Training-induced improvement of noncanonical sentence production does not generalize to comprehension: evidence for modality-specific processes

Abstract

The presence or absence of generalization after treatment can provide important insights into the functional relationship between cognitive processes. The aim of the present study was to investigate the relationship between the cognitive processes that underlie sentence comprehension and production in aphasia. Using data from seven participants who took part in a case-series intervention study that focused on noncanonical sentence production [Stadie et al. (2008). Unambiguous generalization effects after treatment of noncanonical sentence production in German agrammatism. Brain and Language, 104, 211-229], we identified patterns of impairments and generalization effects for the two modalities. Results showed (a) dissociations between sentence structures and modalities before treatment, (b) an absence of cross-modal generalization from production to comprehension after treatment, and (c), a co-occurrence of spared comprehension before treatment and generalization across sentence structures within production after treatment. These findings are in line with the assumption of modality-specific, but interacting, cognitive processes in sentence comprehension and production. More specifically, this interaction is assumed to be unidirectional, allowing treatment-induced improvements in production to be supported by preserved comprehension.

Treatment of sentence comprehension and production in aphasia: is there cross-modal generalisation?

“…With respect to sentence comprehension, IWA often have difficulties in understanding semantically reversible non-canonical structures (object-beforesubject structures, such as object relative clauses, ORC) as opposed to canonical sentence types (subject-before-object order, such as subject relative clauses, SRC) (e.g., Caramazza & Zurif, 1976). Although IWA may show associated deficits, depicting sentence processing deficits in both sentence comprehension and production, performance may also dissociate between these two modalities (e.g., Caplan & Futter, 1986;Caramazza & Hillis, 1989;Caramazza & Miceli, 1991;Luzzatti et al, 2001;Martin & Blossom-Stach, 1986;Miceli, Mazzucchi, Menn, & Goodglass, 1983;Nespoulous et al, 1988;Schröder, Burchert, & Stadie, 2015). These cases of associated and dissociated deficits of comprehension and production form some of the data against which the question of syntactic processing components is assessed: Is there a single syntactic processing system shared by comprehension and production or does each modality draw back onto a modality-specific syntactic processing system, which can be selectively impaired (Caramazza & Hillis, 1989)?…”

Challenges in the use of treatment to investigate cognition

“…Either they used intervention to distinguish between two different theoretical positions (e.g. Schröder et al, 2015, this issue; Smith-Lock, 2015, this issue; Banales, Kohnen and McArthur, 2015, this issue) or they used a confirmatory approach to determine whether the outcome of intervention was consistent with the predictions of a particular theory (e.g. ; Best et al, 2015, this issue; Keane & Kiran, 2015, this issue).…”

“…Papers within this special issue represent examples of each (e.g., causal mechanisms: Banales et al, 2015, this issue; Best et al, 2015, this issue; Keane & Kiran, 2015, this issue; processes/representations: Schröder et al, 2015, this issue; Smith-Lock et al, 2015, this issue).…”

“…Two papers in this special issue use this generalisation “logic” for theory testing (Schröder et al, 2015, this issue; Smith-Lock, 2015, this issue). Schröder et al (2015, this issue) contrasted two hypotheses regarding sentence processing: The hypothesis that production and comprehension share processes or, alternatively, that they are independent.…”

“…Schröder et al (2015, this issue) contrasted two hypotheses regarding sentence processing: The hypothesis that production and comprehension share processes or, alternatively, that they are independent. The former predicts generalisation of treatment effects across modalities while the latter does not.…”