Impaired Verbal Short-term Memory Research Articles

VERBAL SHORT-TERM IMPAIRMENT IN DYSLEXIA

Verbal short-term memory impairment is one of the most consistently associated deficits observed indevelopmental reading disorders such as dyslexia. The mechanisms involved in the short-term retention ofinformation for serial tasks may be shared across domains of short-term memory, such as verbal and visuospatialshort-term memory. Few studies have addressed the nature of verbal short-term impairment, particularly with regardto the possibility of temporary serial storage of information. A short-term memory serial order impairment appearsto occur for the retention of verbal and visuospatial sequence information. Impairment in the serial ordering of shorttermmemory is not a characteristic of every individual dyslexic subject and is not specific to dyslexia. Futurestudies should determine whether verbal short-term serial order memory impairment is a risk factor that, inassociation with a deficit in phonological processing, may lead to dyslexia or whether verbal short-term serial ordermemory impairment reflects related deficits unrelated to dyslexia. The purpose of this article is to consider theimplications for dyslexia of one aspect of short-term memory, memory for serialization

Short term memory in aphasia: effects of modality and relationship with Western Aphasia Battery-R performance

ABSTRACT Background Producing and comprehending language requires maintenance of linguistic units in short term memory (STM). While there is evidence of verbal STM impairments in persons with aphasia (PWA), there are unresolved questions about other aspects of STM in aphasia, particularly the role of input and output modalities on STM performance. This includes the extent to which visual STM abilities are impaired in PWA and if the modality of eliciting responses (verbal versus pointing) influences STM performance. A better understanding of the relationship between STM performance and clinical language assessments of PWA will inform test interpretation. Aims This study investigated three questions about short term memory (STM) performance in post-stroke aphasia: 1) whether visual STM is impaired in PWA given that a common neural network subserves encoding-recall of both verbal and visual STM, 2) whether the response modality (verbal vs pointing) impacts STM score, 3) the relationship between STM and language performance, specifically on the Western Aphasia Battery-Revised (WAB-R). Methods & Procedures Verbal and visuo-spatial performance on a STM battery was compared between 45 PWA and a representative neurotypical sample (N=40). For PWA, individual performance across STM subtasks was examined to identify dissociations and correlated with language performance on the WAB-R. Outcomes & Results PWA scored lower than neurotypical controls on verbal but not visual STM tasks. At the individual level, about one-half of PWA were impaired on the three verbal STM tasks, and one-third had dissociations among the three verbal STM tasks. There was no effect of response modality (verbal versus pointing) on verbal STM performance. There was a strong association between verbal STM and individual subtests of the WAB-R. In general, the relative phonological and semantic demands of the task (e.g. repetition) influenced the association strength with digit recall versus picture recall scores. Conclusions Verbal STM deficits are: 1) more prevalent than visual-spatial STM deficits in PWA, 2) strongly associated with WAB-R performance in a pattern that is consistent with the phonological and semantic demands of the tasks. The clinical implications of this study are that it is crucial to assess STM performance in PWA and examine its potential impact on language assessments. Further, a verbal or pointing response modality can be used for STM measurement without negatively impacting the score (unless there are clear motoric contra-indications). This study provides performance data for a set of aphasia-friendly STM tasks that can serve as future reference.

Integrating Verbal Short-Term Memory Into the Assessment and Treatment of Aphasia

Purpose: Verbal short-term memory (STM) impairment is ubiquitous in people with aphasia, and its severity generally parallels the severity of word processing impairment. In language-based models of STM, verbal STM arises from the activation and maintenance of linguistic representations. Measures of verbal STM can provide insight into the nature of language processing deficits in aphasia and should be a component of comprehensive assessment and treatment plans. Although verbal STM impairment in aphasia is widely studied in the research community, inclusion of verbal STM assessment and treatment in clinical practice remains limited. Method: This tutorial presents a description of language-based models of verbal STM and factors that contribute to performance in verbal STM tasks. We outline a model of verbal STM assessment and intervention that considers two levels of linguistic processing deficits (i.e., semantic vs. phonological), temporal variability in performance and access to representations (activation transmission vs. maintenance), and the effects of memory load. This tutorial presents a practical framework for the integration of measures of verbal STM in both assessment and treatment. Case studies are included to facilitate learning. Conclusions: This tutorial provides clinicians with the theoretical background and practical framework for integration of verbal STM in both treatment and assessment. While the assessment and treatment of verbal STM deficits in aphasia is in the beginning stages of implementation in the clinical setting, it offers a promising avenue for aphasia rehabilitation.

Investigating the Disturbance Impact of Background Speech on Verbal and Visual-Spatial Short-Term Memory: On the Differential Contributions of Changing-State and Phonology to the Irrelevant Sound Effect

ABSTRACT The empirically robust phenomenon of impaired verbal short-term memory due to task-irrelevant background speech is known as the Irrelevant Sound Effect (ISE). Yet, the underlying cognitive mechanisms are still not fully resolved, like whether phonology-based interference contributes to the disruptive effect of speech on verbal serial recall. Thus, we tested the ISE for such a speech-specific aspect by varying the phonological content of the irrelevant speech and the verbal nature of the task. Furthermore, we also varied the changing-state characteristic of irrelevant speech. Therefore, visual-verbal and visual-spatial serial recall of 70 participants each was measured during silence and syllable series varying in phonological (unaltered speech vs. sinewave speech) and in changing-state content (one repeatedly presented vs. successively changing syllables). Both phonology and changing-state characteristic had significant and independent impacts on each of the two serial recall tasks, and both effects were unrelated to participants’ working memory capacity. Changing-state sequences were more disturbing than steady-state sounds for both serial recall tasks, but the effect of phonological content was not in the same direction for the two tasks. Whereas unaltered speech sounds impaired verbal serial recall more than their phonologically reduced sinewave versions, this was the opposite for visual-spatial serial recall. In the latter task, however, only changing-state sinewave speech reduced performance significantly compared to silence condition. In summary, our results indicate that there is a speech-specific, disruptive effect of phonological content, which is an attention-independent interference effect and presumably restricted to verbal short-term memory.

Effect of Bilateral Opercular Syndrome on Speech Perception.

Speech perception ability and structural neuroimaging were investigated in two cases of bilateral opercular syndrome. Due to bilateral ablation of the motor control center for the lower face and surrounds, these rare cases provide an opportunity to evaluate the necessity of cortical motor representations for speech perception, a cornerstone of some neurocomputational theories of language processing. Speech perception, including audiovisual integration (i.e., the McGurk effect), was mostly unaffected in these cases, although verbal short-term memory impairment hindered performance on several tasks that are traditionally used to evaluate speech perception. The results suggest that the role of the cortical motor system in speech perception is context-dependent and supplementary, not inherent or necessary.

Lesions that do or do not impair digit span: a study of 816 stroke survivors.

Prior studies have reported inconsistency in the lesion sites associated with verbal short-term memory impairments. Here we asked: How many different lesion sites can account for selective impairments in verbal short-term memory that persist over time, and how consistently do these lesion sites impair verbal short-term memory? We assessed verbal short-term memory impairments using a forward digit span task from the Comprehensive Aphasia Test. First, we identified the incidence of digit span impairments in a sample of 816 stroke survivors (541 males/275 females; age at stroke onset 56 ± 13 years; time post-stroke 4.4 ± 5.2 years). Second, we studied the lesion sites in a subgroup of these patients (n = 39) with left hemisphere damage and selective digit span impairment—defined as impaired digit span with unimpaired spoken picture naming and spoken word comprehension (tests of speech production and speech perception, respectively). Third, we examined how often these lesion sites were observed in patients who either had no digit span impairments or digit span impairments that co-occurred with difficulties in speech perception and/or production tasks. Digit span impairments were observed in 222/816 patients. Almost all (199/222 = 90%) had left hemisphere damage to five small regions in basal ganglia and/or temporo-parietal areas. Even complete damage to one or more of these five regions was not consistently associated with persistent digit span impairment. However, when the same regions were spared, only 5% (23/455) presented with digit span impairments. These data suggest that verbal short-term memory impairments are most consistently associated with damage to left temporo-parietal and basal ganglia structures. Sparing of these regions very rarely results in persistently poor verbal short-term memory. These findings have clinical implications for predicting recovery of verbal short-term memory after stroke.

Do preschoolers born premature perform properly on lexical and verbal short-term memory abilities?

To investigate lexical performance and verbal short-term memory ability in premature infants at preschool age and compare the results with their full-term peers. Forty preschool children aged between 4 and 5 years and 11 months participated on the study and were equally divided into two groups considering their gestational age: preterm and full-term. Groups did not differ on age, family income and maternal education. Participants were paired according to their chronological age and their socioeconomic status. Their performance was assessed using expressive vocabulary and verbal short-term memory tests. Inferential statistical analysis was performed using the Mann-Whitney and the Fisher exact test. Group performance did not differ on vocabulary, but premature children showed an inferior performance on nonword repetition tasks. These data indicates that preschoolers born premature performed statistically lower than their peers born full-term on nonword repetition task. Thus, premature birth was associated to vocabulary development on typically developing range, but also to verbal short-term memory impairments.

Converging sources of evidence and theory integration in working memory: A commentary on Morey, Rhodes, and Cowan (2019)

Morey et al. (2019) offer a critique of the dominance of the multiple component framework of working memory in the interpretation of patterns of impairment and sparing in individuals with focal brain damage associated with specific impairments of immediate, serial-ordered verbal recall. They argue that the lack of pure cases of verbal short-term memory impairments, that recognition performance is higher than recall in such patients, that digits are remembered better than other verbal material, and that problems with replicability in patient studies undermine this traditional theoretical interpretation of the impairments from which these patients suffer. They further speculate that an alternative theoretical framework for working memory, incorporating embedded processes and perception-action links offers a more plausible account of the data from these patients. This commentary points to a range of errors and misconceptions in the arguments presented, notably that such patients are not as rare as suggested, that their recognition is actually no better than their recall, that digits offer substantial advantages for memory, and that results have been shown to be replicable between and within individuals. It is proposed that attempts to integrate more recent theoretical developments in working memory with those shown previously to be highly successful in accounting for impairments in these patients, and for generating hypotheses and accounts across a wide range of contexts may be a more fruitful approach to advancing understanding of cognition in the healthy and damaged brain.

Working memory impairment in aphasia: The issue of stimulus modality

Abstract The presence of short-term/working memory deficits in aphasia has been well-established in the relevant literature. Moreover, recent studies have demonstrated such deficits in both the verbal and visuospatial modalities in patients with aphasia following a left hemisphere stroke. The present study aims to investigate the prevalence and possible lesion correlates of modality-dependent and modality-independent short-term/working memory impairment in aphasia. For this purpose, 54 individuals with post-stroke aphasia were recruited. Aphasic disturbances were assessed with the Boston Diagnostic Aphasia Examination (BDAE) and memory deficits with the digit span and Corsi block-tapping tasks. Structural imaging data were obtained for each patient and lesion sites were identified and coded by two independent neuroradiologists for 16 predetermined left hemisphere areas. Results clearly showed that visuospatial deficits were relatively common, even though verbal deficits are more frequent, and further illustrate the existence of distinct performance patterns within each modality. Analyses revealed comparable lesion extent and locations between patients demonstrating modality-independent and patients demonstrating modality-dependent deficits. Hierarchical regression analyses indicated that deficient performance on digit span forward, indicating impaired verbal short-term memory, was associated with lesions encompassing the inferior frontal gyrus and the inferior parietal cortex. Similar analyses for digit span backward, and the two conditions of Corsi did not yield significant results. However, behavioral data indicate a dissociation between forward and backward visuospatial span, which could be explained by selectively impaired primacy and recency effects. The emergence of modality-dependent and modality-independent deficits is further discussed in relation to hemispheric lateralization during the course of human evolution.

Chapter 19 - Memory deficits

In this chapter, the neuropsychologic literature concerning memory deficits following parietal lesions is reviewed. Left inferior parietal lobule lesions definitely cause verbal short-term memory impairments, while right parietal lesions disrupt visuospatial short-term memory. Episodic memory, as well as autobiographic memory, does not seem to be impaired after both unilateral and bilateral parietal lesions, in contrast with neuroimaging studies reporting activation of the lateral parietal cortex during memory tasks. The most substantiated hypothesis is that the parietal lobe is involved in the subjective experience of recollection. Indeed, patients with parietal lesions produce fewer false memories and show lower confidence in their source recollections, possibly due to a limited number of details that they are able to report. Finally, the parietal lobes contribute to semantic memory as far as abstract concepts are concerned; in addition some sparse evidence on traumatic brain injury suggests that the parietal lobe is part of the distributed network involved in prospective memory.

Brodmann Areas 39 and 40: Human Parietal Association Area and Higher Cortical Function

The anatomy and function of the angular gyrus (Brodmann Area 39) and supramarginal gyrus (Brodmann Area 40) are described here. Both gyri constitute the inferior part of the parietal lobe. Association fibers from the angular gyrus project to the dorsolateral prefrontal cortex via the superior longitudinal fasciculus (SLF) II/arcuate fasciculus (AF), whereas those from the supramarginal gyrus project to the ventrolateral prefrontal cortex via SLF III/AF. Damage to the left angular gyrus causes kanji agraphia (lexical agraphia) and mild anomia, whereas damage to the left supramarginal gyrus causes kana alexia (phonological dyslexia) and kana agraphia (phonological agraphia). Damage to either gyrus causes Gerstmann's syndrome (finger agnosia, left-right disorientation, agraphia and acalculia) and verbal short-term memory impairment. "Angular alexia with agraphia" results from damage to the middle occipital gyrus posterior to the angular gyrus. Alexia and agraphia, with lesions in the angular or supramarginal gyrus, are characterized by kana transposition errors in reading words, which suggests the impairment of sequential phonological processing.

Regional structural impairments outside lesions are associated with verbal short-term memory deficits in chronic subcortical stroke.

Background and PurposeWe aimed to explore the neural mechanisms of verbal short-term memory (VSTM) impairment in subcortical stroke by evaluating the contributions of lesion and remote grey matter volume (GMV) reduction.ResultsThere was no significant correlation between lesions and VSTM. In stroke patients with left lesions, GMV reductions in the right middle frontal gyrus and in the left inferior frontal gyrus were positively correlated with VSTM impairment. In patients with right lesions, GMV reduction in the right dorsal posterior cingulate cortex was positively correlated with VSTM impairment.Materials and MethodsNinety-seven patients with chronic subcortical ischemic stroke and seventy-nine healthy controls underwent VSTM and structural MRI examinations. Voxel-based lesion symptom mapping was used to identify correlations between lesions and VSTM. Voxel-wise comparisons were used to identify brain regions with significant GMV reduction in patients with left and right lesions. These regions were used in correlation analyses between GMV and VSTM in each patient subgroup.ConclusionsThese findings suggest that VSTM impairment in subcortical stroke is associated with secondary regional structural damage in non-lesion regions, rather than with the lesion itself. Moreover, different neural substrates may underlie VSTM impairment in stroke patients with left and right lesions.

Interpreting potential markers of storage and rehearsal: Implications for studies of verbal short-term memory and neuropsychological cases.

Neuropsychological studies of verbal short-term memory have often focused on two signature effects - phonological similarity and word length - the absence of which has been taken to indicate problems in phonological storage and rehearsal respectively. In the present study we present a possible alternative reading of such data, namely that the absence of these effects can follow as a consequence of an individual's poor level of recall. Data from a large normative sample of 251 adult participants were re-analyzed under the assumption that the size of phonological similarity and word length effects are proportional to an individual's overall level of recall. For both manipulations, when proportionalized effects were plotted against memory span, the same function fit the data in both auditory and visual presentation conditions. Furthermore, two additional sets of single-case data were broadly comparable to those that would be expected for an individual's level of verbal short-term memory performance albeit with some variation across tasks. These findings indicate that the absolute magnitude of phonological similarity and word length effects depends on overall levels of recall, and that these effects are necessarily eliminated at low levels of verbal short-term memory performance. This has implications for how one interprets any variation in the size of these effects, and raises serious questions about the causal direction of any relationship between impaired verbal short-term memory and the absence of phonological similarity or word length effects.

The heterogeneity of verbal short-term memory impairment in aphasia

Verbal short-term memory (STM) impairment represents a frequent and long-lasting deficit in aphasia, and it will prevent patients from recovering fully functional language abilities. The aim of this study was to obtain a more precise understanding of the nature of verbal STM impairment in aphasia, by determining whether verbal STM impairment is merely a consequence of underlying language impairment, as suggested by linguistic accounts of verbal STM, or whether verbal STM impairment reflects an additional, specific deficit. We investigated this question by contrasting item-based STM measures, supposed to depend strongly upon language activation, and order-based STM measures, supposed to reflect the operation of specific, serial order maintenance mechanisms, in a sample of patients with single-word processing deficits at the phonological and/or lexical level. A group-level analysis showed robust impairment for both item and serial order STM aspects in the aphasic group relative to an age-matched control group. An analysis of individual profiles revealed an important heterogeneity of verbal STM profiles, with patients presenting either selective item STM deficits, selective order STM deficits, generalized item and serial order STM deficits or no significant STM impairment. Item but not serial order STM impairment correlated with the severity of phonological impairment. These results disconfirm a strong version of the linguistic account of verbal STM impairment in aphasia, by showing variable impairment to both item and serial order processing aspects of verbal STM.

“I know your name, but not your number” – Patients with verbal short-term memory deficits are impaired in learning sequences of digits

Studies on verbal learning in patients with impaired verbal short-term memory (vSTM) have revealed dissociations among types of verbal information. Patients with impaired vSTM are able to learn lists of known words but fail to acquire new word forms. This suggests that vSTM is involved in new word learning. The present study assessed both new word learning and the learning of digit sequences in two patients with impaired vSTM. In two experiments, participants were required to learn people's names, ages and professions, or their four digit ‘phone numbers’. The STM patients were impaired on learning unknown family names and phone numbers, but managed to acquire other verbal information. In contrast, a patient with a severe verbal episodic memory impairment was impaired across information types. These results indicate verbal STM involvement in the learning of digit sequences.

Logopenic syndrome and corticobasal dysfunction in a “benign” type 3 familial cortical myoclonic tremor with epilepsy

Myoclonic epilepsies are frequently related to mitochondrial disorders, lysosomal disorders and proteinopathic neurodegenerative diseases. Familial cortical myoclonic tremor with epilepsy (FCMTE) is a genetic form of myoclonic epilepsy. FCMTE is defined by an autosomal dominant inheritance, adult onset cortical myoclonic tremor and inconstant seizures. Electrophysiologic examinations show cortical hyperexcitability (paroxysmal polyspike and wave activity on EEG with a marked photosensitivity, recording of enlarged cortical components of somatosensory evoked potential, enhanced long-loop reflex (C-reflex), and cortical transients preceding the myoclonic jerks using the jerk-locked back-averaging technique). Type 3 FCMTE (FAME3/FCMTE3) is linked to the locus 5p15.31-p15.1 [1]. No obvious candidate gene (like ion channel subunit gene for example) is localized to this locus. Actually, no mutation has been found and the biological mechanism involved in FCMTE3 remains unclear. Fronto-striatal dysfunction, gait impairment and cognitive disorders appearing after several decades of disease progression were reported in FCMTE3 [2]. The patient was a right-handed 52-year-old man with high level of education. No previous personal medical history or neurodevelopmental disorder was reported. A generalized seizure was reported to have occurred at the age of 25, and with a mild bilateral myoclonus in upper limbs beginning at the age of

Do students with Down syndrome have a specific learning profile for reading?

The present study assessed achieved reading stages of 190 school-aged children with Down syndrome (DS, age 6-20) in Bavaria, one of the most populated federal states in Germany. Teachers described the reading stages of their students in a questionnaire. The achieved stages of reading according to the developmental model of Frith are compared to a sample of 1419 students with intellectual disability (ID) regardless of etiology, but excluding DS; thereafter parallelized ID-groups were compared. Results of the questionnaire addressed to the students' teachers showed that 20.2% of the students with DS do not read at all, 7.6% read at a logographic stage, 49.4% at an alphabetic and 22.8% at an orthographic level. Alongside these findings among the whole sample, correlations are described concerning age, gender, IQ and sociocultural background. The students with DS are then compared to other students with ID with mixed etiologies. This comparison stresses the emphasis on the alphabetic level amongst students with DS. This emphasis also exists when DS and non-DS students are parallelized in groups of ID, thus showing that students with DS and severe ID are ahead in reading, but those with mild ID are behind. Knowledge about specific literacy attainment of students with DS is vital for planning instruction, for creating learning environments, and for formulating future fields of research. Especially students with DS need specific teaching which takes their impaired verbal short term memory into account, such as learning to read in syllables.

Long-term maintenance of novel vocabulary in persons with chronic aphasia

Background: The study of novel word learning in aphasia can shed light on the functionality of patients' learning mechanisms and potentially help in treatment planning. Previous studies have indicated that persons with aphasia are able to learn some new vocabulary. However, these learning outcomes appear short-lived and evidence for the ability to use the newly learned words in the long term is lacking. Aims: Participants with aphasia and matched controls underwent short training where they were taught to name novel objects with novel names. We studied the participants' word learning and particularly their long-term maintenance. We also examined whether the language and verbal short-term memory impairments of the participants with aphasia related to their ability to acquire and maintain phonological and semantic information on novel words. Methods & Procedures: Two participants with nonfluent aphasia, LL and AR, and two matched controls took part in the experiment. They were taught to name 20 unfamiliar objects by repeating the names in the presence of the object picture. Half of the items carried a definition that was used to probe incidental semantic learning. There were four training sessions, a post-training test, and follow-up tests up to 6 months post-training. Learning measures included recognition of the trained objects, as well as spontaneous and cued recall in visual confrontation naming. Incidental semantic learning was measured by spontaneous recall of the definitions. Outcomes & Results: Combining spontaneous and phonologically cued responses, LL acquired 70% and AR 55% of the novel words. With phonological cueing, LL named 50% of the items correctly up to 6 months post-training (vs 95–100% for the controls) and AR 25% up to 8 weeks post-training. AR's lexical-semantic processing, pseudoword repetition and verbal short-term capacity were inferior to those of LL. In line with this, AR learned fewer words and showed more decline in recognition memory for the trained items, and weaker recall of the semantic definitions. Conclusions: Our results support previous findings that people with aphasia can learn to name novel items. More importantly, the results show for the first time that, with phonological cueing, an individual with aphasia can maintain some of this learning up to 6 months post-training. Moreover the results provide further evidence for the significance of the functional status of lexical-semantic processing on word learning success.

The neural correlates of verbal short-term memory in Alzheimer's disease: an fMRI study

Although many studies have shown diminished performance in verbal short-term memory tasks in Alzheimer's disease, few studies have explored the neural correlates of impaired verbal short-term memory in Alzheimer's disease patients. In this fMRI study, we examined alterations in brain activation patterns during a verbal short-term memory recognition task, by differentiating encoding and retrieval phases. Sixteen mild Alzheimer's disease patients and 16 elderly controls were presented with lists of four words followed, after a few seconds, by a probe word. Participants had to judge whether the probe matched one of the items of the memory list. In both groups, the short-term memory task elicited a distributed fronto-parieto-temporal activation that encompassed bilateral inferior frontal, insular, supplementary motor, precentral and postcentral areas, consistent with previous studies of verbal short-term memory in young subjects. Most notably, Alzheimer's disease patients showed reduced activation in several regions during the encoding phase, including the bilateral middle frontal and the left inferior frontal gyri (associated with executive control processes) as well as the transverse temporal gyri (associated with phonological processing). During the recognition phase, we found decreased activation in the left supramarginal gyrus and the right middle frontal gyrus in Alzheimer's disease patients compared with healthy seniors, possibly related to deficits in manipulation and decision processes for phonological information. At the same time, Alzheimer's disease patients showed increased activation in several brain areas, including the left parahippocampus and hippocampus, suggesting that Alzheimer's disease patients may recruit alternative recognition mechanisms when performing a short-term memory task. Overall, our results indicate that Alzheimer's disease patients show differences in the functional networks underlying memory over short delays, mostly in brain areas known to support phonological processing or executive functioning.

The relationships among verbal short-term memory, phonological awareness, and new word learning: Evidence from typical development and Down syndrome

This study examined the correlates of new word learning in a sample of 64 typically developing children between 5 and 8 years of age and a group of 22 teenagers and young adults with Down syndrome. Verbal short-term memory and phonological awareness skills were assessed to determine whether learning new words involved accurately representing phonological information in memory. Results showed a relationship between verbal short-term memory measures and typically developing individuals’ ability to learn the phonological form of novel words but not their ability to learn the physical referent of new words. Similarly, individuals with Down syndrome showed impaired verbal short-term memory and impaired form but not referent learning. Together, these findings specify the circumstances in which an accurate phonological representation within short-term memory is required for new word learning.