Using prosody during sentence processing in aphasia: Evidence from temporal neural dynamics

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 13^th 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.

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.

Aprosodia Following Focal Brain Damage: What's Right and What's Left?

PURPOSE

Hemispheric specialization for the comprehension and expression of linguistic and emotional prosody is typically attributed to the right hemisphere. This study used techniques adapted from meta-analysis to critically examine the strength of existing evidence for hemispheric lateralization of prosody following brain damage.

METHOD

Twenty-one databases were searched for articles published from 1970 to 2020 addressing differences in prosody performance between groups defined by right hemisphere damage and left hemisphere damage. Hedges's g effect sizes were calculated for all possible prosody comparisons. Primary analyses summarize effects for four types: linguistic production, linguistic comprehension, emotion comprehension, and emotion production. Within each primary analysis, Hedges's g values were averaged across comparisons (usually from a single article) based on the same sample of individuals. Secondary analyses explore more specific classifications of comparisons.

RESULTS

Out of the 113 articles investigating comprehension and production of emotional and linguistic prosody, 62 were deemed appropriate for data extraction, but only 21 met inclusion criteria, passed quality reviews, and provided sufficient information for analysis. Evidence from this review illustrates the heterogeneity of research methods and results from studies that have investigated aprosodia. This review provides inconsistent support for selective contribution of the two cerebral hemispheres to prosody comprehension and production; however, the strongest finding suggests that right hemisphere lesions disrupt emotional prosody comprehension more than left hemisphere lesions.

CONCLUSION

This review highlights the impoverished nature of the existing literature; offers suggestions for future research; and highlights relevant clinical implications for the prognostication, evaluation, and treatment of aprosodia.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20334987.