Cross-Modal Performance in Patients with Cerebral Lesions

CROSS-MODAL PERFORMANCE IN PATIENTS WITH CEREBRAL LESIONS

c. McNally. G. Ettlinger and A.M.R. Smith (Institute of Psychiatry, De Crespigny Park, London)

INTRODUCTION

Previous studies have suggested that the posterior parietal lobe of the dominant hemisphere is particularly important for cross-modal integration. Semmes, Weinstein, Ghent and Teuber (1954) reported that patients with injury to parietal cortex showed significantly less benefit than other braininjured patients from previous visual experience at solving complex tasks when required to solve the same series of tasks again but by touch alone. Subsequently, Butters and Brody (1968) found a significantly or almost significantly increased number of visual-tactual and tactual-visual matching errors in their left parietal groups (containing up to 7 patients), which could not be attributed to a general deficiency of tactual discrimination. They found no relationship between aphasia and cross-modal matching. Subsequently. Butters, Barton and Brody (1970) extended this study to patients with right parietal lesions. These patients suffered no cross-modal matching deficit relative to their within-modal tactual performance. The results of Butters and colleagues should be treated with caution because of the small number of patients and the way in which the site of lesions was ascertained. In the initial study (1968) the majority of patients, and in the latter study (1970) all patients were allocated to groups according to behavioural signs. The role of language was assessed only in parietal but not in other left hemisphere cases. Moreover, because Butters and his colleagues presented some material successively and other material simultaneously , and exactly the same material was not offered in both sensemodalities, variance within groups may have been increased. The findings of De Renzi and Scotti (1969) on tactual-visual matching of shapes are difficult to evaluate, as even the most severely impaired group (left hemisphere lesions with visual field defect) averaged 7.08 correct out of a possible 8. Cortex (1982) 18, 91-104.

92

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In our experiment, firstly we ensured that all patients had lesions verified by the CAT scan, and/or carotid angiogram or surgical exploration. Right and left hemispheric lesions were tested concurrently. All matching presentations were successive, and the same material was used for both modalities. Also, the role of language in cross-modal performance was studied across all groups. In general we used the tasks devised by G. Ferry (unpublished) for the study of cross-modal development in children of different ages.

MATERIAL AND METHODS

Subjects

Fifty-two subjects, aged 10-60 years. with circumscribed cerebral lesions were compared with a control group of 35 patients with circumscribed posterior fossa or spinal cord lesions. The groups were composed of all patients that met certain lesion criteria. For the experimental group the lesion had to involve less than one cerebral lobe if the pathology was unilateral, and had to be symmetrical involving less than two lobes if the pathology was bilateral. (A few patients with different - e.g. two-lobe - cortical involvement were included if the total area of the lesion was small.) Lesions were either vascular. neoplastic or involved surgical excision. Testing was carried out either before or after treatment, according to the pathology of the lesion. The hand ipsilateral to the lesion (or in bilateral cases the preferred hand) was used for tactual performance. Table I shows the composition of the groups by pathology.

Material Matching

Twenty-four boards each bearing a spatial design in relief were used. Dowelling. arranged on these boards, was varied in length. direction and complexity. The shapes were divided into 2 sets of 12. categorised as "easy" and "hard" to label in previous work by Ferry (unpublished). Within each set, 4 of the 8 shapes were paired (i.e. 2 boards per pair) so that there were only slight differences. generally in the orientation of one or more segments of the design. within pairs. The other 4 shapes were presented twice so that there were no differences at all within pairs of successive presentations. The shapes are shown in Figure 1.

Transfer

Similar material but different shapes were used for the transfer task. There were 8 sets of 4 boards, 4 of these sets having been shown in previous work to be "easy" and 4 "hard to label". The 4 shapes within each set differed from each other only slightly.

Cross-Modal performance and cerebral lesions.

93

IAIlU__ 1

Composition of Groups by Pathology 1. Spinal Control Spinal tumour or cyst Prolapsed disc 2 . Brain Control Tumour in IV ventricle or in medulla Tumour in pituitary fossa Tumour in cerebellum Acoustic Neuroma

2

21

3 4 4 1

12

3. Experimental (cerebral hemispheres) Tumour or sclerosis on CAT but no excision Excised tumour Haematoma on CAT but no evacuation Exercised arterio-venous malformation Infarct on CAT

29 17 4 1 1

52 Composition of Experimental Group: Frontal involvement Temporal involvement Parietal involvement Occipital involvement Left-sided involvement Right-sided involvement Bilateral involvement

Fig. I - A "easy" and B "hard" sets of shapes used for cross-modal matching.

15 19

20

R

2R

25

1

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C. McNally, G. EttlingerandA.M.R. Smith

Procedure

Half the subjects received matching before transfer and half vice versa. Matching was either cross-modal (visual-tactual or tactual-visual) or within-modal (visualvisual or tactual-tactual). Transfer was always cross-modal. All subjects were tested in a quiet room or a quiet part of the ward. The subject sat opposite the examiner, with the materials in between.

Matching Each subject was told: "Please look· at this shape and try to remember it. Now put your hand through the sleeve in front of you and feel the shape which is in the box. I would like you to tell me whether you think that it is the same or different to the one you have just seen. Now I am going to give you other pairs of shapes. Sometimes you will see the first and touch the second, sometimes you will touch the first and see the second, sometimes you will see both and sometimes you will touch both. But all you ever have to do is tell me if you think the second shape is the same as the first one." Shapes were presented for as long as the subject required and the experimenter ensured that in the tactual presentation every part of the shape was felt. The subject was unable to see the tactual shapes; and was not allowed to touch the visual shapes. The experimenter would ask at the second presentation "Is this the same as you just saw/felt? " Even on "same" trials the experimenter made a pretence of selecting another shape from the box. Each of the pairs was presented to every subject once in each of the 2 withinmodal, and 2 cross-modal conditions. The 4 different modality presentations were distributed randomly, as also were the same/different materials and "easy" I"hard" sets. Thus a total of 64 pairs was given. The measure of matching performance was the number of errors made. out of 8. for each modality sequence at each level of difficulty.

Transfer Half the subjects first learnt by vision and then were tested for tactual transfer. and half were tested in the opposite order. In the experimental condition the same materials were presented in the two modalities; in the control condition different materials were presented in the two modalities. Subjects were given the following test instructions for practice in transfer. "Here are 4 patterns". (The 4 shapes were laid out in a 2 x 2 arrangement for the subject to see or feel.) "I have chosen one of these to be correct. You have to guess which one I have chosen to be correct, so you will be able to show me that one every time. The same shape will always be correct. the one I have chosen" . The subject guessed and between guesses the experimenter changed the position of the patterns without the subject seeing. The experimenter continued: "I change the position of the patterns but they always remain the same way up. You have to remember the shape of the pattern. not where it was. " Once the subject had reached criterion (;\ successive correct responses) the experimenter said: " Sometimes you may be lucky and guess correctly on the first go, sometimes you won't know which is correct until you've had 3 goes". A practice task using the same shapes was then given in the alternate sense-modality, and once the same criterion had been reached two further practice tasks were given, in the opposite modality order to the first pair of tasks, but now with different materials in the 2 modalities.

Cross-Modal performance and cerebral lesions.

95

The transfer task itself was divided into experimental conditions (where the same 4 boards were given consecutively in the 2 modalities), and control conditions (where 4 boards were given in the first modality, and 4 different boards in the second). In each modality trials continued until 3 consecutive responses were correct. The transfer task itself was also divided into sets that were "easy" or "hard" to label. AIl "easy" materials were given before "hard" materials. There were 2 experimental and 2 control conditions within each of the easy /hard sets. The order of modalities (VT or TV), of conditions (Experimental or Control) and of material within the easy/hard sets was systematically varied. Savings were separately computed for: levels of difficulty, for experimental and control conditions, and for each modality sequence, using the formula: 1st modality

2nd modality

1st modality

+ 2nd modality

x 100

Assessment of associated defects Intellectual deficit The Vocabulary and Picture Completion sub-tests of the W AIS or WISC were given as the most "lesion free" measures. To be included as subjects, patients had to achieve an age-corrected score of 7 on both tests. For non-fluent dysphasics only the Picture Completion score was considered. Memory impairment Five sets of materials were presented (with a short break between sets) first visuaIly and then again tactually to all patients tested. All materials were shown in pilot work to be "hard to label", to permit valid assessment of dysphasics. Within sets, materials were presented successively, each set comprising 5 new shapes shown once and 1 new shape shown twice (i.e. 7 presentations). The serial position of the repeated shape and the interval was balanced (as far as possible) across sets. The patient was required to indicate when a shape was repeated. Raw scores were used, separately representing false-positive errors (with a maximum possible of 30 per modality) and false-negative errors (maximum possible of 5), individually for vision and for touch. Dysphasia The shortened version of the Token Test (De Renzi and Faglioni. 197X) was given to all patients and served as an overall measure of the severity of dysphasia. If the score was below 29, a level exceeded by 95% of the normal population, or a neurological diagnosis of dysphasia was made, then the patient was classified as dysphasic andf given further tests. These included (i) a test of verbal fluency (Goodglass and Kaplan, 1972); (ii) an assessment of word span (Goodglass, Gleason and Hyde, 1970); and (iii) a picture naming task (Kaplan, Goodglass and Weintraub, 1978).

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Verbal Fluency Patients were shown the picture belonging to the test and instructed to "Tell everything you see going on in this picture." Neglected features were pointed out, and if the patient's response was less than his apparent potential he was asked to elaborate. Patients were given one minute to respond and everything said was written down. Scores ranged from 0 - 5. Word Span A card with eight pictures was placed face downwards in front ofthe subject. A series of words were read out, from two up to six, with two different sets for each length, as with digit span. The card was turned up immediately for the patient to point to the items named in the same order. Testing was contimled until the subject failed to point to all the objects on both trials of a given length. Two different plates were used involving the same items but in different positions, so that subjects would not be aided by positional cues. The score was the longest successful attempt. Picture Naming Drawings of 85 objects were presented successively and the patient was asked to name them. If the picture was not correctly named within 30 seconds a phonemic cue was given by the examiner. The score was the number of items correctly named, either spontaneously or after the prompt.

Tactual and Visual Agnosia All patients were required to explore the same 10 objects (e.g. cup, clothes-peg, screw) by touch alone and then by sight alone, and to name each or describe its use.

Apraxia --

Following the test devised by M.A. Wyke, all patients were required to perform actions to command or imitation, or use objects, to copy hand postures and produce spatial constructions. Errors were cumulated, out of a possible total of 32 and a decision was reached clinically on whether or not the patient showed any of the conventional types of apraxia (e.g. ideomotor, constructional, etc.).

Visual Neglect Patients had to trace 40 lines, each 2,5 cm long, distributed randomly on a 20 x 26 cm sheet (Albert, 1973). Each line not traced was counted as an error, and the patient was judged on clinical grounds to show or not show neglect.

Reduced Tactile Sensitivity Two-point discrimination thresholds were measured on the index, middle and ring fingers of each hand. After 6 easy practice trials, separations were reduced (6

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97

trials per separation, 3 of2-stimuli. 3 of I-stimulus) until the patient made an error. The last separation without error was taken as threshold, and the patient was judged to have a deficit if the threshould was in excess of 4 mm. Visual Field Defect

Testing was done as part of the neurological examination, either to confrontation or by perimetry. The presence of any area of amblyopia was sufficient to establish that the patient had a field defect. Epilepsy

Any history of an epileptic fit was sufficient to designate the patient as epileptic.

RESULTS1

The first analysis indicated no significant difference between the 12 control subjects with brain lesions and the 23 control subjects with spinal lesions on any of the measures for matching or transfer (see Table II for means). ~his outcome was obtained both using T-tests and the test of Kruskal-Wallis (K-W). The 2 control groups were combined for all subsequent analyses. No significant differences were found between control and experimental subjects for the variables age, vocabulary score, picture completion or years of education. Next, the effects of locus of lesion were examined. Frontal patients were compared against non-frontal and against control patients; then similar analyses were made for temporal, parietal and occipital patients, in each instance against all experimental patients not having evidence of a lesion in that locus, and against control patients. All analyses were made both by one-way analysis of variance and also by the K-W analysis; differences between pairs of groups were evaluated by using Tukey's (B) multiple comparison test. There were no significant effects on any measure when the effects of frontal, temporal or occipital lesions were examined. However, significant

1 The authors are aware that the number of statistical tests reported in this publication could be interpreted as possibly misleading, because the chance probabilities are fundamentally in error with such large numbers of comparisons. However. the work in this report should be regarded in the nature of a pilot study, subsequent to which (if there had been any positive findings of note) a detailed replication with explicit strict statistical tests of certain predictions arising from the pilot work would need to be undertaken. The negative findings in this report are not seriously weakened by the number of statistical tests, and no positive finding has been obtained to warrant further replication with strict statistical procedures ..

98

C. McNally, G. EttlingerandA.M.R. Smith

effects were obtained from the comparison of parietal vs non-parietal vs control subjects. These significant effects are shown in Table III, and the means in Table II.

lAHLI: II

Mean Scores (and Standard Deviations) by Groups

Control

A. Matching: V-V. Easy T-T. Easy V-To Easy T-V. Easy V-V. Hard T-T. Hard V-To Hard T-V. Hard B. Transfer: Experimental V-To Easy T-V. Easy V-To Hard T-V. Hard Control V-To Easy T-V. Easy V-To Hard T-V. Hard

All = 35

Experimental -------Parietal Non-Par. N = 20 N = 32

Brain N = 12

Spinal N = 23

N

.42 (.67) \.08 ( \.00) 1.17 ( .72) 2.08 (1.73) .92 (.67) 2.33 (1.23) 2.83 (1.34) 3.08 (2 . 11)

.30 (.64) 1.35 ( \.03) 1.09 ( \,28) 1.91 ( 1.47) .65 (.83) 2. 13 ( \.60) 2.13 0.29) 2.48 (\. 12)

.34 (.64) \.26 (1.01 ) 1.11 (1.1 I) \.97 ( 1.54) .74 (.78) 2.20 ( 1.47) 2.37 ( 1.33) 2.69 ( 1.53)

.30 (.57) 1.80 (1.58) 2.00 ( 1.26) 2.50 ( 1.82) 1.55 (1.40) 2.50 ( 1.15) 2.95 (1.32) 2.90 ( 1.48)

\.87 ( 1.28) .66 (.92) 2. 16 ( 1.55) 2.32 (\.54) 2.87 ( 1.69)

30.9 (72.0) 65 .5 (48.0) 22 .0 (69 .9) 66.3 (46 .7)

37.4 (69.7) 62.8 (47.7) 39.3 (62.0) 52.7 (51.6)

35.2 (69.5) 63.7 (47. I) 33.3 (64.3) 57.4 (49.7)

17.0 (65.2) 45 .2 (46.9) -12.4 (55.2) 29.3 (67 .3)

25 .0 (67. I) 45 .2 (57 .2) 28.6 (69.6) 48.6 (51.3)

-48.3 (56 .8) 75 .9 (24 . I) -0.8 (75 .0) 28.0 (49.8)

-35.1 (47.6) 23. 1 (65.9) -18.6 (61. 9) 28. 1 (48.5)

-39.7 (50.5) 41.2 (60.3) -12.5 (66.1 ) 28. 1 (48.2)

-16.8 (66.3) 28.4 (64. I) -37.5 (45 .0) 50. 1 (39.8)

-29.4 (55 .8) 23.6 (57 . 1) -31.4 (55.0) 48.6 (47 .0)

Scores are errors for matching. savings for transfer.

.29 (.59) 1.35 ( 1.33) 1.48 (\.34)

KruskalWallis

ANOVA

Analysis

I"AHLE III

2/83 2/83 2/83 2/83

3.32 5.68 5.15 3.55

V -T matching, Easy

V-V Matching, Hard

False positives

V-T Transfer, Hard (Experimental)

2 2 2 2

7.02 7.63 7.42 6.96

V-T Matching, Easy

V -V Matching, Hard

False positives

V-T Transfer, Hard (Experimental)

Chi-square

d.f.

Task

F-ratio

.031

.025

.020

.030

.033

.008

-'" ~

Controls and non-parietals fewer than parietals Controls and non-parietals better than parietals

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Controls and non-parietals better than parietals

Controls better than parietals

.041 .005

Source

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Significant Effects (and their Source) from Comparing Parietal vs. Non-parietal vs. Control Subjects

100

C. McNally, G. EttlingerandA.M.R. Smith

Although a cross-modal matching effect was significant in one direction (V -T) when the material was easy, the non-parietal group did not show significantly better performance than the parietal patients, so that there is no evidence that parietal pathology is selectively related to deficient cross-modal matching. Moreover, the parietal patients were significantly impaired at one kind of within-modal matching (V -V, hard material), in this instance not only when compared with the control subjects but also when compared with non-parietal experimental patients. Therefore, the impairment of matching in parietal patients can not be regarded as selectively cross-modal. Both cross-modal and within-modal effects were also significant on the K-W test. The parietal patients also gave significantly more false positive responses overall on the matching task (combining cross- and within-modal versions). At cross-modal transfer. the parietal patients were significantly impaired in comparison with both non-parietal and control patients at only one of the 4 experimental versions: in the direction of Vision to Touch and when the material was hard. When the effects of laterality of lesion were examined, differences were significant on only one task: an experimental transfer task in the direction Touch.to Vision, and when the material was hard (F = 3.17; d.f. = 2, 82; P < .05). The patients with left-sided lesions were significantly impaired relative to the controls, but not relative to patients with right-sided lesions. These latter also did not differ from the controls. The role of associated effects (Table I V) was examined in two ways. Firstly, the experimental group was sub-divided into four groups; making five with the controls. These five groups - controls, subjects with parietal lesions and with an associated defect, parietals without an associated defect, non-parietals with an associated defect and non-parietals withouth an associated defect - were compared using a one-way analysis of variance. Secondly, attention was restricted to the experimental subjects and to locating effects of lesion site and defect in two-way analyses of variance. Further

TABLE IV

Incidence of associated defects in the experimental group Apraxia Dysphasia Epilepsy Memory defect (on special test) Reduced tactile sensitivity Tactual agnosia Visual agnosia Visual field defect Visual neglect

6 12 26

3 R 1 I 13

2

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analyses of higher order effects of lesion site and multiple defects were precluded by the small number of subjects that would have fallen into each sub-category. In both sets of analyses all matching and transfer variables were considered as dependent variables. From the first kind of analyses only the following showed significant differences and detectable pair-wise comparisons on the a posteriori range test (Tukey 'B'. with overall p = .05). (a) With presence or absence of visual field defect. there was a significant difference between groups at visual to visual matching with hard material (F = 3.40; d.f. = 4, 81; P < .013). The parietals with visual defect were significantly more impaired t~an non-parietals withouth visual field defect. (b) With dysphasia as the associated defect, the five groups were significantly different at hard visual to visual matching (F = 5.55; d.f. = 4. 81; P < .005). The parietals with dysphasia made significantly more errors than the other four groups, which did not differ among themselves. This indicates a fairly strong interaction between the locus of lesion and the presence of dysphasia as a source of errors in visual matching when the material was difficult. . (c) The same measure provided significant group differences when apraxia was included as the defect (F = 6.14; d.f. = 4, 81; P < .00(2). Here parietals with apraxia were more impaired than non-parietals without apraxia and than the control group. However. the parietals withouth apraxia were not different from those with; and no comparison was made using the single non-parietal subject with apraxia. A more complicated pattern of results emerged from the two-way analyses of variance, the two factors being parietal versus non-parietal lesion and presence versus absence of defect: (a) With visual neglect as the second factor. parietals were significantly different from non-parietals (F = 6.05; d.f. = 1,46; P < .020) and there was a significant interaction between site of lesion and defect (F = 7.07; d.f. = 1. 46; P < .02) for easy visual to visual matching. On hard visual to tactual matching those with visual neglect were worse than those without (F = 6.22; d.f. = 1,46; P < .016). For the hard visual to visual matching the differences between parietals and non-parietals remained (F = 6.21; d.f. = 1. 46; p < .016) even when visual neglect was included as a factor. (b) With apraxia as the second factor differences were found on easy visual to visual matching, there being a significant interaction (F = 7.36; d. f. = 1, 44; P < .(09) and significant main effect of apraxia (F = 9.52; d. f. = I. 44; P <.020). For easy visual to tactual matching. only apraxia had a significant effect (F = 5.39; d.f. = L 44; P < .025). and again for hard visual to visual matching (F = 10.16; d.f. = 1. 44; P < .003). However. these results are based on 6 subjects with apraxia and only one non-parietal subject had apraxia.

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C. McNally, G. Ettlinger and A.M.R . Smith

( c) With dysphasia as the second factor. significant interactions were found with parietallesiol) on hard visual to visual matching (F = 6.62; d.f. = 1. 47; P < .013) and hard tactual to visual transfer under experimental conditions (F = 4.53; d.f. = 1. 47; P < .038). In each case there was also a main effect of parietal lesion (F = 13.65; d.f. = 1. 47; P < .001. and F = 4:28; d.f. = 1. 47; p < .045. respectively). ( d ) For tactile loss as the second factor. there was a significant interaction between parietal lesion and defect (F = 4.86; d.f. = 1. 44; P < .033) and a main effect for parietal lesion (F = 6.17; d.f. = 1. 44; P < .017) at transfer from touch to vision under experimental conditions. Because of the cell sizes in the two-way analyses , the whole experimental group was divided by presence or absence of associated defect and compared with the controls to ascertain overall effects of defect in one-way analyses of variance. Although there were again some significant effects of apraxia (not selectively related to cross-modal measures) there were no significant effects of dysphasia.

DISCUSSION

The outcome of the study was negative to the extent that no lesion factor was identified that could be selectively related to cross-modal performance. Parietal patients were not impaired on the majority of our cross-modal measures relative to any group. They were impaired on one cross-modal measure. but in that instance only in comparison with the control subjects and not in comparison with the non-parietal experimental subjects. The discrepancy of outcome between this and earlier studies cannot be confidently explained. However. possible sources for the discrepancy are differences in the type or complexity of the material. and/or differences in the modalities that were used. Examination of the means in Table II indicates that on cross-modal measures there were only weak (if any) trends for our parietal patients to be impaired. so that the negative findings are unikely to reflect too small a number of patients. Visual field defect , visual neglect. dyphasia and apraxia each influenct?d within-modality visual-visual matching. but only dysphasia did so strongly: and none of these associated defects was selectively related to cross-modal performance. In particular. even when all experimental patients were considered irrespective of site of lesion , dysphasia did not give rise to selective cross-modal impairment. In this study. the severity of dysphasia was only moderate. with a mean score of 22.6 on the Token Test for 10 dysphasics. Tactile loss interacted with parietal site in producing defect on tactual to visual transfer. but there was no significant main effect of tactual loss. Therefore no strong association was found between an additional neurologi-

Cross-Modal performance and cerebral lesions

103

cal defect (irrespective ofthe site of lesion) and cross-modal impairment. There is no clear evidence from experiments on monkeys as to which region(s) of the brain are particularly concerned with cross-modal performance (Ettlinger and Garcha, IygO). Previous work by Ferry. Ettlinger, Clarke and Smith (unpublished) suggests a developmental progression with our materials. Conceivably. such a progression might imply (in this case) that the neural systems supporting cross-modal performance come to be distributed over larger cerebral regions with age.

ABSTRACf

52 patients with circumscribed cerebral lesions. and 35 control patients (lesions in the posterior fossa or in the spinal cord), were assessed for their ability to match spatial configurations: matching was either cross-modal (visual-tactual or tactualvisual). or within-modal (visual-visual or tactual-tactual). They were also tested for cross-modal transfer (visual-tactual or tactual-visual). All materials were "easy" or "hard". Associated defects (e.g. dysphasia. apraxia) were also assessed. It was found that neither site of lesion, nor laterality of lesion, nor presence of any associated defect was significantly and selectively associated with impairment of cross-modal performance. Aknowledgements. We thank the MRC for supporting this research; the surgeons and neurologists of the Guy's-Maudsley Neurosurgical Unit and of King's College Hospital for permission to study their cases; and Doreen Baxter. Veronique Hassan and Charles Clarke for help in testing the patients.

REFERENCES ALBERT. M.L. (1973) A simple test of visual neglect. Neurology. 23. 65R-664. BUTTERS. N .. BARTON. M .. and BRODY. B.A. (1970) Role of the right parietal lobe in the mediation of cross-modal associations and reversible operations in space. Cortex. 6. 174-190. - . and BRODY. B.A. (196R) The role of the left parietal lobe in the mediation of intra- and cross-modal associations. Cortex. 4. 32R-343. DE RENZI. E .. and FAGLIONI. P. (1978) Normative data and screening power of a shortened version of the Token Test. Cortex. 14.41-49. - . and SCOTTI. G. (1969) The influence of spatial disorders in impairing tactual discrimination of shapes. Cortex. 5. 53-n2. ETTLINGER, G., and GARCHA, H.S. (1980) Cross-modal recognition by the monkey: the effects of cortical removals. Neuropsychologia, 18,685-692. GOODGLASS. H .. GLEASON. J. B .. and HYDE. M. R. ( 1(70) Some dimensions of auditory language comprehension in aphasia. 1. Speech Hear. Res .. 13.595-606. - . and KAPLAN. E. (1972) The Assessment of Aphasia and Related Disorders. Lea and Febiger. Philadelphia. . KAPLAN. E .. GOODGLASS. H.. and WEINTRAUB. S. (197R) The Boston Naming Test. Privatelv published. Boston. .

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J .. WeINsr.I::IN . S . . GHENT. L.. and TE UBER. H .-L. (llJ.54) Performance on complex tactual tasksdfier brain injury in man: analysis by locus of lesion. Am. 1. Psycho I. .67.

SeMMES.

220-240.

Prof. G . Ettlin ge r. Abt. Psychologie. Universitiit Bielefeld ....I-ROO Bielefeld I . W e~t G ermany .