Improving the maintenance of word representations in short-term memory to improve language function: Acquisition and generalization effects

The hallmark of a successful rehabilitation program for aphasia is generalization. We report a treatment program for word processing impairment in aphasia that incorporates methods to promote acquisition and response generalization, as well as generalization of treatment effects to language tasks other than those used in treatment (Kalinyak-Fliszar, Kohen, & Martin, 2011). The program also includes a second feature to promote generalization based on the complexity account of treatment efficacy (CATE; Thompson, Shapiro, Kiran, & Sobecks, 2003; Kiran, 2008)

Remediation of language processing in aphasia: Improving activation and maintenance of linguistic representations in (verbal) short-term memory

Verbal short-term memory (STM) impairments are ubiquitous in aphasia. Empirical evidence supports a relationship between word processing and STM. Current models of word processing emphasize a temporal component: maintenance of semantic and phonological representations of words during comprehension and production of language. Martin and Saffran (1997) proposed that impairment of this ability results in deficits of both word processing and verbal STM. Their account predicts that treatment of the ability to maintain activation of word representations in STM should lead to improvements that generalize beyond content and tasks used in treatment. This hypothesis is tested in this treatment case study

Cross-structural priming in sentences with verb particles and verb prepositions: A replication

Structural (syntactic) priming (Bock, 1986) is an experimental paradigm used to study sentence processing in non-brain damaged individuals. Repetition of a sentence structure in one or more “prime” trials leads to a tendency to use the same structure in a picture description task. Structural priming treatment for aphasia aims to improve sentence processing in aphasia by increasing accessibility of a syntactic structure, and making it temporarily easier to retrieve. However, this technique’s usefulness in treatment depends on the endurance of its effects. Whether structural priming reflects short-term residual activation or short-term learning is a matter of debate (Bock & Griffin, 2000). In treatment studies, this question can be addressed by evaluation of performance at post-treatment assessment

Effects of increased memory load on short-term facilitation of repetition in persons with aphasia

The ability to repeat a word involves activation of phonological and semantic representations of words that must be maintained until the utterance is produced. In aphasia, the language and verbal STM impairment frequently co-occur and studies indicate that the severity of these impairments are highly correlated (Martin & Ayala, 2004). One account of this co-occurrence is that the word processing impairment in aphasia is due to an inability to maintain activation of semantic and phonological representations of words over the time course of comprehending, repeating, or producing a word. When severe, this impairment affects single and multiple word processing as well as verbal STM capacity, as measured by verbal span. When milder, the impairment affects multiple word processing and verbal STM capacity. This intimate relationship of lexical access/retrieval and the ability to maintain activation of a word’s representations suggests a need to consider the role of verbal memory load on language performance. For example, it has been shown recently that performance on semantic judgment tasks is significantly reduced when memory load on the task is increased (Martin, Kohen, Kalinyak-Fliszar, Soveri & Laine, 2012). This study also identified two factors contributing to this effect, semantic STM capacity and an executive function, inhibition (performance on the Simon Task). Additionally, it has been shown that performance on phonological and lexical-semantic tasks is compromised by imposing an interval between stimulus and response (Martin, Kohen & Kalinayk-Fliszar, 2010; Martin, 2012). Evidence that increased memory load impairs language performance has prompted some researchers to target the ability to tolerate increased memory load in language tasks as a means of improving language function as well as increasing verbal STM capacity. For example, Majerus, Van der Kaa, Renard, Van der Linden, & Poncelet (2005) treated a phonological STM deficit using delayed repetition of word pairs. There were improvements in digit and nonword span, nonword repetition, rhyme judgments, and by the client’s self-report, comprehension in conversational contexts. Fridriksson, Holland, Beeson, & Morrow (2005) treated three cases of anomia using spaced-retrieval treatment, which varied interval time between presentations of a picture to be named (more time when named correctly and less time when named incorrectly). Compared to a cueing hierarchy treatment, the spaced retrieval approach showed more lasting improvements in follow-up testing. Kalinyak-Fliszar, Kohen & Martin (2011) used nonword and multisyllabic word repetition tasks combined with a delayed response (5 seconds) to improve phonological abilities of a person with conduction aphasia. Improvements were noted in repetition of treated stimuli and other language and verbal STM measures: rhyming and synonymy judgments, word pair repetition and seven verbal span tasks (of eleven administered). These studies indicate that incorporation of variations in verbal memory load into language treatments can improve language function. However, it has not been demonstrated that the addition of STM load provides any greater benefit over and above the language treatment task. In this study, we use a short-term repetition facilitation paradigm to determine if increased memory load added to a repetition task improves performance more than repetition alone

Improving auditory access to low imageabilty words by embedding them in imageable semantic-syntactic contexts in a case of deep phonological dysphasia

Deep dysphasia is a relatively rare subcategory of aphasia, characterized by word repetition impairment and profound auditory-verbal short-term memory (AVSTM) limitation. Accuracy of word repetition is better for words than nonwords (lexicality effect) and better for high-image than low-image words (imageability effect). The cardinal feature of deep dysphasia is the occurrence of semantic errors in single word repetition (Howard & Franklin, 1988). Phonological dysphasia shares all of these features except that semantic errors in repetition appear in repetition of multiple words and sentences. Thus, it has been proposed that these two ‘syndromes’ are not distinct, but actually are based on an impairment of auditory-verbal STM that can vary by severity, leading to deep dysphasia when severe and phonological dysphasia when mild (Martin, Saffran & Dell, 1996; Ablinger, Ablel & Huber, 2008). First, we report a single case treatment study of a person whose pattern of word repetition performance was consistent with the continuum of phonological-deep dysphasia: poor repetition of nonwords, imageability effects in repetition of single and multiple words and semantic errors in repetition of multiple word utterances. Differences in processing abstract (i.e., low imageability) versus concrete (i.e., high image) have been considered recently in aphasic treatment protocols (Kiran, Sandberg & Abbott, 2009). Here we test the effects of a theoretically motivated treatment that manipulates the semantic cohesiveness of low imageability (i.e., abstract)-low frequency (LI-LF)words to improve access to and short-term retention of LI words in deep-phonological dysphasia. Following presentation of the treatment case study, we describe an experimental protocol to determine if this approach of increasing imageability of abstract words through syntactic and semantic contexts can be extended to other individuals who present along the deep--phonological dysphasia continuum

Comprehension of sentences with reversible semantic roles is sensitive to phonological STM capacity.

Comprehension 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

A Diagnostic Battery to Assess Language and Short-term Memory Deficits in Aphasia

Recent studies in aphasia indicate a role of short-term memory (STM) in language processing. We present a unique diagnostic battery for aphasia that incorporates a STM component into measures of language processing and a comprehensive set of span measures that probe phonological and semantic abilities. Preliminary data demonstrate that the battery can identify the type of language processing deficit and the extent to which verbal STM is impaired. This information will guide and test the efficacy of a treatment program focused on improving the ability to access and maintain activation of semantic and phonological representations of words and sentences

A processing approach to the assessment of language and verbal short-term memory in aphasia

Verbal short-term memory (STM) impairment is virtually always present in aphasia and varies in severity depending on the characteristics of verbal stimuli being held in STM and severity of the word processing disorder. The close association of processing and verbal STM impairment is worth considering in our approaches to assessment and rehabilitation of language disorders in aphasia. In this paper, we present a comprehensive test battery to assess language and verbal STM abilities in aphasia with data from thirty individuals with aphasia and ten aged-matched controls. Clinical and research applications of the test battery are discussed

Syntactic Priming Treatment for Severe Agrammatic Aphasia: A Case Study

Treatment of sentence production deficits in aphasia has been approached from several different perspectives. This study applies a syntactic priming approach, alternating sentence repetition priming trials with picture description trials, to treatment for an individual with a moderate to severe Broca’s aphasia with severe agrammatism. This priming approach, using a simple active subject-verb-object sentence, led to improved syntax and sentence production abilities for all four of our dependent measures: verb inflections, inclusion of subject-verb-object elements, correct word order, and use of well-formed sentences. Ideas for future studies using this syntactic priming treatment are discussed

Verbal Perseveration in Aphasia during Word-String Repetition: Effects of a Filled versus Silent Interstimulus Interval

Verbal perseveration is experienced to varying degrees by many individuals with aphasia. Perseveration is defined as an inappropriate recurrence or repetition of a previously produced response in place of the target item. Despite numerous studies of factors influencing the occurrence of perseverations and several prominent accounts of their occurrence in aphasia (Cohen & Dehaene, 1998; Martin & Dell, 2004; 2007) there are only a few studies that address the treatment of perseveration in aphasia. The theoretical framework of the present study is Dell, Burger & Švec‟s (1997) account of perseverations: Perseverations are more likely to occur when activation of the target word is weak (reduced connection strength) and residual activation of a retrieved lexical representation is strong enough to be selected in error