Aligning sentence structures in dialogue: evidence from aphasia

TelePriming sentence production in aphasia

Background

The application of videoconferencing to the assessment and treatment of aphasia has been rapidly increasing; however, there is a need to develop treatments targeting sentence production in persons with aphasia (PWA) that can be delivered through videoconferencing. Structural priming has received recent attention as a potential training method for PWA. We investigated the feasibility and efficacy of a collaborative structural priming task delivered via the internet, TelePriming, in facilitating sentence production in PWA and healthy adults.

Method

In Study 1, young adults (YA), older adults (OA), and PWA participated in a collaborative dialogue-like priming task through videoconferencing, taking turns with an interlocutor (experimenter) to describe transitive action pictures with the goal of finding matching pictures. We measured whether participants produced more passive sentences to describe their picture after hearing their interlocutor produce passive compared to active sentences (primes). In Study 2, we compared the data from the OA and PWA of Study 1 (TelePriming) to different groups of OA and PWA, who completed the same priming task in person.

Results

All three groups showed robust priming effects in Study 1, producing more passive sentences to describe target pictures after hearing the experimenter produce passive versus active sentences. In Study 2, when controlling for demographic information (age, education) and aphasia severity, TelePriming resulted in larger priming effects for OA and PWA, compared to the in-person priming task. Survey results revealed that both OA and PWA experienced increased comfort and satisfaction with using technology following the task.

Conclusion

Interactive message-structure alignment processes remain largely intact in PWA, and the positive effects of structural priming in a collaborative communicative task are not diminished by remote delivery. The findings demonstrate the feasibility and validity of TelePriming in OA and PWA, laying experimental groundwork for future use of TelePriming in the assessment and treatment of clinical populations with limited access to face-to-face sessions.

Structural priming from production to comprehension in aphasia

Background

Many people with aphasia (PWA) show deficits in sentence production and comprehension, in part, due to an inefficient mapping between messages and syntactic structures. Structural priming-the tendency to repeat previously encountered sentence structures-has been shown to support implicit syntactic learning within and across production and comprehension modalities in healthy adults. Structural priming is also effective in facilitating sentence production and comprehension in PWA. However, less is known about whether priming in one modality changes PWA's performance in the other modality, crucial evidence needed for applying structural priming as a cost-effective intervention strategy for PWA.

Aims

This study examined (a) whether production to comprehension cross-modality priming is effective in PWA, (b) whether priming-induced changes in syntactic comprehension lasted in the absence of an immediate prime, and (c) whether there is a significant correlation between individuals' priming effects and the change in their comprehension following priming.

Methods & Procedures

Thirteen PWA and 13 age-matched control participants completed a pre-test, a production-to-comprehension priming block, and a post-test. In the pre- and post-tests, participants completed a sentence-picture matching task with sentences involving interpretations of an ambiguous prepositional phrase (e.g., The teacher is poking the monk with a bat). Participants were free to choose a picture corresponding to a high attachment (HA; e.g., the teacher is using the bat to poke the monk) or a low attachment (LA; e.g., the monk is holding the bat) interpretation. In the priming block, participants produced LA sentences as primes and then completed a sentence-picture matching task for comprehension targets, similar to the pre-test.

Results

Age-matched controls and PWA showed a significant priming effect when comparing the priming block to the pre-test. In both groups, the priming effect persisted when comparing picture selections in the pre- and post-tests. At the individual level, age-matched controls who showed larger priming effects also selected more LA pictures in the post-test compared to the pre-test, indicating that the priming effect accounted for the magnitude of change from the pre- to post-test. This correlation was also found in PWA.

Conclusions

These findings suggest that production-to-comprehension structural priming is effective and persistent in PWA and controls, in line with the view that structural priming is a form of implicit learning. Further, the findings suggest that syntactic representations are shared between modalities, and therefore, production influences future comprehension. Cross-modality structural priming may have clinical potential to improve sentence processing in PWA.

Priming Sentence Production in Older Adults: Evidence for Preserved Implicit Learning

Purpose

Structural priming- speakers' unconscious tendency to echo previously encountered message-structure mappings - is thought to reflect the processes of implicit language learning that occur throughout the lifespan. Recently, structural priming has also been used as a means to facilitate language re-learning in age-related language disorders such as aphasia. However, little evidence is available on whether structural priming remains effective in healthy aging, limiting clinical translation of the structural priming paradigm. This study examined the impact of aging on the strength and longevity of abstract structural priming and lexical boost effects.

Method

Twenty-four young and 24 older adults participated in a collaborative picture-matching task where the participant and experimenter took turns describing picture cards using transitive and dative sentences. In Experiment 1, a target was elicited immediately following a prime (0-lag), whereas two filler items were embedded between a prime and a target sentence in Experiment 2 (2-lag) to examine longer-term priming effects. In both experiments, the verb was repeated for half of the prime-target pairs to examine lexical boost on structural priming.

Results

At immediate priming, older adults showed both abstract structural priming and lexical boost in transitives and datives, similar to young adults. At longer-term priming, only abstract priming effects were significant in both groups of participants, with no evidence of age-related reduction in priming.

Conclusions

Both lexically-specific and independent mechanisms of structural priming remain resilient in older adults, supporting the view that structural priming reflects life-long language learning. Further, the findings provide empirical basis for applying structural priming to elderly clinical populations.

Effect of lexical accessibility on syntactic production in aphasia: An eyetracking study

PURPOSE

Healthy speakers use both word-level and structure-level information to ease sentence production processes. Structural priming facilitates message-structure mapping in aphasia. However, it remains unclear if and how word-level information affects off-line and on-line sentence production in persons with aphasia (PWA). This eyetracking-while-speaking study examined the effect of lexical priming on production of syntactic (active/passive) structures in PWA.

METHOD

Eleven PWA and twenty healthy older adults (HOA) described transitive actions (woman pulling horse) following lexical priming, wherein the relative ease of lexical retrieval for the Agent or Theme was manipulated via an auditory probe (what is happening with the woman/horse ?). It was examined whether or not PWA produce the sentence structure that allows earlier production of the primed word (e.g., passives when Theme was primed). Participants' eye fixation times to each character (Agent, Theme) were also monitored to examine if PWA show priming-induced preferential looks to one character from the earliest stage of production, consistent with word-driven planning.

RESULTS

HOA showed increased production of passives over actives in the Theme vs. Agent prime condition. In eye fixation data, HOA showed priming-induced Theme advantage from the earliest time window (picture onset-400 milliseconds). PWA also showed a significant priming effect in off-line sentence production, with this priming effect being greater for the individuals whose syntactic processing is better preserved. In eye fixation data, however, PWA showed preferential fixations to the primed character at a later stage of sentence planning (400-800 milliseconds), following equal fixation time to Agent and Theme during the earliest time window.

CONCLUSION

HOA showed word-driven production in both off-line and real-time (eye fixations) production. Lexical accessibility effectively drove off-line syntactic production in PWA, especially for those whose syntactic capacity remains relatively preserved. However, PWA showed advanced processing of both characters in earliest eye fixation data, suggesting that successful word-driven off-line syntactic production was associated with atypical real-time sentence planning in aphasia.

Effects of Verb Overlap on Structural Priming in Dialogue: Implications for Syntactic Learning in Aphasia

Purpose Although there is increasing interest in using structural priming as a means to ameliorate grammatical encoding deficits in persons with aphasia (PWAs), little is known about the precise mechanisms of structural priming that are associated with robust and enduring effects in PWAs. Two dialogue-like comprehension-to-production priming experiments investigated whether lexically independent (abstract structural) priming and/or lexically (verb) specific priming yields immediate and longer, lasting facilitation of syntactic production in PWAs. Method Seventeen PWAs and 20 healthy older adults participated in a collaborative picture-matching task where participant and experimenter took turns describing picture cards using transitive and dative sentences. In Experiment 1, a target was elicited immediately following a prime. In Experiment 2, 2 unrelated utterances intervened between a prime and target, thereby allowing us to examine lasting priming effects. In both experiments, the verb was repeated for half of the prime-target pairs to examine the lexical (verb) boost on priming. Results Healthy older adults demonstrated abstract priming in both transitives and datives not only in the immediate (Experiment 1) but also in the lasting (Experiment 2) priming condition. They also showed significantly enhanced priming by verb overlap (lexical boost) in transitives during immediate priming. PWAs demonstrated abstract priming in transitives in both immediate and lasting priming conditions. However, the magnitude of priming was not enhanced by verb overlap. Conclusions Abstract structural priming, but not lexically specific priming, is associated with reliable and lasting facilitation of message-structure mapping in aphasia. The findings also suggest that implicit syntactic learning via a dialogue-like comprehension-to-production task remains preserved in aphasia.

Priming sentence comprehension in aphasia: Effects of lexically independent and specific structural priming

PURPOSE

Impaired message-structure mapping results in deficits in both sentence production and comprehension in aphasia. Structural priming has been shown to facilitate syntactic production for persons with aphasia (PWA). However, it remains unknown if structural priming is also effective in sentence comprehension. We examined if PWA show preserved and lasting structural priming effects during interpretation of syntactically ambiguous sentences and if the priming effects occur independently of or in conjunction with lexical (verb) information.

METHODS

Eighteen PWA and 20 healthy older adults (HOA) completed a written sentence-picture matching task involving the interpretation of prepositional phrases (PP; the chef is poking the solider with an umbrella) that were ambiguous between high (verb modifier) and low attachment (object noun modifier). Only one interpretation was possible for prime sentences, while both interpretations were possible for target sentences. In Experiment 1, the target was presented immediately after the prime (0-lag). In Experiment 2, two filler items intervened between the prime and the target (2-lag). Within each experiment, the verb was repeated for half of the prime-target pairs, while different verbs were used for the other half. Participants' off-line picture matching choices and response times were measured.

RESULTS

After reading a prime sentence with a particular interpretation, HOA and PWA tended to interpret an ambiguous PP in a target sentence in the same way and with faster response times. Importantly, both groups continued to show this priming effect over a lag (Experiment 2), although the effect was not as reliable in response times. However, neither group showed lexical (verb-specific) boost on priming, deviating from robust lexical boost seen in the young adults of prior studies.

CONCLUSIONS

PWA demonstrate abstract (lexically-independent) structural priming in the absence of a lexically-specific boost. Abstract priming is preserved in aphasia, effectively facilitating not only immediate but also longer-lasting structure-message mapping during sentence comprehension.