Verb Retrieval Research Articles

Does Parkinson's disease affect verb production in picture descriptions?

Research on Parkinson's disease (PD) has documented significant deficits in verb production, with more robust results in single word retrieval tasks than in connected speech, yet the underlying causes of these deficits are disputable, especially concerning connected speech production. We analyzed picture descriptions provided by 48 individuals with PD and 48 age-matched healthy controls, and examined the percent of nouns and verbs of all words, the number of described events, verbs denoting activity, verbs in active morpho-syntactic patterns, and transitive verbs. Individuals with PD produced a lower percent of verbs than did control participants, but the groups differed in no other variable. Scores on a cognitive screening task associated with the percent of verbs and the number of events. We suggest that verb retrieval in connected speech in PD reflects no specific difficulty with action semantics, but rather the spread of PD pathology into more diffuse verb-specific neural networks.

Repetitive Transcranial Magnetic Stimulation for Action Naming in Aphasia Rehabilitation: A Systematic Review and Meta-Analysis.

Anomia, characterized by difficulty in word retrieval, particularly action verbs, poses a significant challenge in post-stroke aphasia. Repetitive transcranial magnetic stimulation (rTMS) has gained attention for language processing investigations and interventions. This systematic review explores the potential of rTMS as a modality to address action-verb deficits in post-stroke aphasia. We searched MEDLINE via PubMed, CINAHL via Ebsco and Web of Science in February 2024 for English articles (1996-2024). Eligible studies involved post-stroke aphasia action naming rehabilitation with rTMS. In some of these studies, rTMS was combined with speech-language therapy. In total, 10 studies were included in this systematic review. These articles highlight the potential of rTMS in improving verb retrieval deficits. While significant improvements may not be evident, notable progress both before and after intervention is observed in this review. However, it also underscores the need for further research to enhance language recovery for individuals with post-stroke aphasia.

Rational adaptation in word production: Strong conceptual ability reduces the effect of lexical impairments on verb retrieval in aphasia

Language users rely on both linguistic and conceptual processing abilities to efficiently comprehend or produce language. According to the principle of rational adaptation, the degree to which a cognitive system relies on one process vs. another can change under different conditions or disease states with the goal of optimizing behavior. In this study, we investigated rational adaptation in reliance on linguistic versus conceptual processing in aphasia, an acquired disorder of language. In individuals living with aphasia, verb-retrieval impairments are a pervasive deficit that negatively impacts communicative function. As such, we examined evidence of adaptation in verb production, using parallel measures to index impairment in two of verb naming's critical subcomponents: conceptual and linguistic processing. These component processes were evaluated using a standardized assessment battery designed to contrast non-linguistic (picture input) and linguistic (word input) tasks of conceptual action knowledge. The results indicate that non-linguistic conceptual action processing can be impaired in people with aphasia and contributes to verb-retrieval impairments. Furthermore, relatively unimpaired conceptual action processing can ameliorate the influence of linguistic processing deficits on verb-retrieval impairments. These findings are consistent with rational adaptation accounts, indicating that conceptual processing plays a key role in language function and can be leveraged in rehabilitation to improve verb retrieval in adults with chronic aphasia.

Neural mechanisms of sentence production: a volumetric study of primary progressive aphasia.

Studies on the neural bases of sentence production have yielded mixed results, partly due to differences in tasks and participant types. In this study, 101 individuals with primary progressive aphasia (PPA) were evaluated using a test that required spoken production following an auditory prime (Northwestern Assessment of Verbs and Sentences-Sentence Production Priming Test, NAVS-SPPT), and one that required building a sentence by ordering word cards (Northwestern Anagram Test, NAT). Voxel-Based Morphometry revealed that gray matter (GM) volume in left inferior/middle frontal gyri (L IFG/MFG) was associated with sentence production accuracy on both tasks, more so for complex sentences, whereas, GM volume in left posterior temporal regions was exclusively associated with NAVS-SPPT performance and predicted by performance on a Digit Span Forward (DSF) task. Verb retrieval deficits partly mediated the relationship between L IFG/MFG and performance on the NAVS-SPPT. These findings underscore the importance of L IFG/MFG for sentence production and suggest that this relationship is partly accounted for by verb retrieval deficits, but not phonological loop integrity. In contrast, it is possible that the posterior temporal cortex is associated with auditory short-term memory ability, to the extent that DSF performance is a valid measure of this in aphasia.

The Effects of Word Frequency, Age of Acquisition, Animacy, and Grammatical Class on Picture Naming by Volunteers and People with Aphasia

ABSTRACT Background Numerous studies have investigated the effects of word frequency (WF), age of acquisition (AoA), and animacy on picture naming in volunteers and those with aphasia. But none have controlled for any possible interactions among these three variables during noun retrieval and whether WF and AoA influence verb retrieval in ways that are similar to that observed during noun retrieval. Aims The main purpose of this study was to examine the influences of WF, AoA, and animacy on noun retrieval in both volunteers and participants with aphasia and to compare these results to the effects of AoA and WF in both groups during verb retrieval. Methods and Procedures A factorial approach was used to study the effects of (a) WF, AoA, and animacy on picture naming for 249 nouns, and (b) the effects of WF and AoA on picture naming for 88 verbs. Fifteen volunteers with no history of neurologic or psychiatric impairment and 13 people with aphasia participated in this study. Naming latencies using key press procedures were used to assess the effects of the independent variables. Linear mixed effects with random intercepts were modeled to analyze the results. Outcomes and Results Nouns with early AoA and high WF were named significantly faster than all nouns with late AoA. There were no differences between naming speeds for animate vs. inanimate nouns. Animate nouns with early AoA and high frequency were named significantly faster than early, animate nouns with low frequency. Low word frequency facilitated naming by the participants with aphasia for early AoA verbs but slowed the volunteers’ naming for these verbs. Participants responded significantly faster to nouns versus verbs regardless of AoA and WF. Conclusions Controlling for animacy in noun picture naming produces novel findings regarding the effects of WF and AoA on word retrieval. The interaction among WF, AoA, and animacy is more consequential for picture naming speed than the specific effects of any one of these variables alone.

Action naming deficits in Parkinson’s disease: the role of semantic complexity

ABSTRACT Background Previous studies have suggested that individuals with Parkinson’s disease (PD) have difficulty retrieving verbs and nouns. Among the factors that have been proposed to contribute to this verb retrieval difficulty is the semantic properties of the verbs. Aims The aim of this study was to investigate the verb and noun naming abilities in Greek speaking individuals with PD. Furthermore, the effect of semantic complexity on verb retrieval ability was explored. Specifically, two verb categories were investigated mainly, instrumental verbs as semantically heavy and non-instrumental verbs that are considered semantically light verbs. Methods and Procedures Participants were 24 non-demented individuals with PD matched for age and education with 15 healthy control participants. Word retrieval abilities for nouns and verbs were evaluated using the Greek Object and Action Test (GOAT), a picture-based assessment of single word retrieval. Outcomes and Results The results revealed that participants with PD performed significantly worse on naming verbs and nouns compared to healthy controls. Specifically, the PD group had a greater difficulty in retrieving verbs compared to nouns. In addition, a positive effect of instrumentality on verb retrieval abilities was observed. Conclusion The results of this study suggest that semantic complexity may play a critical role in verb retrieval abilities in PD. Furthermore, verbs related to upper limb movement with the inclusion of instrumental verbs may have a facilitatory effect on lexical retrieval. This finding emphasizes the need for the inclusion of the evaluation of different verb categories for naming during the initial clinical assessment of cognitive-linguistic abilities of patients with PD.

Verb production and comprehension in primary progressive aphasia

Studies of word class processing have found verb retrieval impairments in individuals with primary progressive aphasia (Bak et al., 2001; Cappa et al., 1998; Cotelli et al., 2006; Hillis, Heidler-Gary, et al., 2006; Hillis, Oh, & Ken, 2004; Marcotte et al., 2014; Rhee, Antiquena, & Grossman, 2001; Silveri & Ciccarelli, 2007; Thompson, Lukic, et al., 2012) associated primarily with the agrammatic variant. However, fewer studies have focused on verb comprehension, with inconsistent results. Because verbs are critical to both production and comprehension of clauses and sentences, we investigated verb processing across domains in agrammatic, logopenic, and semantic PPA and a group of age-matched healthy controls. Participants completed a confrontation naming task for verb production and an eye-tracking word-picture matching task for online verb comprehension. All PPA groups showed impaired verb production and comprehension relative to healthy controls. Most notably, the PPA-S group performed more poorly than the other two PPA variants in both domains. Overall, the results indicate that semantic deficits in the PPA-S extend beyond object knowledge to verbs as well, adding to our knowledge concerning the nature of the language deficits in the three variants of primary progressive aphasia.

Cross-language Generalization in Bilingual Aphasia: Influence of Manner of Second Language Acquisition

ABSTRACT Background Language treatment for bilinguals with aphasia has been shown to result in gains in both the treated language and the untreated language (i.e., cross-language generalization). However, cross-language generalization is not consistently found. This inconsistency may be due to several factors, such as the age of acquisition of, and proficiency in, each language. One often-overlooked factor that may influence whether cross-language generalization occurs is the manner in which bilinguals learned their second language (L2): in a formal educational context (explicitly) or naturalistically through exposure to the language (implicitly). Prior research suggests that implicit L2 learning results in greater overlap in the representation of the first language (L1) and L2 in the brain, particularly for grammar, compared to explicit learning. In contrast, lexical processing in L1 and L2 is proposed to rely more on shared brain regions regardless of the manner of L2 acquisition. Greater overlap should provide a greater likelihood of cross-language generalization effects from treatment. Aims The goal of this study was to determine how the manner of acquisition of L2 may affect cross-language generalization following treatment in L2 separately targeting the lexicon (object naming) and grammar (sentence construction). Methods & Procedures Two Spanish-English bilinguals with aphasia each completed two treatment phases in English of 2-4 weeks each, in succession, with one week between them: semantic feature analysis (SFA) targeting object naming, and Verb Network Strengthening Treatment (VNeST) targeting verb retrieval and sentence construction. Pre- and post-treatment assessments and weekly probes were completed for each phase. Participant P1 learned English explicitly in an educational setting, while participant P2 learned English implicitly. Outcomes & Results As predicted, P2 showed cross-language generalization after verb/grammar treatment (VNeST) whereas P1 did not. However, contrary to the prediction that both participants should show cross-language generalization after noun treatment (SFA), only P1 showed cross-language generalization of object naming. Conclusions Cross-language generalization was observed for both participants but for different aspects of language. The findings suggest that naturalistic second language learning may lead to stronger links between languages in the grammatical system, whereas formal second language learning may lead to stronger links between languages in the lexical-semantic system. Future research should further explore the effects of manner of acquisition as a predictor of language co-activation and cross-language treatment generalization in bilinguals with aphasia.

Comparing the effects of semantically related and non-related verb retrieval treatments in persons with aphasia: a single-case study

ABSTRACT Background Differential topographies of body limbs in the brain would be reflected in differential associations of body-related action verbs. This neuroscience hypothesis may have important implications for the verb dissociations in persons with agrammatic aphasia. Aims This study aimed at examining the effects of semantic feature analysis (SFA) on verb retrieval with an innovation based on the theory of the topographical representation of the verb-semantic functional units through distributed neural circuits. The research question concerned the effect of a verb-oriented SFA approach on two sets of semantically related and non-related verbs for Persian-speaking persons with aphasia. Methods and Procedures Two versions of SFA were applied through a single-subject crossover study with A1B1A2B2/A1B2A2B1 design. The first version utilized semantically related verbs by separating hand- and face-related verbs; the other form used semantically non-related verbs. Participants 1 and 2 received treatment with the A1B2A2B1, and participants 3 and 4 received the A1B1A2B2 order. Level, trend, and slope besides D statistic were analyzed for both the treated and untreated verbs. Outcome and Results SFA was generally effective in both versions; however, greater effect sizes were obtained with semantically related verbs (28.58, 33.48, 7.07, 8.16 for the treated and 13.86, 23.09, 4.38, 4.98 for the untreated verbs in the semantically related version; 15.51, 5.72, 1.73, 6.35 for the treated and 6.35, 4.49, 1.63, 1.29 for the untreated verbs in the semantically non-related verbs). Achievement of the accuracy criterion occurred in less time for the semantically related version. Conclusions Semantic-based treatments were useful with verb problems particularly when they were planned to activate allied neural assemblies. The findings of the present study uphold SFA treatment with semantically related verbs.

Do Cues Facilitate Retrieval of Verbs in Persons with Bilingual Aphasia?

Word retrieval difficulty is commonly seen in persons with aphasia. The cues would repair word retrieval difficulty. The effect of cues during verb retrieval was gauged via Action Naming Test (ANT) in Kannada and English languages in persons with aphasia (PWAs). A total of eight persons with bilingual Aphasia (Broca's, conduction, and isolation type) were recruited for the study. The participants were expected to have a minimum quantum of verbal output were considered for the study. Specifically, the study used phonemic, semantic, and verbal contextual cues to assess verb retrieval abilities. The result of the study manifested that all participants of the study were able to perform better with phonemic cues followed by semantic and verbal contextual cues in both Kannada and English languages.

Bihemispheric Navigated Transcranial Magnetic Stimulation Mapping for Action Naming Compared to Object Naming in Sentence Context

Preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) is currently based on the disruption of performance during object naming. The resulting cortical language maps, however, lack accuracy when compared to intraoperative mapping. The question arises whether nTMS results can be improved, when another language task is considered, involving verb retrieval in sentence context. Twenty healthy German speakers were tested with object naming and a novel action naming task during nTMS language mapping. Error rates and categories in both hemispheres were compared. Action naming showed a significantly higher error rate than object naming in both hemispheres. Error category comparison revealed that this discrepancy stems from more lexico-semantic errors during action naming, indicating lexico-semantic retrieval of the verb being more affected than noun retrieval. In an area-wise comparison, higher error rates surfaced in multiple right-hemisphere areas, but only trends in the left ventral postcentral gyrus and middle superior temporal gyrus. Hesitation errors contributed significantly to the error count, but did not dull the mapping results. Inclusion of action naming coupled with a detailed error analysis may be favorable for nTMS mapping and ultimately improve accuracy in preoperative planning. Moreover, the results stress the recruitment of both left- and right-hemispheric areas during naming.

Mapping Verb Retrieval With nTMS: The Role of Transitivity.

Navigated Transcranial Magnetic Stimulation (nTMS) is used to understand the cortical organization of language in preparation for the surgical removal of a brain tumor. Action naming with finite verbs can be employed for that purpose, providing additional information to object naming. However, little research has focused on the properties of the verbs that are used in action naming tasks, such as their status as transitive (taking an object; e.g., to read) or intransitive (not taking an object; e.g., to wink). Previous neuroimaging data show higher activation for transitive compared to intransitive verbs in posterior perisylvian regions bilaterally. In the present study, we employed nTMS and production of finite verbs to investigate the cortical underpinnings of transitivity. Twenty neurologically healthy native speakers of German participated in the study. They underwent language mapping in both hemispheres with nTMS. The action naming task with finite verbs consisted of transitive (e.g., The man reads the book) and intransitive verbs (e.g., The woman winks) and was controlled for relevant psycholinguistic variables. Errors were classified in four different error categories (i.e., non-linguistic errors, grammatical errors, lexico-semantic errors and, errors at the sound level) and were analyzed quantitatively. We found more nTMS-positive points in the left hemisphere, particularly in the left parietal lobe for the production of transitive compared to intransitive verbs. These positive points most commonly corresponded to lexico-semantic errors. Our findings are in line with previous aphasia and neuroimaging studies, suggesting that a more widespread network is used for the production of verbs with a larger number of arguments (i.e., transitives). The higher number of lexico-semantic errors with transitive compared to intransitive verbs in the left parietal lobe supports previous claims for the role of left posterior areas in the retrieval of argument structure information.

Do gestures have a hand in verb retrieval? Investigation of iconic and non-iconic gestures in aphasia

ABSTRACT Background According to the lexical retrieval hypothesis (LRH), the primary function of gestures is to facilitate word retrieval. Thus, individuals with aphasia (IWA) might benefit from gestures in case of word retrieval impairments. However, the facilitative effect of gestures on word finding is still unclear since most facilitation/treatment studies combined gesture with linguistic cues. The LRH claims that the semantic content of a gesture is decisive for a facilitation effect on word retrieval. However, it remains unclear if and how IWA can perform adequate iconic gestures, especially in the presence of hemiparesis or limb apraxia. Thus, in the present study, we systematically studied the effect of iconic and non-iconic gesture production on oral verb naming in IWA and analysed the iconicity of gestures produced by IWA and healthy controls. Aims In the present study, we aimed (1) to investigate the potential facilitation effect of iconic and non-iconic gestures on verb retrieval in IWA and (2) to examine the IWA’s ability to produce adequate iconic gestures. Methods & Procedures Six IWA with impairments in naming verbs arising from a phonological, a lexical-semantic, or a combined deficit participated in a multiple single-case study targeting oral verb production. In the first experiment, IWA were asked to name pictures and to simultaneously perform either a relevant iconic gesture, a non-iconic gesture, or no gesture at all. In the second experiment, the video-recorded gestures produced during verb naming in the iconic gesture condition were rated for iconicity and compared to the iconicity of iconic gestures produced by 12 language-unimpaired controls. Results The accuracy in oral naming of verbs (Experiment 1) did not differ significantly between all conditions. Most IWA (n = 5) were able to produce iconic gestures, irrespective of hemiparesis or limb apraxia, since the iconicity ratings did not differ significantly from language-unimpaired controls (Experiment 2). Conclusions In contrast to the general assumption of the LRH, no gesture facilitation effect was observed in the verb naming performance of IWA. Moreover, the majority of the IWA could perform iconic gestures in a similar way as language-unimpaired participants despite the presence of a hemiparesis or limb apraxia. Hence, the absence of a facilitation effect in the iconic gesture condition seems not to originate from an inability to produce adequate iconic gestures. Further research with more IWA is required in order to replicate our results.

Lexical category differences in bilingual picture naming: Implications for models of lexical representation

AbstractBilingual speakers are less accurate and slower than monolinguals in word production. This bilingual cost has been demonstrated primarily for nouns. This study compared verb and noun retrieval to better understand bilingual lexical representation and test alternate hypotheses about bilingual cost. Picture naming speeds from highly proficient English–Spanish bilinguals showed a smaller bilingual cost for verbs compared to nouns. In Experiment 1, picture naming speeds were influenced by name agreement, age-of-acquisition and word length. Additionally, noun (but not verb) naming speed was predicted by word frequency. Experiment 2 examined two potential explanations for the smaller bilingual cost for verbs: verbs experience weaker cross-language interference (measured by translation speed) and smaller frequency effects. Both these predictions were confirmed, showing crucial differences between verbs and nouns and suggesting that cross-language facilitation rather than interference influences bilingual lexical retrieval, and that the frequency lag account of bilingual cost is more applicable to nouns than to verbs. We propose a Bilingual Integrated Grammatical Category model for highly proficient bilinguals to represent lexical category differences.

White-Matter Neuroanatomical Predictors of Aphasic Verb Retrieval

Background: Current neurocognitive models of language function have been primarily built from evidence regarding object naming, and their hypothesized white-matter circuit mechanisms tend to be coarse grained. Methods: In this cross-sectional, observational study, we used novel correlational tractography to assess the white-matter circuit mechanism behind verb retrieval, measured through action picture-naming performance in adults with chronic aphasia. Results: The analysis identified tracts implicated in current neurocognitive dual-stream models of language function, including the left inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and arcuate fasciculus. However, the majority of tracts associated with verb retrieval were not ones included in dual-stream models of language function. Instead, they were projection pathways that connect frontal and parietal cortices to subcortical regions associated with motor functions, including the left corticothalamic pathway, frontopontine tract, parietopontine tract, corticostriatal pathway, and corticospinal tract. Conclusions: These results highlight that corticosubcortical projection pathways implicated in motor functions may be importantly related to language function. This finding is consistent with grounded accounts of cognition and may furthermore inform neurocognitive models. Impact statement This study suggests that in addition to traditional dual-stream language fiber tracts, the integrity of projection pathways that connect frontal and parietal cortices to subcortical motor regions may be critically associated with verb-retrieval impairments in adults with aphasia. This finding challenges neurological models of language function.

Rational Adaptation in Using Conceptual Versus Lexical Information in Adults With Aphasia.

The information theoretic principle of rational adaptation predicts that individuals with aphasia adapt to their language impairments by relying more heavily on comparatively unimpaired non-linguistic knowledge to communicate. This prediction was examined by assessing the extent to which adults with chronic aphasia due to left-hemisphere stroke rely more on conceptual rather than lexical information during verb retrieval, as compared to age-matched neurotypical controls. A primed verb naming task examined the degree of facilitation each participant group received from either conceptual event-related or lexical collocate cues, compared to unrelated baseline cues. The results provide evidence that adults with aphasia received amplified facilitation from conceptual cues compared to controls, whereas healthy controls received greater facilitation from lexical cues. This indicates that adaptation to alternative and relatively unimpaired information may facilitate successful word retrieval in aphasia. Implications for models of rational adaptation and clinical neurorehabilitation are discussed.

Increased links between language and motor areas: A proof-of-concept study on resting-state functional connectivity following Personalized Observation, Execution and Mental imagery therapy in chronic aphasia

A tight coupling of language and motor processes has been established, which is consistent with embodied cognition theory. However, very few therapies have been designed to exploit the synergy between motor and language processes to help rehabilitate people with aphasia (PWA). Moreover, the underlying mechanisms supporting the efficacy of such approaches remain unknown.Previous work in our laboratory has demonstrated that personalized observation, execution, and mental imagery therapy (POEM)—a new therapy using three sensorimotor strategies to trigger action verb naming—leads to significant improvements in verb retrieval in PWA. Moreover, these improvements were supported by significant activations in language and sensorimotor processing areas, which further reinforce the role of both processes in language recovery (Durand et al., 2018). The present study investigates resting state functional connectivity (rsFC) changes following POEM in a pre-/post-POEM therapy design. A whole brain network functional connectivity approach was used to assess and describe changes in rsFC in a group of four PWA, who were matched and compared with four healthy controls (HC).Results showed increased rsFC in PWA within and between visuo-motor and language areas (right cuneal cortex—left supracalcarin (SCC) cortex/right precentral gyrus (PreCG)—left lingual gyrus (LG)) and between areas involved in action processing (right anterior parahippocampal gyrus (aPaHC)—left superior parietal lobule (SPL). In comparison to HC, the PWA group showed increased rsFC between the right inferior frontal gyrus (IFG) and left thalamus, which are areas involved in lexico-semantic processing. This proof-of-concept study suggests that the sensorimotor and language strategies used in POEM may induce modifications in large-scale networks, probably derived from the integration of visual and sensorimotor systems to sustain action naming, which is consistent with the embodied cognition theory.

Psycholinguistic norms for 92 action pictures and verbs in the Persian language in young- and middle-aged people

A verb as the fundamental part of a sentence is important and its retrieval consists of different cognitive stages. Additionally, verb retrieval difficulty is reported in some types of aphasia and other neurological diseases, and some psycholinguistic variables can influence the verb retrieval process. This study aimed to provide a normative database in the Persian language for 92 black and white action pictures and related verbs in two groups of young ages (20 to 40 years old) and middle ages (41 to 64 years old). A total of 150 volunteers participated in this study, and the groups had similar characteristics due to education. The pictures were normed for variables such as name agreement, familiarity, visual complexity, age of acquisition, and image agreement. Correlation coefficients were calculated values among these measures, and comparisons were made between the two age groups. The results of the comparisons between the two groups showed that name agreement and familiarities were age-dependent. The results revealed that all measures varied with age. Also, the present study provided a set of verbs and their pictures in the Persian language and normative data were obtained on the psycholinguistic variables such that it can be used for clinical practice and research in the areas of verb processing and their naming.

Effect of Mandarin Verb Network Strengthening Treatment (VNeST) in Mandarin-English bilinguals with aphasia: A single-case experimental design

ABSTRACT This study aimed to improve verb retrieval ability in Mandarin-English bilinguals with aphasia by adapting the Verb Network Strengthening Treatment (VNeST) into Mandarin Chinese. Two Mandarin-English bilingual patients with chronic post-stroke aphasia participated in this study via online conferencing system following a multiple-baseline design. Both of them completed a 10-week of Mandarin VNeST treatment, and were probed on verb retrieval ability in a sentence context in both languages. Response accuracy was analysed to investigate the treatment acquisition, within-language generalization, and cross-language generalization effects. Standardized language assessments in both languages were administered pre- and post-treatment to further examine generalization to other linguistic tasks. Error analysis was conducted to investigate the evolution of within- and cross-language errors. Both patients improved after training in Mandarin VNeST, and showed different patterns of within-language and cross-language generalizations. They also improved in a variety of standardized language tasks. Error analysis showed a decline in semantic errors over the course of treatment in both patients, with cross-linguistic errors showing a decrease during Mandarin probes and an increase during English probes in one of the patients. This study contributes to our current understanding of theories of bilingual verb processing, and provides treatment guidance in Mandarin-English bilinguals with aphasia.

Neural Correlates of Verb Fluency Performance in Cognitively Healthy Older Adults and Individuals With Dementia: A Pilot fMRI Study.

Currently there are ~6 million Americans who are affected by dementia. Verbal fluency tasks have been commonly and frequently utilized to document the disease progression in many forms of dementia. Verb fluency has been found to display substantial potential to detect and monitor the cognitive declines of individuals with dementia who have fronto-striatal involvement. The neural substrates underlying verb fluency task performance, however, have remained unclear so far, especially in individuals with dementia. Therefore, in the current study, brain activation patterns of seven individuals with dementia and nine healthy older adults were investigated using functional MRI. The participants performed in the scanner an overt, subject-paced verb fluency task, representative of fluency tasks used in clinical settings. The brain activation patterns during the verb fluency task were compared between the two groups, and a correlational analysis was conducted to determine the neural correlates of verb fluency performance. The results suggest that compared to healthy older adults, individuals with dementia demonstrated poorer verb fluency performance and showed higher activation in specific neural regions, such as the bilateral frontal lobe. In addition, the correlational analysis revealed that poorer verb fluency performance lead to increased activation in certain cortical and subcortical areas, including left hippocampus and right supramarginal gyrus. The current findings are consistent with previous neurophysiological findings related to semantic (noun) fluency performance in older adults and individuals with dementia and add to the empirical evidence that supports the role of the frontal lobe and hippocampus in verb retrieval and search. Declines in verb fluency performance cannot only be used as a cognitive marker, but also represent neuropathological changes due to the neurodegenerative disease.