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Discourse about discourse: What is it and how does it progress in Alzheimer’s disease?
Brain and Cognition 53 (2003) 177–180 www.elsevier.com/locate/b&c
Discourse about discourse: What is it and how does it progress in AlzheimerÕs disease? Anh Duong, Andreanne Tardif, and Bernadette Ska Ecole d’orthophonie et d’audiologie, Facult e de M edecine, Universit e de Montr eal, Centre de recherche, Institut universitaire de g eriatrie de Montr eal, Canada Accepted 7 May 2003
Abstract Discourse about discourse or a subjectÕs comments about his/her performance during a discourse task can be defined as modalizing discourse (discours modalisateur; Nespoulous, 1980; Nespoulous, Code, Virbel, & Lecours, 1998). Since it does not convey the expected content of the discourse task (referential discourse), modalizing discourse has often been considered non-informative, and as such, has received little interest. The present study investigated the modalizing aspect of discourse production and its evolution in AlzheimerÕs disease (AD). Five AD patients produced a picture-induced narrative across five consecutive assessments. Two measures were derived: the modalizing/referential ratio (M/R ratio) and the percentage of repeated ideas. Results revealed that, compared to a group of 27 normal controls matched for age and education, AD patients: (1) obtained higher M/R ratios that tended to diminish as the number of assessments increased, and (2) produced higher percentages of repeated ideas throughout all assessments. These results suggest that modalizing discourse makes up a large proportion of AD patientsÕ discourse and should be included in further studies to accurately describe their discourse behavior. The implications of modalizing discourse on preserved pragmatic abilities and its inclusion in comprehensive management programs of AD patients are discussed. Ó 2003 Elsevier Inc. All rights reserved.
1. Introduction Patients with AlzheimerÕs disease (AD) typically exhibit impairments at the discourse level (for a review, see Caramelli, Mansur, & Nitrini, 1998). While there are many types of discourse (conversational, procedural, narrative, etc), narrative discourse, and in particular picture-induced narrative discourse, has enjoyed a considerable amount of attention for at least two reasons. First, it reduces memory demands because the story content is displayed statically in front of the patient, and second, it facilitates discourse analysis because target contents can be derived from the picture(s). Using this method, a number of researchers have reported that the narrative discourse of patients with AD appears more empty than that of their normal aging counterparts and contains fewer ideas and more repetitions of ideas (Giles, Patterson, & Hodges, 1996; Nicholas, Obler, Albert, & Helm-Estabrooks, 1985; Ska & Guenard, 1993; Tomoeda & Bayles, 1993; Tomoeda, Bayles, Trosset, Azuma, & McGee, 1996; Vuorinen, Laine, & Rinne, 2000). 0278-2626/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0278-2626(03)00104-0
Interestingly, most of these studies have focused on the referential content of discourse; that is that portion of the discourse that pertains to the expected story line. Measures such as circumlocutions, content units, cohesive devices, and semantic propositions, to name a few, have been derived to adequately describe and qualify the various levels of discourse impairment, albeit only with regard to the referential portion of discourse. Although Nicholas et al. (1985) included comments and empty phrases, their measures were composed of both referential and non-referential discourse. Most often, patientsÕ comments regarding the task, the uncertainty with which they express their story, and their feelings about the story have been systematically discarded from analysis. Omission of this discourse-about-discourse, referred to as modalizing discourse (discours modalisateur; Nespoulous, 1980; Nespoulous et al., 1998) or enunciative modalizations (Cardebat, Demonet, & Doyon, 1993), means that the entire communication behavior of AD patients is not captured, and the importance of the reduction and repetition of ideas in the discourse of
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A. Duong et al. / Brain and Cognition 53 (2003) 177–180
AD patients may be underestimated. Furthermore, little is known about the progression of this modalizing behavior over the course of the disease. The present study describes AD patientsÕ discourse and the repetition of ideas with respect to the dichotomy of modalizing vs referential discourse in a longitudinal perspective.
2. Methods 2.1. Participants Five AD patients and 27 normal aging subjects participated in the present study. They were selected on the basis of age, education, and the availability of longitudinal data from of a cohort of subjects who took part in a larger study on normal and pathological aging (Joanette et al., 1995). At the time of testing, all five AD patients had received a diagnosis of probable AD according to the NINCDS-ADRDA criteria (McKhan et al., 1984) and were considered mild to moderate, GDS ¼ 3 or 4 on the Reisberg scale (Reisberg, Ferris, de Leon, & Crook, 1982). AD patients were Frenchspeakers from the Montreal metropolitan area and were aged between 63 and 78 and had 6 to 10 years of formal education. They were assessed in 5 consecutive sessions at 6-month intervals. During the course of the assessments, all AD patients remained at GDS4 except for 1 patient (P444) who evolved to GDS4 at the 5th assessment from an entry level of GDS3. AD patients were compared to 27 right-handed French-speaking subjects from the Montreal metropolitan area who presented no neurological, psychiatric or medical problems at the time of testing. Normal subjects ranged from 65 to 84 years of age and had 4 to 11 years of formal education. They had only been assessed once at entry.
2.3. Discourse measures For each of the discourse samples, two measures were obtained from the transcribed discourse samples. The ratio of modalizing discourse to referential discourse (M/R ratio) was computed by dividing the percentage of modalizing words by the percentage of referential words. A measure of 1 indicates equal proportion of modalization to referential discourse, a measure of less than 1 indicates a higher proportion of referential discourse, and a measure of more than 1 indicates a higher proportion of modalizing discourse. Modalizing discourse was defined as any comment, judgment or uncertainty made by the subject about the actual narrative task and that did not refer to the expected story line. Below is an example such an analysis. Produced sentence: ‘‘I think this is a policeman’’ (translated from French) Target sentence: ‘‘This is a policeman’’ Nb of modalizing words: 2 Nb of total words: 6 Percent of modalization words ¼ 2/6 ¼ 0.33 Percent of referential words ¼ 1 ) 0.33 ¼ 0.67 Ratio ¼ 0.33/0.67 ¼ 0.5 The repetition of expected ideas was derived only from the referential portion of discourse samples. In order to correct for the number of ideas produced, this measure was obtained by dividing the number of produced ideas by the number of repeated ideas. The presence of an expected idea from the storyline was obtained by comparing the ideas produced with a list of expected ideas that had been previously derived by consensus between the three authors. An idea was defined as any concept pertaining to the story that could be expressed using either a single word or a number of words.
3. Results 2.2. Task All subjects were asked to verbally produce a story induced by the presentation of a single picture depicting a bank robbery (Nespoulous et al., 1992). To eliminate any memory-specific effect, the picture stimulus was left uncovered for the duration of the session. Instructions given to subjects were ‘‘Look at this picture and tell me the story that you see.’’ Subjects were allowed as much time as was necessary for them to complete their story. In order to elicit more verbal output in subjects whose stories were felt to be incomplete, prompts that did not reveal the content of the stories such as ‘‘do you have anything else to add?’’ were offered. All discourse samples (25 for the five patients and 27 for normal controls) were audiotaped and transcribed verbatim for discourse analyses.
The M/R ratios for AD patients are displayed in Fig. 1. The first finding is that there appears to be a high level of variability between patients. Despite the
Fig. 1. M/R ratio for the five AD patients as a function of assessment.
A. Duong et al. / Brain and Cognition 53 (2003) 177–180
Fig. 2. Percent repetitions of expected ideas in the referential portion of discourse for five AD.
variability, M/R ratios for patients were most often higher than that of normal controls (M=R ratio ¼ 0.25; SD ¼ 0:02), suggesting that patients produced a higher amount of modalizing discourse relative to referential discourse than the control subjects. A second finding was that a general trend towards a decrease in the M/R ratio from the first to the 5th assessment could be detected for most patients, suggesting that they tend to produce less modalizing discourse towards the final assessment. Except for subject P734, the other four patients obtained M/R ratios that were similar to normal controls by the 5th assessment. The percent of repetitions of expected ideas for AD patients are displayed in Fig. 2. Again, a high level of variability can be observed between patients, ranging from 0% (subjects P719 and P734) to 50% (subject P416), suggesting that up to half of the ideas produced were repeated during a referential discourse. Despite this variability, the percentage of repetitions in most AD patients was much higher than that of normal controls (percentage of repetitions ¼ 9.18%, SEM ¼ 2:00%). Unlike the M/R ratios, there does not appear to be a general trend towards a decrease as a function of assessment. This suggests that the level of repetitions remained high for some subjects, even towards the 5th assessment. This high level of repetition coupled with a reduction in number of ideas produced could lead to an important decrease in informative content in the referential discourse of AD patients.
4. Discussion The present study investigated a particular discourse behavior that has been otherwise neglected in most discourse studies, namely modalizing discourse. Results suggest that an important portion of the entire production was devoted to modalizations in all five patients during the initial assessments, and that this proportion decreased to the level of normal controls only towards the last assessment. During the initial stages of the disease, the high proportion of modalizing discourse
179
reinforces the importance of its inclusion in further discourse studies. Furthermore, repetitions of informative content relative to the proportion of referential discourse may yield a more accurate description of AD patientsÕ behavior during a discourse production task. When modalizing discourse is factored in, the emptiness and reduced content, as perceived by an interlocutor, might be more severe than that reported in the literature. Inclusion of modalizing discourse could at the very least provide a more accurate description of the discourse production of AD patients. Modalizing discourse may also contain valuable information about the discourse production abilities of AD patients. Cardebat et al. (1993) included modalization measures to account for the pragmatic aspects of AD patientsÕ narratives. According to these authors, modalizing comments represent the subjectÕs intellectual judgment about his/her difficulties during the task. They also suggest that this meta-discourse, or discourse about discourse, could therefore, reflect the patientÕs consciousness about his/her impairments. Modalizations could also reflect the patientÕs attempt at maintaining communication when faced with narrative impairments. This explanation suggests that picture-induced narratives could also bring out pragmatic demands that are more prominently observed during conversational discourse. The fact that AD patients produce a large number of modalizations in order to maintain their communicative turn reinforces the belief that pragmatic abilities in AD patients, as evidenced in conversational studies, are relatively well preserved during the initial stages of the disease (for a review, see Erhlich, 1994). An increased interest in modalizing discourse may also shed light on the strategies used by AD patients during a discourse task. For example, it would be interesting to describe in more detail the different types of modalizations, such as comments regarding uncertainties, feelings invoked by the stimulus, or the types of difficulties experienced during referential discourse that lead to modalization comments. These observations could be contrasted with those obtained from normal controls. Although the present study did not report longitudinal data on normal controls, there is evidence that the normal aging process also leads to a variety of discourse processing impairments that could be mistaken for AD (for a review, see Mackenzie, 2000; Wingfield & Stine-Morrow, 2000). A better description of modalizations in normal aging as a function of age might contribute to a more accurate differential diagnosis. From a pragmatic point of view, modalizing discourse should be perceived as a strength, not as an impairment. Its importance should thus be recognized as it may constitute a starting point for a comprehensive discourse communication management program in AD.
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Acknowledgments This research was supported by a grant from the Fonds de la recherche en Santedu Quebec (FRSQ) awarded to A.D., and from the Fonds Canadien dÕAide a la recherche (FCAR) awarded to B.S. References Caramelli, P., Mansur, L. L., & Nitrini, R. (1998). Language and communication disorders in dementia of the Alzheimer type. In B. Stemmer, & H. A. Whitaker (Eds.), Handbook of neurolinguistices (pp. 463–473). New York: Academic Press. Cardebat, D., Demonet, J.-F., & Doyon, B. (1993). Narrative discourse in dementia. In H. H. Brownell, & Y. Joanette (Eds.), Narrative discourse in neurologically impaired and normal aging adults (pp. 317–332). San Diego, CA: Singular. Erhlich, J. S. (1994). Studies of discourse production in Adults with AlzheimerÕs disease. In R. L. Bloom, K. Obler, S. De Santi, & J. S. Ehrlich (Eds.), Discourse analysis and applications: Studies in adult clinical populations (pp. 149–160). Hillsdale, NJ: Erlbaum. Giles, E., Patterson, K., & Hodges, J. R. (1996). Performance on the Boston Cookie Theft picture description task in patients with early dementia of the AlzheimerÕs type: Missing information. Aphasiology, 10, 395–408. Joanette, Y., Ska, B., Poissant, A., Belleville, S., Lecours, A.-R., & valuation neuropsychologique dans la demence Peretz, I. (1995). E de type Alzheimer: Un compromis optimal. Annee gerontologique (suppl Maladie dÕAlzheimer), 2, 69–83. Mackenzie, C. (2000). Adult spoken discourse: The influences of age and education. International Journal of Language and Communication Disorders, 35, 269–285. McKhan, G., Drachman, D., Folstein, M., Katzman, R., Price, D., & Stadlan, E. M. (1984). Clinical diagnosis of AlzheimerÕs disease: Report of the NINCDS-ADRDA work group under the auspices
of the Department of Health and Human Services task force on AlzheimerÕs disease. Neurology 34, 939–944. Nespoulous, J.-L. (1980). De deux comportements verbaux de base: Referential et modalisateur. De leur dissociation dans le discourse aphasique. Cahiers de Psychologie, 23, 195–210. Nespoulous, J.-L., Code, C., Virbel, J., & Lecours, A.-R. (1998). Hypotheses on the dissociation between ‘‘referential’’ and ‘‘modalizing’’ verbal behavior in aphasia. Applied Psycholinguistics, 19, 311–331. Nespoulous, J.-L., Lecours, A. R., Lafond, D., Lemay, A., Puel, M., & Joanette, Y., et al. (1992). Protocole Montreal-Toulouse. Examen de ditions Ortho. l’aphasie, version Beta modifiee. E Nicholas, M., Obler, L. K., Albert, M. L., & Helm-Estabrooks, N. (1985). Empty speech in AlzheimerÕs disease and fluent aphasia. Journal of Speech and Hearing Research, 28, 405–410. Reisberg, B., Ferris, S. H., de Leon, M. J., & Crook, T. (1982). The Global Deterioration Scale for assessment of primary degenerative dementia. American Journal of Psychiatry, 139, 1136– 1139. Ska, B., & Guenard, D. (1993). Narrative schema in dementia of the AlzheimerÕs type. In H. H. Brownell, & Y. Joanette (Eds.), Narrative discourse in neurologically impaired and normal aging adults (pp. 299–316). San Diego, CA: Singular. Tomoeda, C. K., & Bayles, K. A. (1993). Longitudinal effects of Alzheimer disease on discourse production. Alzheimer Disease and Associated Disorders, 4, 223–236. Tomoeda, C. K., Bayles, K. A., Trosset, M. W., Azuma, T., & McGee, A. (1996). Cross-sectional analysis of Alzheimer Disease effects on oral discourse in a picture description task. Alzheimer Disease and Associated Disorders, 4, 204–215. Vuorinen, E., Laine, M., & Rinne, J. (2000). Common pattern of language impairment in vascular dementia and Alzheimer disease. Alzheimer Disease and Associated Disorder, 14, 81–86. Wingfield, A., & Stine-Morrow, E. A. L. (2000). Language and speech. In F. I. M. Craik, & T. A. Salthouse (Eds.), The handbook of aging and cognition (pp. 359–415). London: Laurence Erlbaum Associates Publishers.
Discourse about discourse: What is it and how does it progress in AlzheimerÕs disease? Anh Duong, Andreanne Tardif, and Bernadette Ska Ecole d’orthophonie et d’audiologie, Facult e de M edecine, Universit e de Montr eal, Centre de recherche, Institut universitaire de g eriatrie de Montr eal, Canada Accepted 7 May 2003
Abstract Discourse about discourse or a subjectÕs comments about his/her performance during a discourse task can be defined as modalizing discourse (discours modalisateur; Nespoulous, 1980; Nespoulous, Code, Virbel, & Lecours, 1998). Since it does not convey the expected content of the discourse task (referential discourse), modalizing discourse has often been considered non-informative, and as such, has received little interest. The present study investigated the modalizing aspect of discourse production and its evolution in AlzheimerÕs disease (AD). Five AD patients produced a picture-induced narrative across five consecutive assessments. Two measures were derived: the modalizing/referential ratio (M/R ratio) and the percentage of repeated ideas. Results revealed that, compared to a group of 27 normal controls matched for age and education, AD patients: (1) obtained higher M/R ratios that tended to diminish as the number of assessments increased, and (2) produced higher percentages of repeated ideas throughout all assessments. These results suggest that modalizing discourse makes up a large proportion of AD patientsÕ discourse and should be included in further studies to accurately describe their discourse behavior. The implications of modalizing discourse on preserved pragmatic abilities and its inclusion in comprehensive management programs of AD patients are discussed. Ó 2003 Elsevier Inc. All rights reserved.
1. Introduction Patients with AlzheimerÕs disease (AD) typically exhibit impairments at the discourse level (for a review, see Caramelli, Mansur, & Nitrini, 1998). While there are many types of discourse (conversational, procedural, narrative, etc), narrative discourse, and in particular picture-induced narrative discourse, has enjoyed a considerable amount of attention for at least two reasons. First, it reduces memory demands because the story content is displayed statically in front of the patient, and second, it facilitates discourse analysis because target contents can be derived from the picture(s). Using this method, a number of researchers have reported that the narrative discourse of patients with AD appears more empty than that of their normal aging counterparts and contains fewer ideas and more repetitions of ideas (Giles, Patterson, & Hodges, 1996; Nicholas, Obler, Albert, & Helm-Estabrooks, 1985; Ska & Guenard, 1993; Tomoeda & Bayles, 1993; Tomoeda, Bayles, Trosset, Azuma, & McGee, 1996; Vuorinen, Laine, & Rinne, 2000). 0278-2626/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0278-2626(03)00104-0
Interestingly, most of these studies have focused on the referential content of discourse; that is that portion of the discourse that pertains to the expected story line. Measures such as circumlocutions, content units, cohesive devices, and semantic propositions, to name a few, have been derived to adequately describe and qualify the various levels of discourse impairment, albeit only with regard to the referential portion of discourse. Although Nicholas et al. (1985) included comments and empty phrases, their measures were composed of both referential and non-referential discourse. Most often, patientsÕ comments regarding the task, the uncertainty with which they express their story, and their feelings about the story have been systematically discarded from analysis. Omission of this discourse-about-discourse, referred to as modalizing discourse (discours modalisateur; Nespoulous, 1980; Nespoulous et al., 1998) or enunciative modalizations (Cardebat, Demonet, & Doyon, 1993), means that the entire communication behavior of AD patients is not captured, and the importance of the reduction and repetition of ideas in the discourse of
178
A. Duong et al. / Brain and Cognition 53 (2003) 177–180
AD patients may be underestimated. Furthermore, little is known about the progression of this modalizing behavior over the course of the disease. The present study describes AD patientsÕ discourse and the repetition of ideas with respect to the dichotomy of modalizing vs referential discourse in a longitudinal perspective.
2. Methods 2.1. Participants Five AD patients and 27 normal aging subjects participated in the present study. They were selected on the basis of age, education, and the availability of longitudinal data from of a cohort of subjects who took part in a larger study on normal and pathological aging (Joanette et al., 1995). At the time of testing, all five AD patients had received a diagnosis of probable AD according to the NINCDS-ADRDA criteria (McKhan et al., 1984) and were considered mild to moderate, GDS ¼ 3 or 4 on the Reisberg scale (Reisberg, Ferris, de Leon, & Crook, 1982). AD patients were Frenchspeakers from the Montreal metropolitan area and were aged between 63 and 78 and had 6 to 10 years of formal education. They were assessed in 5 consecutive sessions at 6-month intervals. During the course of the assessments, all AD patients remained at GDS4 except for 1 patient (P444) who evolved to GDS4 at the 5th assessment from an entry level of GDS3. AD patients were compared to 27 right-handed French-speaking subjects from the Montreal metropolitan area who presented no neurological, psychiatric or medical problems at the time of testing. Normal subjects ranged from 65 to 84 years of age and had 4 to 11 years of formal education. They had only been assessed once at entry.
2.3. Discourse measures For each of the discourse samples, two measures were obtained from the transcribed discourse samples. The ratio of modalizing discourse to referential discourse (M/R ratio) was computed by dividing the percentage of modalizing words by the percentage of referential words. A measure of 1 indicates equal proportion of modalization to referential discourse, a measure of less than 1 indicates a higher proportion of referential discourse, and a measure of more than 1 indicates a higher proportion of modalizing discourse. Modalizing discourse was defined as any comment, judgment or uncertainty made by the subject about the actual narrative task and that did not refer to the expected story line. Below is an example such an analysis. Produced sentence: ‘‘I think this is a policeman’’ (translated from French) Target sentence: ‘‘This is a policeman’’ Nb of modalizing words: 2 Nb of total words: 6 Percent of modalization words ¼ 2/6 ¼ 0.33 Percent of referential words ¼ 1 ) 0.33 ¼ 0.67 Ratio ¼ 0.33/0.67 ¼ 0.5 The repetition of expected ideas was derived only from the referential portion of discourse samples. In order to correct for the number of ideas produced, this measure was obtained by dividing the number of produced ideas by the number of repeated ideas. The presence of an expected idea from the storyline was obtained by comparing the ideas produced with a list of expected ideas that had been previously derived by consensus between the three authors. An idea was defined as any concept pertaining to the story that could be expressed using either a single word or a number of words.
3. Results 2.2. Task All subjects were asked to verbally produce a story induced by the presentation of a single picture depicting a bank robbery (Nespoulous et al., 1992). To eliminate any memory-specific effect, the picture stimulus was left uncovered for the duration of the session. Instructions given to subjects were ‘‘Look at this picture and tell me the story that you see.’’ Subjects were allowed as much time as was necessary for them to complete their story. In order to elicit more verbal output in subjects whose stories were felt to be incomplete, prompts that did not reveal the content of the stories such as ‘‘do you have anything else to add?’’ were offered. All discourse samples (25 for the five patients and 27 for normal controls) were audiotaped and transcribed verbatim for discourse analyses.
The M/R ratios for AD patients are displayed in Fig. 1. The first finding is that there appears to be a high level of variability between patients. Despite the
Fig. 1. M/R ratio for the five AD patients as a function of assessment.
A. Duong et al. / Brain and Cognition 53 (2003) 177–180
Fig. 2. Percent repetitions of expected ideas in the referential portion of discourse for five AD.
variability, M/R ratios for patients were most often higher than that of normal controls (M=R ratio ¼ 0.25; SD ¼ 0:02), suggesting that patients produced a higher amount of modalizing discourse relative to referential discourse than the control subjects. A second finding was that a general trend towards a decrease in the M/R ratio from the first to the 5th assessment could be detected for most patients, suggesting that they tend to produce less modalizing discourse towards the final assessment. Except for subject P734, the other four patients obtained M/R ratios that were similar to normal controls by the 5th assessment. The percent of repetitions of expected ideas for AD patients are displayed in Fig. 2. Again, a high level of variability can be observed between patients, ranging from 0% (subjects P719 and P734) to 50% (subject P416), suggesting that up to half of the ideas produced were repeated during a referential discourse. Despite this variability, the percentage of repetitions in most AD patients was much higher than that of normal controls (percentage of repetitions ¼ 9.18%, SEM ¼ 2:00%). Unlike the M/R ratios, there does not appear to be a general trend towards a decrease as a function of assessment. This suggests that the level of repetitions remained high for some subjects, even towards the 5th assessment. This high level of repetition coupled with a reduction in number of ideas produced could lead to an important decrease in informative content in the referential discourse of AD patients.
4. Discussion The present study investigated a particular discourse behavior that has been otherwise neglected in most discourse studies, namely modalizing discourse. Results suggest that an important portion of the entire production was devoted to modalizations in all five patients during the initial assessments, and that this proportion decreased to the level of normal controls only towards the last assessment. During the initial stages of the disease, the high proportion of modalizing discourse
179
reinforces the importance of its inclusion in further discourse studies. Furthermore, repetitions of informative content relative to the proportion of referential discourse may yield a more accurate description of AD patientsÕ behavior during a discourse production task. When modalizing discourse is factored in, the emptiness and reduced content, as perceived by an interlocutor, might be more severe than that reported in the literature. Inclusion of modalizing discourse could at the very least provide a more accurate description of the discourse production of AD patients. Modalizing discourse may also contain valuable information about the discourse production abilities of AD patients. Cardebat et al. (1993) included modalization measures to account for the pragmatic aspects of AD patientsÕ narratives. According to these authors, modalizing comments represent the subjectÕs intellectual judgment about his/her difficulties during the task. They also suggest that this meta-discourse, or discourse about discourse, could therefore, reflect the patientÕs consciousness about his/her impairments. Modalizations could also reflect the patientÕs attempt at maintaining communication when faced with narrative impairments. This explanation suggests that picture-induced narratives could also bring out pragmatic demands that are more prominently observed during conversational discourse. The fact that AD patients produce a large number of modalizations in order to maintain their communicative turn reinforces the belief that pragmatic abilities in AD patients, as evidenced in conversational studies, are relatively well preserved during the initial stages of the disease (for a review, see Erhlich, 1994). An increased interest in modalizing discourse may also shed light on the strategies used by AD patients during a discourse task. For example, it would be interesting to describe in more detail the different types of modalizations, such as comments regarding uncertainties, feelings invoked by the stimulus, or the types of difficulties experienced during referential discourse that lead to modalization comments. These observations could be contrasted with those obtained from normal controls. Although the present study did not report longitudinal data on normal controls, there is evidence that the normal aging process also leads to a variety of discourse processing impairments that could be mistaken for AD (for a review, see Mackenzie, 2000; Wingfield & Stine-Morrow, 2000). A better description of modalizations in normal aging as a function of age might contribute to a more accurate differential diagnosis. From a pragmatic point of view, modalizing discourse should be perceived as a strength, not as an impairment. Its importance should thus be recognized as it may constitute a starting point for a comprehensive discourse communication management program in AD.
180
A. Duong et al. / Brain and Cognition 53 (2003) 177–180
Acknowledgments This research was supported by a grant from the Fonds de la recherche en Santedu Quebec (FRSQ) awarded to A.D., and from the Fonds Canadien dÕAide a la recherche (FCAR) awarded to B.S. References Caramelli, P., Mansur, L. L., & Nitrini, R. (1998). Language and communication disorders in dementia of the Alzheimer type. In B. Stemmer, & H. A. Whitaker (Eds.), Handbook of neurolinguistices (pp. 463–473). New York: Academic Press. Cardebat, D., Demonet, J.-F., & Doyon, B. (1993). Narrative discourse in dementia. In H. H. Brownell, & Y. Joanette (Eds.), Narrative discourse in neurologically impaired and normal aging adults (pp. 317–332). San Diego, CA: Singular. Erhlich, J. S. (1994). Studies of discourse production in Adults with AlzheimerÕs disease. In R. L. Bloom, K. Obler, S. De Santi, & J. S. Ehrlich (Eds.), Discourse analysis and applications: Studies in adult clinical populations (pp. 149–160). Hillsdale, NJ: Erlbaum. Giles, E., Patterson, K., & Hodges, J. R. (1996). Performance on the Boston Cookie Theft picture description task in patients with early dementia of the AlzheimerÕs type: Missing information. Aphasiology, 10, 395–408. Joanette, Y., Ska, B., Poissant, A., Belleville, S., Lecours, A.-R., & valuation neuropsychologique dans la demence Peretz, I. (1995). E de type Alzheimer: Un compromis optimal. Annee gerontologique (suppl Maladie dÕAlzheimer), 2, 69–83. Mackenzie, C. (2000). Adult spoken discourse: The influences of age and education. International Journal of Language and Communication Disorders, 35, 269–285. McKhan, G., Drachman, D., Folstein, M., Katzman, R., Price, D., & Stadlan, E. M. (1984). Clinical diagnosis of AlzheimerÕs disease: Report of the NINCDS-ADRDA work group under the auspices
of the Department of Health and Human Services task force on AlzheimerÕs disease. Neurology 34, 939–944. Nespoulous, J.-L. (1980). De deux comportements verbaux de base: Referential et modalisateur. De leur dissociation dans le discourse aphasique. Cahiers de Psychologie, 23, 195–210. Nespoulous, J.-L., Code, C., Virbel, J., & Lecours, A.-R. (1998). Hypotheses on the dissociation between ‘‘referential’’ and ‘‘modalizing’’ verbal behavior in aphasia. Applied Psycholinguistics, 19, 311–331. Nespoulous, J.-L., Lecours, A. R., Lafond, D., Lemay, A., Puel, M., & Joanette, Y., et al. (1992). Protocole Montreal-Toulouse. Examen de ditions Ortho. l’aphasie, version Beta modifiee. E Nicholas, M., Obler, L. K., Albert, M. L., & Helm-Estabrooks, N. (1985). Empty speech in AlzheimerÕs disease and fluent aphasia. Journal of Speech and Hearing Research, 28, 405–410. Reisberg, B., Ferris, S. H., de Leon, M. J., & Crook, T. (1982). The Global Deterioration Scale for assessment of primary degenerative dementia. American Journal of Psychiatry, 139, 1136– 1139. Ska, B., & Guenard, D. (1993). Narrative schema in dementia of the AlzheimerÕs type. In H. H. Brownell, & Y. Joanette (Eds.), Narrative discourse in neurologically impaired and normal aging adults (pp. 299–316). San Diego, CA: Singular. Tomoeda, C. K., & Bayles, K. A. (1993). Longitudinal effects of Alzheimer disease on discourse production. Alzheimer Disease and Associated Disorders, 4, 223–236. Tomoeda, C. K., Bayles, K. A., Trosset, M. W., Azuma, T., & McGee, A. (1996). Cross-sectional analysis of Alzheimer Disease effects on oral discourse in a picture description task. Alzheimer Disease and Associated Disorders, 4, 204–215. Vuorinen, E., Laine, M., & Rinne, J. (2000). Common pattern of language impairment in vascular dementia and Alzheimer disease. Alzheimer Disease and Associated Disorder, 14, 81–86. Wingfield, A., & Stine-Morrow, E. A. L. (2000). Language and speech. In F. I. M. Craik, & T. A. Salthouse (Eds.), The handbook of aging and cognition (pp. 359–415). London: Laurence Erlbaum Associates Publishers.