What can amnesic patients learn?

Ne~~~~~holoda,

1976, Vol. 14, pp. 11 I-122. Pergamon Press. Prinled in England.

WHAT CAN AMNESIC PATIENTS LEARN? D. N. BR~x~ Southern General Hospital, Glasgow and A. D. BADDELEY* University of Stirling, Stirling, Scotland (Received 20 Februury 1975) Abstract-Long term learning abilities of amnesic patients were investigated on a number of tasks ranging from verbal paired-associate learning and free recall, to pursuit rotor performance. On verbal long-term memory, amnesics, as expected, showed a severe deficit, but on perceptual-motor learning (Porteus Maze, jig-saw puzzle assembly and pursuit rotor) the deficit was considerably less severe, with a completely normal performance on pursuit rotor and only a mild deficit on Porteus Maze time and error scores. The results suggest not only that the deficits in amnesia may be less global than we suspected hitherto, but also that tests measured on an error criterion may show impairment in amnesic patients, while those measured in terms of time may not.

INTRODUCTION ALTHOUGHthe severity of the memory defect in amnesic patients has been adequately documented [I, 21 there are clear indications that not all memory functions are equally affected. Simple span techniques give consistently normal results [3,1,4] in amnesic patients, who also show a normal recency effect in verbal free recall procedures [3] and in memory for visual location [5]. There is also evidence that at least some amnesic patients may be unimpaired on the Peterson Short-Term Forgetting task [3], although this is not universally the case [2, 61. In general, however, the tests on which amnesic patients have been shown to perform normally, could all be classified as those relying on short-term or primary memory [3]. The present study is concerned with the question of whether any aspect of long-term learning is unimpaired in amnesics. There is existing evidence that certain testing procedures such as prompting by partial information [7j may reduce the amnesic performance decrement. There is also evidence that continuous motor skills may be learned by amnesic patients. MILNER [2] and STARR and PHILLIPS[f?]both report amnesic patients in whom motor skill learning was less dramatically impaired than verbal learning, but in neither study could it be claimed that performance was entirely normal. The present study, therefore, aims to compare the learning abilities of amnesic and control patients on a range of tasks. In all cases both learning within a test session and retention after a week’s delay are studied. Tasks were selected to run the gamut from verbal paired-associate learning, in which previous work suggests that considerable impair* Present address: Medical Research Council, Applied Psychology Unit, Cambridge, England. 111

112

D.N.

BROOKS and A. D. BADDELEY

ment might be expected, through to the continuous motor skill of pursuit rotor performance. The aim was, therefore, not to test a specific theory of amnesia, but to explore empirically the extent of the long-term learning deficit in a sample of amnesic patients across a range of tasks. EXPERIMENT Five amnesic patients were studied (see Table 1) and 5 non-amnesic controls approximately equal in age and I.Q. Four of the controls had suffered limb injuries, and 1 had undergone a laryngectomy. The latter patient had no difficulties in communication and his results were in all respects similar to those of the remaining controls. The inclusion of both encephalitic and Korsakoff patients can be criticized as introducing heterogeneity into the results, particularly as the two types of patient, in our study, differ considerably in age. However, amnesic patients who are not also diffusely intellectually deteriorated are extremely difficult to find, and in the event, although there were differences in performance between the two amnesic sub-groups, these were not consistent in size or direction. Data will be given for the two sub-groups independently, each sub-group matched with its own age and I.Q. control. In cases where the overall pattern is comparable, statistical comparisons will be made between the total amnesic and the total control groups. Table 1. Age, diagnosis and I.Q. for amnesic and control patients SN” 1 2 3 4 5

Age 17 17 46 49 48

Mean

35.4

Amnesics Diagnosis Encephalitis Encephalitis Alcoholic Korsakotf Alcoholic Korsakoff Alcoholic Korsakoff

Verbal I.Q. 91 89 :: 95

Performance 89 87 95 90 90

97

90

110

115

100 86 90 10s 98

100 92 95 105 101

I.Q.

Controls 6 ;: 9 10 MWl

15 27 19 51 57 33.8

Non-neurological

injury

METHODS 1. Verbal paired associate learning This test was chosen to demonstrate the severity of the amnesic verbal learning defect since there is considerable evidence for impaired verbal learning in amnesics (l-3). Patients were presented verbally with 8 pairs of high frequency words chosen to exclude obvious associations. Pairs were presented at a 2 set rate. Immediately after the presentation of the complete list, the first word of each of the pairs was spoken and patients attempted to give the appropriate response. Order of presenting and testing the pairs was varied randomly on successive trials, and errors were corrected. Four trials were given. Testing was repeated after a delay of one week, commencing with a single “recall” trial when the first word of each pair was presented. This was followed by a further 4 “relearning” and test trials identical to the original learning procedure. 2. Verbal free recall The patient was presented with a list of 10 high frequency words which he then attempted to recall in any order he wished. In normals the test is commonly assumed to comprise two components, a stable long-term, and a labile short-term component, the latter being suggested by the higher probability of recall of words at the end of the list (the recency effect). If recall is delayed for 20-30 set, the recency effect disappears leaving only the stable long-term component. Whether the two components are interpreted in terms of long- and short-term memory stores [9] or are attributed to different retrieval processes [lo]. there

WHAT

CAN AMNESIC

PATIENTS

LEARN?

113

is abundant evidence that they are influenced by different variables [I 11. Furthermore, BADDEUY and WNUINGTON 131have observed unimpaired recency in amnesic patients who show grossly defective performances on earlier items, and on delayed recall. This task should, therefore, allow a direct comparison with the Baddeley and Warrington study based on a different sample of amnesic patients. Comparable results would imply broadly comparable patients. Twenty lists of 10 words were prepared for verbal presentation at the rate of 1 word every 2 sec. For 10 lists the patient recalled immediately after the final word (indicated by E dropping his voice), and for the remaining 10 lists recall was after an interval of 30 set filled by the patient counting back in 3’s as fast as possible from a 3 digit number presented by E. A different number was used on each delayed recall trial. All patients began with the easier immediate free recall condition. 3. Porteus mazes The maze learning performance of the bilateral temporal lobe amnesic H.M. has been studied by CORKIS 112, 131 who found considerable impairment in a complex tactile maze, but some evidence of learning when the maze was simplified. However, as WCK~DWORTH [14] has pointed out, subjects typically use either verbal or visual imagery coding to learn tactile mazes. Since both of these have been shown to be impaired in amnesics [15] the interpretation of H.M.‘s decrement is not straightforward. We, therefore decided to study the learning of the visually presented Porteus Maze, a task which we hoped would be less likely to evoke either verbal or imagery coding than a tactualiy presented maze. Subjects were given 10 consecutive trials on the adult version of the Porteus Maze Visual Test [16] followed after a delay of one week by a further 10 trials on the same mare, a new blank sheet being used for each trial. Performance was scored in terms of time taken to achieve a correct solution, and in terms of number of erroneously entered blind alleys per trial. 4. Card sorting Patients sorted as rapidly as possible a standard pack of 52 playing cards into four suits. Sorting was carried out six times in succession followed after a delay of one week by a further single sorting (“retest”). It was hoped that this would allow us to observe the learning of a discrete perceptual-motor task, which could then be compared with the continuous perceptual-motor skill involved in pursuit rotor performance. Patients were scored for time to complete each trial, and any erroneous responses noted. 5. Jig-saw puzzle assembly Two simple jig-saw puzzles of 12 pieces each were chosen (Jollytime, Arrow Games Ltd.) suitable for children aged 3-5. Patients were asked to construct one puzzle as rapidly as possible, and were then given 6 consecutive “learning” trials. After a delay of one week, the same puzzle was readministered (“retest*‘) followed immediately by one trial of the second unfamiliar puzzle (“transfer”). This allowed the degree of learning of a specific puzzle to be compared with any general improvement in speed of assembling jig-saw puzzles. Patients were scored for time to construct the puzzles. 6. Pursuit rotor This was included to explore the possibility that amnesic patients may be relatively unimpaired in the learning of continuous perceptual motor skills [g, 12 and 131. A standard (Electronic Developments) pursuit rotor was used at a rate of 1 rev/set. Patients were tested for three 5 min blocks, each separated by a gap of 10 min. After a break of 1 week a further three 5 min tests were given again separated by 10 min gaps. Patients were scored for the percentage time on target for each 5 min block.

RESULTS 1. Verbal paired associate learning

Results are shown in Fig. I, from which it is clear that the performance of the amnesic groups was at a very low level. There was no overlap between the scores of amnesics and controls in either initial learning or relearning (for both, U = 0, NI = N, = 5, P-C 0405). Retention performance after the one week delay was also reliably poorer for the amnesic group (U = I, NI = N, = 5, P < 0.01). It is clear from this task that our amnesic group shows the standard gross impairment of verbal learning that is characteristic of globally amnesic patients. 2. Verbalfiee recall The results for immediate and delayed recall are presented in Figs. 2 and 3. Quantitative

D. N. BROOKSadd A. D. BADDELEY

114

PAIREC - ASSOCIATE

m II ”

*-A n----o

LEARNING -• o----o

ENCEPHALITICS t N:2 I CONTROLS ( N.2 I

KCRSAKOFF i N.3 I CONTROLS t N =3 I

l

1 Week

1 Week Delay

1

2

3

L

Recoil 1

2

3

L TRIAL

TRIAL

1.

Ro.

estimates of the two memory components were made using the method derived by BADDELN [17, 181. Delayed recall is used as an estimate of LTM, and the difference between delayed and immediate recall is taken to represent items in STM, but not in LTM. The total STM contribution to the final free recall score can be represented by the expression N (I - O)/ N - D where N = number of items in the list, I = immediate score, and D = delayed score. These figures are given in Table 2. For the two estimates of STM, there were no significant differences between amnesic and controls (I - D: U = 6.5, NI = Na = 5, P > 0.05: N(I - D)/N - D: TJ= 6, NI = Na = 5, P > 0.05). For LTM (delayed recall) the amnesic patients were significantly poorer than controls. U = 3, NL = N2 = 5, P < 045). Amnesics show, therefore, a normal recency effect but are very poor on performance IMMEDIATE .-. o-----o

1

2

FREE

RECALL .-. o-----o

ENCEPIULITICS I N =2 1 C0NTRU.S ( Nc2 I

3

I. INPUT

5

6

7

6

9

10

1

2

KOR44KoFF f N=3 1 CONTROCS ( N=3 I

3

1

5

6

!NP’JT POSlTlON

POSITW

Fm. 2.

7

6

9

10

WHAT

CAN

115

AMNESIC PATIENTS LEARN?

based on LTM. This parallels the result obtained by BADDELEY and WARRINGTON[3] and suggests that our subjects are at least broadly comparable with theirs. DELAYED 10 9

A-A o-----o

1

FREE

RECALL

ENCEPHALITICS ( N= 2 I CCNTROLS 1 N-2 J

o-----o l

KORSAKOFF ( N=3 I CCRdTROLS ( N=3 I

8 7

6

i

1

2

3

L

5

6

7

8

9

10

INPUT POSITON

INPUT POSITION

FIG. 3.

An analysis was made of the number and type of errors produced. Table 2. Estimates of LTM and STM in free recall Amnesics

Encephalitic Korsakoff I 5 Mean

I 3.8 4.3 4.6 4.4 4.2

0.8 0.8 2.2

2.0

N(I - D) N-D 2.62 3.80 4.24 3% 2.57

4.26

1.24

3.04

3.43

4.4 S-4 45 4.6 S-3

3.4 ::: 3.6 2.7

2.0 3.0 2.4 ::i

4.84

264

2.16

D ;I;

I-D 2.2 3.5

Controls

Mean

3.04 I.56 3.29 2.66

Errors that did not represent intrusions from previous lists were scored as related semantically (S), acoustically (A) or unrelated (U) to words in the list from which the erroneous recall was made. This was done by transferring all intrusions to anonymous data sheets which were submitted blind to 4 raters (including DNB) for assessing as A, S or U. Of the 177 non-prior intrusions only 17 were not rated consistently by at least three of the four judges. These 17 were added to the U errors. The resulting pattern of intrusions is shown

116

D. N. BIUXKS and A. D. BADDELEY

in Table 3. Although there is a general tendency for the amnesics to make more intrusions, this was not uniformly true, indeed one Korsakoff patient made no intrusions. The only significant differences in intrusions frequency between amnesic and control patients occurred in the base of acoustic intrusions (U = 3, Nr = Nz = 5, P < O-05) and perseverative unrelated errors (U = 2, NI = N, = 5, P < O-05). While it would be unwise Table 3. Intrusion

errors in free recall Amnesics

Prior List

Patient 1 2 3 4 5

Encephalitic

I

Korsakoff

4 2 1 4 0 1.6

Mean

Acoustic

Semantic

1; 6 I 0 2.0

0 3 1 4 0 1.6

6 4 0 5.0

10 38 31 5 0 168

0 21

0 41

0 3

Controls 0 1

Unrelated ;

Perseverative

1 :

0 1::

4 5

9 2

0 0

4 0

4 1

:. 0

5.6

@4

1.4

2.0

1.2

Mean

to make too much of differences selected in this post hoc manner, the tendency of amnesics to make acoustic confusions is consistent with the suggestion that they may be particularly prone to encode acoustically rather than semantically [19] and their performance less impaired when coding in this way [ 151. 3. Porteus maze The mean time to complete the Porteus Maze on each trial is shown for the two amnesic and two control groups in Figs. 4 and 5. The graphs show a considerable degree of learning in both amnesic sub-groups, particularly in savings over the one week delay. Learning was examined by subtracting the trial 10 score from the trial 1 score; the difference between the two groups failed to reach significance (U = 6, NI = Nz = 5, P > 0.05). A further measure of learning was taken by comparing the two groups on the total time scores summed over all 10 trials giving a significantly smaller degree of learning in the amnesic patients (U = 2, Nr = Np = 5, P = O-016). Retention was compared in the two groups by subtracting the score for the tirst relearning trial from the 10th learning trial score, giving no significant difference (U = 12, NI = N, = 5, P > O-05). The results suggest that although amnesic patients do show a marked degree of learning on this task in terms of Maze completion time, the learning is probably not as great as for normals, although the statistical results are equivocal. However in terms of retention, the amnesic patients are clearly fully equivalent to normals. On errors there were very wide individual differences, but these were not associated with amnesic aetiology. Error scores ranged from a total of 26 (amnesic) to 0 (1 amnesic and 3 controls). There was a tendency for amnesics to make more errors. This failed to reach statistical significance on the first set of 10 trials (amnesics = 10.4, controls = 3:

WHAT

CAN

AhlNESIC

PATIENlX

117

LEARN?

but was significant on the second set of 10 trials one U = 5.5, Ni = Ne = 5,P > O-053, week later, (U = 3.5, NI = Nz = 5, P < O-05). PORTEUS

MAZE

1 Week .-•

KORSAKOFFS

‘J----0

CONTROLS ( N=31

( N= 3

I

, \ 1 \ \

\

O-1

I

1

$

I

I

I

I

I

I

I

4

2

3

4

5

6

7

8

9

10

1

2

3

4

5

TRIAL

6

7

0

9

Ib

TRIAL Pm.

4.

PORTEUS MAZE

X-I o----o

100

AMNESKYS CONTROCS

[ ENCEPHALITIC I N:2)

1 1 N=2 )

4

8

60-

2

3

4

5

6

7

8

9

10

1

2

3

5

6

7

9

10

TRIAL

TRIAL

FIG. 5.

The pattern of maze learning performance is therefore, somewhat complex. There is a tendency for amnesics to make more errors but this varies considerably from patient to patient and is not associated in any obvious way with aetiology. Errors might be expeded

D. N. BROOKSand A. D. BADDELEY

118

to lead to an increase in solution time, and amnesics were significantly worse on one of the time scores used. However, the results suggest that amnesic patients show clear learning and at least as good retention as controls. Broadly speaking then the amnesic patients show some impairment on an error measure, and some learning impairment on one time score. 4. Card sorting On this test performance was extremely variable for all patients, and there was little convincing evidence of learning either in the amnesic or in the control group. There were no significant differences between the two groups, on any score. It seems likely that this skill was so overlearned in most subjects that any improvement was slight and likely to be masked by random fluctuations in performance. No errors occurred, which suggests that subjects were operating well within their performance capacity throughout. 5. Jig-saw puzzle assembly The mean time to complete the jig-saw puzzle is shown in Fig. 6. On overall level of performance the Korsakoff patients and their controls appeared to be rather worse than the encephalitics or their controls, possibly reflecting an age difference, and making interpretation of results a little difficult. However, in terms of learning, both amnesic subgroups showed very clear learning curves. However, whereas the Korsakoff patients are consistently worse than their controls, the encephalitic patients show a suggestion of a crossover effect during learning. Learning was examined in the two patient groups by subtracting the score for trial 6 from the trial 1 score. No significant differences occurred (U= ll,N,=N,= 5, P > O-OS).Similarly when the two groups were compared on the total time score summed over all the 6 trials, the difference was again not significant (U = 5, Nr = N2 = 5, P > O-05) although larger groups might possibly have revealed a significant difference. JIG-SAW

PUZZLE ASSEMBLY l-•KJX?SMWFLN~31 o---o

a--rE-TtC

1

no lw

a----0CoNTRCi

123L56

CONTROL

I Na3 I

/

I N.21 (N.21 1 We& O&y I,

Retest

Tmnsfer

123L56

Retest

Tmntfer

FIG. 6.

Retention over one week was examined by subtracting from the 6th “learning” trial the

WHAT

CAN AMuEsxc

PATIENTS

119

LEARN?

score at the “retest” trial. There was again no difference between the two groups, (U = 9, N1 = Np = 5, P > O-05). Degree of transfer was examined by subtracting the “retest” time from the “transfer” time (based on the unfamiliar jig-saw). Again the amnesic and control groups did not differ (U = 8, N1 = Ne = 5, P > 005). 6. Pursuit rotor The mean percentage of time spent on target for each 5 min block is shown in Fig. 7. Clearly there is no difference between either group of amnesics and their respective controls. The amnesics display a completely normal rate of learning. Pursuit rotor performance typically shows clear reminiscence effects, with performance at the end of a trial being lower than performance at the beginning of the following trial. Reminiscence effects were tested statistically by comparing for each patient, the performance on the first 30 set of each 5 min block with the last 30 set of the preceding block. This gave a total of five comparisons which were then summed and compared between groups. Although there was a tendency for the amnesics to show more reminiscence, this difference was not statistically significant (U = 9, N1 = N, = 5, P > O-0.5). PURSUIT -4 o--

ROTOR PERFORMANCE

ENCEPHALlTlCS t N=2 I CONTROLS I N =2 1

--0

l -•

KORSAKOFFS ,I N=3 I CONTROLS I N=3)

o----o

0 1

2

3

L

5

6

1

5 MIN TEST RUNS

2

3

L

5

6

5 MIN TEST RUNS Pm.

7.

DISCUSSION It is clear from our results that patients showing grossly defective long-term verbal learning may show quite normal acquisition of a continuous perceptual-motor skill. This pattern was substantially the same for both encephalitic and Korsakoff patients on Pursuit Rotor and Porteus Mazes, although on the jig-saw task encephalitic patients seemed rather better than Korsakoff’s. The Korsakoff patients’ performance did not approach that of their control group, although the encephalitics showed a crossover effect and were overall rather better than their control group. This picture of normal or near normal acquisition reinforces the growing suspicion that global amnesia may be considerably less global than it at first appeared. This in turn suggests that a more detailed knowledge of the limits of the learning impairment shown by amnesic patients may have both practical and theoretical implications of considerable importance.

120

D. N. Broods

and A. D. BADDEUY

A more detailed examination of our results gives some preliminary cues to the nature of the long-term learning defect in the patients studied. While it would be unwise to assume that our Korsakoff and encephalitic patients have an identical deficit, we do not feel able on our available data to distinguish unequivocally between the performance of the two groups, and for the present at least, will refer to them as a single group. Consider first of all the tasks on which amnesics showed impairment. These comprise the two long-term verbal learning tasks, and possibly the Porteus Maze error score. In contrast no decrement was found in pursuit rotor learning, and despite a tendency for overall performance to be rather slower there was no clear evidence of marked impairment of learning or degree of retention for the jig-saw puzzle assembly, or the Porteus Maze test, when a completion time score is used. It is certainly premature to generalize from this somewhat fragmentary picture, but a number of possibilities seem worth exploring further. First there is a suggestion that tests measured on an error criterion show impairment, while those measured in terms of time do not. This may be purely coincidental but it is perhaps worth pursuing further: in particular it would be interesting if a long-term verbal learning task, relying on time rather than errors could be studied, together with a motor skills learning task with a high error rate. The study was not set up to test any existing theory of amnesia, but as has been pointed out elsewhere, [20] the failure of the jig-saw assembly task to show any marked decrement in amnesics does not fit readily into a semantic coding interpretation of amnesia. It is unfortunately possible that subjects learned the puzzles as a stereotyped series of perceptual motor responses. Casual observation suggests that this was not the case, but it would clearly be desirable to check this point. In conclusion our study suggests that the long-term learning capabilities of grossly amnesic patients may be considerably less generally impaired than we, at least suspected. A more precise charting of the limits of the amnesic syndrome however, must await further experimentation. Acknowledgements-We would like to thank Dr. IVAN DRAPER, Consultant Neurologist at the Institute of Neurological Sciences, Glasgow and Dr. J. D. CHICK, Registrar, Royal Edinburgh Hospital, for permission to study amnesic patients under their care.

REFERENCES 1. DRACHMAN,D. A. and ARBIT, J. Memory and the hippocampal complex II. Is memory a multiple process? Arch. Neural. 15, 52-61, 1966. 2. MILNEX, B. Memory and the Medial Temporal Regions of the Brain. In Siology of Memory, K. H. PRIBIUM and D. E. BROADBENT (Editors). Academic Press, New York, 29-50, 1970. 3. BADDELEY,A. D. and WARRINGTON,E. K. Amnesia and the distinction between long- and short-term memory. J. Verb. Learn. verb. Behav. 9, 176-189, 1970. 4. ZANG~ILL, 0. L. Some qualitative observations on verbal memory in cases of cerebral lesion. Br. J. Psychol. 37,81-89, 1946. 5. WA~IUNGTON,E. K. and BADDUEY, A. D. Amnesia and memory for visual location. Neuropsychologia 12, 257-263.1974. 6. CERMAK,L. S., Burrarts, N. and GOODGLASS, H. The extent of memory loss in Korsakoff patients. Neuropsychologia 9,307-315, 1971. 7. WEISKRANTZ,L. and WUIUNGTON, E. K. A study of forgetting in amnesic patients. Neuropsychologia 8,281-288,1973. 8. ST-, A. and PHILtIps, L. Verbal and motor memory in the amnesic syndrome. Neuropsychologiu 8, 75-88, 1970. 9. GLANZER,M. and CUNITZ, A. R. Two storage mechanisms in free recall. J. verb. Learn. verb. Behav. 5, 351-360,1966. 10. BADDELEY. A. D. and HITCH.G. Working memory. In The Psychology oflearning and Motivation VIII. G. H. BOAR (Editor). Academic Press,New York, 47-89, 1974. 11. GLANZER.M. Storage mechanisms in free recall in The Psychology of Learning and Motivation V G. H. BOWER(Editor). Academic Press, New York, 129-193, 1972.

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12. CORKIN, S. Tactualiy guided maze learning in man: effects of unilateral cortical excisions and bilateral hippocampal lesions. Neuropsychologia 3, 339-351, 1965. 13. CORKIN, S. Acquisition of motor skill after bilateral temporal lobe excisions. Neuropsychologia 6, 225-265, 1968. 14. WOODWORTH,G. S. ExperimentaZ Psychology. Holt, New York, 1938. 15. BADDELEY,A. D. and WARIUNGTQN,E. K. Memory coding and amnesia. Neuropsychologia 11,159-165, 1973. 16. PORN, S. D. The Maze Tesf and Clinical Psychology. Pacific Books, Palo Alto, 1959, 17. BADDELEY,A. D., Scorr, D., DRYNAN,R. and SMITH,J. C. Short-term memory and the limited capacity hypothesis. Br. J. Psychol. 60,X-55, 1969. 18. BADDELEY,A. D. Estimating the short-term component in free recall. Br. J. Psychol. 61, 13-15,197O. 19. CERMAK,L. S., BUTI-ERS,N. and GERREIN,J. The extent of the verbal encoding ability of Korsakoff patients. Neuropsychologia 11,85-94,1973. 20. BADDELEY,A. D. Theories of Amnesia. In Studies in Long-Term Memory. R. A. KENNEDYand A. L. WILKES(Editors). Wiley, London.

On a Studid les capacites d'apprentissage amnesiques

sur un certain nombre d'epreuves

de paires associees

2 long terme des malades

allant de l'apprentissage

verbales et de rappel libre, B des performances

pour-suite circulaire.

cornme on s'y attendait,

de

les amnesiques montraient

un deficit grave de la memoire verbale 3 long terme mais le deficit etait considgrablement circulaire); circulaire

moins important lors des apprentissaqes

(labyrinthe de Porteus, assemblage

tivo-moteur

la performance

Btait complStement

normale sur la poursuite

et le daficit Btait leger sur le ten@

reurs du labyrinthe Ces resultats

percep-

de puzzle et poursuite et les scores d'er'

de Porteus. suqqerent non seulement que les deficits peuvent etre

dans 1'amnSsie moins globaux qu'on le suspectait

jusqu'ici mais Bgale-

d&nontrer un deficit chez les malades amneeiques tandis que ceux dont les mesures

ment que les tests utilisant sont faites en

un criterium d'erreur peuvent

terme de temps peuvent ne pas le demontrer.

Zeutsc'nsprachigeZusacmenfassuq:

Es wurde die Langzeit-LernfShigkeit amnestischer Patienten anhand einer Reihe van Aufgaben untersucht, die vom ErgSnzen von Yortpaaren und den freien Evozieren bis zum Umgang r.it dem Rn-suit rotor reichte. Bei der sprachgebundenen LangzeitIierkfghigkeitzeigten die amnestischen Patienten, wie zu erMarten, s&were

AusfSlle; dagegen war das Defizit beim per-

zeptuellen und notorischen Lernen (Porteus irrgarten, beim puzzle-Zusammensetzspiel und pursuit-rotor-Iiandhabung)deutlich geringer ausgepr?lgt,wobei die Leistungen tit den pursuit rotor vollkowen

normal ausfielen und bei d.erDurch-

f%run.; der Porfeus-Irrgarten-Aufgabe nur geringe TXngel iti 3ezuz au? Zeit- und Fehler-‘:erteacftraten.

D. N. BROOKSand A. D. BADDELEY

Die Ergebnisse sprechen nicht nur dafiir,da8 die Ausfkillebei aer Amnesie weniger global sind als wir bisher vermuteten, sondern such dafiir,daR die Versuche, die auf der i3asisvon Fehlern gemessen wurden, eine Leistungsminderunc bei den amnestischen Fatienten zeigen, Ghrend

d-asnicht der Fall zu

sein braucht, wenn auf Zeit-Basis gemessen wird.