Vol. XXVII, No. 8 Printed in U.S.A.
JOURNAL OF T H E AMERICAN GERIATRICS SOCIETY Copyright 0 1979 by the American Geriatrics Society
Development and Application of the Extended Scale for Dementia EDWIN L. HERSCH, MA*
Psychogeriatric Unit, London Psychiatric Hospital, London, Ontario, Canada ABSTRACT: As part of an interdisciplinary study of organic dementia, a psychologic test for assessing the degree of dementia-the Extended Scale for Dementia-was developed through the expansion and rescoring of the original Mattis Dementia Scale. Statistical analyses of the 23 test items resulted in a scoring scheme which includes the “weighting” of items for scoring purposes. The test was successfully administered to 90 subjects from 6 hospitals in the London (Ontario) region. With use of the Extended Scale, it was possible to discriminate between dementia and non-dementia groups of psychogeriatric inpatients and to correlate the findings closely with those of another measure of the degree of dementia, viz, the London Psychogeriatric Rating Scale (Ment.). Dementia patients who were retested after 6-month and 12-month intervals showed a significant decline in scores. No significant scoring differences were noted between males and females or between Alzheimer dementia and multiinfarct dementia. assessment of the degree of dementia even in severe cases. In order to overcome the foregoing difficulties, two paths usually are followed: 1) the use of simplified psychologic tests with items appropriate for the limited levels of functioning, and 2) when even this fails (as in extremely regressed psychogeriatric inpatients), the use of behavior rating scales for which the patient is rated by staff members. It would be desirable to use both of these assessment techniques whenever possible. During the past two years, reasonably good results have been achieved already in the assessment of psychogeriatric patients with the London Psychogeriatric Rating Scale (LPRS) (1, 2). Hence, our attention has now turned to the first possibility-the simplified test. Several dementia tests and mental status questionnaires provide at least a rough psychologic assessment of dementia patients. A review of some of these led to the selection of the Mattis Dementia Scale (3) as the basic instrument, largely because of its comprehensive use of a variety of cognitive tasks (with a wider scope than simple orientation and memory questionnaires) and because its items appeared to be suited to the expected level of functioning.
In February, 1977, an interdisciplinary study group was established at the University of Western Ontario to conduct a comprehensive, longitudinal study of organic dementia. Representatives from such disciplines as psychiatry, neurology, geriatrics, neuropathology, and psychology were included in the group. The purpose of this report is to outline psychology’s role in the study, i.e., the use of psychometrics to assess the degree of dementia. As the ultimate aim was to conduct a comprehensive study of dementia, it seemed appropriate to use comprehensive psychometric tools for the purpose of psychologic assessment. One of the difficulties in such assessment, however, is that dementia patients are often too disturbed or confused to achieve even minimal scores on standard psychometric tests. This is particularly true with regard to subjects who have already been admitted to long-term psychiatric facilities. Nevertheless, it might be possible to develop a method for reliable * Unit Psychometrist, Psychogeriatric Unit, London Psychiatric Hospital. Address for correspondence: Edwin L. Hersch, MA, Department of Education and Research, London Psychiatric Hospital, 850 Highbury Avenue, London, Ontario, Canada N6A 4H1.
348
August 1979
EXTENDED SCALE FOR DEMENTIA
Although the Mattis Scale offered much promise, some questions initially were raised on the basis of face validity. Since some of the items were more difficult or more clinically relevant than others, it was felt that they should be scored accordingly rather than with the original “one point per each answer” format. It was also uncertain whether the factorial structure of the Mattis Scale would be replicated in our study population. Moreover, it would seem necessary to supplement Mattis’ pool of items by others reported in the literature. Therefore, it was decided to develop an extended scale for the assessment of dementia, derived as an extension, revision and rescoring of the Mattis Dementia Scale. The validity of the extended scale, and normative data for dementia patients would be established. MATERIAL AND METHODS The Mattis Dementia Scale was extended by adding certain items. Then the extended scale was administered to as many dementia patients as were available. Subsequent revisions and refinements were made in the light of statistical analyses of the findings. The patients The dementia patients were from six hospitals in the London, Ontario, region. All but five were inpatients in facilities providing management and, if necessary, long-term care for patients with well established illnesses. The hospitals were the London Psychiatric Hospital (a public psychiatric hospital), Homewood Sanitarium (a private psychiatric hospital), Parkwood Hospital (geriatric and long-term care), St. Mary’s Hospital (long-term care), St. Joseph’s Hospital-Policlinic (geriatric outpatients), and Westminster Hospital (a Veterans Administration facility). Only patients with relatively clear diagnoses of progressive dementia, and with no additional psychiatric diagnoses, were included. This group consisted of: a) the Alzheimer type (regardless of age, no definite history of a stroke); and b) the arteriosclerotic or multi-infarct type, in whom a definite history of a cerebrovascular accident was associated with the dementia process. From the participating settings, 2 14 dementia patients were available in the first year of the study. However, of the 214, only 90 (42 percent) could achieve even a minimal score: the remainder
were considered “untestable” or too regressed to be tested. Of the 90 subjects tested, 34 were male and 56 were female. The age range was 46-96 years, with most subjects being in their 60’s or 70’s. Forty-nine (54 percent) of the 90 “testable” subjects were inpatients on the Psychogeriatric Unit of the London Psychiatric Hospital. A psychogeriatric inpatient control group of 39 patients from this Unit, with diagnoses other than dementia, was also tested. The test items Table 1 lists the items employed in the present version of the test. Fourteen of the 23 items (Nos. 1-6, 8-12, 17, 22, 23) were borrowed from the Mattis Dementia Scale. The two writing or copying items on the Mattis Scale (“Graphomotor” and “Construction”) were combined in one item called “Graphomotor” (No. 6). Orientation, treated as one item on the Mattis Scale, was divided into three sections, viz, orientation for time (No. 13), place (No. 14), and age (No. 15), involving the use of questions common to a variety of mental status questionnaires (4-6). Questions such as “Who is the Prime Minister (or President)?” and “How many weeks (or months) are there in a year?” have been found useful in previous questionnaires and were added in the item called “Information” (No. 16); also added were “Count Backwards” (No. 18),“Count by 3’s” (No. 19), and “Simple Arithmetic” (No. 20) (7-9). Paired-Associate Learning tests are reported to be sensitive to memory impairment in the elderly (10, ll),so a simple version (No. 21) was added to the Scale. Block Designs have also been used successfully in the intellectual assessment of elderly subjects (12), so a relatively simple Block Design item (No. 7) was added (three examples from the Wechsler Intelligence Scale-Children). Statistical analyses The following statistical analyses were conducted on the data, to assist in the validation, evaluation, further revision and rescoring of the scale: a) A six-week test-retest reliability study; b) Examination of the means, variances, and frequency distributions for each item of the scale, as well as its correlation with other items and total scores; c) Factor analyses of the items; d) KR-20 analysis of the internal consistency of
349
E. HERSCH
the scale as a whole; e) Discriminant Function analyses between high-scoring and low-scoring dementia patients, as well as between dementia and nondementia patients; f) Correlation studies between the Extended Scale scores and the ratings achieved on the Mental Disorganization/Confusion subscale of the London Psychogeriatric Rating Scale; and g) Comparisons of results (means) from different settings, diagnostic groups, and sexes. In addition, 6-month and 12-month test-retest means comparison studies were made (for purposes of a longitudinal study), to assess changes in the test performance of dementia patients as a function of time. Subjects in this study will be retested bi-annually as long as they are alive, available, and testable. RESULTS
Vol. XXVI
difficult,” “fairly difficult,” and “relatively easy” questions. As this classification agreed substantially with the inspection-of-item statistics, it was taken as further support for the validity of weighting the items according to their relative difficulty, and of making corresponding changes in the scoring. Following the weighting of the items (as will be discussed), the new scores were also factor-analyzed. However, no factorial structure of any kind was found. All 23 items loaded best on one large factor accounting for almost all of the total variance. Furthermore, the Kuder-Richardson 20 (KR-20) calculation, based on all 23 items, yielded a coefficient of .943. This indicated a high level of internal consistency for the scale as a whole. ItemTotal correlations calculated at this point between each item score and the subject’s total score ranged from .43 to .76 (Table l),with only the first item (a screening question) showing a correlation of less than 50. The majority of Item-Total correlations were above .60.
Reliability Assignment of item weightings and rescorings Although the items in the test are fairly familiar ones, a test-retest reliability study was conducted. A Pearson-Product moment correlation of r = .94 was calculated, based on the scores of 24 dementia patients tested on two occasions six weeks apart.
Original item statistics Inspection of the means and frequency distributions of scores on the individual items confirmed our suspicions that some of the 23 items were much more difficult than others for dementia patients to answer. The two sections of the Graphomotor item (distinct items on two different factors on the Mattis Scale) were well correlated with each other (r = .73). This suggested that they could be treated as one item.
Factor analysis and item-total correlations Although the Mattis Scale involves both total and factor scores, we could not replicate this factorial structure in our analysis. Before introducing the weighting of items, we factor-analyzed the scores of 90 dementia patients and obtained what initially appeared to be three factors. However, on inspection of these “factors” it was found that they did not fall into three clinically relevant dimensions, but rather into the categories of “very
350
As the foregoing results supported the facevalue observations indicating that some items were worth more points than others, the items were weighted (and rescored) in accordance with the following criteria: a) Item values were balanced in such a manner that each of the items when properly weighted would account for an approximately equal portion of the total, and no one item score could significantly “tip the balance” of the total. Thus, weightings were assigned in accordance with both the mean scores for dementia patients achieved on a given item and the maximum possible score on the item. Consequently, the items were weighted so that both mean scores and maximum scores would be similar from item to item. b) Items could be scored easily while the psychologist was administering the test. The resultant weighted-item statistics are shown in Table 1. The individual item means ranged from 1.1 to 8.2, with most items having a mean of 3-6 points. The maximum possible scores for the items ranged from 5 to 18 points, with most items being worth 8-16 points. Points for individual answers or responses (within the items) ranged from ?hto 4. Thus, no single answer was worth more than 4 points and no single item (or section) was worth more than 18 points out of a maximum
August 1979
EXTENDED SCALE FOR DEMENTIA
possible total score of 250. The mean total score for the dementia patients studied was slightly less than 100. For two of the items, viz, Sentences (Construction and Memory) (No. 12) and Associate Learning (No. 2l), the means suggested that the questions were usually too difficult for our population, even after weighting. These items were retained because of their good discriminant abilities and relevance to dementia, by face-value. However, to aid in administration, a scoring instruction was added so that item No. 21 would be directed only to those patients who scored over 12 points on items No. 8 and No. 9 combined (both of which are correlated fairly well with item No. 21). Of all the patients tested, none proved able to score any points on item No. 21 without having scored 12 or more points on items No. 8 and No. 9 combined. This rescored version of the scale is henceforth referred to as the Extended Scale for Dementia (ESD).
Validation of the Extended Scale Because of our use of mean scores in assigning weightings to particular items, it was important to split the sample, to be sure that the relative proportions of the unweighted mean scores between items was consistent from group to group. In this respect, the first 45 subjects scored similarly to the next 45, and subjects from the six different settings did not show significant differences from each other, i.e., some items were consistently more difficult and others were consistently easier. Although reliability is essential, the test of a scale is not merely how consistent it is statistically, but how well it works in practice. The main purpose for development of the Extended Scale was the assessment of the degree of dementia present in various patients. Thus it would be expected that the scale would enable one to discriminate significantly between high-scoring and low-scoring dementia patients, and to differentiate diagnostically (at least to some extent) dementia patients from non-dementia psychogeriatric patients. If this new test is valid, one would assume that the scores would be correlated with those on other recognized measures of the degree of dementia.
dementia, we compared the high total scorers with the low total scorers on the test. The high-scoring group consisted of the top-scoring 25 percent of the testable dementia subjects (N= 22), and the low-scoring group consisted of the lowest-scoring 25 percent of those subjects. Discriminant function analysis for these two groups (S.P.S.S. computer package used for calculations) (13) showed that 20 of the items in the analysis added a significant, nonredundant contribution to the scale’s overall discriminating ability (based on Wilkes A, p < .001 in each case, with changes in Rao’s V significant at p < .05) (Table 1). Discriminant function analysis was also conducted for the scores of 39 non-dementia psychogeriatric inpatients and 90 dementia patients. The resultant Wilkes X coefficients showed that 22 of the items added significant nonredundant contributions to the scale’s ability to differentiate between the two diagnostic groups at p < .001 levels. However, calculations of differences in Rao’s V coefficients were significant at p < .05 for only six items (Nos. 3, 5, 8, 12, 13 and 17) (Table 1).Thus it would seem that if we wished to make predictions based on a minimal number of items, the use of the six mentioned would probably be sufficient. Correct prediction of group classification based on 22 items was 81 percent in this analysis, with an overall chi-square value significant at p < .001. Of the 7 non-dementia patients who were misclassified as dementia subjects (in the predictions), 5 had other “organic” disorders and another was subsequently reclassified because of a change in diagnosis. In 2 of the 18 misclassified subjects originally in the dementia group, the diagnosis was later changed so that they were classified in the non-dementia group. One interesting finding was that some of the best items for predicting the degree of dementia (e.g., counting backward, block design, verbal recognition and memory, arithmetic) were much less predictive in distinguishing dementia from nondementia subjects, and vice versa (e.g., orientation for time, naming, sentence construction). Thus, an item’s usefulness proved to be dependent upon which of these functions the researchers had in mind. Each of the 23 Extended Scale items added a significant contribution in at least one of these two analyses.
Discriminant function analyses To investigate whether the individual items of the Extended Scale (with the weighted item scoring) adequately differentiated between degrees of
Correlations between the ESD and the LPRS (Ment.) The principal method of psychologic assessment
351
E. HERSCH
-~
-
Vol. XXVI
TABLE 1 Item Statistics ~~~~
~
~~~~~~~
~~
~~
~~~~
~~
Discriminant Function Analyses Significance Levels*
Scores
Dementia
Item
-
1. Commands
2. Digits 3 . Naming 4. Repeating 5. Movements 6. Graphomotor 7. Block Design 8. Similarities 9. Differences 10. Similarities (multi-choice) 11. Identities , 12. Sentences 13. Orientation (Time) 14. Orientation (Place) 15. Orientation (Age) 16. Information 17. Count A’s 18. Count Backwards 1 19. Count by 3’s
‘
j
3.9
.58
.Ooo
5.2
.53
.Ooo
,020
.Ooo ,000
,002 .250 ,013
3.8 3.9
3.8 2.0 2.8
, 1
I
4.6 3.2 3.3 3.1
.7 1 .74 .72 .70 .72 .74 .64
12 2 1
4
12
.66 .72
9
.51 .66
~
3
.Ooo ,000
1 .o ’
OOO
j
.Ooo
_ .Ooo .Ooo
.317 ,238 .048 ,447 .671 ,725 ,014
,731
.Ooo .66 .69 .62
.Ooo .Ooo
.76
.Ooo
.Ooo
.Ooo
.Ooo
.ooo
.o .Ooo .Ooo
,342
-
X ~
___
~
-
~
~
~
p
* Missing observations are for variables which did not meet the “F to enter” criteria.
of psychogeriatric patients currently in use at the London Psychiatric Hospital is the London Psychiatric Rating Scale (LPRS) for behavior rating, which is completed by the ward staff. This scale is useful in assessing a patient’s degree of disability, and also is a reasonably good discriminator between dementia and non-dementia patients. We hypothesized that, although two different types of psychologic measure were involved, a patient’s scores on the Extended Scale should prove to be correlated fairly well with the scores on the Mental Disorganization/Confusion (Ment.) subscale of the LPRS. The ESD-LPRS (Ment.) correlation (PearsonProduct moment) for the 55 dementia patients who were both tested and rated in the summer of 1977 was calculated at r = .62. In addition to the patients previously mentioned, another 49 dementia patients were rated at this time. However, they were unable to achieve even a minimal score on the ESD. If one wished to include these patients in the computation by assigning them an ESD score of zero, the ESD-LPRS (Ment.) correlation
(for N = 104) would rise to .93, as the “untestable” patients invariably had poor LPRS scores.
Extended Scale-means, comparisons
variances, and mean
The Extended Scale means and standard deviations for various groupings of patients are listed in Table 2. It may be seen that: a) The means were quite comparable from setting to setting in the study; b) No significant sex differences were found, with respective means of 97.0 for males (N = 34) and 95.8 for females (N = 56); c) No significant differences were found between the Alzheimer (N = 75) and the Multiinfarct (N = 15) dementia groups, although the latter group tended to score slightly lower; d) The psychogeriatric inpatient control group (largely composed of patients with diagnoses of chronic schizophrenia) scored significantly higher (better) than did the dementia pa-
August 1979
EXTENDED SCALE FOR DEMENTIA
TABLE 2 Statistical Findings. by Setting, Sex, and Diagnosis N X a -
Dementia Group London Psychiatric Hospital Homewood Sanitarium Parkwood Hospital St. Mary’s Hospital St. Joseph’s HospitalPoliclinic Westminster Hospital Total
49
94.2
52
13 12 7 5
103.7 88.1 95.6 104.4
63 50 64 63
4 90
108.9 96.3
91 -
Fem a1es Males
56 34
95.8 97.0
50 68
Alzheimer type Multi-infarct Type Tctal
75 15 90
99.1 82.0 96.3
52 62
56
Although the scores for the dementia group as a whole showed a decline at the 6-month retesting interval, the scores for the Alzheimer group showed more decline (average, 36 points; paired ttest results significant at p < .001) than did the Multi-infarct group (average, 16 points; paired ttest results significant at p < .01). This finding, however, was not conclusive, as the retested Multiinfarct group was small (N = 8) and they began with a lower mean (59.9) than did the Alzheimer group (N = 23, X = 99.7) at the initial testing. Thirteen dementia subjects from the London Psychiatric Hospital were tested three times during a period of one year. This group showed significant declines in mean scores at both the first and second 6-month intervals (Table 3).
p < ,001 (pooled t-test result)
Control G r o w
39
159.0
60
tients. The pooled t-test result was significant at p < .001. A summary of the test-retest results is presented in Table 3. Only 50 percent of the testable patients visited in the summer of 1977 were still available and testable six months later. During this period about 30 percent had been discharged, 15 percent were no longer testable, and 5 percent had died in the hospital. The scores of 31 dementia patients tested in the summer of 1977 and subsequently retested 6 months later showed a significant decline. The paired t-test results were significant a t p < .001.
DISCUSSION The Extended Scale for Dementia (ESD) for assessing the degree of dementia was developed through the expansion and rescoring of the Mattis Dementia Scale. Statistical findings with the ESD did not suggest any clinically significant factorial structure for the items, but did reveal that the scale as a whole had a high degree of internal consistency. Therefore, it was decided that ESD results would be reported simply as total scores. The validity of the Extended Scale was established with respect to: a) its capabilities for discriminating between dementia and non-dementia patients, and b) its correlation with another measure of the degree of dementia (the “Ment.” subscale of the LPRS). Twenty of the individual items
TABLE 3 Dementia Subjects-Test-Retest Results 6-Week retested group
1st testing 2nd testing
N
X
24 24
88.2 83.6
-~
a
57 58
&Month retested groups
r
=
.94
Paired t-test significance levels p < ,001
Alzheimer type
1st 2nd A
23 23
99.7 63.6 36.1
57 53
Multi-infarct type
1st 2nd A
8 8
59.9 43.9 16.0
30 25
p < .01
Total
1st 2nd A
31 31
89.4 58.4 31.0
57 53
p < ,001
1st testing 2nd (at 6 mos.) 3rd (at 1 vr.)
13 13 13
92.8 68.3 56.0
-
p < ,001 p < .05
1 - Year retested group, London Psy. Hosp. dementia Datients
-
353
VOl. X X V I
E. HERSCH
also discriminated well between high-total scorers and low-total scorers among the dementia patients. The high scorers were clinically classified as those with a “mild” degree of dementia, and the low scorers were classified as those with “severe” dementia but still testable within the context of institutional care. Some of the items were more useful as predictors of diagnosis than of the degree of dementia, and vice versa. The significant decline in the ESD scores of dementia patients over a 6-month period suggests that the test is appropriate and the time interval is not too short for purposes of a longitudinal study. Although some subjects showed more decline than others, almost all retested dementia patients had lower scores at the 6-month interval. This is in accordance with the progressive decline observed in Alzheimer’s disease and multi-infarct dementia. It should be noted, however, that patients who were discharged before being retested are not included in this statistic, though they would be the ones most likely to have improved (or declined the least). We hope to obtain followup data on these subjects at a later date. At present it would seem that a test series consisting of the ESD and the LPRS is suitable for studies of progressive dementia. The average administration time for the two tests is less than one hour per patient. For purposes of a longitudinal study, one would hope to obtain data with both the ESD and the LPRS for as long as the patient remains “testable”; thereafter, the LPRS ratings could continue. With the inclusion of more outpatients and newly admitted patients (who presumably are at an earlier stage of the dementia process), the percentage of “testable” subjects might increase. This test series could prove to be a cost-effective means of assessing dementia patients psychometrically, and could be of clinical and research value in a variety of institutions.
354
Acknowledgments This project was conducted as part of The University of Western Ontario Dementia Study. Particular thanks are due to the other original members of the study group including Drs. M. J . Ball, R. T . D. Cape, P. Henschke, V. A. Kral, H. Merskey, R. B. Palmer, and D. Robertson of T h e University of Western Ontario. I am grateful to Drs. M. 0. Vincent and J . A. Watt for access to patients a t Homewood Sanitarium and to Mr. William Weiner who did much of the testing for the project. This project was supported in part by a grant from the Canadian Geriatric Research Society and the Academic Development Fund of T h e University of Western Ontario.
1. Hersch EL, Kral VA and Palmer RB: Clinical value of the London Psychogeriatric Rating Scale, J Am Geriatrics SOC 26: 348, 1978. 2. Hersch EL, Csapo KG and Palmer RB: Development of the London Psychogeriatric Rating Scale, London Psychiat Hosp Res Bull 1: 3, 1978. 3. Coblentz J M , Mattis S, Zingesser H et al: Presenile dementia, Arch Neurol 29: 299, 1973. 4. Kahn RL, Goldfarb AI, Pollack M et al: Brief objective measures for the determination of mental status in the aged, Am J Psychiat 117: 326, 1960. 5. Blessed G , Tomlinson BE and Roth M: T h e association between quantitative measures of dementia and of senile change in the cerebral grey matter of elderly subjects, Brit J Psychiat 114: 797, 1968. 6. Fishback DB: Mental status questionnaire for organic brain syndrome, with a new visual counting test, J Am 25: 167, 1977. Geriatrics SOC 7. Pfeiffer E: A Short Portable Mental Status Questionnaire for the assessment of organic brain deficit in elderly patients, J Am Geriatrics SOC23: 433, 1975. 8. Qureshi KN and Hodkinson HM: Evaluation of a tenquestion mental test in the institutionalized elderly, Age & Ageing 3: 152, 1974. 9. Wechsler D: Manual for the Wechsler Adult Intelligence Scale. New York, T h e Psychological Corporation, 1955. 10. Inglis JL: A Paired-Associate Learning Test for use with elderly patients, J Mental Sci 105: 440, 1959. 11. Klingner A, Kachanoff R, Dastoor D P et al: A psychogeriatric assessment program. 111. Clinical and experimental psychologic aspects, J Am Geriatrics SOC24: 17, 1976. 12. Britton PG and Savage RD: A short form of the WAIS for use with the aged, Brit J Psychiat 112: 417, 1966. 13. Hie NH, Hull CE, Jenkins J G et al: Statistical Package For the Social Sciences. New York, McGraw Hill, 1970.
JOURNAL OF T H E AMERICAN GERIATRICS SOCIETY Copyright 0 1979 by the American Geriatrics Society
Development and Application of the Extended Scale for Dementia EDWIN L. HERSCH, MA*
Psychogeriatric Unit, London Psychiatric Hospital, London, Ontario, Canada ABSTRACT: As part of an interdisciplinary study of organic dementia, a psychologic test for assessing the degree of dementia-the Extended Scale for Dementia-was developed through the expansion and rescoring of the original Mattis Dementia Scale. Statistical analyses of the 23 test items resulted in a scoring scheme which includes the “weighting” of items for scoring purposes. The test was successfully administered to 90 subjects from 6 hospitals in the London (Ontario) region. With use of the Extended Scale, it was possible to discriminate between dementia and non-dementia groups of psychogeriatric inpatients and to correlate the findings closely with those of another measure of the degree of dementia, viz, the London Psychogeriatric Rating Scale (Ment.). Dementia patients who were retested after 6-month and 12-month intervals showed a significant decline in scores. No significant scoring differences were noted between males and females or between Alzheimer dementia and multiinfarct dementia. assessment of the degree of dementia even in severe cases. In order to overcome the foregoing difficulties, two paths usually are followed: 1) the use of simplified psychologic tests with items appropriate for the limited levels of functioning, and 2) when even this fails (as in extremely regressed psychogeriatric inpatients), the use of behavior rating scales for which the patient is rated by staff members. It would be desirable to use both of these assessment techniques whenever possible. During the past two years, reasonably good results have been achieved already in the assessment of psychogeriatric patients with the London Psychogeriatric Rating Scale (LPRS) (1, 2). Hence, our attention has now turned to the first possibility-the simplified test. Several dementia tests and mental status questionnaires provide at least a rough psychologic assessment of dementia patients. A review of some of these led to the selection of the Mattis Dementia Scale (3) as the basic instrument, largely because of its comprehensive use of a variety of cognitive tasks (with a wider scope than simple orientation and memory questionnaires) and because its items appeared to be suited to the expected level of functioning.
In February, 1977, an interdisciplinary study group was established at the University of Western Ontario to conduct a comprehensive, longitudinal study of organic dementia. Representatives from such disciplines as psychiatry, neurology, geriatrics, neuropathology, and psychology were included in the group. The purpose of this report is to outline psychology’s role in the study, i.e., the use of psychometrics to assess the degree of dementia. As the ultimate aim was to conduct a comprehensive study of dementia, it seemed appropriate to use comprehensive psychometric tools for the purpose of psychologic assessment. One of the difficulties in such assessment, however, is that dementia patients are often too disturbed or confused to achieve even minimal scores on standard psychometric tests. This is particularly true with regard to subjects who have already been admitted to long-term psychiatric facilities. Nevertheless, it might be possible to develop a method for reliable * Unit Psychometrist, Psychogeriatric Unit, London Psychiatric Hospital. Address for correspondence: Edwin L. Hersch, MA, Department of Education and Research, London Psychiatric Hospital, 850 Highbury Avenue, London, Ontario, Canada N6A 4H1.
348
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EXTENDED SCALE FOR DEMENTIA
Although the Mattis Scale offered much promise, some questions initially were raised on the basis of face validity. Since some of the items were more difficult or more clinically relevant than others, it was felt that they should be scored accordingly rather than with the original “one point per each answer” format. It was also uncertain whether the factorial structure of the Mattis Scale would be replicated in our study population. Moreover, it would seem necessary to supplement Mattis’ pool of items by others reported in the literature. Therefore, it was decided to develop an extended scale for the assessment of dementia, derived as an extension, revision and rescoring of the Mattis Dementia Scale. The validity of the extended scale, and normative data for dementia patients would be established. MATERIAL AND METHODS The Mattis Dementia Scale was extended by adding certain items. Then the extended scale was administered to as many dementia patients as were available. Subsequent revisions and refinements were made in the light of statistical analyses of the findings. The patients The dementia patients were from six hospitals in the London, Ontario, region. All but five were inpatients in facilities providing management and, if necessary, long-term care for patients with well established illnesses. The hospitals were the London Psychiatric Hospital (a public psychiatric hospital), Homewood Sanitarium (a private psychiatric hospital), Parkwood Hospital (geriatric and long-term care), St. Mary’s Hospital (long-term care), St. Joseph’s Hospital-Policlinic (geriatric outpatients), and Westminster Hospital (a Veterans Administration facility). Only patients with relatively clear diagnoses of progressive dementia, and with no additional psychiatric diagnoses, were included. This group consisted of: a) the Alzheimer type (regardless of age, no definite history of a stroke); and b) the arteriosclerotic or multi-infarct type, in whom a definite history of a cerebrovascular accident was associated with the dementia process. From the participating settings, 2 14 dementia patients were available in the first year of the study. However, of the 214, only 90 (42 percent) could achieve even a minimal score: the remainder
were considered “untestable” or too regressed to be tested. Of the 90 subjects tested, 34 were male and 56 were female. The age range was 46-96 years, with most subjects being in their 60’s or 70’s. Forty-nine (54 percent) of the 90 “testable” subjects were inpatients on the Psychogeriatric Unit of the London Psychiatric Hospital. A psychogeriatric inpatient control group of 39 patients from this Unit, with diagnoses other than dementia, was also tested. The test items Table 1 lists the items employed in the present version of the test. Fourteen of the 23 items (Nos. 1-6, 8-12, 17, 22, 23) were borrowed from the Mattis Dementia Scale. The two writing or copying items on the Mattis Scale (“Graphomotor” and “Construction”) were combined in one item called “Graphomotor” (No. 6). Orientation, treated as one item on the Mattis Scale, was divided into three sections, viz, orientation for time (No. 13), place (No. 14), and age (No. 15), involving the use of questions common to a variety of mental status questionnaires (4-6). Questions such as “Who is the Prime Minister (or President)?” and “How many weeks (or months) are there in a year?” have been found useful in previous questionnaires and were added in the item called “Information” (No. 16); also added were “Count Backwards” (No. 18),“Count by 3’s” (No. 19), and “Simple Arithmetic” (No. 20) (7-9). Paired-Associate Learning tests are reported to be sensitive to memory impairment in the elderly (10, ll),so a simple version (No. 21) was added to the Scale. Block Designs have also been used successfully in the intellectual assessment of elderly subjects (12), so a relatively simple Block Design item (No. 7) was added (three examples from the Wechsler Intelligence Scale-Children). Statistical analyses The following statistical analyses were conducted on the data, to assist in the validation, evaluation, further revision and rescoring of the scale: a) A six-week test-retest reliability study; b) Examination of the means, variances, and frequency distributions for each item of the scale, as well as its correlation with other items and total scores; c) Factor analyses of the items; d) KR-20 analysis of the internal consistency of
349
E. HERSCH
the scale as a whole; e) Discriminant Function analyses between high-scoring and low-scoring dementia patients, as well as between dementia and nondementia patients; f) Correlation studies between the Extended Scale scores and the ratings achieved on the Mental Disorganization/Confusion subscale of the London Psychogeriatric Rating Scale; and g) Comparisons of results (means) from different settings, diagnostic groups, and sexes. In addition, 6-month and 12-month test-retest means comparison studies were made (for purposes of a longitudinal study), to assess changes in the test performance of dementia patients as a function of time. Subjects in this study will be retested bi-annually as long as they are alive, available, and testable. RESULTS
Vol. XXVI
difficult,” “fairly difficult,” and “relatively easy” questions. As this classification agreed substantially with the inspection-of-item statistics, it was taken as further support for the validity of weighting the items according to their relative difficulty, and of making corresponding changes in the scoring. Following the weighting of the items (as will be discussed), the new scores were also factor-analyzed. However, no factorial structure of any kind was found. All 23 items loaded best on one large factor accounting for almost all of the total variance. Furthermore, the Kuder-Richardson 20 (KR-20) calculation, based on all 23 items, yielded a coefficient of .943. This indicated a high level of internal consistency for the scale as a whole. ItemTotal correlations calculated at this point between each item score and the subject’s total score ranged from .43 to .76 (Table l),with only the first item (a screening question) showing a correlation of less than 50. The majority of Item-Total correlations were above .60.
Reliability Assignment of item weightings and rescorings Although the items in the test are fairly familiar ones, a test-retest reliability study was conducted. A Pearson-Product moment correlation of r = .94 was calculated, based on the scores of 24 dementia patients tested on two occasions six weeks apart.
Original item statistics Inspection of the means and frequency distributions of scores on the individual items confirmed our suspicions that some of the 23 items were much more difficult than others for dementia patients to answer. The two sections of the Graphomotor item (distinct items on two different factors on the Mattis Scale) were well correlated with each other (r = .73). This suggested that they could be treated as one item.
Factor analysis and item-total correlations Although the Mattis Scale involves both total and factor scores, we could not replicate this factorial structure in our analysis. Before introducing the weighting of items, we factor-analyzed the scores of 90 dementia patients and obtained what initially appeared to be three factors. However, on inspection of these “factors” it was found that they did not fall into three clinically relevant dimensions, but rather into the categories of “very
350
As the foregoing results supported the facevalue observations indicating that some items were worth more points than others, the items were weighted (and rescored) in accordance with the following criteria: a) Item values were balanced in such a manner that each of the items when properly weighted would account for an approximately equal portion of the total, and no one item score could significantly “tip the balance” of the total. Thus, weightings were assigned in accordance with both the mean scores for dementia patients achieved on a given item and the maximum possible score on the item. Consequently, the items were weighted so that both mean scores and maximum scores would be similar from item to item. b) Items could be scored easily while the psychologist was administering the test. The resultant weighted-item statistics are shown in Table 1. The individual item means ranged from 1.1 to 8.2, with most items having a mean of 3-6 points. The maximum possible scores for the items ranged from 5 to 18 points, with most items being worth 8-16 points. Points for individual answers or responses (within the items) ranged from ?hto 4. Thus, no single answer was worth more than 4 points and no single item (or section) was worth more than 18 points out of a maximum
August 1979
EXTENDED SCALE FOR DEMENTIA
possible total score of 250. The mean total score for the dementia patients studied was slightly less than 100. For two of the items, viz, Sentences (Construction and Memory) (No. 12) and Associate Learning (No. 2l), the means suggested that the questions were usually too difficult for our population, even after weighting. These items were retained because of their good discriminant abilities and relevance to dementia, by face-value. However, to aid in administration, a scoring instruction was added so that item No. 21 would be directed only to those patients who scored over 12 points on items No. 8 and No. 9 combined (both of which are correlated fairly well with item No. 21). Of all the patients tested, none proved able to score any points on item No. 21 without having scored 12 or more points on items No. 8 and No. 9 combined. This rescored version of the scale is henceforth referred to as the Extended Scale for Dementia (ESD).
Validation of the Extended Scale Because of our use of mean scores in assigning weightings to particular items, it was important to split the sample, to be sure that the relative proportions of the unweighted mean scores between items was consistent from group to group. In this respect, the first 45 subjects scored similarly to the next 45, and subjects from the six different settings did not show significant differences from each other, i.e., some items were consistently more difficult and others were consistently easier. Although reliability is essential, the test of a scale is not merely how consistent it is statistically, but how well it works in practice. The main purpose for development of the Extended Scale was the assessment of the degree of dementia present in various patients. Thus it would be expected that the scale would enable one to discriminate significantly between high-scoring and low-scoring dementia patients, and to differentiate diagnostically (at least to some extent) dementia patients from non-dementia psychogeriatric patients. If this new test is valid, one would assume that the scores would be correlated with those on other recognized measures of the degree of dementia.
dementia, we compared the high total scorers with the low total scorers on the test. The high-scoring group consisted of the top-scoring 25 percent of the testable dementia subjects (N= 22), and the low-scoring group consisted of the lowest-scoring 25 percent of those subjects. Discriminant function analysis for these two groups (S.P.S.S. computer package used for calculations) (13) showed that 20 of the items in the analysis added a significant, nonredundant contribution to the scale’s overall discriminating ability (based on Wilkes A, p < .001 in each case, with changes in Rao’s V significant at p < .05) (Table 1). Discriminant function analysis was also conducted for the scores of 39 non-dementia psychogeriatric inpatients and 90 dementia patients. The resultant Wilkes X coefficients showed that 22 of the items added significant nonredundant contributions to the scale’s ability to differentiate between the two diagnostic groups at p < .001 levels. However, calculations of differences in Rao’s V coefficients were significant at p < .05 for only six items (Nos. 3, 5, 8, 12, 13 and 17) (Table 1).Thus it would seem that if we wished to make predictions based on a minimal number of items, the use of the six mentioned would probably be sufficient. Correct prediction of group classification based on 22 items was 81 percent in this analysis, with an overall chi-square value significant at p < .001. Of the 7 non-dementia patients who were misclassified as dementia subjects (in the predictions), 5 had other “organic” disorders and another was subsequently reclassified because of a change in diagnosis. In 2 of the 18 misclassified subjects originally in the dementia group, the diagnosis was later changed so that they were classified in the non-dementia group. One interesting finding was that some of the best items for predicting the degree of dementia (e.g., counting backward, block design, verbal recognition and memory, arithmetic) were much less predictive in distinguishing dementia from nondementia subjects, and vice versa (e.g., orientation for time, naming, sentence construction). Thus, an item’s usefulness proved to be dependent upon which of these functions the researchers had in mind. Each of the 23 Extended Scale items added a significant contribution in at least one of these two analyses.
Discriminant function analyses To investigate whether the individual items of the Extended Scale (with the weighted item scoring) adequately differentiated between degrees of
Correlations between the ESD and the LPRS (Ment.) The principal method of psychologic assessment
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E. HERSCH
-~
-
Vol. XXVI
TABLE 1 Item Statistics ~~~~
~
~~~~~~~
~~
~~
~~~~
~~
Discriminant Function Analyses Significance Levels*
Scores
Dementia
Item
-
1. Commands
2. Digits 3 . Naming 4. Repeating 5. Movements 6. Graphomotor 7. Block Design 8. Similarities 9. Differences 10. Similarities (multi-choice) 11. Identities , 12. Sentences 13. Orientation (Time) 14. Orientation (Place) 15. Orientation (Age) 16. Information 17. Count A’s 18. Count Backwards 1 19. Count by 3’s
‘
j
3.9
.58
.Ooo
5.2
.53
.Ooo
,020
.Ooo ,000
,002 .250 ,013
3.8 3.9
3.8 2.0 2.8
, 1
I
4.6 3.2 3.3 3.1
.7 1 .74 .72 .70 .72 .74 .64
12 2 1
4
12
.66 .72
9
.51 .66
~
3
.Ooo ,000
1 .o ’
OOO
j
.Ooo
_ .Ooo .Ooo
.317 ,238 .048 ,447 .671 ,725 ,014
,731
.Ooo .66 .69 .62
.Ooo .Ooo
.76
.Ooo
.Ooo
.Ooo
.Ooo
.ooo
.o .Ooo .Ooo
,342
-
X ~
___
~
-
~
~
~
p
* Missing observations are for variables which did not meet the “F to enter” criteria.
of psychogeriatric patients currently in use at the London Psychiatric Hospital is the London Psychiatric Rating Scale (LPRS) for behavior rating, which is completed by the ward staff. This scale is useful in assessing a patient’s degree of disability, and also is a reasonably good discriminator between dementia and non-dementia patients. We hypothesized that, although two different types of psychologic measure were involved, a patient’s scores on the Extended Scale should prove to be correlated fairly well with the scores on the Mental Disorganization/Confusion (Ment.) subscale of the LPRS. The ESD-LPRS (Ment.) correlation (PearsonProduct moment) for the 55 dementia patients who were both tested and rated in the summer of 1977 was calculated at r = .62. In addition to the patients previously mentioned, another 49 dementia patients were rated at this time. However, they were unable to achieve even a minimal score on the ESD. If one wished to include these patients in the computation by assigning them an ESD score of zero, the ESD-LPRS (Ment.) correlation
(for N = 104) would rise to .93, as the “untestable” patients invariably had poor LPRS scores.
Extended Scale-means, comparisons
variances, and mean
The Extended Scale means and standard deviations for various groupings of patients are listed in Table 2. It may be seen that: a) The means were quite comparable from setting to setting in the study; b) No significant sex differences were found, with respective means of 97.0 for males (N = 34) and 95.8 for females (N = 56); c) No significant differences were found between the Alzheimer (N = 75) and the Multiinfarct (N = 15) dementia groups, although the latter group tended to score slightly lower; d) The psychogeriatric inpatient control group (largely composed of patients with diagnoses of chronic schizophrenia) scored significantly higher (better) than did the dementia pa-
August 1979
EXTENDED SCALE FOR DEMENTIA
TABLE 2 Statistical Findings. by Setting, Sex, and Diagnosis N X a -
Dementia Group London Psychiatric Hospital Homewood Sanitarium Parkwood Hospital St. Mary’s Hospital St. Joseph’s HospitalPoliclinic Westminster Hospital Total
49
94.2
52
13 12 7 5
103.7 88.1 95.6 104.4
63 50 64 63
4 90
108.9 96.3
91 -
Fem a1es Males
56 34
95.8 97.0
50 68
Alzheimer type Multi-infarct Type Tctal
75 15 90
99.1 82.0 96.3
52 62
56
Although the scores for the dementia group as a whole showed a decline at the 6-month retesting interval, the scores for the Alzheimer group showed more decline (average, 36 points; paired ttest results significant at p < .001) than did the Multi-infarct group (average, 16 points; paired ttest results significant at p < .01). This finding, however, was not conclusive, as the retested Multiinfarct group was small (N = 8) and they began with a lower mean (59.9) than did the Alzheimer group (N = 23, X = 99.7) at the initial testing. Thirteen dementia subjects from the London Psychiatric Hospital were tested three times during a period of one year. This group showed significant declines in mean scores at both the first and second 6-month intervals (Table 3).
p < ,001 (pooled t-test result)
Control G r o w
39
159.0
60
tients. The pooled t-test result was significant at p < .001. A summary of the test-retest results is presented in Table 3. Only 50 percent of the testable patients visited in the summer of 1977 were still available and testable six months later. During this period about 30 percent had been discharged, 15 percent were no longer testable, and 5 percent had died in the hospital. The scores of 31 dementia patients tested in the summer of 1977 and subsequently retested 6 months later showed a significant decline. The paired t-test results were significant a t p < .001.
DISCUSSION The Extended Scale for Dementia (ESD) for assessing the degree of dementia was developed through the expansion and rescoring of the Mattis Dementia Scale. Statistical findings with the ESD did not suggest any clinically significant factorial structure for the items, but did reveal that the scale as a whole had a high degree of internal consistency. Therefore, it was decided that ESD results would be reported simply as total scores. The validity of the Extended Scale was established with respect to: a) its capabilities for discriminating between dementia and non-dementia patients, and b) its correlation with another measure of the degree of dementia (the “Ment.” subscale of the LPRS). Twenty of the individual items
TABLE 3 Dementia Subjects-Test-Retest Results 6-Week retested group
1st testing 2nd testing
N
X
24 24
88.2 83.6
-~
a
57 58
&Month retested groups
r
=
.94
Paired t-test significance levels p < ,001
Alzheimer type
1st 2nd A
23 23
99.7 63.6 36.1
57 53
Multi-infarct type
1st 2nd A
8 8
59.9 43.9 16.0
30 25
p < .01
Total
1st 2nd A
31 31
89.4 58.4 31.0
57 53
p < ,001
1st testing 2nd (at 6 mos.) 3rd (at 1 vr.)
13 13 13
92.8 68.3 56.0
-
p < ,001 p < .05
1 - Year retested group, London Psy. Hosp. dementia Datients
-
353
VOl. X X V I
E. HERSCH
also discriminated well between high-total scorers and low-total scorers among the dementia patients. The high scorers were clinically classified as those with a “mild” degree of dementia, and the low scorers were classified as those with “severe” dementia but still testable within the context of institutional care. Some of the items were more useful as predictors of diagnosis than of the degree of dementia, and vice versa. The significant decline in the ESD scores of dementia patients over a 6-month period suggests that the test is appropriate and the time interval is not too short for purposes of a longitudinal study. Although some subjects showed more decline than others, almost all retested dementia patients had lower scores at the 6-month interval. This is in accordance with the progressive decline observed in Alzheimer’s disease and multi-infarct dementia. It should be noted, however, that patients who were discharged before being retested are not included in this statistic, though they would be the ones most likely to have improved (or declined the least). We hope to obtain followup data on these subjects at a later date. At present it would seem that a test series consisting of the ESD and the LPRS is suitable for studies of progressive dementia. The average administration time for the two tests is less than one hour per patient. For purposes of a longitudinal study, one would hope to obtain data with both the ESD and the LPRS for as long as the patient remains “testable”; thereafter, the LPRS ratings could continue. With the inclusion of more outpatients and newly admitted patients (who presumably are at an earlier stage of the dementia process), the percentage of “testable” subjects might increase. This test series could prove to be a cost-effective means of assessing dementia patients psychometrically, and could be of clinical and research value in a variety of institutions.
354
Acknowledgments This project was conducted as part of The University of Western Ontario Dementia Study. Particular thanks are due to the other original members of the study group including Drs. M. J . Ball, R. T . D. Cape, P. Henschke, V. A. Kral, H. Merskey, R. B. Palmer, and D. Robertson of T h e University of Western Ontario. I am grateful to Drs. M. 0. Vincent and J . A. Watt for access to patients a t Homewood Sanitarium and to Mr. William Weiner who did much of the testing for the project. This project was supported in part by a grant from the Canadian Geriatric Research Society and the Academic Development Fund of T h e University of Western Ontario.
1. Hersch EL, Kral VA and Palmer RB: Clinical value of the London Psychogeriatric Rating Scale, J Am Geriatrics SOC 26: 348, 1978. 2. Hersch EL, Csapo KG and Palmer RB: Development of the London Psychogeriatric Rating Scale, London Psychiat Hosp Res Bull 1: 3, 1978. 3. Coblentz J M , Mattis S, Zingesser H et al: Presenile dementia, Arch Neurol 29: 299, 1973. 4. Kahn RL, Goldfarb AI, Pollack M et al: Brief objective measures for the determination of mental status in the aged, Am J Psychiat 117: 326, 1960. 5. Blessed G , Tomlinson BE and Roth M: T h e association between quantitative measures of dementia and of senile change in the cerebral grey matter of elderly subjects, Brit J Psychiat 114: 797, 1968. 6. Fishback DB: Mental status questionnaire for organic brain syndrome, with a new visual counting test, J Am 25: 167, 1977. Geriatrics SOC 7. Pfeiffer E: A Short Portable Mental Status Questionnaire for the assessment of organic brain deficit in elderly patients, J Am Geriatrics SOC23: 433, 1975. 8. Qureshi KN and Hodkinson HM: Evaluation of a tenquestion mental test in the institutionalized elderly, Age & Ageing 3: 152, 1974. 9. Wechsler D: Manual for the Wechsler Adult Intelligence Scale. New York, T h e Psychological Corporation, 1955. 10. Inglis JL: A Paired-Associate Learning Test for use with elderly patients, J Mental Sci 105: 440, 1959. 11. Klingner A, Kachanoff R, Dastoor D P et al: A psychogeriatric assessment program. 111. Clinical and experimental psychologic aspects, J Am Geriatrics SOC24: 17, 1976. 12. Britton PG and Savage RD: A short form of the WAIS for use with the aged, Brit J Psychiat 112: 417, 1966. 13. Hie NH, Hull CE, Jenkins J G et al: Statistical Package For the Social Sciences. New York, McGraw Hill, 1970.
