MOTOR APRAXIA IN DEMENTIA ' ROBERT TAYLOR Deparlment of Clinical Neurosciences Western General Hospifal, Edinburgh

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1 Perceptual and Motor Skills, 1994, 79, O Perceptual and Motor Skills 1994 MOTOR APRAXIA IN DEMENTIA ' ROBERT TAYLOR Deparlment of Clinical Neurosciences Western General Hospifal, Edinburgh Summary.-Motor apraxia was assessed in 25 patients with presumed dementia of the Alzheimer type and 23 patients with presumed multi-infarct dementia. Apraxia was common in both groups and was usually only mild. It correlated most strongly with language-related impairments in the Alzheimer group, as has been found in other patient groups, whereas in the group with multi-infarct dementia the pattern of correlations was less clear. It was not strongly related to performance on tests involving constructional praxis or to age in either group. Implications of the findings for clinical assessment are noted. Apraxia can undoubtedly be seriously disabling. In dementia of the Alzheimer type (DAT), the presence of apraxia (along with aphasia and agnosia) has in addition been suggested as signifying a particularly malignant form of the condition tending to have a relatively early age of onset and rapidly deteriorating course (12). However, clear distinctions are not always made in dementia between motor apraxia, constructional apraxia, and other putative categories of apraxia such as dressing apraxia. In other patient groups motor apraxia has been related particularly to disturbances of language function (6), although its various possible subdivisions and neuropathological substrates remain controversial (2, 5, 8, 11). Motor apraxia is here assessed in Alzheimer-type and multi-infarct dementia (MID) patients using a test (6) intended to avoid some of the conceptual confusion inherent in some traditional classifications of apraxia. METHOD The groups comprised 25 patients with presumed Alzheimer-type dementia (8 men, 17 women; mean age = 74.6 yr., range 54 to 85 years) and 23 patients with presumed multi-infarct dementia (14 men, 9 women; mean age = 75.3 yr., range 44 to 92 years). Al patients were diagnosed by a consulting neurologist or psychogeriatrician; patients with dementia of the Alzheimer type met the NINCDS criteria (7) for probable diagnosis, scored 4 or less in total on the Hachinski index (4), and did not score positively on the Hachinski item concerning history of stroke. MID patients scored 7 or more on the Hachnski index. All patients had at least a six-month history of dementia, and the records of all were reviewed at least six months after assessment. Any patient with an uncertain or mixed diagnosis was excluded. No patient had uncorrected impairment of sight or hearing or physical disability (of 'Correspondence should be addressed to Robert Taylor, Department of Clinical Neurosciences, Western General Hospital, Edinburgh, EH4 2XU, UK.

2 524 R. TAYLOR whatever cause) that would preclude valid testing. On a 13-item orientation questionnaire [consisting of the Information and Orientation section from Pattie and Gilleard (3) plus one additional question on the name of the previous Prime Minister], the mean score in the group with dementia of the Alzheimer type was 6.1 (SD = 3.4) and in the group with multi-infarct dementia 8.0 (SD = 3.0). Motor apraxia was assessed using the test described by Kertesz and Hooper (6), in which the patient is required to carry out five actions in each of four categories: Facial (e.g., whistle), Upper limb intransitive (e.g., wave goodbye), Transitive (e.g., pretend to use a spoon to eat), and Complex (e.g., pretend to light a cigarette). The patient is not penabsed for requiring a demonstration of the required action (thus minimising the potential contribution of receptive dysphasia); actual objects can be provided on some items if the action is not carried out adequately in mime. Each item is scored 0, 1, 2, or 3 according to quality of performance (higher score representing better performance). The authors provide clear scoring instructions and report high interrater reliability. Other tests given to each patient (full details of which are available from the author) were (a) a typical orientation and information questionnaire as described above, (b) immediate and delayed recall of a prose paragraph, (c) drawing from memory a diamond, a star, and two designs from the Wechsler Memory Scales immediately after presentation of each, (d) a 20-item yes-no picture-recognition memory test, (e) a face-name learning test involving three learning trials and a fourth delayed-recall trial, (f) the Weigl sorting test (141, (g) two paper-and-pencil mazes (from lo), (h) a Gibson Spiral Maze test (3) with a compound score involving the time taken to complete the maze and a log-adjusted error score, (i) a similar maze but with Gibson's small round obstacles deleted, (j) fang a grid of boxes with marks like 1s as quickly as possible, (k) a simplified block-design task using flat blocks coloured on one side only, (1) copying the four paper-and-pencil designs previously used in memory for designs and drawing a circle, square, and triangle, (m) miscellaneous brief visuospatial tasks such as constructing a square using sticks, matching target designs to designs in three-choice arrays, estimating the number of cubes represented in perspective drawings of piles of cubes, telling the times shown on clock faces, identifying visually degraded words and objects, and identifying superimposed line drawings of objects, (n) the Token Test (I), (0) repetition of increasingly complex sentences, (p) Digit Span Forward from the WAIS, (q) the Sentence Production subtest from Schuell (l3), (r) writing the patient's own name, a sentence and some numbers to dictation, and copying another sentence having first read it aloud, (s) WAIS Arithmetic items plus other uncomplicated mental arithmetic questions, (t) counting aloud from 1 to 20 and reciting the alphabet, (u) recognition, and (v) naming of objects in which the naming score was the

3 MOTOR APRAXIA IN DEMENTIA 525 proportion of objects named out of those correctly recognised (as shown by naming or by adequate description or demonstration of the object's use, etc.). Tests were not given in the order described. RESULTS AND DISCUSSION Table 1 shows mean scores on each section of the test in each group and percentages of patients showing apraxia according to Kertesz and Ferro's (5) criteria (by which normal subjects should rarely or never be classified as apraxic). Apraxia was common in both groups but was usually no more than dd. Using Kertesz and Ferro's subdivisions of the total apraxia score range, 36% of patients with Alzheimer-type dementia showed mild apraxia, 8% showed moderate, and none showed severe apraxia; none of the patients with multi-infarct dementia showed more than mild apraxia. The relative performance scores on the four sections of the test are consistent with the findings of Kertesz and Hooper (6) for dysphasic patients and with those of Rapcsak, Croswell, and Rubens (11) on another test in patients with senile dementia of the Alzheimer type except facial apraxia was more common in the present study (the criterion in the relevant section here being stringent). Intercorrelations of the scores on the four sections of the test were moderately high (mostly between 0.5 and 0.8; Pearson r), but there were several instances of substantial difference~ (up to 9 points and in different directions in different patients) between individuals' scores on different sections, suggesting that the four sections do not represent a single unidimensional disability. TABLE 1 MEAN APWIA TEST SCORES AND PERCENTAGES OF PATIENTS SHOWING APRAXIA ON EACH TEST SECTION IN GROUPS WITH ~IEIMER-TYPE AND MULTI-INFARCT DEMENTIAS Test Alzheimer-type Multi-infarct (n = 25) (n = 23) M 5D % Awraxic M SD % A~raxic Facial (14") Upper Limb (12*) Transirive (12') Complex (11.7") Total (49.7*) "Criterion level for apraxia given by Kertesz and Ferro (5). Mean scores are lower for the group with Alzheimer-type than for that with multi-infarct dementia in all test categories; however, the former patients were on average more impaired generally than the latter patients as judged by an over-all test score derived from the 22 other tests, i.e., the mean proportion of obtained score on each of the 22 tests over 'best' score for that test. Analyses of covariance showed no significant differences be-

4 526 R. TAYLOR tween the two groups on any of the five apraxia scores when either this over-all test score or the score on the orientation questionnaire was used as covariate. Therefore, the differences in extent of apraxia between groups probably reflect general differences in severity of dementia. Total apraxia score did not correlate significantly with age in the Alzheimer-type group (Pearson r =.lo, p >.05); however, there was a small (nonsignificant) negative correlation between age and over-all performance on the 22 other tests as described above, and the partial correlation between age and apraxia score while controlling for over-all test score was This suggests a weak trend for younger Alzheimer-type patients to show more severe apraxia dowing for their over-all performance in other areas of functioning. As might be expected, similar analysis showed no significant relationships between apraxia and age in the group with multi-infarct dementia. Correlations between total apraxia scores and the other neuropsychological measures are shown in Table 2 (with tests ordered according to strength of correlation in Alzheimer-type patients). In general, intercorrelations between test scores tend to be significant in dementia. In the table, correlations over.7, i.e., the level at which tests share half their variance, are emphasised. In the Alzheimer-type group, the highest correlations are with language-related tests, but this is not clearly the case for the multi-infarct group. Correlations are significantly higher (tested by standard method and using unadjusted.05 significance level) in the Alzheimer-type group than in the multi-infarct group for writing and reading, sentence repetition, and object naming, although there are no significant differences between correlation sizes after Bonferroni adjustment for number of comparisons made. The lack of correspondence between the patterns of correlation in the two groups is illustrated by a Spearman rank-order correlation of only.12 ( p >.05) between correlation sizes in the two groups for the 22 tests as listed in Table 2. This incidentally argues against the patterns found being attributable to some artefact involving test difficulty and suggests that apraxia may be a more genuinely focal deficit in the group with multi-infarct than in that with Alzheimer-type dementia, or that underlying lesions contributing to apraxia may be more varied as might be expected from the nature of the underlying pathology in multi-infarct dementia. Correlations between the different sections of the apraxia test also tended to be lower in the multi-infarct patients than in those with Alzheimer-type dementia, although this may be partly attributable to the narrower score ranges in the former group. The pattern of correlations for the 22 tests in all patients combined, i.e., in a mixed group of patients with dementia, is intermediate between the patterns seen in the two groups but resembles more strongly that found in the one with Alzheimertype dementia (with Spearman correlations between magnitudes of correlations given in Table 2 of.92 for the Alzheimer group and.33 for the multi-infarct group).

5 MOTOR APRAXIA IN DEMENTIA 527 TABLE 2 PEARSON CORRELATIONS BETWEEN TOTAL APRAXIA SCORE AND OTHER TESTS M DEMENTIA OF THE ALZH~ER TYPE, MULTI-INFARCT DEMENTIA, AND COMBMED GROUPS Measure Alzheimer Multi-infarct All (n = 25) (n = 23) (n = 48) Token Test (n).80' Writing and reading (I) Sentence repetition (0) Sentence production (q) Miscellaneous visuospatial tasks (m) Object recognition (u) Arithmetic (s) Object naming (v) Automatic speech (t) Box-filling (i) Copying paper-and-pencil designs (1) Orientation (a) Picture recognition memory (d) Memory for designs (c) Wejgl sorting test (f) Modified block design (k) Paragraph recall (b) Paper-and-pencil mazes (g) Face-name learning (e) Digit span forward (p) Spiral maze 2 (h) Spiral maze 1 (i) Over-d test score *Boldface entries, r>.7. The findings as regards the Alzheimer-type group are comparable to those of Kertesz and Hooper (6), who found that apraxia correlated most strongly with language comprehension deficit and next most strongly with a score representing over-all severity of aphasia in a large group consisting mainly of dysphasic stroke patients. Those authors discussed the theoretical implications of such associations between apraxia and language function. Of the nonverbal tests used in that study, performance on a drawing test was most strongly related to apraxia scores. In Table 2, for both groups, apraxia correlates only moderately with copying designs and less strongly with performance on the modified block-design task. Clearly, motor apraxia is not particularly strongly related to performance on tests involving constructional praxis. The correlation in each group between apraxia and object recognition may support an association between apraxia and agnosia (12), while that between apraxia and performance on miscellaneous visuospatial tasks may partly reflect the fact that the latter includes a range of tasks. It may also be noted that severity of apraxia correlates most highly of all with the over-all test score derived from a wide range of tests.

6 528 R. TAYLOR The present results can be summarised as follows. Motor apraxia was common in both groups. It was usually only mild in these samples, but its prevalence and severity are likely to increase as dementia progresses. Severity was related to performance on many other tests and to over-all severity of impairment. It was particularly strongly associated with language dysfunction in the group with Alzheimer-type dementia, as has been observed in other patient groups, whereas in the multi-infarct group the pattern of correlations was more mixed, perhaps as a consequence of underlying neuropath~log~. Severity of motor apraxia was not particularly strongly related to performance on tests involving constructional praxis (such as block design and design copying) or to age in either group of patients even when over-atl severity of dementia as judged by other test performances was taken into account. None of the correlations between apraxia severity and other measures was so high as to make the assessment of apraxia redundant. Different aspects of motor praxis can be differentially impaired in dementia, and the test adopted here covers a range of aspects in a brief and practical manner. Routine clinical testing for apraxia in dementia seems justified. REFERENCES 1. DE RENZI, E. (1979) A shortened version of the Token Test. In F. Boller & M. Dennis (Eds.), Auditory comprehension: clinical and experimental studies with the Token Test. London: Academic Press. Pp FOSTER, N. L., CHASE, T. N., PATRONAS, N. J., GUESPIE, M. M., & FEDIO, I? (1986) Cerebral mapping of apraxia in Alzheimer's disease by positron emission tomography. An- nals of Neurology, 19, GIBSON, H. B. (1965) Manual of the Gibson Spiral Maze. London: Univer. of London Press. 4. HACHINSKI, V. C., ILIFF, L. D., ZILHKA, E., DUBOULAY, G. H., MCALLISTER, V. L., MARSHALL, J., RUSSEL, R. W. R., & SYMON, L. (1975) Cerebral blood flow in dementia. Archives of Neurology, 32, KERTESZ, A,, & FERRO, J. M. (1984) Lesion size and location in ideomotor apraxia. Brain, 107, KERTESZ, A,, & HOOPER, P. (1982) Praxis and language: the extent and variety of apraxia in aphasia. Neuropsychologia, 20, E. 7. MCKHANN, G., DRACHMAN, D., FOLSTEIN, M., KATZMAN, R., PRICE, D., & STADLAN, M. (1984) Clinical diagnosis of Alzheimer's disease: report of the NINCDS-ADRDA work group. Neurology, 34, OCI-IIPA, C., GONZALES ROTHI, L. J., & HEILMAN, K. M. (1992) Conceptud apraxia in Alzheimer's disease. Brain, 115, PATTIE, A. H., & GILLEARD, C. J. (1979) Clifton Assessment Procedures for the Elderly. Sevenoaks, Kent, UK: Hodder & Stoughton. 10. PORTEUS, S. D. (1965) Porteus Maze Test: fifty years of applicafion. Pdo Alto, CA: Pacific Books. 11. RAPCSAK, S. Z. CROSWELL, S. C., & RUBENS, A. B. (1989) Apraxia in Alzheirner's disease. Neurology, 39, ROTH, M. (1386) The association of clinical and neurological findin s and its bearing on the dassiflcatlon and aetiology of Alzheimer's disease. British ~ejical Bulle!in, 42, SCHUELL, H. (1965) Diflerential diagnosis of aphasia with the Minnesota test. Mimeapolis, MN: Univer. of Minnesota Press. 14. WEIGL, E. (1941) On the sychology of the so-called process of abstraction. Journal of Abnormal and Social ~syc!ology, 36, Accepted July 5, 1994.