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Verifying a Computational Model of Word Production with Voxel-based lesion-parameter Mapping
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Voxel-lesion symptom mapping of coarse coding and suppression deficits in right hemisphere damaged patients
No full textSeveral accounts of narrative comprehension deficits in adults with right hemisphere damage (RHD) focus on the basic comprehension processes of coarse semantic coding (CC) and suppression (SUP)1,2. CC activates wide-ranging aspects of word meaning, independent of the surrounding context. In RHD, CC deficits impair processing of more remote meanings/features of lexical-semantic representations (e.g., “rotten” as a feature of “apple”)3. The normal SUP process reduces mental activation of concepts that become contextually incompatible. SUP impairment in RHD is indexed by prolonged processing interference from contextually-inappropriate interpretations (e.g., the “ink” meaning of “pen,” in “He built a pen”)4,5. Adults with RHD may have deficits in CC, SUP, both, or neither6.
Voxel-based lesion symptom mapping was used to identify right hemisphere (RH) anatomical correlates of CC and SUP deficits. Lesion-deficit correspondence data should help predict which RHD patients have which deficits and may be candidates for a deficit-focused treatment approach that simultaneously improves narrative comprehension7-9. The Bilateral Activation, Integration, and Selection (BAIS) framework of language processing10 suggests some basic hypotheses1. CC, related to the activation component, is hypothesized to involve posterior MTG and STG10,11. SUP, related to the attentionally-driven selection component, modulates lexical-level activation and message-level semantic integration to narrow representations to those most relevant to a comprehender’s goal. Selection is strongly associated with left IFGe.g,12 but RH IFG also is crucial for semantic filtering and selection13,14, especially for information more strongly active in the RH15. Basal ganglia circuits are likely involved, as well13,16
Aphasia United - A Unified Voice for Aphasia
No full textAphasia United is a new peak international organization that aims to bring together the global aphasia community and represent its voice to the World Stroke Organization. The aim of this paper is to describe the processes of development and the strategic direction of Aphasia United, and its proposed process for developing an international research agenda. Initial discussions and a summit have prioritized capacity building of consumer organization, building consensus around best practice, raising awareness and creating a governance structure as well as developing an international research agenda for aphasia. Opportunities for involvement are outlined
Comprehension of sentences with reversible semantic roles is sensitive to phonological STM capacity.
No full textComprehension of sentences with reversible semantic roles (e.g., The boy is kissing the girl.)is difficult for many individuals with agrammatic aphasia (e.g., Schwartz, Saffran & Marin, 1980), especially in the context of non-canonical sentence structures (e.g., passive). Early accounts attributed this difficulty to a specific deficit in syntactic processing that affected both comprehension and production Caramazza & Zurif, 1976; Caramazza & Berndt, 1981). This account was challenged in subsequent studies reporting that impaired comprehension of ‘semantically reversible sentences was not present in all people with agrammatic aphasia (e.g., Miceli, Mazzucchi, Menn, & Goodglass 1983) and that it was present in some people with other aphasic syndromes (e.g., Caplan & Hildebrandt, 1988). Even in their seminal paper, Caramazza & Zurif (1976) reported the difficulty in comprehending semantically reversible sentences in conduction aphasia, but attributed this to an impairment of short-term memory (STM). In another seminal study, Linebarger, Saffran & Schwartz (1983) who demonstrated that impairment in comprehending sentences with reversible roles did not preclude the ability to judge grammaticality of sentences. From this, they proposed the “Mapping Hypothesis”: Difficulty with comprehending semantically reversible sentences lies in the mapping of grammatical roles specified in the syntactic representation onto the underlying thematic roles in the semantic representation of that utterance. These and other similar findings (see R. Martin,
2006 for review) led to an increased interest in the role of verbal STM (semantic and phonological) in sentence comprehension. In the context of the mapping hypothesis, that role would be related to a reduction in processing capacity needed to assign grammatical roles of a sentence’s surface structure onto the underlying thematic roles.
In this study, we provide evidence that is consistent with this hypothesis. We examined the comprehension of five sentence structures with and without reversible semantic roles by people with aphasia under two response conditions. We compared performance on the two semantic role conditions (reversible vs. not reversible) and examined the contributions of aphasia severity and verbal STM deficits (WAB-R score, semantic STM and phonological STM) to detriments in performance on the reversible semantic role condition
Description of an Intensive Residential Aphasia Treatment Program: Rationale, Clinical Processes, and Outcomes
No full textThe influence of treatment intensity on treatment response in persons with aphasia (PWA) has received considerable attention in the aphasia treatment literature over the past 15 years. A meta-analysis of 55 aphasia treatment studies conducted by Robey (1998) revealed that treatment gains were greatest when therapy was provided more than two hours per week. In a subsequent review of 10 aphasia treatment studies, Bhogal, Teasell, & Speechley (2003) reported a positive relationship between treatment intensity and treatment outcomes. More recently, systematic evidenced-based reviews that included 4 RCTs (Kelly, Brady, & Enderby 2010), and 11 other studies (Cherney, Patterson, Raymer 2011) directly comparing more vs. less intensive treatment schedules reported only modest or equivocal evidence in favor of intensive treatment.
During this same period, changes in reimbursement models have resulted in decreasing lengths of stay for inpatient rehabilitation and an increasing shift to outpatient settings (Ottenbacher et al, 2004). The change to outpatient service delivery has limited access to care for many PWAs who live outside of urban centers or who lack adequate transportation services. For example, despite the exemption of Veterans Healthcare Administration (VHA) enrollees from private pay therapy caps, a search of VHA’s Corporate Data Warehouse revealed that of the 10,371 enrollees carrying a diagnosis of aphasia in FY12, only 30% (3198) received speech-language rehabilitation services, with an average treatment dose of 12 hours.
Within this context, several non-hospital-based intensive aphasia rehabilitation programs have emerged in recent years in an attempt to improve access to services and to maximize patient outcomes (Cherney et al., 2011). In this poster we provide a brief overview and describe the treatment philosophy, clinical processes and clinical outcomes of an intensive, residentially-based aphasia treatment program operated by the Veterans Healthcare Administration
Personalizing AAC for People with Aphasia: The Role of Text and Pictures
Get PDFOver time, and with intensive instruction, people with aphasia (PWAs) can learn to use grid-based, categorically organized, high-technology AAC layouts during structured tasks (e.g., Hough & Johnson, 2009). In an effort to reduce the training intensity required to teach PWAs to use AAC; researchers developed visual scene displays (VSDs), designed to complement the residual cognitive and linguistic abilities of PWAs by tapping their intact episodic memory. VSD interfaces incorporate personally relevant (PR) photos, text, and speech output (Dietz, McKelvey, & Beukelman, 2006; Weissling & Beukelman, 2006). VSDs appear to facilitate improved communication success (e.g., McKelvey, Dietz, Hux, Weissling, & Beukelman, 2007) as well as relatively efficient learning of system navigation with less instruction than reported for traditional grid layouts (McKelvey et al., 2007; Wallace & Hux, 2012). Figure 1 contrasts VSD and grid interfaces. The success of VSDs is frequently attributed to the PR photographs; however, investigators have not examined the impact of the various VSD elements on communication behaviors. Therefore, the purpose of this study was to examine the influence of PR photographs and the presence of text on a VSD interface on the communication behaviors of PWAs during a narrative retell task
Stability of a Measure of Lexica Diversity (D) in Narrative Discourse
No full textResearch into treatment for improving word retrieval ability in aphasia is increasingly focused on assessing outcomes at a discourse level. One of the challenges in this regard is choosing a measure to assess word retrieval in discourse. Some researchers (Fergadiotis & Wright, 2011; MacWhinney, Fromm, Forbes, & Holland, 2011; Rider, Wright, Marshall, & Page, 2008; Wright & Capiluto, 2009; Wright, Silverman, & Newhoff, 2003) have proposed using a measure of lexical diversity (D) as a proxy measure of word retrieval in aphasic discourse, reasoning that as word retrieval ability improves, a wider variety of words should be produced. Fegadiotis and Wright (2011) define lexical diversity as the range of vocabulary deployed in a discourse sample by a speaker, reflecting the speaker’s capacity to access and retrieve target words. D is a measure of lexical diversity that is robust to length variation, allowing comparison of discourses over time or between participants (MacWhinney et al., 2011)
A Treatment Sequence for “Phonological Aphasias”: Strengthening the Core Deficit
No full textPhonological impairment is a common core deficit in individuals with left perisylvian damage resulting in the classic aphasia syndromes (Broca’s, Wernicke’s, and Conduction aphasia). The impairment is particularly evident on written language tasks that require transcoding of sound-letter correspondences, such as nonwords, but many individuals with these chronic “phonological aphasias” have limited residual ability to write real words as well. We report here on a treatment sequence intended to strengthen phonological skills in individuals with aphasia and global agraphia. Treatment outcomes from a case series of 16 participants demonstrated the value of this approach for written and spoken language
Comparison of performance of concussed and non-concussed individuals on Subtest VIII of the C-RTT
No full textThe purpose of this study was to investigate auditory comprehension in concussed and non-concussed individuals using Subtest VIII of the C-RTT. Thirty non-concussed individuals were matched as closely as possible on gender, age, education and history of concussion to a group of concussed individuals. A Mann-Whitney found that the two samples were significant different at p = .020, and a t-test found a significant difference at p = .008 on the Efficiency Score (ES) of Subtest VIII. The non-concussed individuals performed better than the concussed individuals. Efficiency Score may be useful in assessing comprehension in concussed individuals
Cortical Stimulation and Language Outcomes in Aphasia
No full textWith the increased focus on evidenced-based outcomes in Speech-Language Pathology, a trend towards inclusion of instrumentation and technology in the treatment of aphasia has emerged. One technique at the forefront of this movement is the use of cortical stimulation as an adjunct to behavioral interventions. The purposes of this brief analysis are to review articles published over the course of six years (2006-2011) that combine stimulation with language treatment and to report trends that emerge