Memory impairment and executive control in individuals with stroke-induced aphasia

Reading for Meaning: The Influence of Reader Characteristics on Paragraph Understanding in Aphasia

PURPOSE

The study improves our understanding of the reading comprehension difficulties seen in people with aphasia. It investigates the influence of reader characteristics, including personal demographic variables, and linguistic and wider cognitive skills, on text comprehension.

METHOD

Seventy-five people with aphasia and 87 neurologically typical readers completed a test of paragraph comprehension. People with aphasia also completed background tests of language, attention, recognition memory, and executive functions. The influence of demographic variables (age, gender, and level of education) was analyzed separately in the group of people with aphasia and the typical readers using analyses of variance. In the people with aphasia, the relationship between paragraph comprehension and the language and cognitive tests was explored using correlational analyses.

RESULTS

In the typical readers, there was a significant effect of gender and level of education and a significant three-way interaction. For the people with aphasia, there were no significant effects of demographic variables. Significant positive correlations were found between performance on paragraph comprehension and each of the language tests and with tests of auditory attention, executive functions, and recognition memory for words.

CONCLUSIONS

In people with aphasia, the effects of demographic variables were overshadowed by the effect of their language difficulties. The association seen across language measures reflects the shared semantic representations across single-word, sentence, and text levels, across modalities. The study emphasizes the importance of attention, executive functions, and short-term memory in the comprehension of and memory for what we read. The contribution of both language difficulties and wider cognitive skills needs to be considered when planning intervention.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24695451.

Eye movement in reading and linguistic processing among bilingualism in oculomotor apraxia in patients with aphasia

The present study compared linguistic processes and eye movement among individuals diagnosed with oculomotor apraxia (OMA) and the influence of bilingualism on OMA. Four patients consisting of one male and three females were diagnosed with OMA, and a group of four healthy individuals, comprising two males and two females who were all right-hand dominant. Also, a group of four stroke patients without ocular apraxia. Findings show that pointing skills in both the first (L1) and second language (L2) have increased, demonstrating statistical significance ( P-value < .001 and P-value = .02, respectively). Also, simple commands over time have increased in L1 and L2, showing statistical significance ( P-value < .01 and P-value < .01, respectively). Naming skills in L1 have increased over time, demonstrating statistical insignificance ( P-value < .01). However, in L2, no statistically significant change was observed ( P-value = .08). This skill in L1 in patients with OMA was significantly reduced compared to the healthy control group ( P-value = .03). Still, patients with OMA showed no statistically significant difference from their healthy counterparts ( P-value = .15). The orthographic ability of patients in L1 during the study period did not statistically change significantly ( P-value = .11). This skill level in L1 between patients with OMA and the healthy control group did not show a statistically significant difference ( P-value = .06). Still, there was a statistically significant change in the healthy control group in L2 ( P-value < .01). These findings suggest that the bilingual does not reflect a general executive in attentional guidance but could reflect more efficient guidance only under specific tasks.

Common Neuroanatomical Substrate of Cholinergic Pathways and Language-Related Brain Regions as an Explanatory Framework for Evaluating the Efficacy of Cholinergic Pharmacotherapy in Post-Stroke Aphasia: A Review

Despite the relative scarcity of studies focusing on pharmacotherapy in aphasia, there is evidence in the literature indicating that remediation of language disorders via pharmaceutical agents could be a promising aphasia treatment option. Among the various agents used to treat chronic aphasic deficits, cholinergic drugs have provided meaningful results. In the current review, we focused on published reports investigating the impact of acetylcholine on language and other cognitive disturbances. It has been suggested that acetylcholine plays an important role in neuroplasticity and is related to several aspects of cognition, such as memory and attention. Moreover, cholinergic input is diffused to a wide network of cortical areas, which have been associated with language sub-processes. This could be a possible explanation for the positive reported outcomes of cholinergic drugs in aphasia recovery, and specifically in distinct language processes, such as naming and comprehension, as well as overall communication competence. However, evidence with regard to functional alterations in specific brain areas after pharmacotherapy is rather limited. Finally, despite the positive results derived from the relevant studies, cholinergic pharmacotherapy treatment in post-stroke aphasia has not been widely implemented. The present review aims to provide an overview of the existing literature in the common neuroanatomical substrate of cholinergic pathways and language related brain areas as a framework for interpreting the efficacy of cholinergic pharmacotherapy interventions in post-stroke aphasia, following an integrated approach by converging evidence from neuroanatomy, neurophysiology, and neuropsychology.

Predictors of Therapy Response in Chronic Aphasia: Building a Foundation for Personalized Aphasia Therapy

Chronic aphasia, a devastating impairment of language, affects up to a third of stroke survivors. Speech and language therapy has consistently been shown to improve language function in prior clinical trials, but few clinicially applicable predictors of individual therapy response have been identified to date. Consequently, clinicians struggle substantially with prognostication in the clinical management of aphasia. A rising prevalence of aphasia, in particular in younger populations, has emphasized the increasing demand for a personalized approach to aphasia therapy, that is, therapy aimed at maximizing language recovery of each individual with reference to evidence-based clinical recommendations. In this narrative review, we discuss the current state of the literature with respect to commonly studied predictors of therapy response in aphasia. In particular, we focus our discussion on biographical, neuropsychological, and neurobiological predictors, and emphasize limitations of the literature, summarize consistent findings, and consider how the research field can better support the development of personalized aphasia therapy. In conclusion, a review of the literature indicates that future research efforts should aim to recruit larger samples of people with aphasia, including by establishing multisite aphasia research centers.

Sentence types and complexity of spontaneous discourse productions by Cantonese-speakers with traumatic brain injury- a preliminary report

Previous investigations on sentence production in English-speaking individuals with traumatic brain injury (TBI) have yielded mixed conclusions based on their findings. While some studies found comparable sentence complexity between speakers with TBI and control speakers, others reported more syntactic and lexical errors, reduced sentence complexity, and erroneous word order transpositions in the sentence production of speakers with TBI. These contradictory findings could possibly be due to the use of language measures that were less sensitive to subtle syntactic impairments among speakers with TBI. In this preliminary report, the language samples obtained from 11 Cantonese-speaking participants with mild-moderate TBI in Guangzhou, with a mean age of 37.6 and mean years of education of 10 years, and nine control speakers with a similar age range and education background were analyzed using in-depth linguistic-oriented frameworks adopted from pervious works in Cantonese. The results indicated that the TBI group produced more errors, different varieties of sentence types, and lower syntactic complexity in their sentence production compared with the control group. The findings suggested that the more refined and linguistic-oriented measures used in the present study were more sensitive in identifying the subtle syntactic impairments produced by the participants with TBI.

Altered hippocampal functional connectivity patterns in patients with cognitive impairments following ischaemic stroke: A resting-state fMRI study

BACKGROUND

Ischemic stroke with cognitive impairment is a considerable risk factor for developing dementia. Identifying imaging markers of cognitive impairment following ischemic stroke will help to develop prevention strategies against post-stroke dementia.

METHODS

We investigated the hippocampal functional connectivity (FC) pattern following ischemic stroke, using resting-state fMRI (rs-fMRI). Thirty-three cognitively impaired patients after ischemic stroke and sixteen age-matched controls with no known history of neurological disorder were recruited for the study. No patient had a direct ischaemic insult to hippocampus on the examination of brain imaging. Seven subfields of hippocampus were used as seeds region for FC analyses.

RESULTS

Across all hippocampal subfields, FC with the inferior parietal lobule was reduced in stroke patients as compared with healthy controls. This decreased FC included both supramarginal gyrus and angular gyrus. The FC of hippocampal subfields with cerebellum was increased. Importantly, the degree of the altered FC between hippocampal subfields and inferior parietal lobule was associated with their impaired memory function.

CONCLUSION

Our results demonstrated that decreased hippocampal-inferior parietal lobule connectivity was associated with cognitive impairment in patients with ischemic stroke. These findings provide novel insights into the role of hippocampus in cognitive impairment following ischemic stroke.

Post-Stroke Working Memory Dysfunction: A Meta-Analysis and Systematic Review

This review investigates the severity and nature of post-stroke working memory deficits with reference to the multi-component model of working memory. We conducted a systematic search in PubMed up to March 2019 with search terms for stroke and memory. Studies on adult stroke patients, that included a control group, and assessed working memory function, were selected. Effect sizes (Hedges' g) were extracted from 50 studies (in total 3,084 stroke patients) based on the sample size, mean and standard deviation of patients and controls. Performance of stroke patients was compared to healthy controls on low-load (i.e. capacity) and high-load (executively demanding) working memory tasks, grouped by modality (verbal, non-verbal). A separate analysis compared patients in the sub-acute and the chronic stage. Longitudinal studies and effects of lesion location were systematically reviewed. Stroke patients demonstrated significant deficits in working memory with a moderate effect size for both low-load (Hedges' g = -.58 [-.82 to -.43]) and high-load (Hedges' g = -.59 [-.73 to -.45]) tasks. The effect sizes were comparable for verbal and non-verbal material. Systematically reviewing the literature showed that working memory deficits remain prominent in the chronic stage of stroke. Lesions in a widespread fronto-parietal network are associated with working memory deficits. Stroke patients show decrements of moderate magnitude in all subsystems of working memory. This review clearly demonstrates the global nature of the impairment in working memory post-stroke.

Performance differences between aphasia and healthy aging on an executive function test battery

Purpose: Executive function (EF) deficits commonly co-occur with other linguistic and non-linguistic deficits in aphasia. The questions about whether, and to what extent, people with aphasia (PWA) present deficits on different executive functions (EFs) is relatively understudied.Method: In this study, four EFs, set-switching, updating, inhibition, and dual task processing were evaluated in aphasia and healthy groups. Three groups of participants: 30 healthy young, 30 healthy old, and 10 PWA were assessed on four tasks, Colour Trails Test (CTT 1 and 2), Conners' Continuous Performance Test II (CPT II), n-back (1- and 2-back), and divided attention task that tapped into different EFs. In order to examine performance differences on the EF tasks between the participant groups, repeated measures and multivariate analysis of variances with follow-up pairwise comparisons were computed. Pearson product-moment correlations were conducted to evaluate the strength and direction of the association between aphasia severity (on Western Aphasia Battery-Revised) and executive functioning.Result: PWA demonstrated significantly diminished performance on all EF tasks in comparison to healthy groups and differences were distinct on the higher-level complexity tasks such as the 2-back and CTT 2. The healthy older group demonstrated elevated response times on the CTT, CPT II, and divided attention tasks, and decreased sensitivity scores on the CPT II and n-back in comparison to the younger group. Also, aphasia severity correlated with reduced performance on selective EF measures.Conclusion: This study emphasises the importance of investigating EF deficits in PWA and its potential relationship to language behaviour. Understanding EF is critical for comprehension of linguistic and non-linguistic deficits and in planning treatment for PWA.

Task-Related Differences in Eye Movements in Individuals With Aphasia

Background: Neurotypical young adults show task-based modulation and stability of their eye movements across tasks. This study aimed to determine whether persons with aphasia (PWA) modulate their eye movements and show stability across tasks similarly to control participants.

Methods: Forty-eight PWA and age-matched control participants completed four eye-tracking tasks: scene search, scene memorization, text-reading, and pseudo-reading.

Results: Main effects of task emerged for mean fixation duration, saccade amplitude, and standard deviations of each, demonstrating task-based modulation of eye movements. Group by task interactions indicated that PWA produced shorter fixations relative to controls. This effect was most pronounced for scene memorization and for individuals who recently suffered a stroke. PWA produced longer fixations, shorter saccades, and less variable eye movements in reading tasks compared to controls. Three-way interactions of group, aphasia subtype, and task also emerged. Text-reading and scene memorization were particularly effective at distinguishing aphasia subtype. Persons with anomic aphasia showed a reduction in reading saccade amplitudes relative to their respective control group and other PWA. Persons with conduction/Wernicke’s aphasia produced shorter scene memorization fixations relative to controls or PWA of other subtypes, suggesting a memorization specific effect. Positive correlations across most tasks emerged for fixation duration and did not significantly differ between controls and PWA.

Conclusion: PWA generally produced shorter fixations and smaller saccades relative to controls particularly in scene memorization and text-reading, respectively. The effect was most pronounced recently after a stroke. Selectively in reading tasks, PWA produced longer fixations and shorter saccades relative to controls, consistent with reading difficulty. PWA showed task-based modulation of eye movements, though the pattern of results was somewhat abnormal relative to controls. All subtypes of PWA also demonstrated task-based modulation of eye movements. However, persons with anomic aphasia showed reduced modulation of saccade amplitude and smaller reading saccades, possibly to improve reading comprehension. Controls and PWA generally produced stabile fixation durations across tasks and did not differ in their relationship across tasks. Overall, these results suggest there is potential to differentiate among PWA with varying subtypes and from controls using eye movement measures of task-based modulation, especially reading and scene memorization tasks.

Role of the left hemisphere in visuospatial working memory

Visuospatial processing deficits are typically associated with damage to the right hemisphere. However, deficits on spatial working memory have been reported among some individuals with focal left hemisphere damage (LHD). It has been suggested that the left hemisphere may play a role in such non-verbal working memory tasks due to the use of subvocal, verbally-mediated strategies. The current study investigated the role of the left hemisphere in spatial working memory by testing spatial span performance, both forward and backward, in a large group of individuals with a history of left hemisphere stroke. Our first aim was to establish whether individuals with LHD are indeed impaired on spatial span tasks using standardized span tasks with published normative data. Our second aim was to identify the role that language plays in supporting spatial working memory by comparing LHD individuals with and without aphasia, and by relating spatial span performance to performance on a series of language measures. Our third aim was to identify left hemisphere brain regions that contribute to spatial working memory using voxel-based lesion symptom mapping (VLSM), a whole-brain statistical approach that identifies regions critical to a particular behavior on a voxel-by-voxel basis. We found that 28% of individuals with LHD performed in the clinically-impaired range on forward spatial span and 16% performed in the clinically-impaired range on backward spatial span. There were no significant differences in performance between individuals with and without aphasia, and there were no correlations between spatial span performance and language functions such as repetition and comprehension. The VLSM analysis showed that backward spatial span was associated with a left fronto-parietal network consisting of somatosensory cortex, the supramarginal gyrus, lateral prefrontal cortex, and the frontal eye fields. Regions identified in the VLSM analysis of forward spatial span did not reach the conservative statistical threshold for significance. Overall, these results suggest that spatial working memory, as measured by spatial span, can be significantly disrupted in a subset of individuals with LHD whose lesions infringe on a network of regions in the left hemisphere that have been implicated in domain-general working memory and attentional control mechanisms.

Aerobic Exercise as an Adjuvant to Aphasia Therapy: Theory, Preliminary Findings, and Future Directions

PURPOSE

This study investigated whether participation in aerobic exercise enhances the effects of aphasia therapy, and the degree to which basal serum brain-derived neurotropic factor (BDNF) concentrations fluctuate after the beginning of aerobic exercise or stretching activities in individuals with poststroke aphasia.

METHODS

The study used a single-subject, multiple-baseline design. Seven individuals with chronic poststroke aphasia participated in 2 Blocks of aphasia therapy: aphasia therapy alone (Block 1), followed by aphasia therapy with the addition of aerobic activity via bicycle ergometer (n = 5) or stretching (n = 2) (Block 2). Serum BDNF concentrations from blood draws were analyzed in 4 participants who exercised and in 1 participant who stretched.

FINDINGS

Three of the five exercise participants demonstrated larger Tau-U effects when aphasia therapy was paired with aerobic exercise, whereas 1 of the 2 stretching participants demonstrated a larger effect size when aphasia therapy was paired with stretching. Group-level comparisons revealed a greater overall increase in effect size in the aerobic exercise group, as indicated by differences in Tau-U weighted means. BDNF data showed that all 4 exercise participants demonstrated a decrease in BDNF concentrations during the first 6 weeks of exercise and an increase in BDNF levels near or at baseline during the last 6 weeks of exercise. The stretching participant did not show the same pattern.

IMPLICATIONS

Additional research is needed to understand the mechanism of effect and to identify the factors that mediate response to exercise interventions, specifically the optimal dose of exercise and timing of language intervention with exercise. ClinicalTrials.gov identifier: NCT01113879.

Neuropsychological assessment of 86-year-old man with Broca's aphasia complaining of memory difficulties

We report the clinical assessment of J.P., an 86 year-old man with Broca's aphasia complaining of memory problems. Our aim was to objectively investigate his level of cognitive functioning using standardized neuropsychological tests in order to determine the nature of his memory impairment. J.P.'s medical history included left-middle cerebral artery (left-MCA) stroke, high frequency hearing loss, macular degeneration, and a recent hospitalization related to a fall. Results from his neuropsychological testing and from information gathered during the clinical interview with his wife suggested that a deficit in executive functioning might have been the source for some of his perceived memory problems. We were unable to detect any progressive cognitive decline that might have been suggestive of something more sinister. Despite his age J.P. was a fully functioning and highly contributing member of his society who was completing quite complex activities of daily living (ADLs). We provided J.P. with a compensatory set of strategies in order for him to circumvent his executive difficulties and impairment in expressive language. In the elderly population survivors of stroke are continuing to rise with improvements in drug treatment and primary care. This case study is important as it provides information on neuropsychological assessment in aphasia; and draws attention to valuable information in a client's clinical history that might help clarify the prognosis.

Different Cognitive Profiles of Patients with Severe Aphasia

Cognitive dysfunction frequently occurs in aphasic patients and primarily compromises linguistic skills. However, patients suffering from severe aphasia show heterogeneous performance in basic cognition. Our aim was to characterize the cognitive profiles of patients with severe aphasia and to determine whether they also differ as to residual linguistic abilities. We examined 189 patients with severe aphasia with standard language tests and with the CoBaGA (Cognitive Test Battery for Global Aphasia), a battery of nonverbal tests that assesses a wide range of cognitive domains such as attention, executive functions, intelligence, memory, visual-auditory recognition, and visual-spatial abilities. Twenty patients were also followed longitudinally in order to assess their improvement in cognitive skills after speech therapy. Three different subgroups of patients with different types and severity of cognitive impairment were evidenced. Subgroups differed as to residual linguistic skills, in particular comprehension and reading-writing abilities. Attention, reasoning, and executive functions improved after language rehabilitation. This study highlights the importance of an extensive evaluation of cognitive functions in patients with severe aphasia.

Influence of Cognitive Ability on Therapy Outcomes for Anomia in Adults With Chronic Poststroke Aphasia

PURPOSE

The relationship between cognitive abilities and aphasia rehabilitation outcomes is complex and remains poorly understood. This study investigated the influence of language and cognitive abilities on anomia therapy outcomes in adults with aphasia.

METHOD

Thirty-four adults with chronic aphasia participated in Aphasia Language Impairment and Functioning Therapy. A language and cognitive assessment battery, including 3 baseline naming probes, was administered prior to therapy. Naming accuracy for 30 treated and 30 untreated items was collected at posttherapy and 1-month follow-up. Multiple regression models were computed to evaluate the relationship between language and cognitive abilities at baseline and anomia therapy outcomes.

RESULTS

Both language and cognitive variables significantly influenced anomia therapy gains. Verbal short-term memory ability significantly predicted naming gains for treated items at posttherapy (β = -.551, p = .002) and for untreated items at posttherapy (β = .456, p = .014) and 1-month follow-up (β = .455, p = .021). Furthermore, lexical-semantic processing significantly predicted naming gains for treated items at posttherapy (β = -.496, p = .004) and 1-month follow-up (β = .545, p = .012).

CONCLUSIONS

Our findings suggest that individuals' cognitive ability, specifically verbal short-term memory, affects anomia treatment success. Further research into the relationship between cognitive ability and anomia therapy outcomes may help to optimize treatment techniques.

Cognitive performance in aphasia due to stroke: a systematic review

Aphasia persists in about one third of the patients with left hemisphere stroke, yet it is not known if it enhances the risk of dementia, beyond what results from any focal brain lesion. This lack of knowledge is mostly related to the difficulty of cognitive evaluation in people with aphasia. The development of tools aiming to assess cognitive functioning in people with aphasia could overcome this limitation. The aim of this systematic review was to evaluate the frequency and the profile of cognitive impairment in stroke patients with aphasia, to assemble existing non-verbal instruments to be used in patients with language disorders.

We conducted a systematic review, through Web of Science, Medline and PsycINFO electronic databases, of articles published between January 1995 and October 31, 2015 related to aphasia due to stroke and non-verbal neurobehavioral tests.

The electronic search identified 2487 citations. After screening 38 were included in this review. Additionally 53 articles were selected among the references of analyzed publications of which nine were included producing a total of 47 articles. The cognitive tests more frequently used in persons with aphasia are the Figures Memory Tests, Visual Memory Span, Progressive Matrices, Wisconsin Card Sorting Test and some measures of the Test of Everyday Attention, covering a reasonable range of cognitive domains. The majority of studies across cognitive domains reported lower scores for patients with aphasia compared with controls. No specific difficulties were reported regarding tests applicability.

There are several tools available to assess cognitive functions in aphasia. Although there is some variability, patients with aphasia tend to present lower scores than those with left hemisphere stroke without aphasia or healthy subjects. A consensus tool should be developed to screen or evaluate cognition and dementia in individuals with language impairment.

Novel word acquisition in aphasia: Facing the word-referent ambiguity of natural language learning contexts

Recent research suggests that some people with aphasia preserve some ability to learn novel words and to retain them in the long-term. However, this novel word learning ability has been studied only in the context of single word-picture pairings. We examined the ability of people with chronic aphasia to learn novel words using a paradigm that presents new word forms together with a limited set of different possible visual referents and requires the identification of the correct word-object associations on the basis of online feedback. We also studied the relationship between word learning ability and aphasia severity, word processing abilities, and verbal short-term memory (STM). We further examined the influence of gross lesion location on new word learning. The word learning task was first validated with a group of forty-five young adults. Fourteen participants with chronic aphasia were administered the task and underwent tests of immediate and long-term recognition memory at 1 week. Their performance was compared to that of a group of fourteen matched controls using growth curve analysis. The learning curve and recognition performance of the aphasia group was significantly below the matched control group, although above-chance recognition performance and case-by-case analyses indicated that some participants with aphasia had learned the correct word-referent mappings. Verbal STM but not word processing abilities predicted word learning ability after controlling for aphasia severity. Importantly, participants with lesions in the left frontal cortex performed significantly worse than participants with lesions that spared the left frontal region both during word learning and on the recognition tests. Our findings indicate that some people with aphasia can preserve the ability to learn a small novel lexicon in an ambiguous word-referent context. This learning and recognition memory ability was associated with verbal STM capacity, aphasia severity and the integrity of the left inferior frontal region.

Cognitive deficits in post-stroke aphasia

The assessment of aphasics' cognitive performance is challenging and such patients are generally excluded from studies that describe cognitive deficits after stroke. We evaluated aphasics' performance in cognitive tasks compared to non-aphasic subjects. A sample of 47 patients (21 aphasics, 17 non-aphasics with left hemisphere lesions and 9 non-aphasics with right hemisphere lesions) performed cognitive tasks (attention, verbal and visual memory, executive functions, visuospatial skills and praxis). Aphasic patients performed poorer than all non-aphasics in Digit Span (p < 0.001), Clock-Drawing Test (p = 0.006), Verbal memory (p = 0.002), Visual Memory (p < 0.01), Verbal Fluency (p < 0.001), and Gesture Praxis (p < 0.001). Aphasia severity correlated with performance in Trail Making test part B (p = 0.004), Digit Span forward (p < 0.001) and backwards (p = 0.011), and Gesture Praxis (p = 0.002). Aphasia is accompanied by deficits not always easy to be evaluated by cognitive tests due to speech production and motor impairments. Assessment of cognitive functions in aphasics might contribute to optimize therapeutic intervention.

Comprehension of Co-Speech Gestures in Aphasic Patients: An Eye Movement Study

BACKGROUND

Co-speech gestures are omnipresent and a crucial element of human interaction by facilitating language comprehension. However, it is unclear whether gestures also support language comprehension in aphasic patients. Using visual exploration behavior analysis, the present study aimed to investigate the influence of congruence between speech and co-speech gestures on comprehension in terms of accuracy in a decision task.

METHOD

Twenty aphasic patients and 30 healthy controls watched videos in which speech was either combined with meaningless (baseline condition), congruent, or incongruent gestures. Comprehension was assessed with a decision task, while remote eye-tracking allowed analysis of visual exploration.

RESULTS

In aphasic patients, the incongruent condition resulted in a significant decrease of accuracy, while the congruent condition led to a significant increase in accuracy compared to baseline accuracy. In the control group, the incongruent condition resulted in a decrease in accuracy, while the congruent condition did not significantly increase the accuracy. Visual exploration analysis showed that patients fixated significantly less on the face and tended to fixate more on the gesturing hands compared to controls.

CONCLUSION

Co-speech gestures play an important role for aphasic patients as they modulate comprehension. Incongruent gestures evoke significant interference and deteriorate patients' comprehension. In contrast, congruent gestures enhance comprehension in aphasic patients, which might be valuable for clinical and therapeutic purposes.

Assessment and treatment of short-term and working memory impairments in stroke aphasia: a practical tutorial

BACKGROUND

Aphasia following stroke refers to impairments that affect the comprehension and expression of spoken and/or written language, and co-occurring cognitive deficits are common. In this paper we focus on short-term and working memory impairments that impact on the ability to retain and manipulate auditory-verbal information. Evidence from diverse paradigms (large group studies, case studies) report close links between short-term/working memory and language functioning in aphasia. This evidence leads to the hypothesis that treating such memory impairments would improve language functioning. This link has only recently been acknowledged in aphasia treatment but has not been embraced widely by clinicians.

AIMS

To examine the association between language, and short-term and working memory impairments in aphasia. To describe practical ways of assessing short-term and working memory functioning that could be used in clinical practice. To discuss and critically appraise treatments of short-term and working memory reported in the literature.

METHODS & PROCEDURES

Taking a translational research approach, this paper provides clinicians with current evidence from the literature and practical information on how to assess and treat short-term and working memory impairments in people with aphasia. Published treatments of short-term and/or working memory in post-stroke aphasia are discussed through a narrative review.

MAIN CONTRIBUTIONS

This paper provides the following. A theoretical rationale for adopting short-term and working memory treatments in aphasia. It highlights issues in differentially diagnosing between short-term, working memory disorders and other concomitant impairments, e.g. apraxia of speech. It describes short-term and working memory assessments with practical considerations for use with people with aphasia. It also offers a description of published treatments in terms of participants, treatments and outcomes. Finally, it critically appraises the current evidence base relating to the treatment of short-term and working memory treatments.

CONCLUSIONS

The links between short-term/working memory functioning and language in aphasia are generally acknowledged. These strongly indicate the need to incorporate assessment of short-term/working memory functioning for people with aphasia. While the supportive evidence for treatment is growing and appears to highlight the benefits of including short-term/working memory in aphasia treatment, the quality of the evidence in its current state is poor. However, because of the clinical needs of people with aphasia and the prevalence of short-term/working memory impairments, incorporating related treatments through practice-based evidence is advocated.

Characteristics of Cognitive Impairment in Patients With Post-stroke Aphasia

Objective

To analyze cognitive functions of post-stroke aphasia patients compared to patients having right hemispheric stroke and left hemispheric lesions without aphasia, and to look for a relationship between cognitive deficits and aphasia severity.

Methods

Thirty-six patients with right hemispheric stroke (group 1), 32 with left hemispheric lesion without aphasia (group 2), and 26 left hemispheric stroke patients with aphasia (group 3) completed a set of tests in the computerized neurocognitive function batteries for attention, executive function and intelligence and Korean version of Western Aphasia Battery. Data analyses explored cognitive characteristics among the three groups and the correlation between cognitive deficits and aphasia severity.

Results

Right hemispheric and left hemispheric stroke patients without aphasia showed similar findings except for digit span forward test. Cognitive tests for working memory and sustained attention were significantly impaired in the aphasic patients, but intelligence was shown to be similar in the three groups. Significant correlation between cognitive deficit and aphasia severity was only shown in some attention tests.

Conclusion

Cognitive deficits may be accompanied with post-stroke aphasia and there are possible associations between language and cognitive measures. Therefore, detection and treatment towards coexisting cognitive impairment may be necessary for efficient aphasia treatment.

Psychophysiological Analysis of the Influence of Vasopressin on Speech in Patients with Post-Stroke Aphasias

Speech is an attribute of the human species. Central speech disorders following stroke are unique models for the investigation of the organization of speech. Achievements in neurobiology suggest that there are possible neuroendocrine mechanisms involved in the organization of speech. It is known that the neuropeptide vasotocin, analogous of vasopressin in mammals, modulates various components of vocalization in animals. Furthermore, the positive influence of vasopressin on memory, which plays an important role in the formation of speech, has been described. In this study, speech organization processes and their recovery with the administration of vasopressin (1-desamino-8-D-arginin-vasopressin) to 26 patients with chronic aphasias after stroke were investigated. Results showed that sub-endocrine doses of the neuropeptide with intranasal administration had positive influence primarily on simple forms of speech and secondarily on composite forms. There were no statistically significant differences between the sensory and integrative components of the organization of speech processes with vasopressin. In all cases, the positive effect of the neuropeptide was demonstrated. As a result of the effects, speech regulated by both brain hemispheres improved. It is suggested that the neuropeptide optimizes the activity both in the left and right hemispheres, with primary influence on the right hemisphere. The persistence of the acquired effects is explained by an induction of compensatory processes resulting in the reorganization of the intra-central connections by vasopressin.

Old and recent approaches to the problem of non-verbal conceptual disorders in aphasic patients

From the first research on aphasia, it has been shown that, in addition to verbal communication disorders, aphasic patients often have difficulty on non-verbal cognitive tasks, which can actually be solved without the use of language. In this survey, I will discuss in a historical perspective the different interpretations provided by classical and contemporary authors to explain this puzzling observation. First, I will take into account the different positions of classical authorities on this topic, starting from the first debates (mainly based on anatomo-clinical observations) on the organisation of language in the brain. Then, I will attempt to summarize the work of authors who have tackled this complex issue more recently, in systematic investigations using methods drawn from experimental psychology, to clarify the meaning of non-verbal cognitive disorders in aphasia. Finally, in the last part of the survey, I will discuss the interpretation of proponents of the 'semantic hub' hypothesis who have tried to analyse and explain the differences between the non-verbal semantic defects of patients with semantic dementia and aphasic stroke patients. The hypothesis which assumes that most non-verbal cognitive disorders observed in aphasic patients are due to a preverbal conceptual disorder, which cannot be attributed to a loss of semantic representations but rather to a defect in their controlled retrieval, seems substantially confirmed. Nevertheless, two main issues must still be clarified. The first is that some of the non-verbal cognitive defects of aphasic patients seem due to the negative influence of language disturbances on abstract non-verbal cognitive activities, rather than to a preverbal conceptual disorder. The second issue concerns the exact nature and the neuroanatomical correlates of the defective controlled retrieval of unimpaired conceptual representations, which should subsume most of the non-verbal cognitive disorders of aphasic patients.

Measuring working memory deficits in aphasia

PURPOSE

Many adults with aphasia demonstrate concomitant deficits in working memory (WM), but such deficits are difficult to quantify because of a lack of validated measures as well as the complex interdependence between language and WM. We examined the feasibility, reliability, and internal consistency of an n-back task for evaluating WM in aphasia, then explored the influence of domain-general (WM load, reaction time, age) and domain-specific (language) factors.

METHOD

Fourteen adults with aphasia and 12 age-and education-matched controls completed n-back tasks varying in stimulus type (high-frequency, low-frequency, or non-nameable stimuli) and WM load (0-, 1-, and 2-back). Data analyses explored the impact of these variables within and across participants and groups.

RESULTS

n-Back scores were collectively reliable across conditions. Both groups performed similarly across stimulus types with significantly greater WM accuracy for nameable versus non-nameable stimuli. Compared to the controls, adults with aphasia were significantly more affected by increasing WM load. RT effects generally paralleled accuracy data, whereas age effects were inconsistent across tasks.

CONCLUSIONS

These data are consistent with WM deficits in aphasia, for which the n-back task holds promise for clinical quantification.

LEARNING OUTCOMES

Readers will be able to: (a) define working memory, (b) discuss the difficulty inherent in removing language from a complex cognitive task, and (c) describe how the n-back task may contribute to measuring working memory capacity in individuals with aphasia.

Short-term and working memory impairments in aphasia

The aim of the present study is to investigate short-term memory and working memory deficits in aphasics in relation to the severity of their language impairment. Fifty-eight aphasic patients participated in this study. Based on language assessment, an aphasia score was calculated for each patient. Memory was assessed in two modalities, verbal and spatial. Mean scores for all memory tasks were lower than normal. Aphasia score was significantly correlated with performance on all memory tasks. Correlation coefficients for short-term memory and working memory were approximately of the same magnitude. According to our findings, severity of aphasia is related with both verbal and spatial memory deficits. Moreover, while aphasia score correlated with lower scores in both short-term memory and working memory tasks, the lack of substantial difference between corresponding correlation coefficients suggests a possible primary deficit in information retention rather than impairment in working memory.

Performance of Individuals with Left-Hemisphere Stroke and Aphasia and Individuals with Right Brain Damage on Forward and Backward Digit Span Tasks

BACKGROUND: Working memory (WM) limitations have been suggested as a significant source of the linguistic processing deficits observed in individuals with aphasia (IWA). Digits forward (DF) and digits backward (DB) span tasks are frequently used to study WM in both healthy and clinical populations. Unfortunately, only a handful of studies have explored digit span in IWA. AIMS: The purpose of the current study is to measure the DF and DB spans of IWA and compare their digit spans to a group with right brain damage, but no aphasia (RBD). Additionally, DF and DB span is compared within each group to determine if there is indeed a performance differential that may support the idea that DB is a more difficult WM task in these populations. METHODS AND PROCEDURES: Seventeen IWA and 14 individuals with RBD participated in a DF and DB span task. Modifications to the span tasks were implemented to accommodate language deficits. A series of two digits were orally presented to each participant continuing to a maximum of eight digits. There were seven trials per digit series. Participants were asked to point to the correct order of digits on a written 1-9 digit list provided on individual note cards or verbally repeat the numbers if the participant was able to do so. OUTCOMES AND RESULTS: IWA demonstrated shorter digit spans than the RBD group. Both groups performed worse on the DB span tasks than the DF span tasks. CONCLUSIONS: The results are consistent with previous studies suggesting that DB span is shorter than DF span in other populations and that there are differences in performance on digit span tasks between the two groups. The differences between RBD group and IWA may be explained by decreased attentional capacity or inefficient resource allocation in IWA, or alternatively, a deficient phonological loop. Future studies should explore these possibilities.

Factors Influencing AAC Usage by Individuals With Aphasia

Instructing individuals with aphasia in the usage of AAC strategies and devices is a challenging endeavor. Not only does this population present with a wide range of linguistic impairments, but many individuals also demonstrate cognitive deficits, which may adversely affect communication. This paper will summarize the wide variety of cognitive deficits demonstrated by individuals with aphasia, specifically attention, memory and executive functioning problems. In addition, we will review the impact of these cognitive impairments on communicative competence. Finally, we will discuss an intervention, the Multimodality Communication Training Program (MCTP), designed to address the cognitive impairments that influence AAC intervention.

Verbal learning in Alzheimer's disease: cumulative word knowledge gains across learning trials

Research regarding learning in Alzheimer's disease (AD) patients has been mixed. Learning capacity might be better indexed using a score that reflects the interaction between the learning slope and total recall, referred to as the Cumulative Word Learning (CWL) score. We compared a group of AD patients to normal participants using a traditional index of learning and the CWL score that were derived from the Hopkins Verbal Learning Test-Revised (HVLT-R). The HVLT-R is a supra-span, list-learning test containing 12 words from three semantic categories. The results indicated that the sample of AD patients performed within the average range, using the traditional learning z score. Although mild AD patients were not found to differ from controls in the traditional learning z score, a significant difference was noted for the CWL score. The moderate AD patients differed from the normal controls in both learning measures. Furthermore, unlike the traditional learning score, the CWL score was a significant predictor of overall cognitive functioning, as indexed using their Mini-Mental State Examination (MMSE) score. Thus, the CWL score might be a more sensitive indicator overall of total learning capacity and may be useful in staging Alzheimer's disease because of increased resilience to floor effects.

Stroke and episodic memory disorders

Memory impairments are common after stroke, and the anatomical basis for impairments may be quite variable. To determine the range of stroke-related memory impairment, we identified all case reports and group studies through the Medline database and the Science Citation Index. There is no hypothesis about memory that is unique to stroke, but there are several important facets of memory impairment after stroke: (1) Every node of the limbic system implicated in memory may be damaged by stroke but very rarely in isolation and the combination of amnesia with the associated deficits often illuminates additional aspects of memory functions. (2) Stroke produces amnesia by damage to critical convergence white matter connections of the limbic system, and stroke is the only etiology of amnesia that can delineate the entire pathway of memory and critical convergence points. (3) Stroke also impairs memory, without causing classical amnesia, by damaging brain regions responsible for cognitive processes, some modality specific and some more generally strategic, that are essential for normal learning and recall.

Prediction of functional rehabilitation outcomes in clients with stroke

OBJECTIVES

To evaluate the validity of the Neurobehavioral Cognitive Status Examination (NCSE or Cognistat) and to determine its effects in order to estimate the functional outcomes of survivors with stroke.

METHODS

The present study first studied the factor structure NCSE in 148 Chinese survivors with stroke (aged 45-91 years). They were admitted to hospital consecutively and recruited prospectively. The relationship of NCSE with Functional Independence Measures (FIM), a set of measures commonly adopted as an indicator of the outcome of rehabilitation, was studied.

RESULTS

One hundred and forty-eight patients with stroke (49.3% male, 50.7% female), with a mean age of 70.38 and an average number of years of education of 3.50 years joined the study. A two-factor NCSE structure was obtained, namely verbal-spatial and integrated cognition, accounting for 62.77% of the variance. A significant relationship between NCSE factors and the functional status of clients with stroke on admission and upon discharge, as well as age, years of education and length of hospital stay were indicated.

CONCLUSIONS

This study supports a systematic relationship between cognitive factors and functional outcome in Chinese patients with stroke. Similarities and differences in the NCSE factor structure between the population with stroke and general neurological populations were discussed and the utility of NCSE in stroke rehabilitation, such as its predictive validity in functional independence is suggested.

The relationship between non-linguistic cognitive deficits and language recovery in patients with aphasia

BACKGROUND AND PURPOSE

Non-linguistic cognitive impairments may limit rehabilitation efficacy in patients with aphasia. The aim of this study was to determine whether post-stroke aphasia was associated with impairments of visuo-spatial working memory and abstract thinking and whether these deficits adversely affected language recovery.

METHODS

Baseline visuo-spatial memory and abstract thinking abilities were assessed in 78 patients with post-stroke aphasia and 38 healthy controls. Then, 47 of the 78 patients with aphasia completed three weeks of speech and language training. Therapy outcome was assessed by comparing pre- and post-treatment scores on the Boston Diagnostic Aphasia Examination.

RESULTS

Even though the patients' non-linguistic cognitive abilities were impaired in general, the patients were heterogeneous with regard to their deficits. Linguistic and non-linguistic deficits appeared to be distinct, although they could be concurrent. Visuo-spatial working memory was associated with the degree of improvement in two functions crucial to language communication: naming and comprehension. No relationship was found between language therapy outcome and abstract thinking ability.

MAAS (Multi-axial Aphasia System): realistic goal setting in aphasia rehabilitation

Treatment success in aphasia is influenced by various factors. Clinical decisions, including patient selection and decisions on frequency and content, are often guided by a clinician's implicit opinions. The Multi-axial Aphasia System (MAAS) was developed to structure linguistic, somatic, neuropsychological, psychosocial and socio-economic information on five separate axes, enabling an explicit and interdisciplinary process of clinical decision-making. The objectives of this study were to investigate the potentialities of MAAS in predicting the outcome of cognitive-linguistic treatment. A group of 58 aphasic patients were investigated prospectively. All received cognitive-linguistic treatment during a randomized, controlled study on the efficacy of lexical semantic treatment. An interdisciplinary aphasia team rated the pretreatment MAAS profiles of all patients. The team was blinded for treatment allocation and outcome. A multiple linear regression analysis was performed with the posttreatment verbal communication score as the variable to be predicted and the overall MAAS rating, age and type of treatment as predictor variables. In a second multiple regression analysis, the ratings for each of the five MAAS axes were used as candidate predictors. The team's overall rating contributed significantly to the prediction of verbal communicative ability after linguistic treatment. Of the five MAAS axes, the neuropsychological axis contributed to the prediction. An interdisciplinary approach to aphasia assessment may contribute to realistic goal setting in aphasia rehabilitation. The results of this study stress the importance of neuropsychological assessment of aphasic patients before treatment.

Exploring cognitive effects of self reported mild stroke in older adults: selective but robust effects on story memory

Relatively little systematic information is available regarding patterns of cognitive effects of mild stroke in older adults. We explored this problem with a series of two independent samples from the Victoria Longitudinal Study data archives. In Study 1, self-reported mild stroke and neurologically intact matched controls were (a) confirmed as similar on a set of neurocognitive speed, basic cognition, and awareness indicators, and (b) compared for differences on a set of episodic, semantic, and working memory tasks. The mild stroke group was selectively worse on the language intensive story memory task. This effect was partially attributable to a deficit in remembering the most thematic information. Study 2 closely replicated these procedures and results. In addition, Study 2 follow-up analyses, comparing provisional right-hemisphere damaged and left-hemisphere damaged (LHD) participants, revealed that the thematic story memory deficit for mild stroke participants could be due to the selective impairment of LHD participants.

Cognitive impairment after stroke

The concept of vascular dementia is undergoing revision. The multi-infarct model and the Alzheimer's model of dementia, usually referred to as 'multi-infarct dementia', are gradually being replaced by a much broader concept of vascular cognitive impairment. This conceptual evolution reflects a more profound understanding of the pathogenic mechanisms that underlie this complex syndrome. As a consequence of this revision new diagnostic criteria have been established during the past 25 years, resulting in new problems with regard to precise disease definition and limited inter-rater reliability. The particular criteria chosen by a clinician or investigator to diagnose vascular dementia have a major impact on epidemiology, disease management and health economic estimates.

Neural basis for sentence comprehension: grammatical and short-term memory components

We monitored regional cerebral activity with BOLD fMRI while subjects were presented written sentences differing in their grammatical structure (subject-relative or object-relative center-embedded clauses) and their short-term memory demands (short or long antecedent-gap linkages). A core region of left posterior superior temporal cortex was recruited during all sentence conditions in comparison to a pseudofont baseline, suggesting that this area plays a central role in sustaining comprehension that is common to all sentences. Right posterior superior temporal cortex was recruited during sentences with long compared to short antecedent-gap linkages regardless of grammatical structure, suggesting that this brain region supports passive short-term memory during sentence comprehension. Recruitment of left inferior frontal cortex was most clearly associated with sentences that featured both an object-relative clause and a long antecedent-gap linkage, suggesting that this region supports the cognitive resources required to maintain long-distance syntactic dependencies during the comprehension of grammatically complex sentences.

Aphasia, depression, and non-verbal cognitive impairment in ischaemic stroke

Aphasia, depression, and cognitive dysfunction are common consequences of stroke, but knowledge of their interrelationship is limited. This 1-year prospective study was designed to evaluate prevalence and course of post-stroke aphasia and to study its psychiatric, neurological, and cognitive correlates. We studied a series of 106 consecutive patients (46 women and 60 men, mean age 65. 8 years) with first-ever ischaemic brain infarction. The patients were clinically examined, and presence and type of aphasia were evaluated during the 1st week after stroke and 3 and 12 months later. Psychiatric and neuropsychological evaluations were performed 3 and 12 months after stroke. Aphasia was diagnosed in 34% of the patients during the acute phase, and two thirds of them remained so 12 months later. Seventy percent of the aphasic patients fulfilled the DSM-III-R criteria of depression 3 months and 62% 12 months after stroke. The prevalence of major depression increased from 11 to 33% during the 12-month follow-up period. The non-verbal neuropsychological test performance in the aphasic patients was significantly inferior to that of the patients with dominant hemisphere lesion without aphasia. One third of the patients with ischaemic stroke suffer from communicative disorders which seem to increase the risk of depression and non-verbal cognitive deficits. Although the prevalence of depression in aphasic patients decreases in the long term, the proportion of patients suffering from major depression seems to increase. We emphasize the importance of the multidimensional evaluation of aphasic stroke patients.

Spoken language of individuals with mild fluent aphasia under focused and divided-attention conditions

The spoken language of individuals with mild aphasia and age-matched control subjects was studied under conditions of isolation, focused attention, and divided attention. A picture-description task was completed alone and in competition with a tone-discrimination task. Regardless of condition, individuals with aphasia performed more poorly on most morphosyntactic, lexical, and pragmatic measures of spoken language than control subjects. Increasing condition complexity resulted in little quantitative or qualitative change in the spoken language of the control group. In contrast, the individuals with aphasia showed dual-task interference; as they shifted from isolation to divided-attention conditions, they produced fewer syntactically complete and complex utterances, fewer words, and poorer word-finding accuracy. In pragmatic terms, their communication was considered less successful and less efficient. These results suggest that decrements of attentional capacity or its allocation may negatively affect the quantity and quality of the spoken language of individuals with mild aphasia.

Auditory processing in individuals with mild aphasia: a study of resource allocation

This study examined the effects of lesion location (frontal vs. posterior) and nature of distraction (nonverbal vs. verbal secondary, competing task) on mildly aphasic individuals' performances of listening tasks that required semantic judgments and lexical decisions under isolation, focused attention, and divided attention conditions. Despite comparable accuracy among all groups during isolation conditions, the aphasic groups responded less accurately and more slowly than the normal control group during focused and divided attention conditions. Generally, the two aphasic groups performed similarly, quantitatively and qualitatively. Demographic characteristics such as time post stroke did not correlate with performance decrements. Independent of group, all individuals showed greater disruption of auditory processing skills when the secondary task was verbal rather than nonverbal. Within a limited-capacity model of attention, the results suggest that aphasic individuals display impairments of attention and resource allocation and that these impairments negatively interact with their auditory processing abilities.

Memory and aphasia

Sixty-one acute and 17 chronic vascular left-hemisphere damaged patients were tested with five memory tasks that investigated verbal short-term (digit span) and long-term (paired-associate and story learning) memory, and spatial short- and long-term memory (Corsi's span and learning). Both brain-damaged groups were significantly impaired in all memory tasks (except for chronic patients in the story learning task) compared to normal controls. The presence of aphasia and locus of lesion (anterior, posterior and deep) had no effect on the memory impairment, with only one exception of paired-associate learning that was better performed by non-aphasic than aphasic patients. Eleven subjects were better at paired-associate learning than story recall, the reverse dissociation was never found. Finally, chronic patients performed significantly better than acute patients only in the Corsi's learning task.

Is prefrontal cortex involved in cued recall? A neuropsychological test of PET findings

Positron emission tomography (PET) experiments have detected blood flow activations in right anterior prefrontal cortex during performance of a word stem cued recall task [3, 38]. Based on findings from a variety of PET studies, the "hemispheric encoding/retrieval asymmetry model" [44] was proposed to explain the role of the frontal lobes in episodic memory. This model asserts that left prefrontal cortex is preferentially involved in the encoding of new information into episodic memory, whereas right prefrontal cortex is more involved in episodic memory retrieval. As a neuropsychological test of this hypothesis, a group of frontal patients with lesions in areas 6, 8, 9, 10, 44, 45 and/or 46 (11 left, five right) were run on word stem cued recall under two semantic study conditions. As a group, these patients were not significantly impaired in cued recall. In the first but not the second experiment, left frontal patients recalled fewer words than controls. Right frontal patients were not impaired on either list. Right prefrontal cortex could be activated by several strategic aspects of the cued recall paradigm that were minimized in the present experiment. Brain reorganization in the lesioned patients could also account for their intact performance. The regions of prefrontal cortex activated in PET studies of young controls are not necessary for patients to perform the task.

Semantic and episodic memory in aphasia

Within the framework of the distinction between episodic and semantic memory, it has been argued that these two memory Systems are organised in a hierarchical way. The hierarchical hypothesis assumes that episodic memory is a specific subsystem of semantic memory and therefore implies that episodic memory cannot exist without semantic memory. If this hypothesis is correct, it should be expected that (episodic) yes/no recognition performance would improve in patients with preserved semantic memory, following semantic encoding. In the present study we investigated the influence of semantic encoding on recognition memory performance in a population of 28 aphasic patients (AA) and 14 normal controls (NC). Experiment 1 considered recognition memory for semantically unrelated items, whereas Experiments 2 and 3 assessed recognition memory for semantically related items. In Experiment 3, but not in Experiment 2, subjects were explicitly instructed to make a semantic association between the items. AA were impaired, compared to NC, only on the recognition memory performance of Experiment 1. The ability to make a semantic association between two items was significantly and positively correlated to the ability to recognise, in a subsequent test, those same items. A further analysis showed that patients who were impaired on the semantic association task did significantly worse on the recognition task of Experiment 3 than NC and than patients who were unimpaired on the semantic association task. These findings are discussed in the context of memory deficits in aphasia and interpreted as giving support to the view that episodic memory for an item is affected by the level of semantic awareness of that same item.

Comparison of personalized cueing and provided cueing on the facilitation of verbal labeling by aphasic subjects

This study investigated the effects of two associative learning tasks on aphasic subjects' labeling of novel symbols. It was designed to determine if aphasic subjects need to develop their own associations for word-symbols pairs (personalized cueing) to obtain the long-term labeling benefits observed in prior research or if comparable results are obtained when "ready-made" associations are used during training (provided cueing). The results showed that the two cueing techniques were equal in their ability to elicit correct responses from the subjects. The results also demonstrated the long-term effectiveness of both cueing procedures on the subjects' labeling accuracy up to 30 days after training was discontinued.

Visuoperceptual-spatial ability and visual memory in vascular dementia and dementia of the Alzheimer type

This study investigated the relationship between visuoperceptual ability and visual memory in dementia. Twenty individuals with probable dementia of the Alzheimer type, 24 individuals with probable vascular dementia, and 20 healthy, elderly adults underwent neuropsychological evaluation. Hierarchical multiple regression analyses suggested that perceptual organization skills contributed to a significant amount of the variance in novel, but not famous, face recognition. This finding was most robust in the clinical groups. Causality cannot be attributed from this regression model. Results suggest, however, that visual processing deficits are more strongly related to the memory process at the time of encoding rather than during recognition of remote information.