Sophia van Hees

A Functional MRI Study of the Relationship Between Naming Treatment Outcomes and Resting State Functional Connectivity in Post-Stroke Aphasia

The majority of studies investigating the neural mechanisms underlying treatment in people with aphasia have examined task‐based brain activity. However, the use of resting‐state fMRI may provide another method of examining the brain mechanisms responsible for treatment‐induced recovery, and allows for investigation into connectivity within complex functional networks

Aphasia LIFT: Exploratory investigation of an intensive comprehensive aphasia programme

Background: Intensive comprehensive aphasia programs (ICAPs) are gaining popularity in the international aphasia rehabilitation community. ICAPs comprise at least three hours of treatment per day over at least two weeks, have definable start and end dates for one cohort and use a variety of formats including individual treatment, group therapy, education and technology to improve language and communication. While intensive treatment approaches have demonstrated equivocal results on impairment-based measures, positive changes on activity/participation measures provide support for ICAPs in rehabilitation of chronic aphasia. Aphasia Language Impairment and Functional Therapy (LIFT) is a research-based ICAP developed for the purpose of evaluating treatment outcomes across the International Classification of Functioning, Disability and Health (ICF) domains. Aims: The aim of this study was to estimate the magnitude of treatment effects yielded by Aphasia Aphasia LIFT in the domains of language impairment, functional communication and communication-related quality of life (QOL). Methods & Procedures: Eleven individuals with chronic post-stroke aphasia (mean = 26.9 months) completed Aphasia LIFT. The programme comprised individual impairment-based and functional treatment, group therapy, and computer-based treatment for 40 hours over two weeks (n = 4, LIFT 1) or 100 hours over four weeks (n = 7, LIFT 2). Assessments of confrontation naming, discourse production, functional communication and communication-related quality of life were completed at pre-treatment, immediately post-treatment and six to eight weeks following treatment termination. Outcomes & Results: Group-level analyses revealed acquisition and maintenance of treatment effects, as evidenced by significant improvement on at least one outcome measure at follow-up in all domains. The most consistent pattern of improvement at an individual level was observed on measures of functional communication and communication-related QOL. Conclusions: Aphasia LIFT yielded positive outcomes across ICF domains, and in many cases the treatment effect was enduring. These results demonstrate that Aphasia LIFT was successful in meeting the overarching goal of ICAPs, to maximise communication and enhance life participation in individuals with aphasia. Further research into ICAPs is warranted.

Priming picture naming with a semantic task: An fMRI investigation

Prior semantic processing can enhance subsequent picture naming performance, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This functional magnetic resonance imaging study examined whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from a semantic task in healthy older adults. Both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Region of interest results identified decreased activity for long-term facilitated items compared to unfacilitated and short-term facilitated items in the mid-portion of the middle temporal gyrus, indicating lexical-semantic priming. Additionally, in the whole brain results, increased activity for short-term facilitated items was identified in regions previously linked to episodic memory and object recognition, including the right lingual gyrus (extending to the precuneus region) and the left inferior occipital gyrus (extending to the left fusiform region). These findings suggest that distinct neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by a semantic task, with long-term effects driven by lexical-semantic priming and short-term effects by episodic memory and visual object recognition mechanisms.

Changes in White Matter Connectivity Following Therapy for Anomia Post stroke

Background. The majority of studies investigating the neural mechanisms underlying treatment-induced recovery in aphasia have focused on the cortical regions associated with language processing. However, the integrity of the white matter connecting these regions may also be crucial to understanding treatment mechanisms. Objective. This study investigated the integrity of the arcuate fasciculus (AF) and uncinate fasciculus (UF) before and after treatment for anomia in people with aphasia. Method. Eight people with aphasia received 12 treatment sessions to improve naming; alternating between phonologically-based and semantic-based tasks, with high angular resolution diffusion imaging conducted pre and post treatment. The mean generalized fractional anisotropy (GFA), a measure of fiber integrity, and number of fibers in the AF and UF were compared pre and post treatment, as well as with a group of 14 healthy older controls. Results. Pre treatment, participants with aphasia had significantly fewer fibers and lower mean GFA in the left AF compared with controls. Post treatment, mean GFA increased in the left AF to be statistically equivalent to controls. Additionally, mean GFA in the left AF pre and post treatment positively correlated with maintenance of the phonologically based treatment. No differences were found in the right AF, or the UF in either hemisphere, between participants with aphasia and controls, and no changes were observed in these tracts following treatment. Conclusions. Anomia treatments may improve the integrity of the white matter connecting cortical language regions. These preliminary results add to the understanding of the mechanisms underlying treatment outcomes in people with aphasia post stroke.

Neural mechanisms underlying the facilitation of naming in aphasia using a semantic task: an fMRI study

BackgroundPrevious attempts to investigate the effects of semantic tasks on picture naming in both healthy controls and people with aphasia have typically been confounded by inclusion of the phonological word form of the target item. As a result, it is difficult to isolate any facilitatory effects of a semantically-focused task to either lexical-semantic or phonological processing. This functional magnetic resonance imaging (fMRI) study examined the neurological mechanisms underlying short-term (within minutes) and long-term (within days) facilitation of naming from a semantic task that did not include the phonological word form, in both participants with aphasia and age-matched controls.ResultsBehavioral results showed that a semantic task that did not include the phonological word form can successfully facilitate subsequent picture naming in both healthy controls and individuals with aphasia. The whole brain neuroimaging results for control participants identified a repetition enhancement effect in the short-term, with modulation of activity found in regions that have not traditionally been associated with semantic processing, such as the right lingual gyrus (extending to the precuneus) and the left inferior occipital gyrus (extending to the fusiform gyrus). In contrast, the participants with aphasia showed significant differences in activation over both the short- and the long-term for facilitated items, predominantly within either left hemisphere regions linked to semantic processing or their right hemisphere homologues.ConclusionsFor control participants in this study, the short-lived facilitation effects of a prior semantic task that did not include the phonological word form were primarily driven by object priming and episodic memory mechanisms. However, facilitation effects appeared to engage a predominantly semantic network in participants with aphasia over both the short- and the long-term. The findings of the present study also suggest that right hemisphere involvement may be supportive rather than maladaptive, and that a large distributed perisylvian network in both cerebral hemispheres supports the facilitation of naming in individuals with aphasia.

Neural activity associated with semantic versus phonological anomia treatments in aphasia

Naming impairments in aphasia are typically targeted using semantic and/or phonologically based tasks. However, it is not known whether these treatments have different neural mechanisms. Eight participants with aphasia received twelve treatment sessions using an alternating treatment design, with fMRI scans pre- and post-treatment. Half the sessions employed Phonological Components Analysis (PCA), and half the sessions employed Semantic Feature Analysis (SFA). Pre-treatment activity in the left caudate correlated with greater immediate treatment success for items treated with SFA, whereas recruitment of the left supramarginal gyrus and right precuneus post-treatment correlated with greater immediate treatment success for items treated with PCA. The results support previous studies that have found greater treatment outcome to be associated with activity in predominantly left hemisphere regions, and suggest that different mechanisms may be engaged dependent on the type of treatment employed.

Facilitation of naming in aphasia with auditory repetition: an investigation of neurocognitive mechanisms.

Prior phonological processing can enhance subsequent picture naming performance in individuals with aphasia, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This study used functional magnetic resonance imaging to examine the short-term (within minutes) and long-term (within days) facilitation effects from a phonological task in both participants with aphasia and age-matched controls. Results for control participants suggested that long-term facilitation of subsequent picture naming may be driven by a strengthening of semantic-phonological connections, while semantic and object recognition mechanisms underlie more short-term effects. All participants with aphasia significantly improved in naming accuracy following both short- and long-term facilitation. A descriptive comparison of the neuroimaging results identified different patterns of activation for each individual with aphasia. The exclusive engagement of a left hemisphere phonological network underlying facilitation was not revealed. The findings suggest that improved naming in aphasia with phonological tasks may be supported by changes in right hemisphere activity in some individuals and reveal the potential contribution of the cerebellum to improved naming following phonological facilitation. Conclusions must be interpreted with caution, however, due to the comparison of corrected group control results to that of individual participants with aphasia, which were not corrected for multiple comparisons.

Neuroimaging the short- and long-term effects of repeated picture naming in healthy older adults.

Repeated attempts to name pictures can improve subsequent naming for aphasic individuals with anomia, however, the neurocognitive mechanisms responsible for such improvements are unknown. This study investigated repeated picture naming in healthy older adults over a period of minutes (short-term) after one repetition and a period of days (long-term) after multiple repetitions. Compared to unprimed pictures, both repeated conditions showed faster naming latencies with the fastest latencies evident for the short-term condition. Neuroimaging results identified repetition suppression effects across three left inferior frontal gyrus regions of interest: for both the short- and long-term conditions in the pars orbitalis, and for long-term items in the pars triangularis and pars opercularis regions. The whole brain analysis also showed a repetition suppression effect in bilateral pars triangularis regions for the long-term condition. These findings within the inferior frontal gyrus suggest that effects of repeated naming may be driven by a mapping mechanism across multiple levels of representation, possibly reflecting different levels of learning, and lend support to the idea that processing may be hierarchically organised in the left inferior frontal gyrus. The whole brain analysis also revealed repetition suppression for the long-term condition within the posterior portion of bilateral inferior temporal gyri, which may reflect attenuation of integration processes within this region following the learning of task-relevant information.

Semantic feature training for the treatment of anomia in alzheimer disease: A preliminary investigation

Objective:This is a preliminary investigation into the effectiveness of semantic feature training for the treatment of anomia in Alzheimer disease (AD). Background:Anomia is a common clinical characteristic of AD. It is widely held that anomia in AD is caused by the combination of cognitive deficits and progressive loss of semantic feature information. Therapy that aims to help participants relearn or retain semantic features should, therefore, help treat anomia in AD. Methods:Two men with AD and one man with progressive nonfluent aphasia received 10 treatment sessions focused on relearning the names of 20 animals and 20 fruits. Within each category, half of the items were of high and half were of low typicality. We individualized treatment items to each participant, using items that each had not named correctly at baseline. Treatment sessions consisted of naming, category sorting, and semantic feature verification tasks. Results:Both participants with AD showed post-treatment improvements in naming, and one maintained the treatment effects at 6-week follow-up. The semantic category of the treatment items influenced post-treatment outcomes, but typicality did not. In contrast to the participants with AD, the man with progressive nonfluent aphasia had no improvement in naming ability. Conclusions:Our results suggest the potential viability of semantic feature training to treat anomia in AD and, therefore, the need for further research.

An fMRI investigation of the effects of attempted naming on word retrieval in aphasia.

In healthy controls, picture naming performance can be facilitated by a single prior exposure to the same picture (“priming”). This priming phenomenon is utilized in the treatment of aphasia, which often includes repeated picture naming as part of a therapeutic task. The current study sought to determine whether single and/or multiple exposures facilitate subsequent naming in aphasia and whether such facilitatory effects act through normal priming mechanisms. A functional magnetic resonance imaging paradigm was employed to explore the beneficial effects of attempted naming in two individuals with aphasia and a control group. The timing and number of prior exposures was manipulated, with investigation of both short-term effects (single prior exposure over a period of minutes) and long-term effects (multiple presentations over a period of days). Following attempted naming, both short-term and long-term facilitated items showed improvement for controls, while only the long-term condition showed benefits at a behavioral level for the participants with aphasia. At a neural level, effects of long-term facilitation were noted in the left precuneus for one participant with aphasia, a result also identified for the equivalent contrast in controls. It appears that multiple attempts are required to improve naming performance in the presence of anomia and that for some individuals with aphasia the source of facilitation may be similar to unimpaired mechanisms engaged outside the language network.