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acquisition of new words in normal subjects: a suggestion for the treatment of anomia

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Brain and Language 77, 45–59 (2001)
doi:10.1006/brln.2000.2422, available online at http://www.idealibrary.com on
Acquisition of New ‘‘Words’’ in Normal Subjects:
A Suggestion for the Treatment of Anomia
Anna Basso,*,† Paola Marangolo,† Fabrizio Piras,† and Claudia Galluzzi†
*Clinica Neurologica, Università di Milano, Milan, Rome; and †IRCCS S. Lucia, Milan, Rome
Published online February 15, 2001
The study explores the efficacy of three learning methods in normal controls. Thirty subjects,
randomly assigned to the repetition, reading aloud, or orthographic cueing method, were asked
to learn 30 new ‘‘words’’ (legal nonwords arbitrarily assigned to 30 different pictures); 30
further new ‘‘words’’ were used as controls. Number of trials to criterion was significantly
lower, and number of words remembered at follow-up was significantly higher for the orthographic cueing method. Two aphasic patients with damage to the output lexicons were also
rehabilitated with the same three methods. In both patients the orthographic cueing method
was significantly more efficacious. The differences in learning efficacy of the three methods
are discussed.  2001 Academic Press
INTRODUCTION
When we speak, word retrieval is usually a quick and easy process albeit wordfinding difficulties may also occur in normal speakers. At times, proper names or
precise words may in fact be difficult to retrieve even if we know them. In aphasic
patients difficulty in word retrieval is the most pervasive symptom of language breakdown, and naming disorders may result in a wide variety of errors due to damage
to different stages in the process of naming. The similarities between aphasic errors
and normal slips of the tongue have been noted by many authors. Freud claimed that
‘‘the paraphasia in aphasic patients does not differ from the incorrect use and the
distortion of words which the healthy person can observe in himself in states of
fatigue or divided attention’’ (1953, p. 13).
The pervasiveness of word-finding difficulties has motivated several studies devoted to the management of the deficit and its effectiveness. Group studies suggest
that word-finding deficits in general can be ameliorated (Hillis, 1989; Howard, Patterson, Franklin, Orchard-Lisle, & Morton, 1985a, 1985b; Marshall, Pound, WhiteThompson, & Pring, 1990; Myers-Pease & Goodglass, 1978) but in group studies it
is difficult to evince what treatment has been useful for what type of patients. Error
types in normal subjects and aphasic patients have provided important clues to the
architecture of the normal lexical processing system and many authors have recently
proposed relying on cognitive neuropsychological models to reach a functional diagnosis, which should then be used as a guide to aphasia therapy (Behrmann, 1987;
Byng, 1988; Hillis & Caramazza, 1987). Theoretically based treatments have been
published presenting cases of patients whose deficits were identified relative to a
Address correspondence to Anna Basso, Neurological Clinic Milan University, Via F. Sforza 35,
20122 Milan, Italy. Fax: 39 02 546 3834. E-mail: [email protected]
45
0093-934X/01 $35.00
Copyright  2001 by Academic Press
All rights of reproduction in any form reserved.
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BASSO ET AL.
FIG. 1. Functional architecture of the lexical-semantic system and the sublexical-conversion mechanisms.
functional model of single word processing and rehabilitated following the cognitive
neuropsychological approach (Howard et al., 1985b; Miceli, Amitrano, Capasso &
Caramazza, 1996).
The background model we will refer to has the functional architecture shown in
Fig. 1 (for a detailed description of the model see Caramazza & Hillis, 1990; Miceli,
Giustolisi, & Caramazza, 1991). Briefly, the model assumes that written language
does not depend on spoken language and makes a distinction between input and
output word-form stores. The single semantic component is independently connected
with the phonological and the orthographic input and output lexicons, which contain
the phonological and the orthographic representations of words. The segmental processing of new words in reading aloud is based on grapheme-to-phoneme conversion
rules, and in writing to dictation on phoneme-to-grapheme conversion rules; the seg-
ACQUISITION OF NEW WORDS
47
mental processing in repetition is based on input to output phoneme conversion rules
that are not represented in Fig. 1. Repetition, writing, and reading aloud of regular
words can be performed by the dual activation of the lexical and the sublexical procedures. Finally, it is assumed that the lexical and sub-lexical procedures interact.
This model predicts different error types in a naming task according to the site of
the functional damage. In the present study, we are only interested in damage to the
phonological output lexicon, and thus our focus will be on patients with a loss of
information about the phonological representations and intact verbal semantics. In
these patients, the complete semantic information fails to activate an unavailable (or
inaccessible) lexical representation and patients produce either omissions, descriptions of the object to be named (circumlocutions), or partial phonological renditions
of the target word. It has also been argued that semantic paraphasias can results from
damage to the output lexicon (see, for instance, Caramazza & Hillis, 1990).
The cognitive approach allows us to reach a precise functional diagnosis but it
does not provide guidelines for the implementation of rehabilitation (for a discussion,
see Caramazza, 1989). In fact the models fail to include many important aspects of
the rehabilitation process, such as treatment techniques likely to modify the identified
functional damage/s.
To build a theory of rehabilitation, the hypothesis at the basis of the proposed
intervention must clearly be made explicit and the proposed intervention should then
be tested. It is our opinion that, short of counterevidence about its lack of effectiveness, therapy should be directly aimed at the functional damage. We also argue that,
with some obvious limitations (such as those due to the general effect of the presence
of brain damage, which obviously plays an important role), we can compare a normal
subject performing a given task to a brain-damaged patient performing the same task.
If this is the case, the techniques most successful in normal subjects for solving a
given task can be used as a starting point for implementing a therapeutic method for
patients with a functional damage which impairs the execution of the same task.
In this study our aim is to identify the technique that is most successful in normal
subjects’ learning of new words.
When asked to learn words in an unknown second language or non words associated with a given picture, normal subjects have a complete semantic information
about the concept. They cannot, however, activate the word in the output lexicon
because, by definition, the phonological representation of the word is not there. Aphasic patients with an intact semantic component and damage to the phonological output
lexicon would be in the same situation (except, as we pointed out earlier, for the
consequences of brain damage that obviously play a role). If we can identify such
a technique, the following rational step would be to see whether it is successful with
patients with the same functional ‘‘damage’’ of normal subjects, namely damage to
the phonological output lexicon with an intact semantic system. Tikofsky and coworkers (Tikofsky, 1971; Carson, Carson, & Tikofsky, 1968) have in fact reported
data that indicate that relative to normal controls, aphasic patients as a group show
reduced rates and amounts of verbal learning but that their performance patterns are
quite similar.
The paper reports on an experimental study in normal controls who where asked
to learn new ‘‘words’’ associated with pictures. We decided to test three techniques
normally used in aphasia therapy for the rehabilitation of anomia: reading aloud,
repetition, and the use of a phonological cue. However, instead of the phonological
cue we used an orthographic cue. We chose an orthographic instead of the more usual
phonological cue for two main reasons. First, the ‘‘prosody’’ of the phonological cue
is by itself an important cue; it can be produced with a rising tone that can provoke
a quasi automatic response from the patient (see, for instance patient JCU who said
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BASSO ET AL.
tiger in front of the picture of a lion if cued with /t/; Howard & Orchard-Lisle, 1984)
and we wanted to elicit an intentional response. Second, since the orthographic cue
remains in view of the subject, he or she has longer to search for the target word.
The orthographic cue can be used to implement oral naming because the orthographic
output can ‘‘recirculate’’ in the lexical system. The written response can be converted
by grapheme-to-phoneme conversion rules and produced orally.
In order to study the efficacy of the three learning methods, we asked three groups
of normal subjects to learn new words, each associated with a picture, and compared
the efficacy of the three methods.
We also tested two anomic patients, RF and MR, with damage to the output lexicons and intact conversion mechanisms necessary for reading aloud and repetition.
EXPERIMENT
Subjects
Thirty healthy right-handed volunteers (18 men and 12 women) participated in the study. All subjects
gave informed consent; they were native Italian speakers aged between 29 and 63 years (mean ⫽ 49.3,
SD ⫽ 8.5) with 8 to 17 years of formal education (mean ⫽ 12.4, SD ⫽ 2.5). Subjects were randomly
subdivided into three groups (10 subjects in each group) matched for age and educational level.
Stimuli
A set of 60 bisyllabic invented words was prepared. Words were construed in such a way as to have
a very low level of similarity with Italian words, to include a consonant cluster, and to have a one-toone phoneme-to-grapheme correspondence. Thirty words were used for learning (experimental) and 30 as
controls. Sixty pictures of low, medium, and high familiarity, belonging to different semantic categories
(animals, tools, body parts, clothes, fruits and vegetables, and musical instruments) from the Snodgrass
and Vanderwart’s (1980) picture-set, were selected. The 60 pictures were randomly matched to the
invented words, one picture per word, with the same number of low, medium, and high familiarity
pictures in the experimental and control group. The 60 new words and the associated Italian words are
reported in the appendix.
Procedure
Subjects were tested individually. The experiment included three phases: a training phase, a learning
phase, and a follow-up. The first two phases were run on two consecutive days, and the third a week
later.
Training. The procedure for the training phase was identical for the three learning methods and was
as follows: the 60 pictures were presented one by one to the subject in pseudorandom order while the
examiner clearly said the corresponding invented words. The subject was instructed to pay attention to
each word-picture pair without repeating the word aloud. The pictures were presented three times and
at the end of the third presentation, the subject was presented with a display of the 60 pictures and was
required to point to the picture named by the examiner. If he or she pointed to an incorrect picture, the
examiner pointed to the correct one saying the corresponding word and then went on to the following
stimulus. The number of pictures correctly indicated by the subjects varied from 4 to 16 (mean ⫽ 9.8,
SD ⫽ 3.3).
On the second day, the subject was first presented once again with the display of the 60 pictures, and
was required to point to the picture named by the examiner. If the subject pointed to an incorrect picture,
the examiner did not comment on the error in any way and said the following word. The number of
pictures correctly pointed to by the subjects varied from 3 to 20 (mean ⫽ 8.8, SD ⫽ 4.0). The 60 pictures
were then presented one by one to the subject and he or she was asked to name them without any
feedback; the number of correct responses was recorded (baseline).
Learning. The learning phase followed immediately and was different for the three experimental
groups. In the learning phase and in the subsequent naming condition the pictures were presented in
pseudorandom order. For each group of subjects a different cueing method was used. The first group
was asked to learn the words by repeating aloud the experimental stimulus presented by the examiner
together with the corresponding picture. The examiner showed the pictures one by one and waited three
49
ACQUISITION OF NEW WORDS
seconds for the subject to say the corresponding word. If he or she failed, the examiner said the word
and the subject was required to repeat it. After presentation of the 30 experimental pictures, the subjects
was presented with all the pictures (30 experimental and 30 control pictures) and asked to say the ‘‘name’’
of each picture. The number of correct experimental and control words was recorded. The whole naming
procedure was then repeated until the subject correctly named all 30 experimental words (or for a maximum of 20 trials. All subjects, however, learned the 30 experimental words in less than 20 presentations
and only one subject required as many as 10).
Subjects in the second group were asked to learn the words by reading aloud the written word presented
with the corresponding picture. The procedure was the same as for the repetition group.
The third group was asked to learn the words using an orthographic cue. The examiner presented the
pictures one by one and asked the subject to say the name; if he or she could not say it in three seconds,
the examiner wrote the first letter of the corresponding word and waited 3 s for the subject to complete
the word. If he or she could not, the same procedure was used for the following letters until the subject
completed the written word and then said it. The procedure was then the same as for the reading and
the repetition groups.
Follow-up. A week later and without previous notice, the subjects were once again presented with
the 60 pictures one by one and asked to name them without any feedback.
STATISTICAL PROCEDURE AND RESULTS
Table 1 reports for each of the 10 subjects of the repetition group the number of
experimental and control pictures correctly named at baseline, the number of presentations necessary to learn the 30 experimental words, and the number of experimental
and control pictures correctly named at follow-up. Tables 2 and 3 report the same
data for the reading aloud and the orthographic cueing group, respectively. The graph
in Fig. 2 illustrates the same data for the three groups.
Number of presentations to criterion. For each subject in each experimental
group the number of presentations necessary to learn the 30 experimental words was
computed and the results of the three groups were compared. The data were analyzed
using an Anova with one within–subject factor (cueing method: repetition, reading
aloud, orthographic cue). The analysis revealed a significant difference between the
three cueing methods: F ⫽ 19.528, df 2, 27; p ⫽ .0000. The mean number of presentations in learning the 30 experimental words with the orthographic cue was significantly lower (5.1) than the number of presentations in learning the experimental
TABLE 1
Repetition Method: Number of Stimuli (Experimental and Control) Correctly Named by
the Subjects at Baseline and Follow-Up, and Number of Presentations Necessary to Learn
the 30 Experimental Words
Baseline
(stimuli)
Subjects
AA
MB
AP
AM
ED
GB
ADF
CDF
GL
LL
Mean (SD)
Exp.
Contr.
4
3
5
1
6
3
3
3
4
5
3.7 (1.4)
2
4
6
1
4
3
7
2
3
4
3.6 (1.8)
Note. Exp, experimental; Contr., control.
Number of
presentations
6
7
8
10
6
8
7
9
9
7
7.7 (1.3)
Follow-up
(stimuli)
Exp.
Contr.
5
6
12
6
12
10
8
9
7
10
8.5 (2.5)
2
1
4
0
3
2
3
2
2
3
2.2 (1.1)
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BASSO ET AL.
TABLE 2
Reading Aloud Method: Number of Stimuli (Experimental and Control) Correctly Named
by the Subjects at Baseline and Follow-Up, and Number of Presentations Necessary to Learn
the 30 Experimental Words
Baseline
(stimuli)
Subjects
CA
CA
MDL
MI
NL
MG
FC
LB
FL
VP
Mean (SD)
Exp.
Contr.
Number of
presentations
3
1
3
6
3
5
3
2
3
0
2.9 (1.7)
4
2
3
3
1
1
2
2
2
0
2 (1.1)
6
9
7
7
8
6
8
7
8
7
7.3 (0.9)
Follow-up
(stimuli)
Exp.
Contr.
10
6
10
7
8
13
8
8
7
16
9.3 (3)
3
0
2
2
2
1
1
2
3
1
1.7 (0.9)
Note. Exp., experimental: Contr., control.
words with the repetition (7.7) or the reading aloud method (7.3) (Duncan’s test: p
⬍ .01). The repetition and the reading aloud methods did not differ from each other
(Duncan’s test: not significant).
Number of experimental words correctly remembered at follow-up. For each subject in each experimental group, the number of experimental and control pictures
correctly named at baseline and follow-up was computed. The data were analyzed
with an Anova with one within-subject factor (cueing method: repetition, reading
aloud, and orthographic cue) and two between-subject factors (time, baseline vs follow-up; number of pictures, experimental vs control). Results showed three significant main effects: method (F ⫽ 10.168, df 2, 27, p ⫽ .0005), time (F ⫽ 148.654,
df 1, 27, p ⫽ .0000), and number of pictures (F ⫽ 215.586, df 1, 27, p ⫽ .0000).
TABLE 3
Orthographic Cueing Method: Number of Stimuli (Experimental and Control) Correctly
Named by the Subjects at Baseline and Follow-Up, and Number of Presentations Necessary
to Learn the 30 Experimental Words
Baseline
(stimuli)
Subjects
AG
BG
BL
AG
LC
MP
AP
AG
MP
SF
Mean (SD)
Exp.
Contr.
3
3
3
4
3
3
3
2
2
4
3.0 (0.7)
2
3
2
4
4
3
4
3
2
1
2.8 (1.0)
Exp. ⫽ experimental, Contr. ⫽ control
Number of
presentations
5
5
6
5
5
5
5
5
6
4
5.1 (0.6)
Follow-up
(stimuli)
Exp.
Contr.
17
10
16
17
16
15
18
18
15
22
16.4 (3.0)
2
3
1
3
3
1
2
2
2
1
2.0 (0.8)
ACQUISITION OF NEW WORDS
51
FIG. 2. Mean number of experimental stimuli correctly named by the three groups of control subjects
at baseline and follow-up.
The two-way interactions were also significant: cueing method ⫻ time (F ⫽ 20.420,
df 2, 27, p ⫽ .0000), cueing method ⫻ number of pictures (F ⫽ 13.484, df 2, 27,
p ⫽ .0000), and time ⫻ numbers of pictures (F ⫽ 260.943, df 2, 27, p ⫽ .0000).
Finally, there was a significant three-way interaction: F ⫽ 21.407, df 2, 27, p ⫽
.0000. The interactions were further submitted to a planned comparison analysis. The
results showed that for all methods the number of experimental pictures correctly
named at follow-up was significantly higher than that at baseline (orthographic cue,
F ⫽ 198.36, df 1, 27, p ⫽ .0000; reading, F ⫽ 45.25, df 1, 27, p ⫽ .0000; repetition,
F ⫽ 25, 453, df1, 27, p ⫽ .0000).
In addition, the mean number of experimental pictures correctly named with the
orthographic cue at follow-up (16.4) was significantly higher than that with the repetition (8.5; F ⫽ 40.85, df 1, 27, p ⫽ .0000) and the reading aloud method (9.3; F ⫽
27.06, df 1, 27, p ⫽ .0000), which did not differ from each other (F ⫽ 1.41, df 1,
27, p ⫽ .24).
For the control pictures, with the orthographic and the repetition methods, the mean
number of pictures correctly named at follow-up was significantly lower than that
correctly named at baseline (orthographic cue, F ⫽ 198.36, df 1, 27 p ⫽ .02; repetition, F ⫽ 17.58, df 1, 27 p ⫽ .0000). The difference was not significant for the
reading aloud method (F ⫽ 0.81, df 1, 27, p ⫽ .37). The graph in Fig. 3 illustrates
these results.
APHASIC PATIENTS
RF is a 66-year-old right-handed university teacher with a degree in pedagogy.
He suffered an occlusion of the left posterior cerebral artery with aphasia and right
hemiparesis on January 1999. An MRI showed the presence of a large cortico-subcortical occipital-temporal lesion involving the thalamus and the internal and external
capsule. In February 1999, his speech was fluent and grammatically correct with
frequent word-finding difficulties. Comprehension was relatively spared (23/36 on
the Token test; cutoff score, 29; De Renzi & Faglioni, 1978). Reading was impaired
and reading treatment was started. In July he was reassessed; his comprehension was
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BASSO ET AL.
FIG. 3. Mean number of control stimuli correctly named by the three groups of control subjects at
baseline and follow-up.
within normal limits (Token test: 29/36) and his reading was much improved; wordfinding difficulties were still evident and more marked for nouns (11/30 correct) than
for verbs (21/28 correct). All errors were omissions. The decision was made to submit
the patient to the three experimental methods for the rehabilitation of anomia.
MR is a 42-year-old right-handed man with a degree in law, who worked as an
Italian Red Cross army officer. In December 1996 he underwent an evacuation of a
haemorrhage due to the rupture of an artero-venous malformation of the posterior
communicating artery. A CT-scan performed in January 1997 showed a hypodense
area in the left temporal region. He then showed a full-blown Wernicke aphasia with
severely impaired comprehension, fluent speech with semantic and phonemic paraphasias and word-finding difficulties. A rehabilitation program was started and
when reassessed in October 1999 MR showed marked improvement. Comprehension
was fair (Token test: 25/36), speech was fluent with word-finding difficulties more
marked for nouns (11/30 correct) than for verbs (22/28 correct). His errors were
mainly failures to respond. He was then submitted to the three experimental methods
for the rehabilitation of anomia.
Procedure
Two hundred fourteen pictures of different semantic categories were selected; frequency varied from low to high. The pictures were presented once to the patients
for three consecutive days, and the examiner waited 5 s for the response. The pictures
the patients could not name and for which they always produced an omission were
selected (103 for patient RF and 88 for patient MR). The selected pictures were then
presented three times for comprehension. They were presented once with the correct
name, once with a semantic alternative and once with an unrelated name (for table,
for instance, they were told once table, once writing desk, and once car); the patient
had to say whether the name was correct or not. Only the pictures for which the
patients’ answers were always correct were chosen for the experimental naming therapy (92 for patient RF and 88 for patient MR).
Orthographic
Repetition
Reading
Methods
2
3
2
Exp
Baseline
4
4
3
Contr
21
10
13
Exp
5
5
4
Contr
Fifth day
16
8
5
Exp
5
4
5
Contr
Follow-up 1
10
7
6
Exp
3
3
5
Contr
Follow-up 2
TABLE 4
Number of Stimuli Correctly Named by RF, at Baseline, at the End of Treatment (Fifth Day), and at Follow-Ups 1 and
2 with Each Learning Method
ACQUISITION OF NEW WORDS
53
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BASSO ET AL.
Therapy
The selected pictures were subdivided in four subgroups of 23 (for RF) and 22
(for MR) pictures each, controlled for frequency of use. Three groups were used for
the three learning methods and one as a control. The same control pictures were used
for all therapy programs, which were performed on three subsequent weeks. For
patient RF the order of presentation was orthographic cue, repetition, and reading
aloud. For patient MR the order was repetition, orthographic cue, and reading.
Before starting therapy the patients were presented with the control pictures and
the group of pictures for the naming program to be started (baseline). The treatment
was the same as for the control subjects with two differences. In the orthographic
cueing method, the examiner waited 5 s (and not 3) before adding another letter to
the preceding ones, and for all three methods the procedure was repeated three times
a day for 5 consecutive days.
Follow-up. At follow-up, performed independently for each therapy program,
the patients were asked to name the control pictures and the pictures belonging to
the last program performed. Patient RF was tested 1 and 12 weeks after the end of
each treatment, and patient MR after 1, 3, and 5 weeks after the end of each treatment.
RESULTS
RF. Table 4 and Fig. 4 show, for each method, the number of pictures (experimental and control) correctly named during the baseline condition, at the end of
treatment, after 1 (follow-up 1) and 12 weeks (follow-up 2).
Naming accuracy at the end of treatment was significantly different from baseline
for the words treated with the orthographic cueing and the reading methods: orthographic cueing, χ 2 17, p ⬍ .001; reading, χ 2 7.7, p ⬍ .01 (McNemar’s test). The
difference was not significant for the repetition method. A second analysis compared
the pictures correctly named during baseline with the pictures named at follow-ups
1 and 2. Naming accuracy was significantly different for the orthographic cueing
method both at follow-up 1 (χ 2 10.5, p ⬍ .01) and at follow-up 2 (χ 2 4.9, p ⬍ .05;
McNemar’s test). The differences for the reading and the repetition methods were
not significant.
FIG. 4. Number of experimental stimuli correctly named by RF at baseline, end of treatment (fifth
day), and at follow-ups 1 and 2 with each learning method.
Repetition
Orthographic
Reading
Methods
4
2
2
Exp
2
5
4
Contr
Baseline
17
22
16
Exp
2
4
4
Contr
Fifth day
10
18
8
Exp
4
4
4
Contr
Follow-up 1
8
18
6
Exp
3
4
3
Contr
Follow-up 2
8
15
7
Exp
5
6
5
Contr
Follow-up 3
TABLE 5
Number of Stimuli Correctly Named by MR at Baseline, End of Treatment (Fifth Day), and at Follow-Ups 1, 2, and 3
with Each Learning Method
ACQUISITION OF NEW WORDS
55
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BASSO ET AL.
FIG. 5. Number of experimental stimuli correctly named by MR, at baseline, end of treatment (fifth
day), and at follow-ups 1, 2, and 3 with each learning method.
MR. Table 5 and Fig. 5 show, for each method, the number of pictures (experimental and control) correctly named during the baseline condition, at the end of
treatment, after 1 (follow-up 1), 3 (follow-up 2), and 5 weeks (follow-up 3) after the
end of treatment.
Naming accuracy at the end of treatment was significantly different from baseline
for all three methods (orthographic cueing, χ 2 18.05, p ⬍ .001; reading, χ 2 12, p ⬍
.001; repetition, χ 2 11, p ⬍ .001; McNemar’s test). A second analysis revealed that
naming accuracy was still significantly different from baseline only for the orthographic cueing at follow-up 1 (χ 2 12.5, p ⬍ .001), follow-up 2 (χ 2 14, p ⬍ .001),
and follow-up 3 (χ 2 11.07, p ⬍ .001; McNemar’s test). The differences for the reading
and the repetition methods were not significant.
DISCUSSION
Not unexpectedly all the control subjects reached criterion with the three learning
methods and retained some learning at follow-up. The use of the orthographic cue
was found to be significantly more successful with regards both to the number of
presentations necessary to reach criterion (which was lower for the orthographic
method than for the other two methods), and to the number of ‘‘words’’ remembered
at follow-up, a week later (which was higher for the orthographic method than for
the other two methods). The other two methods did not differ.
Results were similar for the two aphasic patients. Some learning was possible with
all three methods (the difference was not significant with the repetition method for
RF) but the patients did not learn all the experimental words. In addition, both RF
and MR retained some learning at follow-ups, and this was significantly higher than
baseline when words had been acquired with the orthographic cueing method.
What aspects of the orthographic cueing method and of the other two methods,
reading aloud and repetition, can explain their different effectiveness in learning? In
all three cases, the target is activation of the phonological representation in the output
lexicon. The search for the correct response, however, seems to be more under intentional control in the case of the orthographic cueing method than in reading or repetition; in these cases the response is given to the subject and all he or she has to do
ACQUISITION OF NEW WORDS
57
is to transcode it from orthography to phonology in reading, and from input to output
phonology in repetition.
In normal subjects, active participation in the learning process is known to produce
better retention than passive observation. The generation effect is the advantage in
memory of self-produced as opposed to externally presented information (Slamecka & Graf, 1978). Researchers do not agree on the possible explanations of the
generation effect. The various interpretations can be divided into two categories,
those that implicate semantic memory explaining the effect as due to some more
general principle of memory (such as depth of encoding, for instance) and those that
attribute it to the intrinsic characteristics of the generation task (for a review, see Mc
Elroy & Slamecka, 1982). Be it as it may, the important point for us here is that the
generation effect has been proved sound. It has been found in a wide variety of tasks,
such as frequency judgments (Green, 1988; Smith, 1996), procedural learning (Vakil,
Hoffman, & Myzliek, 1998), and acquisition of new words (Mc Elroy & Slamecka,
1982).
Our results with normal control subjects confirm the effectiveness of generation
over less effortful methods (reading and repetition) although other explanations cannot be ruled out. An obvious difference between the three methods lies in the amount
of time allowed for each response, which is longer in the orthographic cueing method.
However, in a pilot study with control subjects carried out in order to identify the
number of new ‘‘words’’ needed to be learned, leaving more time for the answer
did not help the subjects. For aphasic patients, however, time may be an important
factor. The following step consisted in evaluating the three methods with aphasic
subjects. We argued that temporal absence of a phonological representation in the
mother tongue or absence of a phonological representation in a second language in
normal controls can be compared to functional damage to the phonological output
lexicon in aphasic patients and that the same learning strategies could be successful,
albeit less effective in aphasic patients because of a general loss of capacity to learn
(Tikofsky, 1971; Carson et al., 1968). The effect of the three methods would be less
but the orthographic cueing method, being the most effective one in normal controls,
would still induce some learning. Our results confirm this hypothesis.
To conclude, let us briefly recapitulate our main points. We argued that as long as
it has not proven to be ineffective, aphasia therapy should be directed at the functional
damage and not to finding alternative solutions, and that aphasic patients with specific
functional damages can be compared to normal controls in special situations. We
also argued that strategies that work with normal subjects in such situations can also
be successful with aphasic patients. We therefore identified a highly effective learning
method with normal subjects and verified its effectiveness with aphasic patients.
58
BASSO ET AL.
Appendix
Fam
M
H
L
H
H
H
M
H
H
L
L
M
L
L
M
M
L
M
H
L
M
H
M
L
L
L
H
M
L
H
H
L
M
M
L
L
M
L
H
L
L
L
M
H
M
M
H
M
H
H
H
H
L
L
M
M
L
H
L
H
Pictures
Ago (needle)
Camicia (shirt)
Cigno (swan)
Telefono (telephone)
Libro (book)
Cucina (kitchen)
Pesce (fish)
Naso (nose)
Bicchiere (glass)
Capra (goat)
Leone (lion)
Zucca (pumpkin)
Arpa (harp)
Corona (crown)
Arancia (orange)
Stella (star)
Struzzo (ostrich)
Sedano (celery)
Porta (door)
Bruco (caterpillar)
Freccia (arrow)
Gamba (leg)
Lucchetto (padlock)
Canguro (kangaroo)
Giraffa (giraffe)
Foca (seal)
Pantaloni (trousers)
Scala (ladder)
Lumaca (snail)
Calzino (sock)
Vestito (dress)
Serpente (snail)
Carota (carrot)
Cappello (hat)
Mulino (mill)
Pecora (sheep)
Pinze (pliers)
Scimmia (monkey)
Stampella (hanger)
Orso (bear)
Ancora (anchor)
Topo (mouse)
Ciliegia (cherry)
Occhio (eye)
Palla (ball)
Chiodo (nail)
Chiave (key)
Sega (saw)
Braccio (arm)
Dito (finger)
Frigorifero
(refrigerator)
Cane (dog)
Leopardo (leopard)
Botte (barrel)
Anguria
(watermelon)
Lima (file)
Telaio (loom)
Letto (bed)
Scarafaggio (beetle)
Capelli (hair)
Note. Fam, familiarity; H, high; M, medium; L, low.
Invented
words
Lasba
Grole
Zaclo
Nuspo
Norli
Velba
Mible
Bippo
Vorpa
Pilca
Nunco
Lansi
Cirli
Bepri
Pirga
Lorba
Bleti
Lutre
Fimpo
Dresi
Svife
Dongi
Lerpo
Milvo
Svuna
Gilne
Tucce
Revra
Filco
Tiblo
Rundo
Galpo
Silpo
Lecri
Gluve
Lorfe
Pasbi
Clesi
Tabri
Drelo
Fitre
Trulo
Nirgo
Senci
Relga
Sdeta
Sbulo
Lovri
Dippa
Zirve
Zilci
Zunde
Nipra
Pruso
Nulge
Rembe
Docle
Tepro
Furra
Dunlo
ACQUISITION OF NEW WORDS
59
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