Lesion loci of impaired affective prosody: A systematic review of evidence from stroke

Perceiving and misperceiving speech: lexical and sublexical processing in the superior temporal lobes

Listeners can use prior knowledge to predict the content of noisy speech signals, enhancing perception. However, this process can also elicit misperceptions. For the first time, we employed a prime-probe paradigm and transcranial magnetic stimulation to investigate causal roles for the left and right posterior superior temporal gyri (pSTG) in the perception and misperception of degraded speech. Listeners were presented with spectrotemporally degraded probe sentences preceded by a clear prime. To produce misperceptions, we created partially mismatched pseudo-sentence probes via homophonic nonword transformations (e.g. The little girl was excited to lose her first tooth-Tha fittle girmn wam expited du roos har derst cooth). Compared to a control site (vertex), inhibitory stimulation of the left pSTG selectively disrupted priming of real but not pseudo-sentences. Conversely, inhibitory stimulation of the right pSTG enhanced priming of misperceptions with pseudo-sentences, but did not influence perception of real sentences. These results indicate qualitatively different causal roles for the left and right pSTG in perceiving degraded speech, supporting bilateral models that propose engagement of the right pSTG in sublexical processing.

Apragmatism: The renewal of a label for communication disorders associated with right hemisphere brain damage

BACKGROUND

Right hemisphere communication disorders are neither consistently labelled nor adequately defined. Labels associated with right hemisphere brain damage (RHD) are broad and fail to capture the essence of communication challenges needed for stroke-related service provisions. Determination of rehabilitation needs and best-practice guidelines for the education, management and functional improvement of communication disorders after RHD are all predicated on an apt diagnostic label and disorder characteristics.

AIMS

In this paper apragmatism is proposed as a potential communication-specific diagnostic label for the impairments in communication that occur after RHD. In particular, the researchers aimed: (1) to establish an operational definition of apragmatism; and (2) to describe the linguistic, paralinguistic and extralinguistic communication deficits under the umbrella term apragmatism.

METHODS & PROCEDURES

An international collaborative of researchers with expertise in RHD followed a multilevel approach to consider the utility of apragmatism as a diagnostic label. Adopting the relational approach to concept mapping, the researchers engaged in a series of group meetings to complete four levels of mapping: (1) identify and review, (2) define, (3) expert discussion and (4) label determination.

MAIN CONTRIBUTION

Apragmatism was established as a suitable diagnostic label for the impairments in communication associated with RHD. The paper offers an operational definition and description of the linguistic, paralinguistic and extralinguistic features of apragmatism through evidence summaries and examples from people with RHD retrieved from the RHDBank.

CONCLUSIONS & IMPLICATIONS

The adoption of the term apragmatism offers an opportunity to capture the hallmark of RHD communication deficits. The use of the term is recommended when referencing the pragmatic language impairments in this population. Apragmatism, which may co-occur with or be exacerbated by cognitive impairments, can interfere with the ability to interpret and convey intended meaning and impact the lives of right hemisphere stroke survivors and their families.

WHAT THIS PAPER ADDS

What is already known on the subject RHD results in a heterogeneous group of deficits that range in cognitive-communicative complexity. Many of the deficits are subsumed under pragmatics. For example, adults with RHD may demonstrate tangential or verbose communication, insensitivity to others' needs and feelings, prosodic changes, minimal gesture use and facial expression, and more. While descriptions of pragmatic impairments pervade the literature, there is no consistently used diagnostic label. The clinical consequences of this absence include difficulty with inter- and intra-disciplinary communication about these patients, difficulty consolidating findings across research studies, and challenges in communicating about these pragmatic changes with patients, families and other stakeholders. What this paper adds to existing knowledge The term apragmatism is proposed as a diagnostic label to consistently describe pragmatic communication changes after RHD. Apragmatism is characterized using three components of pragmatics: linguistic, paralinguistic and extralinguistic. Descriptions and examples of these three components are provided with supplemental transcripts retrieved from the RHDBank. What are the potential or actual clinical implications of this work? Adoption of the term apragmatism by speech and language therapists and other medical and rehabilitation professionals has the potential to provide consistency in describing the abilities and challenges experienced by people following a right hemisphere stroke. Such improvements may help drive the development of evidence-based assessments and treatments for this population.

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.

Left Hemisphere Bias of NIH Stroke Scale Is Most Severe for Middle Cerebral Artery Strokes

NIHSS score is higher for left vs. right hemisphere strokes of equal volumes. However, differences in each vascular territory have not been evaluated yet. We hypothesized that left vs. right differences are driven by the middle cerebral artery (MCA) territory, and there is no difference between hemispheres for other vascular territories. This study is based on data from 802 patients with evidence of acute ischemic stroke in one major arterial territory (MCA, n = 437; PCA, n = 209; ACA, n = 21; vertebrobasilar, n = 46). We examined differences in patients with left or right strokes regarding to lesion volume, NIHSS, and other covariates (age, sex, race). We used linear models to test the effects of these covariates on NIHSS. We looked at the whole sample as well as in the sample stratified by NIHSS (≤5 or >5) and by lesion location (MCA or PCA). Patients with left MCA strokes had significantly higher NIHSS than those with right strokes. Only patients with MCA strokes showed NIHSS score affected by the hemisphere when controlling for stroke volume and patient's age. This difference was driven by the more severe strokes (NIHSS>5). It is important to consider this systematic bias in the NIHSS when using the score for inclusion criteria for treatment or trials. Patients with right MCA stroke may be under-treated and left with disabling deficits that are not captured by the NIHSS.

The neurologist who could not stop rhyming and rapping

.A neurologist, at age 55, developed an irrepressible urge to rhyme after a series of strokes and seizures. His strokes included right posterior cerebellar and right thalamic infarctions, and his subsequent focal-onset seizures emanated from the left frontotemporal region. On recovery, he described the emergence of an irresistible urge to rhyme, even in thought and daily speech. His pronounced focus on rhyming led him to actively participate in freestyle rap and improvisation. This patient's rhyming and rapping may have been initially facilitated by epileptiform activation of word sound associations but perpetuated as compensation for impaired cerebellar effects on timed anticipation.

Psychiatric sequelae of stroke affecting the non-dominant cerebral hemisphere

There are a plethora of cognitive sequelae in addition to neglect and extinction that arise with unilateral right hemispheric stroke (RHS). Cognitive deficits following non-dominant (right) hemisphere stroke are common with unilateral neglect and extinction being the most recognized examples. The severity of RHS is usually underestimated by the National Institutes of Health Stroke Scale (NIHSS), which in terms of lateralized right hemisphere cognitive deficits, tests only for visual inattention/extinction. They account for 2 out of 42 total possible points. Additional neuropsychiatric sequelae include but are not limited to deficiencies in affective prosody comprehension and production (aprosodias), understanding and expressing facial emotions, empathy, recognition of familiar faces, anxiety, mania, apathy, and psychosis. These sequelae have a profound impact on patients' quality of life; affecting communication, interpersonal relationships, and the ability to fulfill social roles. They also pose additional challenges to recovery. There is presently a gap in the literature regarding a cohesive overview of the significant cognitive sequelae following RHS. This paper serves as a narrative survey of the current understanding of the subject, with particular emphasis on neuropsychiatric poststroke syndromes not predominantly associated with left hemisphere lesions (LHL), bilateral lesions, hemiplegia, or paralysis. A more comprehensive understanding of the neuropsychological consequences of RHS extending beyond the typical associations of unilateral neglect and extinction may have important implications for clinical practice, including the ways in which clinicians approach diagnostics, treatment, and rehabilitation.