Effect of sentence length on the production of linguistic stress by left- and right-hemisphere-damaged patients

A targeted review of prosodic production in agrammatic aphasia

It is unclear whether individuals with agrammatic aphasia have particularly disrupted prosody, or in fact have relatively preserved prosody they can use in a compensatory way. A targeted literature review was undertaken to examine the evidence regarding the capacity of speakers with agrammatic aphasia to produce prosody. The aim was to answer the question, how much prosody can a speaker "do" with limited syntax? The literature was systematically searched for articles examining the production of grammatical prosody in people with agrammatism, and yielded 16 studies that were ultimately included in this review. Participant inclusion criteria, spoken language tasks, and analysis procedures vary widely across studies. The evidence indicates that timing aspects of prosody are disrupted in people with agrammatic aphasia, while the use of pitch and amplitude cues is more likely to be preserved in this population. Some, but not all, of these timing differences may be attributable to motor speech programming deficits (AOS) rather than aphasia, as these conditions frequently co-occur. Many of the included studies do not address AOS and its possible role in any observed effects. Finally, the available evidence indicates that even speakers with severe aphasia show a degree of preserved prosody in functional communication.

Speech error rates after a sports-related concussion

Background

Alterations in speech have long been identified as indicators of various neurologic conditions including traumatic brain injury, neurodegenerative diseases, and stroke. The extent to which speech errors occur in milder brain injuries, such as sports-related concussions, is unknown. The present study examined speech error rates in student athletes after a sports-related concussion compared to pre-injury speech performance in order to determine the presence and relevant characteristics of changes in speech production in this less easily detected neurologic condition.

Methods

A within-subjects pre/post-injury design was used. A total of 359 Division I student athletes participated in pre-season baseline speech testing. Of these, 27 athletes (18-22 years) who sustained a concussion also participated in speech testing in the days immediately following diagnosis of concussion. Picture description tasks were utilized to prompt connected speech samples. These samples were recorded and then transcribed for identification of errors and disfluencies. These were coded by two trained raters using a 6-category system that included 14 types of error metrics.

Results

Repeated measures analysis of variance was used to compare the difference in error rates at baseline and post-concussion. Results revealed significant increases in the speech error categories of pauses and time fillers (interjections/fillers). Additionally, regression analysis showed that a different pattern of errors and disfluencies occur after a sports-related concussion (primarily time fillers) compared to pre-injury (primarily pauses).

Conclusion

Results demonstrate that speech error rates increase following even mild head injuries, in particular, sports-related concussion. Furthermore, the speech error patterns driving this increase in speech errors, rate of pauses and interjections, are distinct features of this neurological injury, which is in contrast with more severe injuries that are marked by articulation errors and an overall reduction in verbal output. Future studies should consider speech as a diagnostic tool for concussion.

The Company Prosodic Deficits Keep Following Right Hemisphere Stroke: A Systematic Review

OBJECTIVES

The aim of this systematic review was to identify the presence and nature of relationships between specific forms of aprosodia (i.e., expressive and receptive emotional and linguistic prosodic deficits) and other cognitive-communication deficits and disorders in individuals with right hemisphere damage (RHD) due to stroke.

METHODS

One hundred and ninety articles from 1970 to February 2020 investigating receptive and expressive prosody in patients with relatively focal right hemisphere brain damage were identified via database searches.

RESULTS

Fourteen articles were identified that met inclusion criteria, passed quality reviews, and included sufficient information about prosody and potential co-occurring deficits. Twelve articles investigated receptive emotional aprosodia, and two articles investigated receptive linguistic aprosodia. Across the included studies, receptive emotional prosody was not systematically associated with hemispatial neglect, but did co-occur with deficits in emotional facial recognition, interpersonal interactions, or emotional semantics. Receptive linguistic processing was reported to co-occur with amusia and hemispatial neglect. No studies were found that investigated the co-occurrence of expressive emotional or linguistic prosodic deficits with other cognitive-communication impairments.

CONCLUSIONS

This systematic review revealed significant gaps in the research literature regarding the co-occurrence of common right hemisphere disorders with prosodic deficits. More rigorous empirical inquiry is required to identify specific patient profiles based on clusters of deficits associated with right hemisphere stroke. Future research may determine whether the co-occurrences identified are due to shared cognitive-linguistic processes, and may inform the development of evidence-based assessment and treatment recommendations for individuals with cognitive-communication deficits subsequent to RHD.

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.

Aprosodia Subsequent to Right Hemisphere Brain Damage: A Systematic Review and Meta-Analysis

OBJECTIVE

To identify which aspects of prosody are negatively affected subsequent to right hemisphere brain damage (RHD) and to evaluate the methodological quality of the constituent studies.

METHOD

Twenty-one electronic databases were searched to identify articles from 1970 to February 2020 by entering keywords. Eligibility criteria for articles included a focus on adults with acquired RHD, prosody as the primary research topic, and publication in a peer-reviewed journal. A quality appraisal was conducted using a rubric adapted from Downs and Black (1998).

RESULTS

Of the 113 articles appraised as eligible and appropriate for inclusion, 71 articles were selected to undergo data extraction for both meta-analyses of population effect size estimates and qualitative synthesis. Across all domains of prosody, the effect estimate was g = 2.51 [95% CI (1.94, 3.09), t = 8.66, p < 0.0001], based on 129 contrasts between RHD and non-brain-damaged healthy controls (NBD), indicating a significant random effects model. This effect size was driven by findings in emotional prosody, g = 2.48 [95% CI (1.76, 3.20), t = 6.88, p < 0.0001]. Overall, studies of higher quality (r_pb = 0.18, p < 0.001) and higher sample size/contrast ratio (r_pb = 0.25, p < 0.001) were more likely to report significant differences between RHD and NBD participants.

CONCLUSIONS

The results confirm consistent evidence for emotional prosody deficits in the RHD population. Inconsistent evidence was observed across linguistic prosody domains and pervasive methodological issues were identified across studies, regardless of their prosody focus. These findings highlight the need for more rigorous and sufficiently high-powered designs to examine prosody subsequent to RHD, particularly within the linguistic prosody domain.

Acoustic Measures of Prosody in Right-Hemisphere Damage: A Systematic Review and Meta-Analysis

Purpose The aim of the study was to use systematic review and meta-analysis to quantitatively assess the currently available acoustic evidence for prosodic production impairments as a result of right-hemisphere damage (RHD), as well as to develop methodological recommendations for future studies. Method We systematically reviewed papers reporting acoustic features of prosodic production in RHD in order to identify shortcomings in the literature and make recommendations for future studies. We estimated the meta-analytic effect size of the acoustic features. We extracted standardized mean differences from 16 papers and estimated aggregated effect sizes using hierarchical Bayesian regression models. Results RHD did present reduced fundamental frequency variation, but the trait was shared with left-hemisphere damage. RHD also presented evidence for increased pause duration. No meta-analytic evidence for an effect of prosody type (emotional vs. linguistic) was found. Conclusions Taken together, the currently available acoustic data show only a weak specific effect of RHD on prosody production. However, the results are not definitive, as more reliable analyses are hindered by small sample sizes, lack of detail on lesion location, and divergent measuring techniques. We propose recommendations to overcome these issues: Cumulative science practices (e.g., open data and code sharing), more nuanced speech signal processing techniques, and the integration of acoustic measures and perceptual judgments are recommended to more effectively investigate prosody in RHD.

Acute Ischemic Lesions Associated with Impairments in Expression and Recognition of Affective Prosody

PURPOSE

We aimed to: (a) review existing data on the neural basis of affective prosody;(b) test the hypothesis that there are double dissociations in impairments of expression and recognition of affective prosody; and (c) identify areas of infarct associated with impaired expression and/or recognition of affective prosody after acute right hemisphere (RH) ischemic stroke.

METHODS

Participants were tested on recognition of emotional prosody in content-neutral sentences. Expression was evaluated by measuring variability in fundamental frequency. Voxel-based symptom mapping was used to identify areas associated with severity of expressive deficits.

RESULTS

We found that 9/23 patients had expressive prosody impairments; 5/9 of these patients also had impaired recognition of affective prosody; 2/9 had selective deficits in expressive prosody; recognition was not tested in 2/9. Another 6/23 patients had selective impairment in recognition of affective prosody. Severity of expressive deficits was associated with lesions in right temporal pole; patients with temporal pole lesions had deficits in expression and recognition.

CONCLUSIONS

Expression and recognition of prosody can be selectively impaired. Damage to right anterior temporal pole is associated with impairment of both, indicating a role of this structure in a mechanism shared by expression and production of affective prosody.

Prosodic changes in aphasic speech: timing

Controversy remains about the impairment of prosody in aphasia, particularly with regard to speech timing. This paper addresses this topic through an analysis of timing in four sets of a common morphological paradigm. The paradigm consisted of a basic form (stem) and two longer derived forms (e.g. zip, zipper, zippering). Normally, vowel durations are shorter in longer derived forms (e.g. zippering) than in the stem (e.g. zip), due to a process called 'initial shortening'. Twelve patients with aphasia (four each Broca, Wernicke, and Anomic), and 11 age-matched healthy adults were assessed. Structural (CT) and functional brain imaging (PET) were available for all patients. While all groups showed initial shortening between the stem and the derived forms, the patients with Broca's aphasia presented an inverse pattern between the two derived forms (longer initial vowel in 'zippering' than 'zipper'), and the patients with Wernicke's aphasia produced significantly longer vowel durations overall than the healthy participants. The results are related to radiological information regarding the location of structural and functional brain damage and relative preservation and loss of prosodic features in cerebral damage.

Production of stress retraction by left- and right-hemisphere-damaged patients

An acoustic-perceptual investigation of a phonological phenomenon in which stress is retracted in double-stressed words (e.g., thirTEEN vs THIRteen MEN) was undertaken to identify the locus of functional impairments in speech prosody. Subjects included left-hemisphere-damaged (LHD) and right-hemisphere-damaged (RHD) patients and nonneurological controls. They were instructed to read sentences containing double-stressed target words in the presence of a clause boundary or its absence. Whereas all three groups of subjects were capable of manipulating the acoustic parameters that signal a shift in stress, there were some differences between the performance of the patient groups and that of the normal controls. Further, stress production deficits were more severe in LHD aphasic patients than in RHD patients. LHD speakers exhibited deficits in the control of both temporal and F0 cues. Their F0 disturbance appears to be secondary to a primary deficit in temporal control at the phase or sentence level, as an increased number of continuation rises found for the LHD patients seemed to arise from lengthy pauses within sentences. Findings are highlighted to address the nature of breakdown in speech prosody and the competing views of prosodic lateralization.

Gender and the integration of acoustic dimensions of prosody: implications for clinical studies

This study was conducted to detect the existence of a relationship between spectral and temporal prosodic cues and to examine gender differences in any such relationship. The rationale for the investigation was to gain a greater understanding of normal prosody and the requirements for control groups in clinical studies of prosody. Ten male and 10 female speakers with no known speech or neurological deficits participated in the study. They performed a reading task which involved delivering 10 sentences first with a declarative and then repeated with an interrogative intonation (20 sentences per speaker). Intrasubject and intersubject analyses of the speech data revealed a dependence of pitch on duration that differed between male and female speakers. Significant differences between the genders were also found in speech rate, pitch range, and pitch slope. The findings suggest that an integrated treatment of acoustic cues may provide a more invariant feature of normal prosody against which clinical groups may be compared. The data also imply that in clinical studies of the production of prosody gender should be carefully controlled.

Speech timing in Thai left- and right-hemisphere-damaged individuals

An acoustic analysis of syllable duration in short Thai phrases was conducted to evaluate the effects of focal brain damage on the control of speech timing. Almost all 35 of the subjects had participated in each of four previous companion studies: 13 left-brain-damaged (6 nonfluent aphasics; 7 fluent aphasics), 14 right-brain-damaged patients, and 8 normal controls. Somewhat surprisingly, results revealed relatively normal timing patterns in 3-syllable phrases in all subject groups. A comparison of the current study and the four others, however, led us to conclude that Thai-speaking nonfluent aphasics exhibit a speech timing deficit regardless of the linguistic level of representation, whereas timing deficits in fluent aphasics appear to be restricted to units larger than a syllable. Speech timing, on the other hand, appears to be intact across the board in right-brain-damaged individuals. Findings are brought to bear on theories of temporal control in brain-damaged patients.