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

Exploring generalisation following treatment of language deficits in aphasia can provide insights into the functional relation of the cognitive processing systems involved. In the present study, we first review treatment outcomes of interventions targeting sentence processing deficits and, second report a treatment study examining the occurrence of practice effects and generalisation in sentence comprehension and production. In order to explore the potential linkage between processing systems involved in comprehending and producing sentences, we investigated whether improvements generalise within (i.e., uni-modal generalisation in comprehension or in production) and/or across modalities (i.e., cross-modal generalisation from comprehension to production or vice versa). Two individuals with aphasia displaying co-occurring deficits in sentence comprehension and production were trained on complex, non-canonical sentences in both modalities. Two evidence-based treatment protocols were applied in a crossover intervention study with sequence of treatment phases being randomly allocated. Both participants benefited significantly from treatment, leading to uni-modal generalisation in both comprehension and production. However, cross-modal generalisation did not occur. The magnitude of uni-modal generalisation in sentence production was related to participants' sentence comprehension performance prior to treatment. These findings support the assumption of modality-specific sub-systems for sentence comprehension and production, being linked uni-directionally from comprehension to production.

A systematic review on production and comprehension of linguistic prosody in people with acquired language and communication disorders resulting from unilateral brain lesions.

BACKGROUND: Prosody serves central functions in language processing including linguistic functions (linguistic prosody), like structuring the speech signal. Impairments in production and comprehension of linguistic prosody have been described for persons with unilateral right (RHDP) or left hemisphere damage (LHDP). However, reported results differ with respect to the characteristics and severities of these impairments AIMS: We conducted a systematic literature review focusing on production and comprehension of linguistic prosody at the prosody-syntax interface (i.e., phrase or sentence level) in LHDP and RHDP. METHODS & PROCEDURES: In a systematic literature search we included: (i) empirical studies with (ii) adult RHDP and/or LHDP (iii) investigating production and/or comprehension of linguistic prosody at the (iv) phrase or sentence level (v) reporting quantitative data on prosodic measures. We excluded overview papers; studies involving participants with dysarthria, apraxia of speech, foreign accent syndrome, psychiatric diseases, and/or neurodegenerative diseases; studies focusing primarily on emotional prosody; and on lexical stress / word level; studies of which no full text was available and/or that were published in a language other than English. We searched the databases BIOSIS, MEDLINE, EMBASE, PubMed, Web of Science, CINAHL, Cochrane Library, PSYNDEX, PsycINFO and speechBITE, last searched on January 13th 2022.We found 2,631 studies without duplicates. We identified 43 studies which were included into our systematic review. For data extraction and synthesis of results, we grouped studies by (i) modality (production vs. comprehension), (ii) function (syntactic structure vs. information structure), and (iii) by experiment task. For production studies, outcome measures were defined as the productive use of the different prosodic cues (lengthening, pause, f0, amplitude). For comprehension studies, performance measures (accuracy and reaction times) were defined as outcome measures. In accordance with the PRISMA 2020 statement (Page et al., 2021), we conducted a quality check to assess study risk of bias. Our review was pre-registered with PROSPERO (CRD42019120308). OUTCOMES & RESULTS: Of the 43 studies reviewed, 30 studies involved RHDP (n = 309), assessing production in 15 studies and focusing on comprehension of prosody in 16 studies (one study investigated production and comprehension). LHDP (n = 438) were included in 35 studies of which 15 studied production and 21 evaluated comprehension of prosody (one study investigated production and comprehension). Despite the heterogeneity of results in the studies reviewed, our synthesis of results suggests that both LHDP and RHDP show limitations, but no complete impairment, in their production and/or comprehension of linguistic prosody. Prosodic limitations are evident in different areas of processing linguistic prosody, like syntactic disambiguation or the distinction between sentence types. There is a tendency towards more severe limitations in LHDP as compared to RHDP. CONCLUSIONS: We only included published studies into our review and did not perform an assessment of risk of reporting bias as well as systematic certainty assessments of the outcomes. Despite these limitations, we conclude that both groups show deficits in production and comprehension of linguistic prosody, but neither LHDP nor RHDP are completely impaired in their prosodic processing. This suggests that prosody is a relevant communicative resource for LHDP and RHDP worth being addressed in speech-language-therapy.

Individual Differences in Early Disambiguation of Prosodic Grouping.

Prosodic cues help to disambiguate incoming information in spoken language perception. In structurally ambiguous coordinate utterances, such as three-name sequences, the intended grouping is marked by three prosodic cues: F0-range, final lengthening, and pause. To indicate that the first two names are grouped together, speakers typically weaken the durational and tonal cues on the first name whereas they are strengthened on the second name, compared with a structure without internal grouping. The current study uses a gating paradigm to test whether listeners can decide about the internal grouping of a coordinate structure by already exploiting prosodic information on the first name. One hundred ninety-two stimuli were cut into seven parts (gates) and presented to naive participants (n = 45) successively (gate by gate) with increasing length of the utterance and amount of prosodic information. In a two-alternative forced-choice decision task, accuracy was above chance level after the second name. However, more than half of the participants could already reliably detect grouping patterns after the first name. These interindividual differences point toward the existence of different subgroups with diverging prosodic parsing strategies. Furthermore, listeners were sensitive to speaker-specific prosodic patterns. Depending on speaker-specific characteristics and individual parsing capacities, it seems possible-at least for a subgroup of listeners-to make predictions about the underlying grouping structure of coordinated name sequences based on early prosodic cues.

Production and Comprehension of Prosodic Boundary Marking in Persons With Unilateral Brain Lesions.

PURPOSE: Persons with unilateral brain damage in the right hemisphere (RH) or left hemisphere (LH) show limitations in processing linguistic prosody, with yet inconclusive results on their ability to process prosodically marked structural boundaries for syntactic ambiguity resolution. We aimed at systematically investigating production and comprehension of three prosodic cues (f 0 range, final lengthening, and pause) at structural boundaries in coordinate sequences in participants with right hemisphere brain damage (RHDP) and participants with left hemisphere brain damage (LHDP). METHOD: Twenty RHDP and 15 LHDP participated in our study. Comprehension experiment: Participants and a control group listened to coordinate name sequences with internal grouping by a prosodically marked structural boundary (grouped condition, e.g., "(Gabi und Leni) # und Nina") or without internal grouping (ungrouped condition, e.g., "Gabi und Leni und Nina") and had to identify the target condition. The strength and combinations of prosodic cues in the stimuli were manipulated. Production experiment: Participants were asked to produce coordinate sequences in the two conditions (grouped, ungrouped) in two different tasks: a Reading Aloud and a Repetition experiment. Accuracy of participants' productions was subsequently assessed in a rating study and productions were analyzed with respect to use of prosodic cues. RESULTS: In the Comprehension experiment, RHDP and LHDP had overall lower identification accuracies than unimpaired control participants and LHDP were found to have particular problems with boundary identification when the pause cue was reduced. In production, LHDP and RHDP employed all three prosodic cues for boundary marking, but struggled to clearly mark prosodic boundaries in 28% of all productions. Both groups showed better performance in reading aloud than in repetition. LHDP relied more on using f 0 range and pause duration to prosodically mark structural boundaries, whereas RHDP employed final lengthening more vigorously than LHDP in reading aloud. CONCLUSIONS: We conclude that processing of linguistic prosody is affected in RHDP and LHDP, but not completely impaired. Therefore, prosody can serve as a relevant communicative resource. However, it should also be considered as a target area for assessment and treatment in both groups. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21637505.

Judging the animacy of words: The influence of typicality and age of acquisition in a semantic decision task.

The age at which members of a semantic category are learned (age of acquisition), the typicality they demonstrate within their corresponding category, and the semantic domain to which they belong (living, non-living) are known to influence the speed and accuracy of lexical/semantic processing. So far, only a few studies have looked at the origin of age of acquisition and its interdependence with typicality and semantic domain within the same experimental design. Twenty adult participants performed an animacy decision task in which nouns were classified according to their semantic domain as being living or non-living. Response times were influenced by the independent main effects of each parameter: typicality, age of acquisition, semantic domain, and frequency. However, there were no interactions. The results are discussed with respect to recent models concerning the origin of age of acquisition effects.

A Computational Evaluation of Sentence Processing Deficits in Aphasia.

Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non-canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account (Grodzinsky, 1995, 2000, 2006) attributes this deficit to an impairment in syntactic representations, whereas others (e.g., Caplan, Waters, Dede, Michaud, & Reddy, 2007; Haarmann, Just, & Carpenter, 1997) propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent deficiency, and two versions of the Trace Deletion Hypothesis (TDH), in a computational framework for sentence processing (Lewis & Vasishth, 2005) implemented in ACT-R (Anderson, Byrne, Douglass, Lebiere, & Qin, 2004). The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence-picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser (2011). The data consist of offline (sentence-picture matching accuracies and response times) and online (eye fixation proportions) measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees.

Losing track of time? Processing of time reference inflection in agrammatic and healthy speakers of German.

BACKGROUND: Individuals with agrammatic aphasia (IWAs) have problems with grammatical decoding of tense inflection. However, these difficulties depend on the time frame that the tense refers to. Verb morphology with reference to the past is more difficult than with reference to the non-past, because a link needs to be made to the past event in discourse, as captured in the PAst DIscourse LInking Hypothesis (PADILIH; Bastiaanse, R., Bamyaci, E., Hsu, C., Lee, J., Yarbay Duman, T., Thompson, C. K., 2011. Time reference in agrammatic aphasia: A cross-linguistic study. J. Neurolinguist. 24, 652-673). With respect to reference to the (non-discourse-linked) future, data so far indicate that IWAs experience less difficulties as compared to past time reference (Bastiaanse, R., Bamyaci, E., Hsu, C., Lee, J., Yarbay Duman, T., Thompson, C. K., 2011. Time reference in agrammatic aphasia: A cross-linguistic study. J. Neurolinguist. 24, 652-673), supporting the assumptions of the PADILIH. Previous online studies of time reference in aphasia used methods such as reaction times analysis (e.g., Faroqi-Shah, Y., Dickey, M. W., 2009. On-line processing of tense and temporality in agrammatic aphasia. Brain Lang. 108, 97-111). So far, no such study used eye-tracking, even though this technique can bring additional insights (Burchert, F., Hanne, S., Vasishth, S., 2013. Sentence comprehension disorders in aphasia: the concept of chance performance revisited. Aphasiology 27, 112-125, doi:10.1080/02687038.2012.730603). AIMS: This study investigated (1) whether processing of future and past time reference inflection differs between non-brain-damaged individuals (NBDs) and IWAs, and (2) underlying mechanisms of time reference comprehension failure by IWAs. METHODS AND PROCEDURES: A visual-world experiment combining sentence-picture matching and eye-tracking was administered to 12 NBDs and 6 IWAs, all native speakers of German. Participants heard German sentences with periphrastic future ('will+V') or periphrastic past ('has+V-d') verb forms while they were presented with corresponding pictures on a computer screen. RESULTS AND DISCUSSION: NBDs scored at ceiling and significantly higher than the IWAs. IWAs had below-ceiling performance on the future condition, and both participant groups were faster to respond to the past than to the future condition. These differences are attributed to a pre-existing preference to look at a past picture, which has to be overcome. Eye movement patterns suggest that both groups interpret future time reference similarly, while IWAs show a delay relative to NBDs in interpreting past time reference inflection. The eye tracking results support the PADILIH, because processing reference to the past in discourse syntax requires additional resources and thus, is problematic and delayed for people with aphasia.