Improving Functional Communication Outcomes in Post-Stroke Aphasia via Telepractice: An Alternative Service Delivery Model for Underserved Populations.

Many persons with aphasia (PWA) have limited access to speech-language treatment (SLT) due to limited funding, speech-language pathologist shortages, geographical barriers, physical disabilities, transportation barriers, and the COVID-19 pandemic. The purpose of this study was to determine if telepractice is an effective and feasible service delivery model for PWA. Ten PWA completed 8 hours of remote treatment over 4 weeks. Synchronous telepractice sessions employed Oral Reading for Language in Aphasia (ORLA) and Conversational Script Training (CST). Pre- and post-assessment outcome measures included the Communication Activities of Daily Living-3 (CADL-3) and the Communication Confidence Rating Scale for Aphasia (CCRSA). Participants completed a telepractice satisfaction survey following post-assessment. All participants demonstrated improvements in CCRSA scores, total words produced correctly on trained CST stimuli, and total words produced correctly on trained ORLA stimuli. No differences were noted in CADL-3 scores. All participants were highly satisfied with telepractice as a service delivery model.

Brain damage associated with apraxia of speech: evidence from case studies.

The site of crucial damage that causes acquired apraxia of speech (AOS) has been debated in the literature. This study presents five in-depth cases that offer insight into the role of brain areas involved in AOS. Four of the examined participants had a primary impairment of AOS either with (n = 2) or without concomitant mild aphasia (n = 2). The fifth participant presented with a lesion relatively isolated to the left anterior insula (AIns-L), damage that is rarely reported in the literature, but without AOS. Taken together, these cases challenge the role of the AIns-L and implicate the left motor regions in AOS.

Patterns of poststroke brain damage that predict speech production errors in apraxia of speech and aphasia dissociate.

BACKGROUND AND PURPOSE: Acquired apraxia of speech (AOS) is a motor speech disorder caused by brain damage. AOS often co-occurs with aphasia, a language disorder in which patients may also demonstrate speech production errors. The overlap of speech production deficits in both disorders has raised questions on whether AOS emerges from a unique pattern of brain damage or as a subelement of the aphasic syndrome. The purpose of this study was to determine whether speech production errors in AOS and aphasia are associated with distinctive patterns of brain injury. METHODS: Forty-three patients with history of a single left-hemisphere stroke underwent comprehensive speech and language testing. The AOS Rating Scale was used to rate speech errors specific to AOS versus speech errors that can also be associated with both AOS and aphasia. Localized brain damage was identified using structural magnetic resonance imaging, and voxel-based lesion-impairment mapping was used to evaluate the relationship between speech errors specific to AOS, those that can occur in AOS or aphasia, and brain damage. RESULTS: The pattern of brain damage associated with AOS was most strongly associated with damage to cortical motor regions, with additional involvement of somatosensory areas. Speech production deficits that could be attributed to AOS or aphasia were associated with damage to the temporal lobe and the inferior precentral frontal regions. CONCLUSIONS: AOS likely occurs in conjunction with aphasia because of the proximity of the brain areas supporting speech and language, but the neurobiological substrate for each disorder differs.

Optimizing estimation of hemispheric dominance for language using magnetic source imaging.

The efficacy of magnetoencephalography (MEG) as an alternative to invasive methods for investigating the cortical representation of language has been explored in several studies. Recently, studies comparing MEG to the gold standard Wada procedure have found inconsistent and often less-than accurate estimates of laterality across various MEG studies. Here we attempted to address this issue among normal right-handed adults (N=12) by supplementing a well-established MEG protocol involving word recognition and the single dipole method with a sentence comprehension task and a beamformer approach localizing neural oscillations. Beamformer analysis of word recognition and sentence comprehension tasks revealed a desynchronization in the 10-18Hz range, localized to the temporo-parietal cortices. Inspection of individual profiles of localized desynchronization (10-18Hz) revealed left hemispheric dominance in 91.7% and 83.3% of individuals during the word recognition and sentence comprehension tasks, respectively. In contrast, single dipole analysis yielded lower estimates, such that activity in temporal language regions was left-lateralized in 66.7% and 58.3% of individuals during word recognition and sentence comprehension, respectively. The results obtained from the word recognition task and localization of oscillatory activity using a beamformer appear to be in line with general estimates of left hemispheric dominance for language in normal right-handed individuals. Furthermore, the current findings support the growing notion that changes in neural oscillations underlie critical components of linguistic processing.

Time course of electromagnetic activity associated with detection of rare events.

The neural origins of the cortical response to rare sensory events remain poorly understood. Using simultaneous event-related potentials and magnetic resonance imaging, we investigated the anatomical profile of regional activity at various processing stages during performance of auditory and visual variants of an oddball paradigm. The earliest rarity-detection response was found in sensory-specific cortices, rapidly spreading to tertiary association areas, mesial temporal and frontal cortices by 150-200 ms. P3m-related activity was not found in sensory-specific cortices. On the basis of the anatomic distribution of P3m-related activity, this component is likely to reflect more generalized cognitive abilities hosted by association cortical regions.

Evidence for the solidarity of the expressive and receptive language systems: a retrospective study.

A strong tendency toward left hemisphere (LH) language dominance has been well established, as evidenced by the high prevalence of language impairment following sudden onset lesions in the LH. In the presence of progressive LH pathology, such as epilepsy, substantial deviations in language organization can occur. However, the question regarding whether reorganization involves both expressive and receptive language functions or only the one directly affected by the primary location of pathology has not been settled. Using Wada testing scores from 296 epilepsy patients and estimated rates of typical dominance in the normal population, we assessed the frequency with which left frontal and temporal pathology resulted in reorganization of only the expressive or receptive language function or both. The comparisons revealed: (1) a significantly higher prevalence of atypical organization (i.e., deviations from LH dominance) among the LH patients compared to normal population estimates and right hemisphere patients, and (2) that regardless of pathology location within the LH, the rates of atypical reorganization for both expressive and receptive language were essentially equal. These results constitute evidence that the two language functions are intimately yoked and that when disruption to the system results in reorganization, it usually yields functional changes throughout the system.

Activity in preserved left hemisphere regions predicts anomia severity in aphasia.

Understanding the neural mechanism that supports preserved language processing in aphasia has implications for both basic and applied science. This study examined brain activation associated with correct picture naming in 15 patients with aphasia. We contrasted each patient's activation to the activation observed in a neurologically healthy control group, allowing us to identify regions with unusual activity patterns. The results revealed that increased activation in preserved left hemisphere areas is associated with better naming performance in aphasia. This relationship was linear in nature; progressively less cortical activation was associated with greater severity of anomia. These findings are consistent with others who suggests that residual language function following stroke relies on preserved cortical areas in the left hemisphere.

Age-related relative volume preservation of the dominant hand cortical region.

Aging is usually associated with a progressive difficulty in learning new skills. Similarly, the dexterity in the non-dominant hand is usually decreased with age, while the dominant hand maintains a relative preservation in agility. We investigated if age-related volume loss affects the hand areas asymmetrically by comparing structural measures of the dominant hand area versus the non-dominant area. We performed a region of interest analysis of T1-weighted images focusing on the sensorimotor cortex corresponding to the hand area. We evaluated images from young subjects (younger than 65 years of age, n=38, mean age=24+/-7 years) and senior subjects (65 years or older, n=61, mean age =73+/-6 years). We observed that older adults exhibited greater leftward gray matter asymmetry of sensorimotor cortex, due in large part to more pronounced age-related loss of gray matter in the right hemisphere. These results are consistent with evidence that disuse leads to atrophy and suggest that age-related declines in gray matter, and perhaps function, may be limited by increasing the use of the non-dominant hand.

Temporal order processing of syllables in the left parietal lobe.

Speech processing requires the temporal parsing of syllable order. Individuals suffering from posterior left hemisphere brain injury often exhibit temporal processing deficits as well as language deficits. Although the right posterior inferior parietal lobe has been implicated in temporal order judgments (TOJs) of visual information, there is limited evidence to support the role of the left inferior parietal lobe (IPL) in processing syllable order. The purpose of this study was to examine whether the left inferior parietal lobe is recruited during temporal order judgments of speech stimuli. Functional magnetic resonance imaging data were collected on 14 normal participants while they completed the following forced-choice tasks: (1) syllable order of multisyllabic pseudowords, (2) syllable identification of single syllables, and (3) gender identification of both multisyllabic and monosyllabic speech stimuli. Results revealed increased neural recruitment in the left inferior parietal lobe when participants made judgments about syllable order compared with both syllable identification and gender identification. These findings suggest that the left inferior parietal lobe plays an important role in processing syllable order and support the hypothesized role of this region as an interface between auditory speech and the articulatory code. Furthermore, a breakdown in this interface may explain some components of the speech deficits observed after posterior damage to the left hemisphere.

Neural recruitment for the production of native and novel speech sounds.

Two primary areas of damage have been implicated in apraxia of speech (AOS) based on the time post-stroke: (1) the left inferior frontal gyrus (IFG) in acute patients, and (2) the left anterior insula (aIns) in chronic patients. While AOS is widely characterized as a disorder in motor speech planning, little is known about the specific contributions of each of these regions in speech. The purpose of this study was to investigate cortical activation during speech production with a specific focus on the aIns and the IFG in normal adults. While undergoing sparse fMRI, 30 normal adults completed a 30-minute speech-repetition task consisting of three-syllable nonwords that contained either (a) English (native) syllables or (b) non-English (novel) syllables. When the novel syllable productions were compared to the native syllable productions, greater neural activation was observed in the aIns and IFG, particularly during the first 10 min of the task when novelty was the greatest. Although activation in the aIns remained high throughout the task for novel productions, greater activation was clearly demonstrated when the initial 10 min was compared to the final 10 min of the task. These results suggest increased activity within an extensive neural network, including the aIns and IFG, when the motor speech system is taxed, such as during the production of novel speech. We speculate that the amount of left aIns recruitment during speech production may be related to the internal construction of the motor speech unit such that the degree of novelty/automaticity would result in more or less demands respectively. The role of the IFG as a storehouse and integrative processor for previously acquired routines is also discussed.

Cortical mapping of naming errors in aphasia.

Persons with aphasia vary greatly with regard to clinical profile; yet, they all share one common feature-anomia-an impairment in naming common objects. Previous research has demonstrated that particular naming errors are associated with specific left hemisphere lesions. However, we know very little about the cortical activity in the preserved brain areas that is associated with aphasic speech errors. Utilizing functional magnetic resonance imaging (fMRI), we show for the first time that specific speech errors are associated with common cortical activity in different types and severities of aphasia. Specifically, productions of phonemic errors recruited the left posterior perilesional occipital and temporal lobe areas. A similar pattern of activity was associated with semantic errors, albeit in the right hemisphere. This study does not discount variability in cortical activity following left hemisphere stroke; rather, it highlights commonalities in brain modulation in a population of patients with a common diagnosis but vastly different clinical profiles.

Treating visual speech perception to improve speech production in nonfluent aphasia.

BACKGROUND AND PURPOSE: Several recent studies have revealed modulation of the left frontal lobe speech areas not only during speech production but also for speech perception. Crucially, the frontal lobe areas highlighted in these studies are the same ones that are involved in nonfluent aphasia. Based on these findings, this study examined the utility of targeting visual speech perception to improve speech production in nonfluent aphasia. METHODS: Ten patients with chronic nonfluent aphasia underwent computerized language treatment utilizing picture-word matching. To examine the effect of visual speech perception on picture naming, 2 treatment phases were compared-one that included matching pictures to heard words and another in which pictures were matched to heard words accompanied by a video of the speaker's mouth presented on the computer screen. RESULTS: The results revealed significantly improved picture naming of both trained and untrained items after treatment when it included a visual speech component (ie, seeing the speaker's mouth). In contrast, the treatment phase in which pictures were only matched to heard words did not result in statistically significant improvement of picture naming. CONCLUSIONS: The findings suggest that focusing on visual speech perception can significantly improve speech production in nonfluent aphasia and may provide an alternative approach to treat a disorder in which speech production seldom improves much in the chronic phase of stroke.

Modulation of frontal lobe speech areas associated with the production and perception of speech movements.

PURPOSE: It is unclear whether the production and perception of speech movements are subserved by the same brain networks. The purpose of this study was to investigate neural recruitment in cortical areas commonly associated with speech production during the production and visual perception of speech. METHOD: This study utilized functional magnetic resonance imaging (fMRI) to assess brain function while participants either imitated or observed speech movements. RESULTS: A common neural network was recruited by both tasks. The greatest frontal lobe activity in Broca's area was triggered not only when producing speech but also when watching speech movements. Relatively less activity was observed in the left anterior insula during both tasks. CONCLUSION: These results support the emerging view that cortical areas involved in the execution of speech movements are also recruited in the perception of the same movements in other speakers.

Speech perception in MRI scanner noise by persons with aphasia.

PURPOSE: To examine reductions in performance on auditory tasks by aphasic and neurologically intact individuals as a result of concomitant magnetic resonance imaging (MRI) scanner noise. METHOD: Four tasks together forming a continuum of linguistic complexity were developed. They included complex-tone pitch discrimination, same-different discrimination of minimal pair syllables, lexical decision, and sentence plausibility. Each task was performed by persons with aphasia (PWA) and by controls. The stimuli were presented in silence and also in the noise recorded from within the bore of a 3 Tesla MRI scanner at 3 signal-to-noise (S/N) ratios. RESULTS: Across the 4 tasks, the PWA scored lower than the controls, and performance fell as a function of decreased S/N. However, the rate at which performance fell was not different across the 2 listener groups in any task. CONCLUSIONS: Depending on the relative levels of the signals and noise, the intense noise accompanying MRI scanning has the potential to severely disrupt performance. However, PWA are no more susceptible to the disruptive influence of this noise than are unimpaired individuals usually employed as controls. Thus, functional MRI data from aphasic and control individuals may be interpreted without complications associated with large interactions between scanner noise and performance reduction.

Sentence comprehension and general working memory.

Although the role of working memory in sentence comprehension has received substantial attention, the nature of this relationship remains unclear. The purpose of this study was to examine the interaction between general, nonverbal working memory (WM) and sentence parsing (SP) in normal English-speaking adults. Accuracy and reaction times were recorded for thirty-one young adults during three on-line tasks: nonverbal WM, SP plausibility, and lexical decision (LD). A significant positive correlation was observed between reaction times for WM and SP, but not between LD and SP. These results suggest that SP may be supported by a general WM capacity, and therefore, some sentence comprehension difficulties observed in the clinical population may potentially be related to impairment in general WM.

Neural correlates of phonological and semantic-based anomia treatment in aphasia.

Most naming treatments in aphasia either assume a phonological or semantic emphasis or a combination thereof. However, it is unclear whether semantic or phonological treatments recruit the same or different cortical areas in chronic aphasia. Employing three persons with aphasia, two of whom were non-fluent, the present study compared changes in neural recruitment associated with phonologic and semantic-based naming treatments. The participants with non-fluent aphasia were able to name more items following both treatment approaches. Although this was not the case for the participant who had fluent aphasia, her naming errors decreased considerably following treatment. Post-treatment fMRI revealed similar changes in neural activity bilaterally in the precuneus among the two non-fluent participants--increased activity was noted in the right entorhinal cortex and posterior thalamus on post-treatment scans for the third participant. These findings imply that cortical areas not traditionally related to language processing may support anomia recovery in some patients with chronic aphasia.

Age-related variability in cortical activity during language processing.

PURPOSE: The present study investigated the extent of cortical activity during overt picture naming using functional magnetic resonance imaging (fMRI). METHOD: Participants comprised 20 healthy, adult participants with ages ranging from 20 to 82 years. While undergoing fMRI, participants completed a picture-naming task consisting of 60 high-frequency nouns. RESULTS: Linear regression analysis revealed a positive relationship between age and cortical activation intensity in Broca's and Wernicke's areas as well as the right-hemisphere homologue of Broca's area. In contrast, neural activity in the anterior cingulate gyrus, an area thought to be involved in attentional processing, did not increase as a function of age. CONCLUSIONS: These findings suggest age-related increases in cortical activation during simple language tasks, such as picture naming, in brain areas typically associated with language processing.

Neural recruitment associated with anomia treatment in aphasia.

The purpose of this study was to investigate changes in the spatial distribution of cortical activity associated with anomia treatment in three persons with aphasia. Participants underwent three fMRI sessions before and after a period of intensive language treatment focused on object naming. The results revealed bilateral hemispheric recruitment associated with improved ability to name items targeted in treatment. This is the first study to employ multiple pre- and post-treatment fMRI sessions in the study of treatment-induced recovery from aphasia and has implications for future studies of brain plasticity in stroke.

Speech apraxia without oral apraxia: can normal brain function explain the physiopathology?

Apraxia of speech, usually associated with stroke, refers to the inability to perform speech motor movements typically with an intact ability to execute non-speech oral movements. It is uncertain whether apraxia of speech results from damage affecting the insula or the inferior frontal gyrus. The controversy started because of conflicting results from studies investigating patients with disrupted brain structure, when dysfunction of both sites can coexist. We conducted a functional magnetic resonance imaging study of individuals without neurological disorders comparing speech and non-speech movements. Speech movements did not recruit the insula, but activated the left inferior frontal gyrus, suggesting that Broca's area, but not the insula, is critical for speech articulation.