores or any component scores. The relationship between total test score and age among the nondemented patients is shown in Figure 2. The relationship between total score and education in the patients without dementia is depicted in Figure 3. For the nondemented patients, statistically significant associations were found between total score and age (r = -.23) and between total score and education (r =.35); the younger patients and the better educated patients had higher scores than.their counterparts. mong the 67 patients with lzheimer-type dementia, no significant associations were noted between any of the scores and age or gender; however, a positive association was found between education Ϊ Ϊ? s H- CO ,' >' M i Δ t Δ Pt Δ2ΡΙ // If ge, yr I Fig. 2. Total score on short test of mental status (STMS) plotted against age in 93 patients without dementia. and total score (r =.33), and a negative association was found between duration of disease and total test score (r = -.3). Differences in mean scores between patients with central nervous system and those with peripheral nervous system disorders in the nondemented group were assessed. Because no statistically significant differences were noted, we concluded that these two patient groups could safely be combined as a "nondementia" group. comparison of patients with lzheimer's disease and those without dementia is outlined in Table 2. Both the total score and all component scores for the short test of mental status were significantly lower among the group with «35 a> o 8 3 (O s CO 25 c - * ' ft 8 Δ Δ Δ Δ Δ Δ O Δ Δ Δ O Δ Δ Δ Pt Δ 2 Pt 3 Pt I O Pt 5 Pt O 7 Pt 2 6 Education, yr Fig. 3. Total score of short test of mental status (STMS) plotted against education in 93 patients without dementia. I Δ 2

5 Mayo Clin Proc, pril 987, Vol 62 SHORT TEST OF MENTL STTUS 285 Table 2. Mean and Median Values for Component and Total Scores of the Short Test of Mental Status and Characteristics of 93 Patients Without Dementia and 67 Patients With lzheimer's Dementia* Subtest and patient characteristics Orientation ttention Learning No. of trials Calculation bstraction Information Construction Recall Total score ge (yr) Education (yr) Duration of disease (yr) Patients without dementia Mean ± SD Median 7.9 ±.3 6. ±.8. ±.2 ± ±.9 2. ±. 3.7 ±.7 3. ±. 3.2 ±. 33. ± ± ± Patients with lzheimer's dementia Mean ± SD Median 5. ± ±.9 3. ±. 3. ±..5 ±.5.2 ±.2 2. ±.3.3 ±.3.9 ± ± ± ± ± *Result of Wilcoxon rank sum test for education was not significant (P =.66). Results of Wilcoxon rank sum tests for all other measures were significant (.P). lzheimer-type dementia. The patients with lzheimer's dementia were also significantly older than the nondemented patients. The sensitivity and specificity are shown in Table 3 for various cutoff points of the total score when the short test of mental status was used for screening to detect lzheimer's dementia among 2.8 the 93 patients without dementia and the 67 patients with lzheimer's dementia. Table outlines the effectiveness of this short mental test in detecting any type of dementia at various total scores. Using a threshold of 29 points or less to classify dementia enables us to obtain specificity and sensitivity values of 9% or higher for distinguishing either patients with lzheimer's dementia or patients with any dementia from nondemented patients. In Table 5, the specificity and sensitivity values are shown for 33 patients without dementia and 76 patients with dementia, all of whom were 6 years old or older. Of importance, the sensitivity and the specificity remained high even when the test was restricted to older subjects. Table 6 shows the effectiveness of each test component in distinguishing the 87 patients with dementia from the 93 patients without dementia. No single subtest value simultaneously attained both a sensitivity and a specificity of 85% or better. In the 56 patients with dementia who had IQ component scores recorded, the Pearson correlation between the total score on the short test of mental status and the IQ values from psychometric testing was significant (P; r>.55). DISCUSSION severe language disturbance or inability to speak or understand English would, of course, Table 3. Effectiveness of Short Test of Mental Status in Distinguishing 67 Patients With lzheimer's Dementia From 93 Patients Without Dementia at Various Thresholds Total score* Sensitivity Percent Specificity * score of 29 or less detected dementia with a sensitivity and specificity of 9% or higher. Table. Effectiveness of Short Test of Mental Status in Detecting Dementia at Various Thresholds, Based on Responses of 87 Patients With Dementia and 93 Patients Without Dementia Total score* Sensitivity Percent Specificity * score of 29 or less detected dementia with a sensitivity and specificity of 9% or higher.

6 286 SHORT TEST OF MENTL STTUS Mayo Clin Proc, pril 987, Vol 62 Table 5. Effectiveness of Short Test of Mental Status in Detecting Dementia at Various Thresholds, Based on Responses of 76 Patients With Dementia and 33 Patients Without Dementia, ll 6 Years of ge or Older Total score* Percent Sensitivity Specificity *t a score of 29 or less, the sensitivity and specificity remain high even when the test is administered only to older subjects. preclude use of the short test of mental status. Under such circumstances, the language disturbance should be assessed first, and then alternative methods should be used for evaluating cognition, memory, orientation, intellect, and related functions. We did not encounter severe language disturbances in any of the patients, with or without dementia, who formed the basis of this study. The test could be administered with the help of interpreters to patients who do not speak English. The results obtained from such patients were not included in this report. Detailed qualitative mental status examinations can be performed at the bedside. It is difficult, however, for the practicing physician to have full mastery of all the elements of such a detailed examination. The expense and time needed for formal psychometric testing cannot be justified for most routine medical evaluations. Therefore, several short tests of mental status have been developed for detection of dementia, delirium, and related disorders in a general population, medically ill inpatients, and psychiatric patients. -8 The mental status quotient of Kahn and associates 2 and the short portable mental status questionnaire of Pfeiffer 6 both lack a specific learning and recall task. In the cognitive capacity screening examination of Jacobs and colleagues Table 6. Effectiveness of Short Test of Mental Status Components in Detecting Dementia at Various Scores, Based on Results in 87 Patients With Dementia and 93 Patients Without Dementia Component* Orientation ttention Learning cquisition trials Calculation bstraction Information Construction Recall Test score < <5 <6 <7 <8 < <5 <6 <7 < >3 >2 > < < < < Percent Sensitivity Specificity ' *No single subtest value simultaneously attained both a sensitivity and a specificity of 85% or better. and the memory-concentration test first described by Blessed and co-workers, 5 3 or more items must be tested and scored separately. In their original form, these tests are cumbersome and somewhat difficult to master unless they are used frequently. limited version of the orientation-memoryconcentration test has been shown to distinguish among mild, moderate, and severe degrees of

7 Mayo Clin Proc, pril 987, Vol 62 SHORT TEST OF MENTL STTUS 287 dementia. 3 This short test may be too easy for the usual outpatient. The mini-mental status test of Folstein and associates is the test that has been used most frequently for screening purposes. The mini-mental status test has been validated in various ways and in large populations.,7 ' 9 Even though the test relies heavily on tasks related to language, it does not seem to be a sensitive indicator of focal versus diffuse hemispheric disease. 7 In the mini-mental status test, only three words are used for registration and subsequent recall. The choice of woids is not specified but is left to the discretion of the examiner. Thus, a different set of words could be used for each patient, an approach that could create some difficulties in interpreting the results of the recall task. The short test of mental status we describe herein contains many of the items that are part of the aforementioned tests for evaluation of mental status. The overall test score produced acceptable sensitivity and specificity rates for detection of patients with cognitive intellectual deficits. None of the subtests or components was independently as good as the total score, a finding that has been evident in a study of the mini-mental status test as well. 9 Thus, administering all the components of the test and assessing the total score have definite value. The components of this test are selective, brief items. The orientation items are conventional, but careful assessment and scoring of each of the eight items separately are important. The forward digit span test should be considered a simple test of attentiveness, and the patient's best performance should be recorded. The words to be remembered in the learning subtest have been chosen arbitrarily. They include two common nouns one item that is easy to visualize (apple) and the other item a not-so-common, large structure (tunnel). The other two words selected are a common but abstract concept (charity) and a common proper noun (Mr. Johnson). The calculation items were selected to represent one of each of the four major arithmetic operations (addition, subtraction, multiplication, and division). Each of these operations requires some ability to calculate, and they are not overlearned items such as numbers directly derived from multiplication tables. The similar pairs of words were selected because they are common items, and they therefore present a distraction challenge to the four words that have to be independently learned and retained. The four information items are simple and, to a degree, overlearned. For the task of defining an island, considerable integrative language ability is necessary. The construction task includes not only making a direct copy of an everyday object in stylized fashion but also drawing a conceptualized face of a clock. The scores on the short test of mental status were, to a degree, associated with age and education. Nonetheless, even after restricting the tested group to older patients (age 6 years or older), acceptably high sensitivity and specificity rates were maintained for distinguishing demented from nondemented patients. CONCLUSION single brief test such as this short test of mental status should not be used as the sole basis for the diagnosis of dementia. Some patients with dementia may score high on this test, and some patients without dementia may score poorly. We recommend, however, that all patients who have a total score of 29 or less on this test receive special attention for evaluation of dementia. In many instances, the test profile may provide significant insights into the nature of the dementia and thus may be much more important than a single total score. REFERENCES. Strub RL, Black FW: The Mental Status Examination in Neurology. Philadelphia, F Davis Company, merican Psychiatric ssociation: Diagnostic & Statistical Manual of Mental Disorders. Third edition. Washington, D.C., merican Psychiatric Press, McKhann G, Drachman D, Folstein M, Katzman R, Price D, Stadlan EM: Clinical diagnosis of lzheimer's disease: report of the NINCDS-DRD Work Group under the auspices of Department of Health and Human Services Task Force on lzheimer's Disease. Neurology 3:939-9,98. nthony JC, LeResche L, Niaz U, von Korff MR, Folstein MF: Limits of the 'mini-mental state' as a screening test for dementia and delirium among hospital patients. Psychol Med 2:397-8, Blessed G, Tomlinson BE, Roth M: The association between quantitative measures of dementia and of senile change in the cerebral grey matter of elderly subjects. Br J Psychiatry :797-8, Cooper B, Bickel H: Population screening and the early detection of dementing disorders in old age: a review. Psychol Med :8-95,98 7. Dick JPR, Guiloff RJ, Stewart, Blackstock J, Bielawska C, Paul E, Marsden CD: Mini-mental state examination in neurological patients. J Neurol Neurosurg Psychiatry 7:96-99,98

8 288 SHORT TEST OF MENTL STTUS Mayo Clin Proc, pril 987, Vol Fillenbaum GG: Comparison of two brief tests of organic. brain impairment, the MSQ and the short portable MSQ. J m Geriatr Soc 28:38-38,98 9. Folstein M, nthony JC, Parhad I, Duffy B, Gruenberg EM: The meaning of cognitive impairment in the elderly. J m Geriatr Soc 33: , Folstein MF, Folstein SE, McHugh PR: "Mini-mental state": a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 2:89-98, Jacobs JW, Bernhard MR, Delgado, Strain JJ: Screening for organic mental syndromes in the medically ill. nn Intern Med 86:-6, Kahn RL, Goldfarb I, Pollack M, Peck : Brief objective measures for the determination of mental status in the aged. m J Psychiatry 7: , Katzman R, Brown T, Fuld P, Peck, Schechter R, Schimmel H: Validation of a short orientation-memoryconcentration test of cognitive impairment. m J Psychiatry :73-739,983 Kaufman DM, Weinberger M, Strain JJ, Jacobs JW: Detection of cognitive deficits by a brief mental status examination: the cognitive capacity screening examination, a reappraisal and a review. Gen Hosp Psychiatry :27-255,979 Klein LE, Roca RP, Mcrthur J, Vogelsang G, Klein GB, Kirby SM, Folstein M: Diagnosing dementia: univariate and multivariate analyses of the mental status examination. J m Geriatr Soc 33:83-88,985 Pfeiffer E: short portable mental status questionnaire for the assessment of organic brain deficit in elderly patients. J m Geriatr Soc 23:33-,975 Rosen WG, Mohs RC, Davis KL: new rating scale for lzheimer's disease. m J Psychiatry :356-36, 98 Smyer M, Hofland BF, Jonas E: Validity study of the short portable mental status questionnaire for the elderly. J m Geriatr Soc 27: ,979