Communication deficits: assessment of subjects with frontal lobe

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Bernicot, J., & Dardier, V. (2001). Communication deficits : assessment of frontal
lobe damage subjects in an interview setting. International Journal of Language
Communication Disorders, 36(2), 245-263.
Communication deficits:
assessment of subjects with frontal lobe damage in an interview setting
Josie Bernicot and Virginie Dardier
Laboratoire de Psychologie Langage et Cognition (LaCo)
Université de Poitiers - CNRS
MSHS, 99 avenue du Recteur Pineau - 86022 Poitiers Cedex, France
Tel: 33.5.49.45.32.44 - 33.5.49.45.46.10
Fax: 33.5.49.45.46.16
email: [email protected]
May 2000
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Biographical notes on the authors
Josie Bernicot is a professor of developmental psychology at Poitiers University. She is also
head of the "Pragmatics of Communication" research team at the Language and Cognition
Laboratory (LaCo, Poitiers University/CNRS). Her present research focuses on the field of
developmental pragmatics. She has published theoretical and experimental articles on the
following themes: verb acquisition by children, metaphors, the production and comprehension
of speech acts, metapragmatics, transition from the nonlinguistic period to the linguistic
period, input and pragmatic development, and pathologies and pragmatic development.
Virginie Dardier is writing her Ph D at the University of Paris 5 and is a member of the
Language and Cognition Laboratory (LaCo, Poitiers University/CNRS). She was granted a
scholarship from the Ministry of Higher Education. Her dissertation is on pragmatic
communication deficits in frontal-lobe damaged patients. Generally speaking, her studies deal
with the fields of pragmatics and developmental pragmatics, with special interest in brain
injuries.
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Abstract
This paper is about communication deficits in an interview setting among adolescents with
frontal lobe damage. One of the predominant characteristics of these patients is difficulty
taking the context into account. Pragmatic theories, which attempt to clarify the link between
the formal structure of language and the extra-linguistic context (such as the interlocutor's
characteristics or strategies), may help provide insight into the difficulties of these patients.
An interview setting, viewed here as a communication situation, is governed by an interaction
format based on specific cooperative principles. In this study, the results of subjects with
frontal lobe damage (in the role of interviewee) were first compared with those of normal
subjects in an interview situation. Three pragmatic indexes were considered: the number of
utterances per speaking turn (speech quantity), amount of digression (keeping to the topic or
predefined subject of conversation shared by the interlocutors) and prevalence of withinsubject contingency speaking turns without an intervening remark by the interviewer (topic
development). Secondly, we attempted to determine whether the patients' discourse was
dependent upon the interviewer's conversational strategy (structured, non-structured, or
alternating). The results clearly point out the extent of the difficulty frontal lobe patients have
conforming to the rules of the interview situation, whether regarding the amount of speech
they produce or their ability to keep within and/or development of the topic of conversation.
The data also indicated that the patients' linguistic productions varied with the interviewer's
strategy. The structured strategy did not always give rise to the best performance: while the
unstructured and alternating strategies allowed patients to produce more utterances per
speaking turn, the alternating strategy enabled better development of the interview topic.
These results suggest that such variations could be put to fruitful use in remedial techniques.
Keywords: Frontal lobe lesions - Communication deficits - Interview paradigm Communication formats - Conversational strategies - Pragmatics
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Introduction
Communication deficits are often found in subjects with frontal lobe damage. Our first goal
was to conduct a fine-grained analysis of these deficits during language use in a social
interaction context. Pragmatic theories which attempt to clarify the link between the formal
structure of language and the extra-linguistic context may help improve our understanding of
how hard it is for these patients to communicate (Austin, 1962; Levinson, 1983; Searle, 1969;
Searle & Vanderveken, 1985; Sperber & Wilson, 1986; Vanderveken, 1990; Verschueren,
1998; Verschueren, Östman & Blommaert, 1995). In the present study, we looked at the
characteristics of the discourse of subjects with frontal lobe damage in an interview situation,
where various executive functions are necessary to achieve satisfactory performance. The
results of subjects with frontal lobe damage on various pragmatic indexes were compared
with those of normal subjects during an interview. The second goal of this study was to
determine whether the patients' discourse is dependent upon the characteristics of the
discourse of their conversation partner. This aspect of the study is important for choosing and
improving therapeutic techniques.
These two goals were achieved by analyzing the language and communication deficits of
patients with frontal lobe damage, determining what pragmatic indexes could be used to
capture the flow of conversation, and considering the different remediation techniques used.
Language and communication deficits in patients with frontal lobe damage
As early as 1963, Luria had already suggested that the frontal lobe was involved in various
cognitive functions. Since then, Levin, Heisenberg and Benton (1991) showed that the
prefrontal cortex coordinates many of the executive functions an individual needs to
autonomously carry out a variety of activities (planning and programming action). For
Shallice and Burgess (1996), the prefrontal cortex is what enables the individual to build a
mental representation of the outside world at the same time as it integrates emotions and
motivations.
Behavioural dysfunction following frontal lobe damage is one of the obstacles to the
rehabilitation and the social and occupational reintegration of these patients (Bond &
Godfrey, 1997). Among the dysfunctions (see Fuster, 1999), we find personality disorders,
motor and attention deficits (Brooks, 1984; Eslinger & Damasio, 1985), and language
impairment (Prigatano, Roueche & Fordyce, 1985). Wapner, Hamby and Gardner (1981) and
Kaczmarek (1984) showed that phonological and syntactic abilities remain globally intact.
However, certain frontal lesions have been shown to affect verbal fluency (Stuss, Alexander,
Hamer et al., 1998). Moreover, some studies suggest that the prefrontal areas play an
important role in lexical-semantic processing (Swick, 1998).
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As a whole, the research has shown that pragmatic and paralinguistic skills are impaired in
patients with frontal lobe damage. According to Penn and Cleary (1988), frontal-damaged
patients have a general tendency to oversimplify what they have to say and are excessively
redundant. They exhibit reduced speech spontaneity and slow ideation (Mentis & Prutting,
1987) and there is also evidence of reduced production (Coelho, Liles & Duffy, 1991). In
addition, they appear to suffer from several conversational disorders including attention
deficits, inattentiveness towards the interlocutor, and difficulty carrying on a conversation
(Marsh & Knight, 1991). Mentis and Prutting (1991) and Bond and Godfrey (1997) noted that
the topic changes of subjects with frontal lobe damage during a conversation are often
inappropriate, and that their discourse is filled with inappropriate expressions. Their
impairment also concerns the function of inferential processes, for example in comprehending
irony (McDonald & Pearce, 1996) or understanding ambiguous advertisements (Pearce,
McDonald & Coltheard, 1998). Mood seems to be highly affected in patients with right
frontal lobe damage (Shammi & Stuss, 1999): they appear to react less, with diminished
physical or emotional responses (laughter and smiling). Dennis, Barnes, Wilkinson et al.
(1998) supplemented these studies in showing that in school-aged children, frontal lobe
contusions were associated with poor understanding of deceptive emotion (in short
narratives).
Peter (1995, 1999) noted that other individuals addressing these patients often gear their
discourse to the brain-damaged individual's level by adopting various conversational
strategies. However, Peter (1995, 1999) contends that using such structuring frameworks is
not only constraining for the other person, but may also be frustrating for the patient. It would
therefore seem worthwhile to determine how effective such conversational strategies actually
are, and whether they genuinely improve the quality of exchanges with subjects suffering
from frontal lobe damage.
Conversation, communication formats and pragmatic indexes
Although the pragmatic approaches do not currently form a unified entity, they nonetheless
agree on the following postulate: language is produced and interpreted via a set of
conventions and knowledge that are shared by the speaker and the listener. Variations in
utterances are not considered to be random, but linked instead to the social relationship
between the interlocutors and their respective psychological states (for experimental
illustrations, see Laval & Bernicot, 1999; Marcos & Bernicot, 1994, 1997; Ninio & Snow,
1996). This point of view is clearly based on a "top-down" approach to conversation,
integrating the data into a predetermined framework of rules and units. In a pragmatic
framework, Bruner (1983, 1990) defined an exchange between two individuals as a joint
action which he calls a "format". This concept is very useful for defining the different types of
conversation. A format is the pattern or model of a social relation, and requires the application
of rules by both interlocutors (repetition rules, clarification rules, etc.). In a given context, the
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two conversing partners thus participate in building the interaction format. During an
interaction, the partners' intentions are not necessarily the same, but their expectations must
be contingent (Bernicot, 1994). Every type of conversation is governed by particular rules
that involve the cooperation of both partners (Grice, 1989). These cooperative principles
clearly apply to the interview situation, where both interlocutors must be able to implement
the pragmatic skills required by the interview format. The interviewer's role consists of
encouraging the interviewee to speak, and assessing the relevance of what he/she says in
order to bring the conversation back to the initial interview topic whenever necessary. The
interviewee's task is to try not to digress and to organise his/her discourse in order to answer
in a way that meets the other person's expectations.
The pragmatic approaches propose a variety of indexes for assessing the unfolding of a
conversation between two partners and for measuring any deficits or differences in
populations with disorders (Kerbel & Grunwell, 1998a, 1998b; Leinonen & Kerbel, 1999).
Some of the measures used are speech quantity indexes (number of speaking turns and
utterances, number of utterances per speaking turn), indicators of the social functions fulfilled
(distribution across situations of speech acts such as assertives, directives and commissives),
and contingency indexes indicating the extent to which speakers adapt to their partners and/or
to the communication situation. An utterance is considered to be between-subject contingent
when its topic is the same as in the utterance just made by the other person (Bernicot & Roux,
1999; Hoff-Ginsberg, 1994). An utterance is regarded as within-subject contingent when its
topic is the same as in the utterance just made by the speaker him/herself (Bernicot & Roux,
1999). These indexes can account for the overall structure of a subject's discourse and for
his/her ability to converse in a way that meets the demands of the other speaker and/or the
requirements of the situation.
Patients with frontal lobe damage, communication deficits and remediation
According to McTear and Conti-Ramsden (1992), one of the aims of pragmatic research is to
precisely define the nature of the pragmatic difficulties associated with each disorder under
study. The difficulties in question are not necessarily rooted in linguistic dysfunction, but may
stem from general problems in extracting and inferring information from the context
(Leinonen & Letts, 1997). For McDonald (1992), the contribution of the cognitive-pragmatic
approach is twofold: (1) it enables differentiation between the various communication
contexts and the resulting pragmatic constraints (which vary across contexts) and (2) it may
turn out to be useful in evaluating the different types of therapy proposed to these patients.
For Law (1997), the question of how to assess a subject's impairment is a fundamental one in
the study of communication deficits. Moreover, therapy appears to be more effective when it
takes place in a general learning context.
There are many different therapy techniques for subjects with frontal lobe damage;
substitution or compensation by means of external aids is the oldest one used. Despite its
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apparently positive contribution, however, this type of assistance may turn out to be
unsuitable because the patient plays a passive and non-stimulating role. Ylvisaker and
Szekeres (1989) showed that the use of gradual feedback can help subjects with brain injury
to improve their performance and learn more appropriate behaviours. Recent studies on the
conversations of aphasic patients during therapy (Kagan, 1999; Kagan & Gailey, 1993) or in
everyday situations (Laasko & Klippi, 1999) have shown that a conversation can work despite
aphasia: the other person must consider the aphasic speaker as a real participant in the
conversation and establish with him/her the collaboration rules used. It has been shown, for
example, that in conversations of the problem-solving type (Laasko & Klippi, 1999), the
phases of the conversation are the same with aphasic patients as with normal subjects and that
aphasic speakers prefer self-repair in the same way ordinary non-aphasic people do. Peter's
(1995, 1999) conclusions reflect this point of view, that providing a framework structured by
others may turn out to be ineffective for a patient with frontal lobe damage.
Aims and general hypotheses
This study had two major goals: to precisely analyze deficits in the pragmatic aspects of
language use in subjects with frontal lobe damage, and to assess their ability to adapt to the
discourse characteristics of their addressee. In an attempt to both supplement and refine the
results of prior research in this field (Bond & Godfrey, 1997; Dennis, Barnes, Wilkinson & al.
1998; McDonald & Pearce, 1996; Marsh & Knight, 1991; Mentis & Prutting, 1991; Pearce,
McDonald & Coltheard, 1998; Shammi & Stuss, 1999), we chose to work in the area of
conversational skills, and more specifically, on the interview setting. Participating in an
interview can be regarded as a "frontal" task since it requires the implementation of specific
cognitive capacities and executive functions ensured by the frontal lobe. Indeed, to achieve a
successful exchange, a subject must be able to (1) get involved in the dialogue and take
initiatives (volition), (2) understand not only the primary and secondary goals of the
conversation, but also the necessary steps for constructing sound argumentation (planning),
(3) keep the primary goal of the exchange in mind (goal-oriented action), and (4) assess the
relevance of his/her discourse in order to modify its content (verification of the effectiveness
of one's speech acts). Furthermore, this paradigm offers the possibility of studying subjects in
a natural setting, where systematic analyses can still be conducted using specific pragmatic
indexes already validated in research on normal communication.
To achieve our first goal, we used various pragmatic indexes (such as speaking turns,
digressions, and contingency) to determine the characteristic features of the discourse of
subjects with frontal lobe damage during an interview. This communication situation is
governed by an interaction format based on specific cooperative principles. The interviewer
defines the conversation topic, which the interviewee must develop. Consequently, this
format is characterised by an imbalance in the speech quantity of the two interlocutors. The
interviewee must speak more often and longer than the interviewer. In addition, the
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interviewee must make few digressions and come quickly back to the topic of conversation.
Communication problems already noted in subjects with frontal lobe damage in a
conversational setting suggest that executive dysfunction is likely to be observed during an
interview. Compared to normal subjects, subjects with frontal lobe damage may not be able to
meet the requirements of the interview format.
However, contextual variations such as interlocutor familiarity (Peter, 1995; 1999) have been
shown to affect a patient's discourse. Thus, we can assume that the pragmatic indexes of
subjects with frontal lobe damage depend upon the conversational strategy adopted by the
interviewer, who may provide variable amounts of outside help to the patient. Even if braindamaged patients are unable to abide by the cooperative principles that govern an interview
situation, they should nevertheless exhibit some pragmatic skills, in accordance with the
conversational strategy used by the partner. If this hypothesis turns out to be true, then we can
contend that the interviewer's use of different exchange strategies gives patients the
opportunity to exercise different pragmatic skills. We could then suggest that therapeutic
techniques be geared more towards the exercise of skills than towards strict framing of the
conversation.
Method
Subjects
The experimental group (see Table 1) consisted of nine brain-damaged adolescents and young
adults (6 males and 3 females). Three had a predominantly right frontal lesion, four had a
bilateral frontal lesion, and two had a predominantly left frontal lesion. The brain damage had
occurred at least three years earlier for all subjects, and the mean time since the accident for
the group as a whole was 5 years 8 months. The age range was 15 to 24 years, with a group
mean of 18;8. The subjects' IQ's were above 70 (normality criterion set by the World Health
Organisation), with a group mean of 86 (range: 74-97). They were all attending school at an
institute for motor learning in the Parisian area. The control group (see Table 1) was made up
of nine normal adolescents and young adults who were matched to the subjects with frontal
lobe damage on three variables: age, sex and socio-economic class (defined by the parents'
occupations). In the light of our goals and the characteristics of frontal-lobe damaged patients,
matching the experimental and control groups on IQ did not seem relevant. The subjects with
frontal lobe damage had a mean IQ of 86 due to their discrepant performance on the different
subtests: they obtained high scores in some subtests and mediocre scores on others. In
contrast, normal subjects with an IQ of 86 have a uniform profile across subtests: they obtain
poor scores on all subtests. It is important in making comparisons between brain-damaged
patients and normal subjects that the two groups be equivalent on all other factors. Before the
accident, all our brain-damaged subjects had a "normal" academic record, which is indicative
of a mean IQ of 100 (or above), so comparing them with "normal" subjects is legitimate.
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The results are analyzed by comparing the mean tendencies of the two groups. There were not
enough subjects in the experimental group to form subgroups and analyze the relationships
between their performance and the exact locations of the frontal lobe lesions.
Insert Table 1 about here
Procedure
Subjects volunteered to participate as an interviewee in three interviews to be held over a
three-week period. The experimenter, a young psychologist who knew the subjects, acted as
the interviewer, proposing specific topics of discussion. In each new interview with a given
participant, the experimenter changed the way she related to the interviewee by adopting a
specific conversational strategy. When the "structured" strategy was used, the experimenter
did not let the patient digress; when the "unstructured" strategy was employed, the patient was
allowed to digress; and when the "alternating" strategy was used, the experimenter maintained
a structured framework while still allowing the patient to make a few digressions. Each
frontal-lobe subject was assigned a conversational strategy order (by random drawing) and
each strategy was randomly assigned one of three interview topics: movies, music, or
television. This was designed to eliminate any effects brought about by a given topic-strategy
combination. The control subjects performed the same set of tasks, under the same conditions,
as the matched frontal-lobe damaged subjects.
Description of the three conversational strategies
Structured strategy (S1). The experimenter interviewed the subject on one of the three topics.
Whenever the subject digressed, the experimenter systematically came back to the initial
topic.
Example: Interview about movies
Experimenter: Do you like funny movies?
Subject:
Yeah, because if you go to the movies to see misery, its no use. It's no use
because misery is everywhere -- just look at -Experimenter: And what other kinds of movies do you like? (return to topic)
Unstructured strategy (S2). The experimenter interviewed the subject on one of the three
topics. Whenever the subject digressed, she pursued the topic the subject had brought up.
Example: Interview about music
Experimenter: So you like rock?
Subject:
I went to a concert last week -- the tickets are too expensive!
Experimenter:
Is it really expensive? (continuation of subject's topic)
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Alternating strategy (S3). The experimenter interviewed the subject on one of the three topics.
She allowed the subject to digress periodically by alternating between strategies S1 and S2.
Example: Interview about movies
Experimenter: What kind of movies do you like?
Subject:
Stuff like Vandamme, you know!
Subject:
Karate, I mean, combat sports, is what I really like.
Experimenter: Combat sports? (continuation, unstructured strategy (S2))
Subject:
Karate, boxing and things like that / I used to do those, it's great.
Experimenter: And what about movies? (Return to initial topic, structured strategy (S1))
In all three strategies, if the subject did not digress, the experimenter asked him/her to give
more details about the topic. Before the data collection began, the experimenter was trained
until she was able to consistently follow the rules for each of the three strategies. The training
consisted of recording interviews with persons who were not selected for the experimental
sample and then examining the "errors" made with the help of a trained individual who knew
the rules perfectly.
Transcribing and pragmatic index coding
Each subject (experimental or control) was interviewed individually three times within the
three-week period. A tape recorder was used to avoid cumbersome note taking by the
experimenter and to ensure high-quality transcription. There was no time limit to the
interviews and their duration varied across subjects. However, only the first twelve minutes of
the conversation were transcribed. For the first two minutes, the communication situation was
still getting established, so only the next ten minutes were coded and analysed.
Coding of speaking turns and utterances (measures of speech quantity). The interviews were
transcribed and segmented into speaking turns and utterances in accordance with the dialogue
segmentation criteria previously used by Bernicot, Comeau and Feider (1994). A speaking
turn ended whenever one or both of the following events occurred: a change of speaker, or a
pause of more than two seconds (Sacks, Schegloff & Jefferson, 1974). In a speaking turn, the
utterances are delineated by terminal juncture or paraverbal behaviours (such as laughter).
Terminal juncture was identified by the following phonetic characteristics (Halliday, 1975):
(a) a terminal contour (falling, rising-falling) and (b) a steady intonation pattern followed by
vocal arrest (300 ms).
Coding the digression index (measure of ability to keep to the interview topic). Digressions
were defined here as cases where the subject brought up a topic other than the one initially
proposed by the experimenter (television, movies, or music). Digression and non-contingency
differed in that a subject could exhibit non-contingency (by not responding to the demands of
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others) without digressing (by staying on the topic of the interview). Digressions were
counted by tallying the number of speaking turns where a new digression theme was brought
up (a digression theme could last several speaking turns). The term theme is used here to refer
to a topic of conversation chosen unilaterally by one of the interlocutors. The percentage of
speaking turns where the subject made such digressions was then calculated.
Coding the contingency index (measure of interview topic development). Unlike HoffGinsberg (1994), we used this index to assess contingency across speaking turns rather than
across utterances. In the light of the data collected here, it appeared more appropriate to
consider the speaking-turn level of analysis, which we felt gave a better overall picture of the
interviews. The results presented pertain to within-subject contingent speaking turns without
an intervening remark by the experimenter (WSC). These were characterised by the fact that
the subject continued to talk about the topic he/she had introduced in his/her own last
speaking turn, without experimenter intervention. Only those speaking turns that pertained to
the topic of the interview were taken into account.
Example: interview about television
Subject:
Do I like television -Subject:
Often during vacation there are some beautiful stories on channel 6 and I
often watch channel 6 during vacation.
The interviews of two subjects (i.e., six interviews or 9% of the corpus) were coded by two
separate coders. The inter-coder agreement rate was .84 (number of speaking turns coded in
the same way, divided by the total number of speaking turns).
Experimental hypotheses
Given our main goals and assumptions, our data collection procedure, the rules governing the
interview format, and the indexes chosen, the following experimental hypotheses were set
forth.
1. Speech quantity: An interviewee is supposed to speak for long stretches, so the number of
utterances per speaking turn should be higher for control subjects than for experimental
subjects.
2. Keeping within the interview topic: An interviewee is supposed to stick to the topic defined
by the interviewer and avoid digressions, so the percentage of speaking turns where the
subject digresses should be greater for experimental subjects than for control subjects.
3. Development of the interview topic: An interviewee is supposed to expand upon the topic
defined by the interviewer, so the number of within-subject contingent speaking turns without
an intervening remark by the experimenter (WSC) should be greater for control subjects than
for experimental subjects.
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4. Variations as a function of the experimenter's strategy: The values obtained for the
experimental subjects on the three indexes mentioned above should vary with the
conversational strategy used by the experimenter.
Results
Only the results related to our experimental hypotheses are presented below. For each index
(speech quantity, digression, and contingency), the results of the two groups are compared,
and variations as a function of the conversational strategy are analyzed. The contingency and
digression indexes were expressed as percentages so the data would not be skewed by
differences in the total number of speaking turns made during each interview.
Speech quantity indexes
Figures 1 and 2 give the number of speaking turns and the number of utterances per speaking
turn made by the subjects and by the experimenter in the two groups, for each of the three
conversational strategies. The results were processed for each index using a three-way
ANOVA with a Group (2: Experimental/Control) by Speaker (2: Subjects/Experimenter) by
Strategy (3: Structured/Unstructured/Alternating) design. Any observed differences were
taken to be significant at the .05 level.
As a whole, for the number of speaking turns (Figure 1), the Group effect (F(1, 32) = 168.30;
p < .0001) and the Speaker effect (F(1, 32) = 8.90; p < .005) were significant: speaking turns
in the experimental group interviews outnumbered those in the control group (for both types
of speakers), and there were more turns for the subjects than for the experimenter. In addition,
the Strategy effect (F(1, 32) = 8.90; p < .005) and the Group-by-Strategy interaction (F(2,
64) = 8.58; p < .0004) were also significant: the difference between the strategies was much
greater in the experimental group than in the control group.
Partial comparisons showed that this difference was nonsignificant in the control group but
significant in the experimental group (F(2, 34) = 7.59; p < .002). For the experimental
subjects, there were more speaking turns with the alternating strategy (F(1, 17) = 16.47;
p < .001) and with the unstructured strategy (F(1, 17) = 4.90; p < .04) than with the structured
strategy.
Concerning the number of utterances per speaking turn (Figure 2), the overall Group (F(1,
32) = 25.18; p < .0001) and Speaker (F(1, 32) = 71.40; p < .0001) effects were significant, as
was the Group-by-Speaker interaction (F(1, 32) = 26.07; p < .0001). The difference between
the experimenter and the subjects (with the latter speaking more than the former) was much
more pronounced in the control group (1 vs. 9) than in the experimental group (1 vs. 3). There
was no Strategy effect.
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Partial comparisons showed that while this difference was significant both in the control
group (F(1, 16) = 55.49; p < .0001) and in the experimental group (F(1, 16) = 16.24;
p < .001), the F-value and the significance level were higher for controls. The Group-bySpeaker interaction also pointed out a significant difference between the control and
experimental groups, both for the subjects (favoring the control group: F(1, 16) = 25.63;
p < .001) and for the experimenter (but favoring the experimental group: F(1, 16) = 9.73;
p < .01).
Insert Figure 1 and Figure 2 about here
Digression index
Figure 3 plots the percentage of digressions (ratio of the number of speaking turns containing
a digression to the total number of speaking turns) in the two subject groups, for each of the
three conversational strategies. The results were processed using a two-way ANOVA with a
Group (2: Experimental/Control) by Strategy (3: Structured/Unstructured/Alternating) design.
Any observed differences were taken to be significant at the .05 level.
The group effect was significant (F(1, 16) = 31.77; p < .0001): experimental subjects made
more digressions (about 10%) than controls (about 2%). The effects of the Strategy variable
(F(2, 32) = 11.14; p < .0002) and of the Group-by-Strategy interaction (F(2, 32) = 11.51;
p < .0001) were also significant. The strategy had more effect for the experimental group than
for the control group. Moreover, the effect was not the same for the two groups.
Partial comparisons showed, for the experimental group, that the Strategy effect was
significant (F(2, 16) = 12.44; p < .0005) and that the digression rate was higher with the
unstructured strategy than with the alternating strategy (F(1, 8) = 9.87; p < .01), and higher
with the alternating strategy than with the structured strategy (F(1, 8) = 10.92; p < .01). For
the control group, the Strategy effect was less strong but nevertheless significant (F(2,
16) = 3.86; p < .04): there were more digressions with the alternating strategy than with the
structured strategy (F(1, 8) = 6.62; p < .03).
Insert Figure 3 about here
We felt it would be worthwhile to conduct a qualitative analysis of the themes of digression.
Table 3 and 4 lists the main digression themes found for the experimental and control groups.
For experimental subjects (see Table 2), certain themes were brought up in a large number of
interviews. For example, antiestablishment remarks, and statements about changes due to the
accident, were made in seven interviews. Based on this analysis, we can conclude that there
are certain themes that preoccupy subjects with frontal lobe damage and make their way into
their discourse in a recurring fashion. In addition, the same digression theme was often found
repeatedly in the interviews of a given subject. For example, subject 5 made antiestablishment
14
remarks during all three interviews. Our analysis also showed that the digressions of frontal
patients were often nonsensical and appeared at illogical points in the conversation due to the
inappropriate association of ideas. Their digression themes were far removed from the
interview topic.
Example: Digression of an experimental subject during the interview about music
Subject:
The tune, he sings it too and it's beautiful, and then there's this thing I tell
myself, that seeing the way I think, I could be from the hippie generation! No kidding!
Because, you see, me right now I'm not okay -When the control subjects made digressions (see Table 3), they were followed by a selfinitiated return to the interview topic without experimenter prompting. Also, the control
subjects' digression themes were never very far from the interview topic.
Example: Digression of a control subject during the interview about television
Subject:
Glamour songs are okay for a while, but I really prefer it when things move
because I'm the dynamic type and songs resemble me. I like those styles because they
resemble me.
Subject:
I know that at my aunt's funeral -- I'm getting off track but I'll come back to
it -- they were playing all the songs she used to like. Songs that were with her throughout her
life and that were like her.
Note also that the control subjects digressed at most once within a given interview, and that,
unlike the experimental group, there were no recurring digression themes within or across
subjects.
Insert Table 2 and 3 about here
Contingency index
Figure 4 plots the percentage of within-subject contingent speaking turns with no intervening
experimenter remark (WSC) for each group of subjects and each conversational strategy. The
results were processed for each index using a two-way ANOVA with a Group (2:
Experimental/Control) by Strategy (3: Structured/Unstructured/Alternating) design. Any
observed differences were taken to be significant at the .05 level.
The overall analysis yielded a significant effect of the Group variable (F(1, 16) = 19.36;
p < .0004): control subjects produced more speaking turns of this type than did experimental
subjects.
Although the Strategy effect and the Group-by-Strategy interaction were nonsignificant,
partial comparisons pointed out an interesting tendency: the difference between the control
and experimental subjects was significant (with the latter ahead of the former) for the
15
structured (F(1, 16) = 10.01; p < .006) and unstructured (F(1, 16) = 19.87; p < .0003)
strategies, but not for the alternating strategy.
Insert Figure 4 about here
Discussion
Do patients with frontal lobe damage have trouble abiding by the rules of a particular type of
conversation such as an interview? In the present situation where the patients were in the
interviewee position, did their conversational behaviour depend on the interviewer's strategy?
The data we obtained allow us to answer affirmatively to these two questions and thereby
validate our hypotheses. The fact that the experimenter's behaviour (in terms of number of
utterances per speaking turn) did not vary with the conversational strategy she used further
proves the validity of our results.
Our first hypothesis concerned speech quantity. An interviewee is supposed to speak for long
stretches, so the number of utterances per speaking turn should be higher for control subjects
than for patients. This hypothesis was validated: the normal subjects took speaking turns
made up of nine utterances, whereas the turns of the frontal-lobe damaged subjects only
contained three. Thus, the frontal patients had difficulty fulfilling the interviewee's role by
holding the floor to expand upon the topic the interviewer proposed.
The results for the number of speaking turns in the two groups tells us a little more about the
patients' difficulty. The subjects with frontal lobe damage produced more speaking turns than
the normal subjects. Moreover, for both indexes (speaking turns and utterances per speaking
turn), the experimenter always talked more with the frontal lobe subjects than with the normal
subjects. It thus seems that patients with frontal lobe damage differ from normal subjects in
utterance grouping and distribution: they need substantial prompting by the interviewer.
These findings are compatible with the results obtained in the studies by Mentis and Prutting
(1987), where patients with brain damage exhibited reduced speech spontaneity and had slow
ideation, and by Coelho, Liles and Duffy (1991), where evidence of reduced production was
found in these subjects.
Our second hypothesis dealt with the ability to keep to the interview topic. An interviewee is
supposed to talk solely about the topic set by the interviewer: he/she should not digress too
much. The percentage of speaking turns with interviewee digressions was greater for the
experimental subjects than for the controls. The data we obtained thus validate our hypothesis
and supply some additional information. First of all, patients with frontal lobe damage appear
to have trouble following the rules of interviews: an interviewee must stay on the subject
matter proposed by the interviewer. If we consider the constraints of the interview situation,
we can regard digressions as a breach of the communication contract. However, the initial
rules in the contract can be negotiated and certain digressions can be tolerated, provided they
16
are rare and the subject comes back to the initial topic on his/her own. On this matter, it is
interesting to note that when the normal subjects digressed, they came back to the initial
interview topic without prompting, something the frontal lobe subjects did not do. Secondly,
our qualitative analysis indicated that the nature of the digressions was not the same in the
two groups: the frontal lesioned subjects' digression themes were recurring and unrelated to
the interview topic. In contrast, the normal subjects' digressions were not recurring and they
pertained to subject matters that had some connection with the interview topic. These results
are consistent with those obtained by Mentis and Prutting (1991) and by Bond and Godfrey
(1997). These authors showed that frontal patients have difficulty taking others into account
and remain focused on their own ideas; they also noted that the topic changes of these
subjects during a conversation are often inappropriate. Our results are consistent with the
Marsh and Knight (1991) study too, where the patients exhibited several conversational
disorders such as inattentiveness towards the interlocutor.
Our third hypothesis had to do with the development of the interview topic by the
interviewee. An interviewee must expand upon the topic defined by the interviewer, so the
number of within-subject contingent speaking turns without an intervening remark by the
experimenter should be greater for control subjects than for patients. This hypothesis was also
validated. The normal subjects mainly produced speaking turns without an intervening
remark, which means that, unlike the subjects with frontal lobe damage, they were capable of
holding the floor for several minutes without experimenter intervention. Our results thus
suggest that frontal-damaged patients have trouble constructing an appropriate response and
often need to be prompted by their interlocutors.
Thus, in support of our first three hypotheses, it appears clear here that subjects with frontal
lobe damage have trouble abiding by the rules of the interview situation in three different
ways: speech quantity, staying on the interview topic, and development of that topic.
Our fourth hypothesis concerned potential variations that hinge on the experimenter's
conversational strategy: for the three pragmatic indexes used in this study (speech quantity,
digression, and contingency), the experimental subjects' conversational behaviour was
expected to vary as a function of the strategy implemented by the interviewer. Our results
confirmed this hypothesis. Certain interviewing strategies appear to bring the performance of
patients with frontal lobe damage closer to that of normal subjects. It was when the
experimenter used an unstructured strategy or an alternating strategy that the frontal lobe
subjects produced the greatest number of utterances per speaking turn. The structured strategy
helped keep the patients on track. The alternating strategy enabled them to take more
speaking turns without experimenter prompting. Thus, the frontal subjects' discourse was
indeed dependent upon the conversational strategy adopted by the experimenter. As a whole,
our data is in line with the findings obtained by Peter (1995, 1999), who showed that the
impact of the conversational strategy is great. Our data reinforce Peter's (1995, 1999) results,
17
insofar as the interview strategy variations we found were systematic and the analysis
pertained to nine patients (not just one).
The three conversational strategies used here by the experimenter gave the patients the
opportunity to exercise different pragmatic skills, and to come closer the performance of
normal subjects. Note that the structured strategy (currently the most common rehabilitation
technique) was not always the one that helped patients converse more like normal individuals.
For example, the unstructured strategy or the alternating strategy enabled the frontal lobe
patients to express themselves the most (number of speaking turns). This result is all the more
interesting in that previous studies (Mentis & Prutting, 1987; Coelho, Liles & Duffy, 1991)
have shown that these patients do not often express themselves spontaneously: this strategy
may therefore give them the chance to realize a potential that exists but which is not
expressed in the situations usually proposed to them. The findings for the contingency index
and the alternating strategy are also quite interesting: they show that the alternating strategy
can teach subjects with frontal lobe damage certain interview principles, in addition to
helping them improve the structure of their responses. We saw that the number of speaking
turns without an intervening remark, which were characteristic of normal subjects, increased
in the subjects with frontal lobe damage when the experimenter used the alternating strategy.
Although their performance did not reach the level of the controls, this finding is consistent
with the idea that the alternating strategy helps brain-damaged patients adapt to the
conversational format of interviews. These last conclusions suggest that in therapy programs
for subjects with frontal lobe damage, constraints imposed by others (to optimise
performance) often favour passiveness and do not truly enhance the patient's potential to
learn. The alternating conversational strategy thus appears to be the most advantageous for
these subjects, not only during an actual exchange but also in the long run, for it promotes the
learning of the cooperative principles that underlie any satisfactory conversation. Relating our
conclusions to Bruner's (1983, 1990) theories on child learning of interaction formats, we can
contend that only the alternating strategy offers the potential for regulating the interaction. In
this respect, this strategy not only permits true negotiation of the principles of the interview
format (unlike a structured framework which merely imposes the rules of the communication
contract) but also promotes the learning of that format.
This study showed once again that the creation of experimental paradigms can open up new
pathways for understanding and assessing frontal-lobe disorders (Linscott, Knight & Godfrey,
1996; Mayes & Dauym, 1997). Our results demonstrate in a precise way that patients with
frontal lobe damage have trouble abiding by interview rules about speech quantity and
keeping with and development of the interview topic. In addition, our data contribute to the
body of findings on aphasic patients (Kagan, 1999; Kagan & Gailey, 1993; Laasko & Klippi,
1999) by clearly demonstrating that the verbal productions of these patients vary with their
interlocutor's strategy, and by showing how these variations could be put to fruitful use in
therapeutic techniques.
18
Hence, at the close of this study, it appears worthwhile to conduct further research that relates
the results obtained on pragmatic tasks with the performance observed on certain
neuropsychological tests. Such a two-level analysis should contribute to improving our
understanding of the cognitive processes at play in the communication deficits of subjects
with frontal lobe damage (topic management, building an argumentation, digressions, etc.).
This multimodal approach should also provide the opportunity for developing new therapy
techniques for brain-damaged patients. Future studies on the pragmatic aspects of language in
subjects with frontal lobe damage should therefore be pluridisciplinary, combining the
psychological, linguistic and neurological approaches. Such a pluridisciplinary approach
should enrich current models of communication and also produce additional data on its
anatomical and functional organisation.
Acknowledgements
We are indebted to Pierre Arpino, psychologist, for his support, and to the members of the
medical Department of the Richebourg Institute of Motor Learning (Yvelines, France) for
their collaboration. Special thanks are extended to Vivian Waltz for translating this paper.
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Table 1 - Characteristics of experimental group (subjects with frontal lobe damage) and
control group (normal subjects)
EXPERIMENTAL GROUP
Subjects with
frontal lobe
damage
1
2
3
4
5
6
Sex
Age
IQ
M
F
M
M
M
M
19;8
15;3
18;11
20;7
18;7
16;1
90
93
89
75
79
90
7
F
24;1
97
8
9
M
F
20;6
19;8
89
74
years;months
Time since
accident
years;months
CONTROL GROUP
Normal
subjects
1
2
3
4
5
6
7
8
9
Frontal injury
location
Sex
Age
years;months
M
M
M
M
M
M
F
M
F
19;6
15;1
18;12
20;6
18;9
16;2
24;1
20;6
19;7
Right
Bilateral
Bilateral
Bilateral
Temporal left
Temporal right and tempoparietal left
Temporal left and temporal
right
Bilateral
Temporal right
3;10
3;0
12.6
6;0
4;0
6;7
8;3
4;6
6;5
23
SUBJECTS
60
Nb
50
40
30
20
10
0
Together
Structured
Unstructured
Experimental subjects
Alternating
Control subjects
EXPERIMENTER
50
Nb
40
30
20
10
0
Together
Structured
Unstructured
Experimental subjects
Alternating
Control subjects
Figure 1 - Mean number (Nb) of subject and experimenter speaking turns and standard
deviation by group, for the three conversational strategies taken together and separately.
24
SUBJECTS
16
14
12
10
8
6
4
2
0
Nb
Together
Structured
Unstructured
Experimental subjects
Alternating
Control subjects
EXPERIMENTER
1,2
Nb
1
0,8
0,6
0,4
0,2
0
Together
Structured
Unstructured
Experimental subjects
Alternating
Control subjects
Figure 2 - Mean number (Nb) of subject and experimenter utterances per speaking turn and
standard deviation by group, for the three conversational strategies taken together and
separately.
25
30
%
25
20
15
10
5
0
Together
Structured
Unstructured
Experimental subjects
Alternating
Control subjects
Figure 3 - Mean percentage (%) of digressions and standard deviation by group, for the three
conversational strategies taken together and separately.
26
Table 2 - Main digression themes of the experimental subjects for each of the three
conversational strategies (the number of times a theme was brought up during the interview is
shown in parentheses).
Subject
Structured strategy
Unstructured strategy
Alternating strategy
1
Police state(1) Handicaps (2)
Man’s destructiveness(6)
Man’s destructiveness(2)
The accident(1) Sadness(2)
Animals(4)
Music(3) Police state(5)
Animals(2)
2
3
Sadness(3) Friends(2)
Friends(1) Going out(4)
Handicaps(2) TV movies(3)
Health(1)
Going out(4) Enemies(2)
Friends(1) The accident(2)
Music (4) Boxing(3)
Leisure activities(3)
Bowling(2) Horses(4)
Antiestablishment(2)
4
Antiestablishment(3)
Antiestablishment(3)
Sadness(4) Animals(6)
The accident(4) Handicaps(5)
Cost of living(4)
5
6
Antiestablishment(2)
Antiestablishment(4)
Being poor(2)
Sadness(4)
Leisure activities(5)
Vacation(8)
Telling movie plots(4)
Family(3)
Accident-related changes(2)
Leisure activities(3)
Handicaps(6) Accident-related
Battered women(3)
changes(7) The future(3)
Motherhood(2) Childhood(1)
Antiestablishment (3)
Jokes(4) Accident-related
How the school is run (5)
changes(5) Friends(3)
Personal problems(1)
Personal problems(3)
7
8
9
Jokes (6) The accident (2)
Personal problems(2)
Antiestablishment(5)
27
Table 3 - Main digression themes of the control subjects for each of the three conversational
strategies (the number of times a theme was brought up during the interview is shown in
parentheses).
Subject
Structured strategy
1
Funeral(1)
2
Mother(1)
Unstructured strategy
Alternating strategy
Music(1)
3
4
5
Le Pen(1) (French politician)
Video games(1)
6
7
8
Brother(1)
9
Going out(1)
28
50
45
40
35
30
25
20
15
10
5
0
%
Together
Structured
Unstructured
Experimental subjects
Alternating
Control subjects
Figure 4 - Mean percentage (%) of within-subject contingent speaking turns with no
intervening experimenter remark, and standard deviation, by group, for the three
conversational strategies taken together and separately.