My research focuses on normal and disordered language and how language recovers in persons with brain damage. This work makes use of mutually supportive language representation (linguistic) and processing accounts of normal language to predict breakdown and recovery patterns. These patterns provide blueprints for clinical protocols and, in turn, address the utility of this translational approach for studying language disorders.
The present study addressed open questions about the nature of sentence production deficits in ag... more The present study addressed open questions about the nature of sentence production deficits in agrammatic aphasia. In two structural priming experiments, 13 aphasic and 13 age-matched control speakers repeated visually-and auditorily-presented prime sentences, and then used visually-presented word arrays to produce dative sentences. Experiment 1 examined whether agrammatic speakers form structural and thematic representations during sentence production, whereas Experiment 2 tested the lasting effects of structural priming in lags of two and four sentences. Results of Experiment 1 showed that, like unimpaired speakers, the aphasic speakers evinced intact structural priming effects, suggesting that they are able to generate such representations. Unimpaired speakers also showed reliable thematic priming effects in all conditions; agrammatic speakers did so as well in most experimental conditions, suggesting that access to thematic representations may be intact. Results of Experiment 2 showed structural priming effects of comparable magnitude for aphasic and unimpaired speakers. In addition, both groups showed lasting structural priming effects in both lag conditions, consistent with implicit learning accounts. In both experiments , aphasic speakers with more severe language impairments exhibited larger priming effects, consistent with the ''inverse preference " prediction of implicit learning accounts. The findings indicate that agrammatic speakers are sensitive to structural priming across levels of representation and that such effects are lasting, suggesting that structural priming may be beneficial for the treatment of sentence production deficits in agrammatism.
Background: Implicit learning is a process of learning that occurs outside of conscious awareness... more Background: Implicit learning is a process of learning that occurs outside of conscious awareness and may be involved in implicit, exposure-based language training. However, research shows that implicit learning abilities are variable among individuals with aphasia, and it remains unknown whether individuals who show basic implicit learning abilities also benefit from implicit language training. Aims: The aims of this series of experiments were to test implicit learning in individuals with agrammatic aphasia, examine the effects of a novel implicit language treatment, and investigate whether individuals with aphasia who show implicit learning ability also benefit from implicit treatment focused on passive sentence comprehension. Methods & Procedures: Nine participants with chronic agrammatic aphasia and 21 neurologically intact participants completed a visuomotor serial reaction time test of implicit learning (Experiment 1). The participants with aphasia also completed a short-term novel implicit sentence comprehension treatment (Experiment 2) that consisted of five sessions of repeated exposure to grammatically correct passive sentences and matching photographs. Sentence comprehension was tested in multiple baseline sessions and on each day of training using a sentence–picture matching task. The relation between participants' learning patterns across experiments was also examined. Outcomes & Results: Individuals with agrammatic aphasia as well as neurologically intact adults demonstrated significant implicit sequence learning in the serial reaction time task. However, the participants with aphasia did not show concomitant improvement in sentence comprehension as a result of the implicit treatment protocol. Conclusions: This study suggests that individuals with agrammatic aphasia demonstrate implicit learning ability; however, this ability does not necessarily promote successful outcomes in treatment that is based solely on implicit training methods.
Purpose: Visual-world eyetracking is increasingly used to investigate online language processing ... more Purpose: Visual-world eyetracking is increasingly used to investigate online language processing in normal and language impaired listeners. Tracking changes in eye movements over time also may be useful for indexing language recovery in those with language impairments. Therefore, it is critical to determine the test-retest reliability of results obtained using this method. Methods: Unimpaired young adults and people with aphasia took part in two eyetracking sessions spaced about one week apart. In each session, participants completed a sentence-picture matching task in which they listened to active and passive sentences (e.g., The [ N1þAux woman was] [ V visiting/visited] [ NP/PP2 (by) the man]) and selected between two pictures with reversed thematic roles. We used intraclass correlations (ICCs) to examine the test-retest reliability of response measures (accuracy, reaction time (RT)) and online eye movements (i.e., the likelihood of fixating the target picture in each region of the sentence) in each participant group. Results: In the unimpaired adults, accuracy was at ceiling (thus ICCs were not computed), with moderate ICCs for RT (i.e., 0.4e0.58) for passive sentences and low (<0.4) for actives. In individuals with aphasia, test-retest reliability was strong (0.59 < ICC < 0.75) for accuracy and excellent (>0.75) for RT for both sentence types. Similarly, for the unimpaired listeners, reliability of eye movements was moderate for passive sentences (NP/PP2 region) and low in all regions for active sentences. But, for the aphasic participant group, eye movement reliability was excellent for passive sentences (in the first second after sentence end) and strong for active sentences (V and NP/PP2 regions). Conclusion: Results indicated moderate-to-low reliability for unimpaired listeners; however , reliable eye movement patterns were detected for processes specific to passive sentences (e.g., thematic reanalysis). In contrast, individuals with aphasia exhibited strong and stable performance across sentence types in response measures and online eye movements. These findings indicate that visual-world eyetracking provides a reliable measure of online sentence comprehension in aphasia, and thus may be useful for investigating sentence processing changes over time.
Objective: To identify features of primary progressive aphasia (PPA) associated with Alzheimer di... more Objective: To identify features of primary progressive aphasia (PPA) associated with Alzheimer disease (AD) neuropathology. A related objective was to determine whether logopenic PPA is a clinical marker for AD. Methods: A total of 139 prospectively enrolled participants with a root diagnosis of PPA constituted the reference set. Those with autopsy or biomarker evidence of AD, and who had been evaluated at mild disease stages (Aphasia Quotient $85), were included (n 5 19). All had quantitative language testing and APOE genotyping. Fifteen had MRI morphometry. Results: Impaired word-finding was the universal presenting complaint in the aphasic AD group. PPA clinical subtype was logopenic (n 5 13) and agrammatic (n 5 6). Fluency, repetition, naming, and grammaticality ranged from preserved to severely impaired. All had relative preservation of word comprehension. Eight of the 15 aphasic participants with AD showed no appreciable cor-tical atrophy at the individual level on MRI. As a group, atrophy was asymmetrically concentrated in the left perisylvian cortex. APOE e4 frequency was not elevated. Conclusions: There is a close, but not obligatory, association between logopenic PPA and AD. No language measure, with the possible exception of word comprehension, can confirm or exclude AD in PPA. Biomarkers are therefore essential for diagnosis. Asymmetry of cortical atrophy and normal APOE e4 prevalence constitute deviations from typical AD. These and additional neuropathologic features suggest that AD has biological subtypes, one of which causes PPA. Better appreciation of this fact should promote the inclusion of individuals with PPA and positive AD biomarkers into relevant clinical trials. Neurology ® 2016;87:1–7
The Son-Rise Program is an intensive, child-centered approach to treatment of autism, incorporati... more The Son-Rise Program is an intensive, child-centered approach to treatment of autism, incorporating strategies to promote child-initiated social interactions. Parent training is an important element of the treatment program, which is intended to be implemented in long-term home-based programs. In the present study, parents of children with autism who participated in two five-day parent-training courses in Son-Rise Program intervention (separated by several months) completed questionnaires and the Autism Treatment Evaluation Checklist prior to each course. Changes in scores were examined for parents who reported implementing (1) no treatment, (2) low intensity treatment, or (3) high intensity treatment in their homes in the interval between courses. Parents who administered Son-Rise Program intervention reported improvements in communication, sociability, and sensory and cognitive awareness in their children, with greater gains associated with greater hours of treatment per week. This study represents a first step in examining the effects of home-based Son-Rise Programs for children with autism.
Purpose: The present study tested whether (and how) language treatment changed online sentence pr... more Purpose: The present study tested whether (and how) language treatment changed online sentence processing in individuals with aphasia. Method: Participants with aphasia (n = 10) received a 12-week program of Treatment of Underlying Forms (Thompson & Shapiro, 2005) focused on production and comprehension of passive sentences. Before and after treatment, participants performed a sentence-picture matching task with active and passive sentences as eye movements were tracked. Twelve age-matched controls also performed the task once each. Results: In the age-matched group, eye movements indicated agent-first predictive processing after hearing the subject noun, followed by rapid thematic reanalysis after hearing the verb form. Pretreatment eye movements in the participants with aphasia showed no predictive agent-first processing, and more accurate thematic analysis in active compared to passive sentences. After treatment, which resulted in improved offline passive sentence production and comprehension, participants were more likely to respond correctly when they made agent-first eye movements early in the sentence, showed equally reliable thematic analysis in active and passive sentences, and were less likely to use a spatially based alternative response strategy. Conclusions: These findings suggest that treatment focused on improving sentence production and comprehension supports the emergence of more normal-like sentence comprehension processes.
The role of the right hemisphere (RH) in recovery from aphasia is incompletely understood. The pr... more The role of the right hemisphere (RH) in recovery from aphasia is incompletely understood. The present study quantified RH grey matter (GM) volume in individuals with chronic stroke-induced aphasia and cognitively healthy people using voxel-based morphometry. We compared group differences in GM volume in the entire RH and in RH regions-of-interest. Given that lesion site is a critical source of heterogeneity associated with poststroke language ability, we used voxel-based lesion symptom mapping (VLSM) to examine the relation between lesion site and language performance in the aphasic participants. Finally, using results derived from the VLSM as a covariate, we evaluated the relation between GM volume in the RH and language ability across domains, including comprehension and production processes both at the word and sentence levels and across spoken and written modalities. Between-subject comparisons showed that GM volume in the RH SMA was reduced in the aphasic group compared to the healthy controls. We also found that, for the aphasic group, increased RH volume in the MTG and the SMA was associated with better language comprehension and production scores, respectively. These data suggest that the RH may support functions previously performed by LH regions and have important implications for understanding poststroke reorganization.
Stroke-induced alterations in cerebral blood flow (perfusion) may contribute to functional langua... more Stroke-induced alterations in cerebral blood flow (perfusion) may contribute to functional language impairments and recovery in chronic aphasia. Using MRI, we examined perfusion in the right and left hemispheres of 35 aphasic and 16 healthy control participants. Across 76 regions (38 per hemisphere), no significant between-subjects differences were found in the left, whereas blood flow in the right was increased in the aphasic compared to the control participants. Region-of-interest (ROI) analyses showed a varied pattern of hypo-and hyperperfused regions across hemispheres in the aphasic participants; however, there were no significant correlations between perfusion values and language abilities in these regions. These patterns may reflect autoregulatory changes in blood flow following stroke and/or increases in general cognitive effort, rather than maladaptive language processing. We also examined blood flow in perilesional tissue, finding the greatest hypoperfusion close to the lesion (within 0–6 mm), with greater hypoperfusion in this region compared to more distal regions. In addition, hypoperfusion in this region was significantly correlated with language impairment. These findings underscore the need to consider cerebral perfusion as a factor contributing to language deficits in chronic aphasia as well as recovery of language function.
Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., ... more Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., object-relative clauses) elicits activation in the left inferior frontal gyrus (IFG) and left posterior temporal cortex. However, relatively little is known about the neural correlates of processing passive sentences, which differ from other complex sentences in terms of representation (i.e., noun phrase (NP)-movement) and processing (i.e., the time course of syntactic reanalysis). In the present study, 27 adults (14 younger and 13 older) listened to passive and active sentences and performed a sentence-picture verification task using functional Magnetic Resonance Imaging (fMRI). Passive sentences, relative to active sentences, elicited greater activation in bilateral IFG and left temporo-occipital regions. Participant age did not significantly affect patterns of activation. Consistent with previous research, activation in left temporo-occipital cortex likely reflects thematic reanalysis processes, whereas, activation in the left IFG supports processing of complex syntax (i.e., NP-movement). Right IFG activation may reflect syntactic reanalysis processing demands associated with the sentence-picture verification task.
A primary goal of working memory research has been to understand the mechanisms that permit worki... more A primary goal of working memory research has been to understand the mechanisms that permit working memory systems to effectively maintain the identity and order of the elements held in memory for sufficient time as to allow for their selection and transfer to subsequent processing stages. Based on the performance of two individuals with acquired dysgraphia affecting orthographic working memory (WM; the graphemic buffer), we present evidence of two distinct and dissociable functions of orthographic WM. One function is responsible for maintaining the temporal stability of letters held in orthographic WM, while the other is responsible for maintaining their representational distinctiveness. The failure to maintain temporal stability and representational distinctiveness gives rise, respectively, to decay and interference effects that manifest themselves in distinctive error patterns, including distinct serial position effects. The findings we report have implications beyond our understanding of orthographic WM, as the need to maintain temporal stability and representational distinctiveness in WM is common across cognitive domains.
The present study addressed open questions about the nature of sentence production deficits in ag... more The present study addressed open questions about the nature of sentence production deficits in agrammatic aphasia. In two structural priming experiments, 13 aphasic and 13 age-matched control speakers repeated visually-and auditorily-presented prime sentences, and then used visually-presented word arrays to produce dative sentences. Experiment 1 examined whether agrammatic speakers form structural and thematic representations during sentence production, whereas Experiment 2 tested the lasting effects of structural priming in lags of two and four sentences. Results of Experiment 1 showed that, like unimpaired speakers, the aphasic speakers evinced intact structural priming effects, suggesting that they are able to generate such representations. Unimpaired speakers also showed reliable thematic priming effects in all conditions; agrammatic speakers did so as well in most experimental conditions, suggesting that access to thematic representations may be intact. Results of Experiment 2 showed structural priming effects of comparable magnitude for aphasic and unimpaired speakers. In addition, both groups showed lasting structural priming effects in both lag conditions, consistent with implicit learning accounts. In both experiments , aphasic speakers with more severe language impairments exhibited larger priming effects, consistent with the ''inverse preference " prediction of implicit learning accounts. The findings indicate that agrammatic speakers are sensitive to structural priming across levels of representation and that such effects are lasting, suggesting that structural priming may be beneficial for the treatment of sentence production deficits in agrammatism.
Background: Implicit learning is a process of learning that occurs outside of conscious awareness... more Background: Implicit learning is a process of learning that occurs outside of conscious awareness and may be involved in implicit, exposure-based language training. However, research shows that implicit learning abilities are variable among individuals with aphasia, and it remains unknown whether individuals who show basic implicit learning abilities also benefit from implicit language training. Aims: The aims of this series of experiments were to test implicit learning in individuals with agrammatic aphasia, examine the effects of a novel implicit language treatment, and investigate whether individuals with aphasia who show implicit learning ability also benefit from implicit treatment focused on passive sentence comprehension. Methods & Procedures: Nine participants with chronic agrammatic aphasia and 21 neurologically intact participants completed a visuomotor serial reaction time test of implicit learning (Experiment 1). The participants with aphasia also completed a short-term novel implicit sentence comprehension treatment (Experiment 2) that consisted of five sessions of repeated exposure to grammatically correct passive sentences and matching photographs. Sentence comprehension was tested in multiple baseline sessions and on each day of training using a sentence–picture matching task. The relation between participants' learning patterns across experiments was also examined. Outcomes & Results: Individuals with agrammatic aphasia as well as neurologically intact adults demonstrated significant implicit sequence learning in the serial reaction time task. However, the participants with aphasia did not show concomitant improvement in sentence comprehension as a result of the implicit treatment protocol. Conclusions: This study suggests that individuals with agrammatic aphasia demonstrate implicit learning ability; however, this ability does not necessarily promote successful outcomes in treatment that is based solely on implicit training methods.
Purpose: Visual-world eyetracking is increasingly used to investigate online language processing ... more Purpose: Visual-world eyetracking is increasingly used to investigate online language processing in normal and language impaired listeners. Tracking changes in eye movements over time also may be useful for indexing language recovery in those with language impairments. Therefore, it is critical to determine the test-retest reliability of results obtained using this method. Methods: Unimpaired young adults and people with aphasia took part in two eyetracking sessions spaced about one week apart. In each session, participants completed a sentence-picture matching task in which they listened to active and passive sentences (e.g., The [ N1þAux woman was] [ V visiting/visited] [ NP/PP2 (by) the man]) and selected between two pictures with reversed thematic roles. We used intraclass correlations (ICCs) to examine the test-retest reliability of response measures (accuracy, reaction time (RT)) and online eye movements (i.e., the likelihood of fixating the target picture in each region of the sentence) in each participant group. Results: In the unimpaired adults, accuracy was at ceiling (thus ICCs were not computed), with moderate ICCs for RT (i.e., 0.4e0.58) for passive sentences and low (<0.4) for actives. In individuals with aphasia, test-retest reliability was strong (0.59 < ICC < 0.75) for accuracy and excellent (>0.75) for RT for both sentence types. Similarly, for the unimpaired listeners, reliability of eye movements was moderate for passive sentences (NP/PP2 region) and low in all regions for active sentences. But, for the aphasic participant group, eye movement reliability was excellent for passive sentences (in the first second after sentence end) and strong for active sentences (V and NP/PP2 regions). Conclusion: Results indicated moderate-to-low reliability for unimpaired listeners; however , reliable eye movement patterns were detected for processes specific to passive sentences (e.g., thematic reanalysis). In contrast, individuals with aphasia exhibited strong and stable performance across sentence types in response measures and online eye movements. These findings indicate that visual-world eyetracking provides a reliable measure of online sentence comprehension in aphasia, and thus may be useful for investigating sentence processing changes over time.
Objective: To identify features of primary progressive aphasia (PPA) associated with Alzheimer di... more Objective: To identify features of primary progressive aphasia (PPA) associated with Alzheimer disease (AD) neuropathology. A related objective was to determine whether logopenic PPA is a clinical marker for AD. Methods: A total of 139 prospectively enrolled participants with a root diagnosis of PPA constituted the reference set. Those with autopsy or biomarker evidence of AD, and who had been evaluated at mild disease stages (Aphasia Quotient $85), were included (n 5 19). All had quantitative language testing and APOE genotyping. Fifteen had MRI morphometry. Results: Impaired word-finding was the universal presenting complaint in the aphasic AD group. PPA clinical subtype was logopenic (n 5 13) and agrammatic (n 5 6). Fluency, repetition, naming, and grammaticality ranged from preserved to severely impaired. All had relative preservation of word comprehension. Eight of the 15 aphasic participants with AD showed no appreciable cor-tical atrophy at the individual level on MRI. As a group, atrophy was asymmetrically concentrated in the left perisylvian cortex. APOE e4 frequency was not elevated. Conclusions: There is a close, but not obligatory, association between logopenic PPA and AD. No language measure, with the possible exception of word comprehension, can confirm or exclude AD in PPA. Biomarkers are therefore essential for diagnosis. Asymmetry of cortical atrophy and normal APOE e4 prevalence constitute deviations from typical AD. These and additional neuropathologic features suggest that AD has biological subtypes, one of which causes PPA. Better appreciation of this fact should promote the inclusion of individuals with PPA and positive AD biomarkers into relevant clinical trials. Neurology ® 2016;87:1–7
The Son-Rise Program is an intensive, child-centered approach to treatment of autism, incorporati... more The Son-Rise Program is an intensive, child-centered approach to treatment of autism, incorporating strategies to promote child-initiated social interactions. Parent training is an important element of the treatment program, which is intended to be implemented in long-term home-based programs. In the present study, parents of children with autism who participated in two five-day parent-training courses in Son-Rise Program intervention (separated by several months) completed questionnaires and the Autism Treatment Evaluation Checklist prior to each course. Changes in scores were examined for parents who reported implementing (1) no treatment, (2) low intensity treatment, or (3) high intensity treatment in their homes in the interval between courses. Parents who administered Son-Rise Program intervention reported improvements in communication, sociability, and sensory and cognitive awareness in their children, with greater gains associated with greater hours of treatment per week. This study represents a first step in examining the effects of home-based Son-Rise Programs for children with autism.
Purpose: The present study tested whether (and how) language treatment changed online sentence pr... more Purpose: The present study tested whether (and how) language treatment changed online sentence processing in individuals with aphasia. Method: Participants with aphasia (n = 10) received a 12-week program of Treatment of Underlying Forms (Thompson & Shapiro, 2005) focused on production and comprehension of passive sentences. Before and after treatment, participants performed a sentence-picture matching task with active and passive sentences as eye movements were tracked. Twelve age-matched controls also performed the task once each. Results: In the age-matched group, eye movements indicated agent-first predictive processing after hearing the subject noun, followed by rapid thematic reanalysis after hearing the verb form. Pretreatment eye movements in the participants with aphasia showed no predictive agent-first processing, and more accurate thematic analysis in active compared to passive sentences. After treatment, which resulted in improved offline passive sentence production and comprehension, participants were more likely to respond correctly when they made agent-first eye movements early in the sentence, showed equally reliable thematic analysis in active and passive sentences, and were less likely to use a spatially based alternative response strategy. Conclusions: These findings suggest that treatment focused on improving sentence production and comprehension supports the emergence of more normal-like sentence comprehension processes.
The role of the right hemisphere (RH) in recovery from aphasia is incompletely understood. The pr... more The role of the right hemisphere (RH) in recovery from aphasia is incompletely understood. The present study quantified RH grey matter (GM) volume in individuals with chronic stroke-induced aphasia and cognitively healthy people using voxel-based morphometry. We compared group differences in GM volume in the entire RH and in RH regions-of-interest. Given that lesion site is a critical source of heterogeneity associated with poststroke language ability, we used voxel-based lesion symptom mapping (VLSM) to examine the relation between lesion site and language performance in the aphasic participants. Finally, using results derived from the VLSM as a covariate, we evaluated the relation between GM volume in the RH and language ability across domains, including comprehension and production processes both at the word and sentence levels and across spoken and written modalities. Between-subject comparisons showed that GM volume in the RH SMA was reduced in the aphasic group compared to the healthy controls. We also found that, for the aphasic group, increased RH volume in the MTG and the SMA was associated with better language comprehension and production scores, respectively. These data suggest that the RH may support functions previously performed by LH regions and have important implications for understanding poststroke reorganization.
Stroke-induced alterations in cerebral blood flow (perfusion) may contribute to functional langua... more Stroke-induced alterations in cerebral blood flow (perfusion) may contribute to functional language impairments and recovery in chronic aphasia. Using MRI, we examined perfusion in the right and left hemispheres of 35 aphasic and 16 healthy control participants. Across 76 regions (38 per hemisphere), no significant between-subjects differences were found in the left, whereas blood flow in the right was increased in the aphasic compared to the control participants. Region-of-interest (ROI) analyses showed a varied pattern of hypo-and hyperperfused regions across hemispheres in the aphasic participants; however, there were no significant correlations between perfusion values and language abilities in these regions. These patterns may reflect autoregulatory changes in blood flow following stroke and/or increases in general cognitive effort, rather than maladaptive language processing. We also examined blood flow in perilesional tissue, finding the greatest hypoperfusion close to the lesion (within 0–6 mm), with greater hypoperfusion in this region compared to more distal regions. In addition, hypoperfusion in this region was significantly correlated with language impairment. These findings underscore the need to consider cerebral perfusion as a factor contributing to language deficits in chronic aphasia as well as recovery of language function.
Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., ... more Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., object-relative clauses) elicits activation in the left inferior frontal gyrus (IFG) and left posterior temporal cortex. However, relatively little is known about the neural correlates of processing passive sentences, which differ from other complex sentences in terms of representation (i.e., noun phrase (NP)-movement) and processing (i.e., the time course of syntactic reanalysis). In the present study, 27 adults (14 younger and 13 older) listened to passive and active sentences and performed a sentence-picture verification task using functional Magnetic Resonance Imaging (fMRI). Passive sentences, relative to active sentences, elicited greater activation in bilateral IFG and left temporo-occipital regions. Participant age did not significantly affect patterns of activation. Consistent with previous research, activation in left temporo-occipital cortex likely reflects thematic reanalysis processes, whereas, activation in the left IFG supports processing of complex syntax (i.e., NP-movement). Right IFG activation may reflect syntactic reanalysis processing demands associated with the sentence-picture verification task.
A primary goal of working memory research has been to understand the mechanisms that permit worki... more A primary goal of working memory research has been to understand the mechanisms that permit working memory systems to effectively maintain the identity and order of the elements held in memory for sufficient time as to allow for their selection and transfer to subsequent processing stages. Based on the performance of two individuals with acquired dysgraphia affecting orthographic working memory (WM; the graphemic buffer), we present evidence of two distinct and dissociable functions of orthographic WM. One function is responsible for maintaining the temporal stability of letters held in orthographic WM, while the other is responsible for maintaining their representational distinctiveness. The failure to maintain temporal stability and representational distinctiveness gives rise, respectively, to decay and interference effects that manifest themselves in distinctive error patterns, including distinct serial position effects. The findings we report have implications beyond our understanding of orthographic WM, as the need to maintain temporal stability and representational distinctiveness in WM is common across cognitive domains.
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Papers by Cynthia Thompson