1. Influence of Age and Executive Functions on Story Grammar Performance in Adults Michael S. Cannizzaro & Carl A. Coelho University of Connecticut, Storrs
INTRODUCTION
Previous investigations of age-related cognitive-linguistic decline have demonstrated the value of studying discourse ability (Chapman, Zientz, Weiner, Rosenberg, Frawley, & Burns, 2002; Glosser & Desser, 1992; Makenzie, 2000; Snow & Douglas, 2000; Ulatowska, Freedman-Stern, Doyel, Macaluso-Haynes, & North, 1983). Discourse can be conceptualized as the related, extended, and meaningful representation of communication across multiple language units (van Dijk & Kintsch, 1983). Accurate production and comprehension of narrative discourse requires a complex interaction of linguistic, cognitive, and social abilities (Coelho, 1995; Ylvisaker, Szekeres, & Feeney, 2001). The story narrative genre has frequently been studied because it is considered a stereotypical type of discourse due to its formal and predictable framework (Faylor & Lemaire, 1993). Such narratives follow a cognitively based, measurable, structured set of rules called story grammar, which are not dictated by the specific content of the message conveyed (Coelho, 1998; Liles, Duffy, Merritt, & Purcell, 1995; Mandler & Johnson, 1977; Stein & Glenn, 1979). Liles (1985) describes this underlying rule structure in narratives as a “cognitive skeleton” that creates character identities as well as the relational and causal elements that are fundamental to a well-formed story narrative. The production of discourse combines the use of language and cognitive organizational principles permitting investigation of the interaction of these abilities. Thus, discourse analyses are concerned with the entire discourse text and the relationship between its structure and function (i.e., the language itself and organization of the text) (McDonald, 1998). Indeed, discourse has been aptly described as “one of the critical points of intersection between language and cognition” as cognitive rule systems are employed to guide language production (Ylvisaker, Szekeres, & Feeney, 2001, p. 756).
It has been suggested that the episode structure of story grammar is one aspect of goal directed thinking and behavior referred to as managerial knowledge (Grafman, 1995; Grafman, 1999). According to Grafman (1995) managerial knowledge should be measurable in a variety of goal directed behaviors such as story grammar or executive functioning. Consistent with this notion are recent findings that have noted modest correlations between discourse production abilities and executive functions (Coelho, 2002; Tucker & Hanlon, 1998).
Similarly, interest in age related changes across the life span has led to an increase in the number of investigations of the influence of cognitive performance and ageing on discourse (Chapman et al., 2002 & Mackenzie, 2000). However, relationships between discourse and theoretically similar goal directed behavior, such as executive functioning, are not well established. The purpose of the present study was to investigate the influence of two factors, aging and executive functioning, on story grammar abilities in a large group of neurologically intact adults. Prior research suggests that age is related to declines in executive functioning (Delis, Kaplan, & Kramer, 2001). It was hypothesized that performance on complex executive functions and narrative story structure would be similarly negatively correlated with advanced age, as both are goal conceptually related aspects of managerial knowledge.
STUDY QUESTIONS
What is the nature of the relationship between age and story grammar performance?
Is story grammar performance related to measures of linguistic- and non-linguistic executive functions?
Do EF measures and story grammar measures demonstrate a unified construct of Managerial knowledge?
METHODS
Participants
Forty-Six neurologically intact adults (age 18-98, mean 56.78, sd 27.7) were recruited for this study All participants were living independently in their respective communities and reported negative history of neurological and/or psychiatric disorder, substance abuse, and language/learning disability (Table 1).
Table 2: Story Grammar and demographic correlations
Complete Episodes - Retell
T-units in Episodes - Retell
Complete Episodes - Generation
T-units in Episodes- Generation
Age
r= , p= .85
r = , p= .02*
r = - .33, p= .03*
r= -.19, p= .22
Yrs. of Educ.
r= .11, p= .46
r = , p= .69
r = - .11, p= .42
r= -.17, p= .27
Est.Verb. IQ
r= .12, p= .42
r= , p= .65
r = - .07, p= .63
r= -.23, p= .13
Table 1: Age, EVIQ, and Years of Education
Participants
Age
N (range)
EVIQ
Mean (sd)
YRSED
Male
5 ( )
7 ( )
3 ( )
14.37 (2.29)
16.8(2.68)
Female
9 ( )
11( )
11 ( )
12.4 (2.29)
16.03 (2.21)
All
56.78 (27.7)
13.04 (2.44)
16.28 (2.37)
Table 3: Story grammar and linguistic-executive function correlations
Complete Episodes Retell
T-units in Episodes Retell
Complete Episodes Generation
T-units in Episodes
Generation
Verbal Fluency-
Category Switch
r (p)
.27 (.07)
.29 (.06)
.43* (<.01)
.11 (.48)
20?- Total Asked
-.17 (.27)
-.22 (.16)
-.31* (.04)
-.04 (.81)
20?- Weighted Achievement
.10 (.52)
.26 (.09)
.19 (.22)
.08 (.62)
Stroop -Inhibition
-.11 (.49)
-.39* (<.01)
-.24 (.12)
-.23 (.14)
Discourse Analysis Procedures
1. Story Retelling condition: participants looked through a picture story book and were instructed to tell a story that would go along with the book..
2. Story Generation condition: participants looked at a single picture and instructed to tell a story that would go along with that picture.
In both conditions, participants were instructed to tell the story as if they were telling it to someone who has never seen the book/ picture before. No time limits were imposed in either task. All stories were recorded, transcribed verbatim, parsed into T-units, and analyzed for story grammar content.
Measures:
1. Number of Complete Episodes-an episode consisted of (a) an initiating event that prompts a character to formulate a goal-directed behavior, (b) an action, and (c) a direct consequence marking attainment or non-attainment of the goal.
2. Proportion of T-units Within Episode Structure-this measure was considered to be an indication of participants’ ability to use story grammar as an organizational plan for language.
3. Measures of Executive Function
Seven subtests of the Delis-Kaplan Executive Function System (Delis, Kaplan, & Kramer, 2001) were administered to each participant. These subtests were selected because they are known to be sensitive to subtle differences in EF ability and aging.
Table 4: Story grammar and non-linguistic-executive function correlations
Complete Episodes Retell
T-units in Episodes Retell
Complete Episodes Generation
T-units in Episodes
Generation
Design Fluency -Switch
r (p)
-.12 (.44)
.07 (.66)
.37* (.01)
.10 (.50)
Design Fluency -Total
-.13 (.41)
-.17 (.26)
.07 (.63)
.02 (.92)
Tower Test
-.11 (.47)
-.04 (.79)
-.08 (.62)
-.11 (.49)
Trails - Motor Speed
-.07 (.66)
-.47* (<.01)
-.22 (.16)
Trails – Number-letter
.11 (.48)
-.15 (.34)
-.30* (.05)
-.16 (.31)
Card Sort Total
.03 (.86)
.17 (.28)
.04 (.80)
.08 (.61)
Card Sort Recognition
.29 (.05)
.25 (.10)
.12 (.44)
Card Sort Description
.11 (.49)
.09 (.57)
.01 (.95)
Table 5: Factor analysis - story grammar and executive function measures
Rotated Factor Pattern
Output-Performance
Organization-Efficiency
T-Units in Episode Retell
.65
Complete Episode Gen.
-.52
Trails- Switching
.82
Trails – Motor Speed
.83
Design Fluency - Switching
-.59
Verbal Fluency - Categories
-.70
20?s – Total Asked
-.80
Stroop - Inhibition
-.90
RESULTS
Two measures of story narrative performance, number of complete episodes in story generation and proportion of T-units within episode structure in story retelling, were significantly negatively correlated with age, but not participants’ level of education or estimated verbal IQ (see Table 2). These two measures were also significantly correlated with a number of complex EF measures and participants’ motor speed (see Tables 3 & 4)
Hierarchical cluster analysis based upon story grammar measures identified three distinct clusters. A Tukey-Kramer test for honestly significant differences between groups (e.g., cluster mean age [Older mean = 72.3 sd = 17.6; Mid mean = 61.7 sd = 26.14; & Young mean 49.5 sd = 22.3] ) indicated the oldest age cluster was significantly different from the youngest age cluster. The intermediate age cluster was not significantly different from either the younger or older age clusters (see Figure 1).
Principal components analysis was performed on the correlated discourse and age related variables. Varimax rotation of variables yielded two distinct factors: (1) Output-Fluidity accounting for 39% of the variance, and (2) Organization-Efficiency accounting for 21% of the variance. Greater than 60% of the variance explained overall was accounted for by these two factors. (see Table 5).
Figure 1: Story grammar cluster by age
DISCUSSION
These findings are consistent with previous investigations of cognitive-linguistic changes in aging which have noted that: discourse changes are more pronounced in the older elderly, the noted discourse changes are present even in well educated elderly, age related changes are more evident on complex tasks, and they occur across a variety of discourse genres (Ulatowska, Cannito, Hayashi, & Fleming, 1985). Specifically, decreased episode production in story generation and inclusion of non-episodic information in story retelling were notably different in the older participants in this study. Story grammar appears to be related equally to measures of linguistic and non-linguistic executive function and may provide a balanced ecologically valid measure of executive ability. Additionally, profiles of narrative performance (e.g., cluster analysis) may provide a more appropriate benchmark of elderly performance when assessing and treating older adults with cognitive-communicative deficits.
Poster presented at the 33rd annual Clinical Aphasiology Conference, May