In a majority of languages, the time of an event is expressed by marking tense on the verb. There is substantial evidence that the production of verb tense in sentences is more severely impaired than other functional categories in persons with agrammatic aphasia. The underlying source of this verb tense impairment is less clear, particularly in terms of the relative contribution of conceptual-semantic and processing demands. This study aimed to provide a more precise characterization of verb tense impairment by examining if there is dissociation
Agrammatic aphasia is a cluster of language symptoms following damage to left hemisphere peri-Sylvian regions. The core feature of agrammatic aphasia is severely impoverished sentence production: utterances consist of words strung together in an ungrammatical sequence, or, at best, simple canonical sentences (e.g., subject-verb-object, in English) [
Crosslinguistically, sentence production difficulty in agrammatism is often characterized by exceptional difficulty producing certain types of morphosyntactic structures, such as tense marking, relative to other structures, such as agreement and mood marking (e.g., in English [
Another family of tense-centric accounts of agrammatism draws attention to the fact that, in addition to its morphosyntactic role, verb tense interfaces with semantics of the event. That is, tense is an “interpretable” syntactic feature [
Further, it has been proposed that reference to past events is “selectively impaired in agrammatic aphasia” such that past tense and perfect aspect are particularly challenging to produce compared to present tense and imperfect aspect [
There are other theoretical accounts of agrammatic production that identify more general sources of difficulty. Resource limitation accounts propose an interaction between computational demands and performance success, especially for syntactic computations. Empirical support for the impact of limited processing resources on agrammatic production comes from the influence of task complexity [
To summarize, a variety of accounts have been proposed to characterize the difficulty with production of tense morphology in agrammatism. A majority of the more recent accounts incorporate some reference to the semantics of time, one account proposes further dissociation within temporal morphology, and some accounts allow for performance variation based on task processing demands. Although there is substantial empirical data on agrammatic tense production, it is unclear whether tense morphology is modulated by semantic (or any other) variables. Actually, a precise characterization of the verb tense deficit in agrammatism is lacking, which is a precursor to developing a reasonable explanation for this symptom. This study aims to further our understanding of verb tense performance by investigating the influence of two variables: temporal category (past, present, or future) and the elicitation task. A brief background on these two variables is provided before describing the current study.
Temporal distance (—) between speaking time (S), reference time (R), and event time (E).
Tense/aspect | Example | Linear |
---|---|---|
Simple past | He signs the papers | E, R—S |
Simple present | He signed the papers | S, E, R |
Simple future | He will sign the papers | S—R, E |
Present progressive | He will be signing the papers | S, E~, R |
Past progressive | He was signing the papers | E~, R—S |
Present perfect | He has signed the papers | E—S, R |
Past perfect | He had signed the papers | E—R—S |
Empirical investigations of tense and aspect processing in neurologically healthy adults have mostly examined the extent to which different sentences evoke a mental representation of the event. For example, Magliano and Schleich [
To summarize, data from neurologically healthy adults shows that sentences in the imperfective aspect are consistently faster than perfectives, while present tense is faster than past only when aspect is held constant as in Carreiras et al. [
On the basis of these processing differences observed in healthy adults, one could predict that verb tense/aspect with a greater mismatch between speaking, event, and reference times will be more vulnerable to the effects of aphasia (Table
A third experimental task provides the content words in random order and requires the participant to produce the sentence; a picture may or may not be used to aid the sentence [
To summarize, a theoretical account of tense impairment in agrammatism has been elusive. An impairment in the cognitive representation of time or in conveying temporal reference on verb morphology is currently a promising explanation. In order to evaluate this explanation and further our understanding of tense deficits, we need to unambiguously determine whether there are differences in performance across tenses that supersede crosslinguistic and methodological differences.
This study posed two research questions. First, we asked whether there is a difference in performance across different tenses (past versus present versus future) and relative to tense-neutral stimuli. Although we initially intended to compare perfect versus imperfect aspect, this question could be not addressed because of the small number of studies reporting aspectual comparisons. Second, we asked whether there is an interaction between elicitation task and tense performance. Based on sentence comprehension data from healthy adults and the differences in speaking and event time for past tense, we hypothesized that past tense performance would be worse than present tense. Additionally, we hypothesized that this difference would be evident in select experimental tasks, such as sentence production, but not in grammaticality judgment, due to the more complex computation demands of production tasks.
Published articles in English peer-reviewed journals reporting investigations of functional categories in persons with aphasia were identified using the key words aphasia, morphology, functional categories, tense, aspect, and agrammatism. The electronic databases used for the search were Science Citation Index, Medline (PubMed), PsycInfo, and Academic Search Premier. In addition, citation lists of identified articles were combed for further sources. The search was restricted to research studies available electronically between 1980 and December 2013. This identified approximately 60 potential articles for the review. We read the abstracts of these articles for relevance and excluded several studies based on content, narrowing the number of potential articles down to 38. After reading the text of the remaining articles, we used the following predetermined inclusionary criteria to identify the studies that qualified for the meta-analysis: (1) the study reported original data from participants with a diagnosis of sudden onset aphasia (not progressive); (2) language profile was described in adequate detail to determine the specific symptomatology of the patient (e.g., agrammatic, nonfluent, and fluent); (3) native language performance was reported, although the participants could have been multilingual; (4) the study provided data for individual participants, with breakdown of scores for the various tense types; (5) task/stimuli were presented as sentences (i.e., not single word repetition); (6) syntactically simple sentences were used to minimize the confoundedness of syntactic complexity with tense encoding; (7) the study presented data for some combination of past, present, and future tense stimuli to enable within-subjects comparison (i.e., not just a single tense). Other functional categories such as agreement, mood, and aspect were noted. Reports that duplicated data, such as conference proceedings and full articles, were included only once. Multiple datasets from individual patients were included in the meta-analysis only if each dataset was original to the study. This resulted in a final set of twelve articles, with 106 individual participants totaling to 143 datasets.
All studies were coded for language of testing, description of aphasia profile, description of lesion information, the experimental task, response type (e.g., verbal), the number of stimuli used, raw scores, proportion accuracy, and the conclusions of the authors. Four different experimental tasks were used in the studies reviewed: (1) sentence production priming (SPP), in which participants were provided with a pair of pictures (the examiner modeled the target sentence for the first picture and asked the participant to describe the second picture using a sentence similar to the model); (2) sentence completion (SC), in which participants were required to complete a sentence fragment using the correct form of a given word from among a forced choice (e.g.,
The meta-analysis included 143 total datasets elicited from seven different languages. Sixty-eight of these datasets included three tenses (past, present, and future) while 75 datasets included two of the three tenses. Sentence completion task was used for 60 of the datasets, sentence production priming was used for 49 datasets, sentence production with pictures was used for eight datasets, and 26 datasets used grammaticality judgment. The average age of participants was 55.53 years and the average time following onset was 74.85 months. Of the 106 participants, 77 were male, 26 were female, and three participants’ gender was not reported. The majority of the patients had a left cerebrovascular accident. Individual participant data from each study are presented in Table
Individual participant data from the studies included in the meta-analysis.
Reference | Language | Task and response | Patient | Age/gender | MPO | Lesion/aphasia | Number correct/total | |||
---|---|---|---|---|---|---|---|---|---|---|
Neutral | Past | Present | Future | |||||||
Bastiaanse et al. (2004), page 129 (Table 1) [ |
Dutch | SC, verbal | B1 | NR | NR | NR/Broca’s | 14/30 | 18/30 | ||
B2 | NR | NR | NR/Broca’s | 15/30 | 21/30 | |||||
B3 | NR | NR | NR/Broca’s | 18/30 | 10/30 | |||||
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Bastiaanse et al. (2011), pages 671-672 (Appendices 3 and 4) [ |
Chinese | SPP, verbal | C1 | 42/M | 127 | LCVA/Broca’s | 20/20 | 11/20 | 1/20 | 1/20 |
C2 | 22/M | 96 | TBI/Broca’s | 20/20 | 12/20 | 6/20 | 6/20 | |||
C3 | 50/M | 97 | LCVA/Broca’s | 19/20 | 13/20 | 13/20 | 18/20 | |||
C4 | 41/M | 180 | LCVA/Broca’s | 18/20 | 0/20 | 1/20 | 0/20 | |||
C5 | 55/M | 92 | LCVA/Broca’s | 20/20 | 10/20 | 7/20 | 16/20 | |||
C6 | 65/M | 204 | LCVA/Broca’s | 20/20 | 2/20 | 0/20 | 0/20 | |||
C7 | 33/M | 125 | LCVA/Broca’s | 16/20 | 16/20 | 20/20 | 20/20 | |||
C8 | 55/M | 156 | LCVA/Broca’s | 17/20 | 5/20 | 8/20 | 8/20 | |||
C10 | 50/M | 177 | LCVA/Broca’s | 20/20 | 0/20 | 0/20 | 0/20 | |||
C11 | 51/M | 212 | LCVA/Broca’s | 11/20 | 5/20 | 6/20 | 4/20 | |||
English | SPP, verbal | E1 | 52/M | 59 | LCVA/Broca’s | 16/20 | 13/20 | 19/20 | 19/20 | |
E2 | 47/M | 55 | LCVA/Broca’s | 17/20 | 18/20 | 16/20 | 20/20 | |||
E3 | 64/M | 220 | LCVA/Broca’s | 19/20 | 3/20 | 13/20 | 12/20 | |||
E4 | 48/F | 23 | LCVA/Broca’s | 3/20 | 12/20 | 19/20 | 12/20 | |||
E5 | 53/M | 108 | LCVA/Broca’s | 20/20 | 12/20 | 18/20 | 19/20 | |||
E6 | 60/F | 61 | LCVA/Broca’s | 19/20 | 6/20 | 4/20 | 7/20 | |||
E7 | 53/M | 43 | RCVA/Broca’s | 20/20 | 14/20 | 19/20 | 19/20 | |||
E8 | 68/M | 180 | TBI/Broca’s | 3/20 | 4/20 | 12/20 | 4/20 | |||
E9 | 74/F | 36 | LCVA/Broca’s | 16/20 | 6/20 | 20/20 | 19/20 | |||
E10 | 54/M | 39 | LCVA/Broca’s | 18/20 | 17/20 | 16/20 | 13/20 | |||
E11 | 58/M | 226 | LCVA/Broca’s | 16/20 | 12/20 | 20/20 | 20/20 | |||
E12 | 37/M | 34 | LCVA/Broca’s | 4/20 | 2/20 | 12/20 | 3/20 | |||
Turkish | SPP, verbal | T1 | 68/M | 2 | LCVA/Broca’s | 6/20 | 17/20 | 17/20 | ||
T2 | 54/M | 5 | LCVA/Broca’s | 4/20 | 9/20 | 7/20 | ||||
T3 | 49/F | 84 | LCVA/Broca’s | 11/20 | 15/20 | 18/20 | ||||
T4 | 43/F | 4 | LCVA/Broca’s | 10/20 | 20/20 | 15/20 | ||||
T5 | 68/M | 1 | LCVA/Broca’s | 11/20 | 16/20 | 18/20 | ||||
T6 | 39/F | 7 | LCVA/Broca’s | 10/20 | 16/20 | 18/20 | ||||
T7 | 65/M | 12 | LCVA/Broca’s | 6/20 | 4/20 | 17/20 | ||||
T8 | 59/M | 2 | LCVA/Broca’s | 13/20 | 18/20 | 18/20 | ||||
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Clahsen and Ali (2009), page 446 (Table 6) [ |
English | SC, pointing | BG | 36/M | 60 |
NR/Broca’s | 8/10 | 10/10 | ||
JS | 65/M | 96 |
NR/Broca’s | 2/10 | 8/10 | |||||
KC | 78/M | 96 |
NR/Broca’s | 3/10 | 6/10 | |||||
RC | 77/M | 24 |
NR/Broca’s | 8/10 | 6/10 | |||||
JP | 68/M | 60 |
NR/Broca’s | 10/10 | 7/10 | |||||
KS | 66/M | 18 |
NR/Broca’s | 9/10 | 6/10 | |||||
PB | 82/M | 36 |
NR/Broca’s | 6/10 | 5/10 | |||||
BM | 52/M | 36 |
NR/Broca’s | 9/10 | 5/10 | |||||
BR | 82/M | 36 |
NR/Broca’s | 6/10 | 3/10 | |||||
GJ, verbal | BG | NR/Broca’s | 15/20 | 15/20 | ||||||
JS | NR/Broca’s | 11/20 | 12/20 | |||||||
KC | NR/Broca’s | 13/20 | 12/20 | |||||||
RC | NR/Broca’s | 12/20 | 11/20 | |||||||
JP | NR/Broca’s | 18/20 | 16/20 | |||||||
KS | NR/Broca’s | 13/20 | 14/20 | |||||||
PB | NR/Broca’s | 17/20 | 11/20 | |||||||
BM | NR/Broca’s | 11/20 | 11/20 | |||||||
BR | NR/Broca’s | 15/20 | 14/20 | |||||||
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Dickey et al. (2008) [ |
English | GJ, keyboard | A01 | 60/F | 180 |
NR/Broca’s | 27/30 | 26/60 | 16/30 | 11/30 |
A02 | 63/F | 132 |
NR/Broca’s | 28/30 | 44/60 | 29/30 | 29/30 | |||
A03 | 56/F | 168 |
NR/Broca’s | 26/30 | 36/60 | 14/30 | 15/30 | |||
A04 | 57/F | 48 |
NR/Broca’s | 21/30 | 27/60 | 14/30 | 15/30 | |||
A05 | 50/M | 108 |
NR/Broca’s | 18/30 | 24/60 | 14/30 | 14/30 | |||
A06 | 36/F | 36 |
NR/Broca’s | 19/30 | 30/60 | 14/30 | 14/30 | |||
A07 | 68/F | 144 |
NR/Broca’s | 23/30 | 32/60 | 14/30 | 16/30 | |||
A08 | 66/F | 84 |
NR/Broca’s | 23/30 | 39/60 | 16/30 | 18/30 | |||
A09 | 57/M | 48 |
NR/Broca’s | 7/30 | 4/60 | 4/30 | 4/30 | |||
A10 | 36/F | 24 |
NR/Broca’s | 24/30 | 37/60 | 14/30 | 14/30 | |||
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Dragoy and Bastiaanse (2013), page 127 (Appendix 3) [ |
Russian | SPP, verbal | 1 | 31/F | 35 | NR/nonfluent | 27/40 | 15/20 | 8/20 | |
2 | 32/F | 29 | NR/nonfluent | 31/40 | 11/20 | 10/20 | ||||
3 | 33/F | 20 | NR/nonfluent | 20/40 | 12/20 | 5/20 | ||||
4 | 35/M | 70 | NR/nonfluent | 23/40 | 17/20 | 5/20 | ||||
5 | 36/F | 29 | NR/nonfluent | 19/40 | 17/20 | 10/20 | ||||
6 | 46/M | 16 | NR/nonfluent | 20/40 | 14/20 | 15/20 | ||||
7 | 68/M | 29 | NR/nonfluent | 20/40 | 15/20 | 18/20 | ||||
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Duman and Bastiaanse (2008), page 9 (Appendix A)[ |
Turkish | SC, verbal | B1 | 66/F | 2.5 | LCVA/agrammatic | 16/30 | 15/30 | ||
B2 | 70/M | 6 | LCVA/agrammatic | 4/30 | 18/30 | |||||
B3 | 44/F | 16 | LCVA/agrammatic | 14/30 | 13/30 | |||||
B4 | 47/F | 26 | LCVA/agrammatic | 11/30 | 12/30 | |||||
B5 | 40/M | 28 | LCVA/agrammatic | 13/30 | 15/30 | |||||
B6 | 26/F | 120 | TBI/agrammatic | 16/30 | 16/30 | |||||
B7 | 75/M | 20 | LCVA/agrammatic | 3/30 | 19/30 | |||||
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Faroqi-Shah and Thompson (2004), page 492 (Figure 3) [ |
English | SPPi, verbal | CH | 56/M | 90 | LCVA/Broca’s | 2/17 | 14/17 | 1/17 | |
MK | 54/M | 12 | LCVA/Broca’s | 3/17 | 0/17 | 7/17 | ||||
MR | 44/F | 45 | LCVA/Broca’s | 3/17 | 13/17 | 2/17 | ||||
JP | 65/M | 30 | LCVA/Broca’s | 1/17 | 2/17 | 10/17 | ||||
MD | 62/M | 120 | LCVA/Broca’s | 3/17 | 9/17 | 3/17 | ||||
JO | 69/M | 88 | LCVA/Broca’s | 7/17 | 3/17 | 7/17 | ||||
RH | 64/M | 100 | LCVA/Broca’s | 9/17 | 2/17 | 0/17 | ||||
LD | 52/F | 14 | LCVA/Broca’s | 6/17 | 0/17 | 10/17 | ||||
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Faroqi-Shah and Thompson (2007), pages 139-140 (Figures 2 and 3) [ |
English | SC, verbal | B1 | 55/M | 156 |
LCVA/Broca’s | 11/15 | 19/30 | 14/15 | |
B2 | 58/M | 48 |
LCVA/Broca’s | 15/15 | 18/30 | 14/15 | ||||
B3 | 59/M | 168 |
LCVA/Broca’s | 13/15 | 17/30 | 5/15 | ||||
B4 | 64/M | 60 |
LCVA/Broca’s | 10/15 | 17/30 | 8/15 | ||||
B5 | 55/F | 108 |
LCVA/Broca’s | 11/15 | 14/30 | 5/15 | ||||
B6 | 68/M | 120 |
LCVA/Broca’s | 9/15 | 11/30 | 5/15 | ||||
B7 | 59/F | 96 |
LCVA/Broca’s | 12/15 | 12/30 | 10/15 | ||||
B8 | 63/M | 108 |
LCVA/Broca’s | 12/15 | 20/30 | 5/15 | ||||
B9 | 66/M | 60 |
LCVA/Broca’s | 14/15 | 14/30 | 8/15 | ||||
B10 | 55/F | 72 |
LCVA/Broca’s | 15/15 | 11/30 | 5/15 | ||||
SC, verbal | B1 | LCVA/Broca’s | 3/15 | 10/15 | 7/15 | |||||
B2 | LCVA/Broca’s | 5/15 | 8/15 | 8/15 | ||||||
B3 | LCVA/Broca’s | 10/15 | 8/15 | 9/15 | ||||||
B4 | LCVA/Broca’s | 5/15 | 9/15 | 10/15 | ||||||
B5 | LCVA/Broca’s | 7/15 | 10/15 | 7/15 | ||||||
B6 | LCVA/Broca’s | 8/15 | 7/15 | 7/15 | ||||||
B7 | LCVA/Broca’s | 8/15 | 5/15 | 8/15 | ||||||
B8 | LCVA/Broca’s | 8/15 | 8/15 | 9/15 | ||||||
B9 | LCVA/Broca’s | 3/15 | 9/15 | 8/15 | ||||||
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Fyndanis et al. (2012), page 1140 (Table 4) [ |
Greek | SC, verbal | GT | 44/M | 4.5 | LCVA/agrammatic | 8/21 | 12/16 | 12/19 | |
GL | 59/M | 38 | LCVA/agrammatic | 2/21 | 8/16 | 9/19 | ||||
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Jonkers and de Bruin (2009), page 1265 (Appendix 2) [ |
Dutch | SC, verbal | B1 | 80/M | 26 | NR/Broca’s | 16/20 | 14/20 | ||
B2 | 70/M | 12 | NR/Broca’s | 2/20 | 16/20 | |||||
B3 | 41/F | 4 | NR/Broca’s | 10/20 | 19/20 | |||||
B4 | 55/M | 3 | NR/Broca’s | 19/20 | 19/20 | |||||
B5 | 41/M | 49 | NR/Broca’s | 5/20 | 2/20 | |||||
B6 | 78/M | 42 | NR/Broca’s | 11/20 | 20/20 | |||||
B7 | 41/F | 4 | NR/Broca’s | 16/20 | 13/20 | |||||
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Nanousi et al. (2006), pages 220, 223, and 226 (Tables 6, 8, and 10) [ |
Greek | SPP, verbal | DS | 66/M | 48 |
LCVA/Broca’s | 31/60 | 25/60 | 15/30 | |
PA | 61/M | 48 |
LCVA/Broca’s | 29/60 | 32/60 | 13/30 | ||||
ZA | 41/M | 36 |
LCVA/Broca’s | 25/60 | 19/60 | 9/30 | ||||
AS | 38/M | 96 |
LCVA/Broca’s | 28/60 | 28/60 | 15/30 | ||||
AJ | 55/M | 72 |
LCVA/Broca’s | 23/60 | 19/60 | 10/30 | ||||
RS | 46/M | 108 |
LCVA/Broca’s | 25/60 | 25/60 | 12/30 | ||||
SPP, verbal | DS | LCVA/Broca’s | 19/60 | 21/60 | ||||||
PA | LCVA/Broca’s | 23/60 | 32/60 | |||||||
ZA | LCVA/Broca’s | 11/60 | 20/60 | |||||||
AS | LCVA/Broca’s | 23/60 | 33/60 | |||||||
AJ | LCVA/Broca’s | 2/60 | 18/60 | |||||||
RS | LCVA/Broca’s | 15/60 | 25/60 | |||||||
SC, verbal | DS | LCVA/Broca’s | 26/48 | 34/48 | 13/24 | |||||
PA | LCVA/Broca’s | 34/48 | 35/48 | 11/24 | ||||||
ZA | LCVA/Broca’s | 25/48 | 27/48 | 12/24 | ||||||
AS | LCVA/Broca’s | 30/48 | 32/48 | 16/24 | ||||||
AJ | LCVA/Broca’s | 26/48 | 30/48 | 10/24 | ||||||
RS | LCVA/Broca’s | 29/48 | 27/48 | 14/24 | ||||||
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Wenzlaff and Clahsen (2004), page 64 (Table 4) [ |
German | SC, verbal | DB | 58/F | 276 |
LCVA/Broca’s | 14/20 | 14/20 | ||
EL | 49/F | 264 |
LCVA/Broca’s | 19/20 | 14/20 | |||||
KM | 84/F | 24 |
LCVA/Broca’s | 12/20 | 17/20 | |||||
MH | 59/M | 180 |
LCVA/Broca’s | 12/20 | 15/20 | |||||
HM | 66/M | 144 |
LCVA/Broca’s | 17/20 | 13/20 | |||||
WH | 70/M | 192 |
LCVA/Broca’s | 8/20 | 17/20 | |||||
OP | 69/M | 24 |
LCVA/Broca’s | 12/20 | 7/20 | |||||
GJ, verbal | DB | LCVA/Broca’s | 10/20 | 10/20 | ||||||
EL | LCVA/Broca’s | 10/20 | 10/20 | |||||||
KM | LCVA/Broca’s | 12/20 | 11/20 | |||||||
MH | LCVA/Broca’s | 12/20 | 11/20 | |||||||
HM | LCVA/Broca’s | 18/20 | 17/20 | |||||||
WH | LCVA/Broca’s | 10/20 | 10/20 | |||||||
OP | LCVA/Broca’s | 10/20 | 10/20 |
GJ: grammaticality judgment; LCVA: left cerebrovascular accident; MPO: months post onset; NR: not reported; RCVA: right cerebrovascular accident; SC: sentence completion; SPP: sentence production priming; SPPi: sentence production with picture description; TBI: traumatic brain injury;
Analysis of variance revealed statistically significant main effects of sentence type (
In order to more precisely examine tense differences for each task, four separate ANOVAs were computed for each task. An a priori decision was made to use a more conservative
To summarize, the analysis of 143 published datasets revealed an effect of task on overall accuracy: sentence production with pictures yields significantly lower accuracy than the other three experimental tasks. While there was consistent superiority for neutral sentences over tensed sentences, the differences between past, present, and future sentences were inconsistent across tasks and primarily driven by the sentence production priming task.
In order to further inform our understanding of how persons with agrammatic aphasia are affected by verb tense, we examined previously acquired data from participants reported in our prior studies [
Sixteen participants (10 men, 6 women) with a medical history of left cerebrovascular accident were included in the study. The participants ranged in age from 39 to 70 years (mean = 54.06) and, at the time of testing, and ranged from 14 to 163 months from onset of their left hemisphere damage (mean = 52.56). All participants were native speakers of English and premorbidly right-handed (except AP10 who was left-handed). None of the participants reported a history of any significant speech-language, psychiatric, or neurological diagnoses prior to the onset of left hemisphere damage. Demographic and language profiles of all sixteen participants are reported in Table
Demographic and language data of participants in the sentence production task.
Patient | Age, gender, hand | Educ. years | MPO | Western Aphasia Battery-Revised | Narrative speech analysis | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Aphasia | AQ | Spont. Speech | Compr. | Naming | WPM | MLU | Prop. Sent. | Prop. Gram. Sent. | Open : Closed | Noun : Verb | ||||
AP1 | 59/M/R | 24 | 29 | Broca’s | 66.8 | 13 | 7.6 | 6.4 | 39.04 | 4.08 | 0.43 | 0.11 | 1.09 | 0.96 |
AP3 | 65/M/R | 17 | 73 | Broca’s | 65.9 | 11 | 8.8 | 6.1 | 24.67 | 5.76 | 0.52 | 0.31 | 1.15 | 1.7 |
AP5 | 64/F/R | 19 | 75 | Broca’s | 57.2 | 11 | 7.6 | 5.3 | 48.24 | 2.78 | 0.52 | 0.35 | 2.29 | 2.75 |
AP6 | 70/F/R | 17 | 163 | Broca’s | 65.9 | 14 | 6.35 | 7.8 | 53.44 | 3.68 | 0.22 | 0.1 | 1.26 | 5.25 |
AP8 | 55/F/R | 17 | 114 | Mixed | 90.4 | 18 | 10 | 8.6 | 34.41 | 5.88 | 0.84 | 0.57 | 1.07 | 2.06 |
AP9 | 56/M/R | 14 | 23 | Broca’s | 83.6 | 15 | 9.5 | 7 | 60.3 | 5.89 | 0.8 | 0.63 | 0.9 | 1.87 |
AP10 | 40/M/L | 18 | 115 | Broca’s | 77.4 | 14 | 8.5 | 8.4 | 29.19 | 3.83 | 0.48 | 0.5 | 1.35 | 1.93 |
AP12 | 61/M/R | 16 | 15 | Broca’s | 57.2 | 11 | 6.6 | 6.5 | 68 | 5.4 | 0.76 | 0.36 | 0.67 | 0.61 |
AP14 | 44/M/R | 19 | 14 | Broca’s | 71.6 | 13 | 9.3 | 7.6 | 32.56 | 1.95 | 0.2 | 0 | 5 | 1.41 |
AP15 | 55/M/R | 13 | 16 | Mixed | 80.5 | 13 | 9.45 | 8.6 | 75.82 | 3.41 | 0.36 | 0.39 | 1.8 | 4.23 |
AP17 | 44/F/R | 17 | 15 | Mixed | 45.4 | 7 | 6.3 | 6 | 11.11 | 1.67 | 0.1 | 0 | 58 | 6.57 |
AP18 | 39/M/R | 18 | 26 | Broca’s | 71.8 | 13 | 6.8 | 8.5 | 36 | 3.16 | 0.36 | 0.5 | 1.1 | 5 |
AP19 | 55/M/R | 19 | 14 | Broca’s | 61.8 | 11 | 9.2 | 6.5 | 23.12 | 1.64 | 0.1 | 0 | 4.07 | 3.67 |
AP23 | 47/M/R | 12 | 33 | Broca’s | 68.8 | 11 | 7.9 | 7.1 | 13.76 | 2.68 | 0.18 | 0.44 | 1.18 | 1.79 |
AP24 | 62/F/R | 15 | 61 | Broca’s | 61.2 | 12 | 6.25 | 5.6 | 28.09 | 2.93 | 0.5 | 0.16 | 2.3 | 2.47 |
AP26 | 49/F/R | 14 | 55 | Mixed | 80.3 | 15 | 9.05 | 8.5 | 31.63 | 31.24 | 0.1 | 0 | 6.1 | 5.5 |
AQ: aphasia quotient (max = 100); Compr.: comprehension score (max = 10), Noun : Verb: ratio of nouns to verbs; MLU: mean length of utterance in words; MPO: months post onset, Open : Closed: ratio of open to closed class words; Prop. Gram. Sent.: proportion of grammatically accurate sentences; Prop. Sent.: proportion of sentences; Spont. Speech: spontaneous speech; WPM: words per minute.
All participants were given a battery of speech and language tests and screening for hearing, visual, and cognitive status. This included elicitation of narratives of the cookie theft picture and selected narrative story cards [
The stimuli consisted of twenty black and white line drawings of transitive (
Responses were transcribed by the experimenter during the session and later scored for accuracy. The final self-corrected response was scored as correct if it unambiguously matched the target tense elicited by the appropriate adverb. Hence, a response such as “
One-way analysis of variance found no main effect of tense (mean (SD) present = 0.22 (0.19), past = 0.19 (0.29), and future = 0.30 (0.43),
Individual tense accuracy data for sentence production task.
Participant | Past | Present | Future | |
---|---|---|---|---|
Simple | Progressive | |||
AP1 | 0.4 | 0.8 | 0.0 | 0.0 |
AP3 | 0.0 | 0.0 | 0.2 | 1.0 |
AP5 | 0.0 | 0.0 | 0.0 | 0.0 |
AP6 | 0.0 | 0.0 | 0.0 | 1.0 |
AP8 | 0.6 | 0.0 | 0.6 | 0.2 |
AP9 | 1.0 | 0.0 | 0.2 | 0.0 |
AP10 | 0.0 | 0.3 | 0.0 | 1.0 |
AP12 | 0.2 | 0.0 | 0.4 | 0.0 |
AP14 | 0.0 | 0.0 | 0.8 | 0.4 |
AP15 | 0.0 | 0.0 | 1.0 | 0.0 |
AP17 | 0.0 | 0.0 | 0.6 | 0.2 |
AP18 | 0.2 | 0.0 | 0.0 | 0.0 |
AP19 | 0.0 | 0.0 | 0.2 | 1.0 |
AP23 | 0.4 | 0.4 | 0.2 | 0.0 |
AP24 | 0.2 | 0.0 | 0.0 | 0.0 |
AP26 | 0.0 | 0.6 | 0.6 | 0.0 |
|
||||
Mean (SD) | 0.19 (0.28) | 0.22 (0.3) | 0.30 (0.4) |
Distribution of errors for each participant in the sentence production task.
Participant | Incorrect tense | Unmarked | Others | Total errors |
---|---|---|---|---|
AP1 | 7 | 7 | 0 | 14 |
AP3 | 0 | 13 | 1 | 14 |
AP5 | 0 | 19 | 1 | 20 |
AP6 | 0 | 14 | 1 | 15 |
AP8 | 4 | 8 | 1 | 13 |
AP9 | 12 | 1 | 1 | 14 |
AP10 | 4 | 3 | 0 | 7 |
AP12 | 5 | 9 | 3 | 17 |
AP14 | 0 | 10 | 4 | 14 |
AP15 | 0 | 15 | 0 | 15 |
AP17 | 0 | 15 | 1 | 16 |
AP18 | 2 | 16 | 1 | 19 |
AP19 | 0 | 11 | 3 | 14 |
AP23 | 3 | 9 | 3 | 15 |
AP24 | 1 | 17 | 1 | 19 |
AP26 | 0 | 14 | 0 | 14 |
The aim of this study was to further characterize the tense deficit in persons with agrammatic aphasia in terms of differential impairment across temporal reference and experimental task. This was achieved in two ways: by synthesizing the existing published evidence on tense deficits in 143 datasets of persons with agrammatic aphasia and by contributing new data from sixteen participants using a picture description task. The obvious advantage of analyzing a large dataset, as was done in this study, is to minimize the influence of different sources of variability arising in small group studies: individual variability which can skew group averages, language-specific morphosyntactic patterns, and the experimental manipulations (task instructions, stimuli) which could inadvertently impact one experimental condition. There were three main findings of the meta-analysis. First, the aphasic participants were significantly impaired in the experimental tasks, with an overall accuracy of just 47%. Second, we found a significant effect of experimental task on performance accuracy. Third, there was no striking accuracy difference with respect to temporal reference, but with one exception: only in the sentence production priming task was the past tense worse than present and future tenses (by 12 and 14 percent, resp.). The new data from picture description found no difference among tense types, replicating the findings of the meta-analysis. In the following sections, we will consider the question of between-tense differences, followed by a discussion of the current understanding of verb tense impairment in agrammatism.
As outlined in the Introduction, there were two compelling reasons to predict worse performance on past and future tense compared to present tense for agrammatic aphasic speakers. The first is a divergence between speaking time and reference time for past and future, but not present tense (Table
Findings of the meta-analysis showing mean proportion accuracy sorted by tense and experimental task. The number of datasets for each tense is
An example of a picture sequence used to elicit different tenses. The picture shows the action “folding.” The action is about to begin in the first (future), ongoing in the second (present), and completed in the third (past) picture of the sequence.
The reason for the past tense disadvantage specifically in the sentence production priming task is unclear [
Collective data from 122 persons with agrammatic aphasia (PWAA) analyzed in this study show (1) an overwhelming difficulty in production and processing of verb tense, (2) individual differences in accuracy of different tenses (see the appendix and Table
Numerous theoretical accounts over the past two decades suggest a difficulty in the semantics to morphosyntax interface as the most parsimonious account of verb tense deficits of agrammatism. These include a distinction between interpretable and uninterpretable syntactic features [
The second noteworthy point of verb tense performance is the intraindividual variability across tense types; that is, many PWAA’s accuracy was widely different across tenses (e.g., JS scored 0.3 and 0.8 for past and present tense, [
Finally, we found a robust effect of task difficulty on accuracy, with significantly worse performance on overt production (sentence production priming and sentence production with pictures) compared to selection (grammaticality judgment and sentence completion). This task differential is consistent with the computational accounts of agrammatism proposed by Avrutin [
The data accrued from this study and the past three decades of agrammatism research emphasize that difficulties in processing and producing verb tense are best considered as one of the crucial components of the symptom profile of agrammatism. While mapping of conceptual-semantic representations onto morphosyntax for tense marking is particularly challenging, this is likely to be mediated by processing limitations and accessibility of specific verb forms. At present, there is little evidence of a differential tense impairment; however, future research specifically aimed at examining double dissociations in individual participants and the effect of stimulus manipulations may shed more light on tense differentials. It is also crucial to establish whether a disadvantage for temporally complete events is a general pattern found across several populations or is a core characteristic of agrammatic aphasia, because a parsimonious theory of agrammatism really needs to account for symptoms that are unique to the condition. Data from other populations indicate that the disadvantage for past events is not unique to agrammatism and is found in healthy adults and children, fluent aphasia, and specific language impairment [
Findings from this study were presented at the 2013 Academy of Aphasia Conference in Lucerne, Switzerland.
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors thank Melissa Stockbridge for assistance with data scoring and coding.