Verbal Short-term Memory Deficits Research Articles

Verbal short-term memory and sentence comprehension in German children and adolescents with Down syndrome: Beware of the task

In individuals with Down syndrome (DS) deficits in verbal short-term memory (VSTM) and deficits in sentence comprehension co-occur, suggesting that deficits in VSTM might be causal for the deficits in sentence comprehension. The present study aims to explore the presumed relationship between VSTM and sentence comprehension in individuals with DS by specifically targeting the influence of task demands. The authors assessed VSTM skills in 18 German-speaking children/adolescents with DS by a nonword repetition (NWR) test and elicited data from three different tasks on the comprehension of complex sentence structures: two sentence-picture-matching tasks (TROG-D and a passive test) and one picture-pointing task on object wh-questions. Whereas performance in NWR yielded a significant degree of prediction for scores obtained in the TROG-D and in passive comprehension, no significant degree of prediction was found for NWR and object wh-question comprehension. Moreover, implicational scaling analyses indicated that mental-age adequate performance in sentence comprehension did not imply adequate performance in NWR. Research is needed that specifies the relation between memory systems and sentence comprehension while considering the influence of task demands.

Neural correlates of auditory verbal short-term memory deficits in vascular and neurodegenerative aphasia

Neural correlates of auditory verbal short-term memory deficits in vascular and neurodegenerative aphasia

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.

A meta-analysis of working memory impairments in survivors of moderate-to-severe traumatic brain injury.

To establish the magnitude of deficits in working memory (WM) and short-term memory (STM) in those with moderate-to-severe traumatic brain injury (TBI) relative to age-matched, healthy controls and to explore the moderating effects of time since injury and age at injury on these impairments. Twenty-one studies that compared the WM and/or STM abilities of individuals with at least a moderate TBI relative to healthy controls were included in a random effects meta-analysis. Measures used to examine memory performance were categorized by modality (visuospatial, verbal) and memory system (WM, STM). Individuals with TBI had significant deficits in verbal STM (Cohen's d = .41), visuospatial WM (Cohen's d = .69), and verbal WM (Cohen's d = .37) relative to controls. Greater decrements in verbal STM and verbal WM skills were associated with longer time postinjury. Larger deficits were observed in verbal WM abilities in individuals with older age at injury. Evidence for WM impairments following TBI is consistent with previous research. Larger verbal STM and verbal WM deficits were related to a longer time postinjury, suggesting that these aspects of memory do not "recover" over time and instead, individuals might show increased rates of cognitive decline. Age at injury was associated with the severity of verbal WM impairments, with larger deficits evident for injuries that occurred later in life. Further research needs to chart the long-term effects of TBI on WM and to compare the effects of injury on verbal relative to visuospatial memory. (PsycINFO Database Record

Subject–verb agreement and verbal short-term memory: A perspective from Greek children with specific language impairment

This study investigated the performance of school age Greek-speaking children with SLI on verbal short-term memory (VSTM) and Subject–Verb (S-V) agreement in comparison to chronological age controls and younger typically developing children. VSTM abilities were assessed by means of a non-word repetition task (NRT) and an elicited production task, an off-line grammaticality judgment (GJ) task, and an on-line self-paced listening task were employed to examine S-V agreement abilities. The study found significant between-group differences in the NRT and the off-line GJ task. No significant between-group differences were found for the S-V agreement production task and for reaction times of the on-line task. The authors argue that the children with SLI showed increased grammatical sensitivity in S-V agreement and relate their lower performance on the off-line GJ task to the task’s metalinguistic demands. The findings suggest that deficits in VSTM constitute a robust marker for SLI and claim that S-V agreement can be acquired by SLI individuals with apparent limitations in VSTM.

Verbal Short-Term Memory Deficits in Chinese Children with Dyslexia may not be a Problem with the Activation of Phonological Representations.

This study explored the underlying mechanism of the verbal short-term memory deficit in Chinese children with developmental dyslexia. Twenty-four children with dyslexia and 28 age-matched normal readers participated in the study. They were required to memorize a visually presented series of six Chinese characters and identify them from a list also including code-specific distracters and non-code-specific distracters. Error rates were recorded and were higher for code-specific distracters in all three conditions, revealing phonological, visual, and semantic similarity effects respectively. Group comparisons showed a stronger phonological similarity effect in dyslexic group, suggesting intact activation of phonological representations of target characters. Children with dyslexia also exhibited a greater semantic similarity effect, revealing stronger activation of semantic representations, while visual similarity effects were equivalent to controls. These results suggest that the verbal short-term memory deficit in Chinese dyslexics might not stem from insufficient activation of phonological information. Based the semantic activation of target characters in dyslexics is greater than in controls, it is possible that the memory deficit of dyslexia is related with deficient inhibition of target semantic representations in short-term memory.

“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.

Grouping, semantic relation and imagery effects in individuals with Down syndrome.

Down syndrome (DS) is associated with a specific verbal short-term memory (STM) deficit. This study explored the effects of grouping, semantic relations and visual presentation upon verbal STM recall performance in a group of 15 individuals with DS and 15 vocabulary-matched typically developing (TD) children. Participants were presented with memoranda in either a temporally grouped schedule, such that items were grouped as pairs, or in an equally spaced presentation schedule. The two items constituting each pair were either semantically related or unrelated. Performance across these conditions was compared in verbal or verbal plus visual presentation modes. Significant memory recall benefits were observed across populations as a result of temporal grouping, semantic relations and verbal and visual combined presentation. However, a reduced benefit of semantic relation in the DS group compared to the TD group indicated that those with DS were less influenced by LTM relational knowledge. In addition, those with DS only experienced a grouping benefit during verbal and visual combined presentation, in contrast to the TD group who experienced grouping benefits throughout. This indicates that individuals with DS are poorer at encoding temporal context for purely verbal memoranda. These findings were replicated in a follow-up experiment, aimed at aligning baseline performance in the two populations. This study provides encouraging evidence that, despite their difficulties in some areas, individuals with DS can benefit from the use of grouping and LTM knowledge to assist their verbal STM performance under certain circumstances.

Spinocerebellar Ataxia Type 2 with Only Clinical Feature of Memory Impairment: Case Report

Spinocerebellar ataxia (SCA) is one of a group of genetic disorders characterized by slowly progressive incoordination of gait and often associated with poor coordination of hands, speech, and eye movements. There are more than 35 different types of spinocerebellar ataxias, each caused by a different genetic mutation. Spinocerebellar ataxia type 2 (SCA2) is a subtype of type I autosomal dominant cerebellar ataxia (ADCA type I) characterized by truncal ataxia, dysarthria, slowed saccades and less commonly ophthalmoparesis and chorea. The age at onset varies from 3 to 79 years (mean 33). Usually, the first symptom of the disease is the gait ataxia, followed by the cerebellar dysarthria. Of late, other clinical manifestations of SCA2 are the cognitive dysfunctions, which include frontal executive impairment, verbal short-term memory deficits as well as reduction of attention and concentration. We report a 56-year old woman identified as spinocerebellar ataxia type 2 (SCA2) with only clinical feature of memory impairment. Received: March 18, 2014 Revision received: March 26, 2014 Accepted: March 26, 2014

Initial Neuropsychological Profile of a Series of 20 Patients with Logopenic Variant of Primary Progressive Aphasia

Logopenic variant of primary progressive aphasia (LPPA) is classically considered as an isolated language disorder, but verbal short-term memory deficit induces difficulties in neuropsychological tests that are not intended to evaluate language. The aim of this study is to describe the initial symptoms and neuropsychological profiles of LPPA. A retrospective study was conducted with a series of 20 consecutive patients diagnosed with LPPA. Clinical, neuroimaging, neuropsychological, and linguistic examinations are reported. The first neuropsychological examinations (mean time between neuropsychological assessment and diagnosis: 11 months) were then compared to 20 patients with mild cognitive impairment (MCI) and 20 patients with Alzheimer's disease (AD) matched by age, gender, and education level. A recent onset or aggravation of anxiety disorders was frequently reported. An unusual neuropsychological profile, different from that of AD or MCI, was observed: dissociation between verbal and visual memory performances, poor encoding performances on verbal memory tests, and preserved orientation to time, difficulties with mental calculation and fluency tasks. Biparetal abnormality and left hippocampal diaschisis was frequently observed. Asymptomatic dopaminergic depletion was observed in four patients. Our study identifies that de novo or recently worsening anxiety and specific neuropsychological profiles call for screening for LPPA, including a linguistic examination. Sometimes, there may be a continuum between LPPA and corticobasal syndrome.

Impaired short-term memory for order in adults with dyslexia

Verbal short-term memory (STM) deficits are consistently associated with dyslexia, but the nature of these deficits remains poorly understood. This study used the distinction between item and order retention processes to achieve a better understanding of STM deficits in adults with dyslexia. STM for item information has been shown to depend on the quality of underlying phonological representations, and hence should be impaired in dyslexia, which is characterized by poorly developed phonological representations. On the other hand, STM for order information is considered to reflect core STM processes, which are independent from language processing. Thirty adults with dyslexia and thirty control participants matched for age, education, vocabulary, and IQ were presented STM tasks, which distinguished item and order STM capacities. We observed not only impaired order STM in adults with dyslexia, but this impairment was independent of item STM impairment. This study shows that adults with dyslexia present a deficit in core verbal STM processes, a deficit which cannot be accounted for by the language processing difficulties that characterize dyslexia. Moreover, these results support recent theoretical accounts considering independent order STM and item STM processes, with a potentially causal involvement of order STM processes in reading acquisition.

Poor phonemic discrimination does not underlie poor verbal short-term memory in Down syndrome

Individuals with Down syndrome tend to have a marked impairment of verbal short-term memory. The chief aim of this study was to investigate whether phonemic discrimination contributes to this deficit. The secondary aim was to investigate whether phonological representations are degraded in verbal short-term memory in people with Down syndrome relative to control participants. To answer these questions, two tasks were used: a discrimination task, in which memory load was as low as possible, and a short-term recognition task that used the same stimulus items. Individuals with Down syndrome were found to perform significantly better than a nonverbal-matched typically developing group on the discrimination task, but they performed significantly more poorly than that group on the recognition task. The Down syndrome group was outperformed by an additional vocabulary-matched control group on the discrimination task but was outperformed to a markedly greater extent on the recognition task. Taken together, the results strongly indicate that phonemic discrimination ability is not central to the verbal short-term memory deficit associated with Down syndrome.

Degenerative jargon aphasia: unusual progression of logopenic/phonological progressive aphasia?

Primary progressive aphasia (PPA) corresponds to the gradual degeneration of language which can occur as nonfluent/agrammatic PPA, semantic variant PPA or logopenic variant PPA. We describe the clinical evolution of a patient with PPA presenting jargon aphasia as a late feature. At the onset of the disease (ten years ago) the patient showed anomia and executive deficits, followed later on by phonemic paraphasias and neologisms, deficits in verbal short-term memory, naming, verbal and semantic fluency. At recent follow-up the patient developed an unintelligible jargon with both semantic and neologistic errors, as well as with severe deficit of comprehension which precluded any further neuropsychological assessment. Compared to healthy controls, FDG-PET showed a hypometabolism in the left angular and middle temporal gyri, precuneus, caudate, posterior cingulate, middle frontal gyrus, and bilaterally in the superior temporal and inferior frontal gyri. The clinical and neuroimaging profile seems to support the hypothesis that the patient developed a late feature of logopenic variant PPA characterized by jargonaphasia and associated with superior temporal and parietal dysfunction.

Degenerative Jargon Aphasia: Unusual Progression of Logopenic/Phonological Progressive Aphasia?

Primary progressive aphasia (PPA) corresponds to the gradual degeneration of language which can occur as nonfluent/agrammatic PPA, semantic variant PPA or logopenic variant PPA. We describe the clinical evolution of a patient with PPA presenting jargon aphasia as a late feature. At the onset of the disease (ten years ago) the patient showed anomia and executive deficits, followed later on by phonemic paraphasias and neologisms, deficits in verbal short-term memory, naming, verbal and semantic fluency. At recent follow-up the patient developed an unintelligible jargon with both semantic and neologistic errors, as well as with severe deficit of comprehension which precluded any further neuropsychological assessment. Compared to healthy controls, FDG-PET showed a hypometabolism in the left angular and middle temporal gyri, precuneus, caudate, posterior cingulate, middle frontal gyrus, and bilaterally in the superior temporal and inferior frontal gyri. The clinical and neuroimaging profile seems to support the hypothesis that the patient developed a late feature of logopenic variant PPA characterized by jargonaphasia and associated with superior temporal and parietal dysfunction.

A stroke patient with impairment of auditory sensory (echoic) memory

A 42-year-old man suffered damage to the left supra-sylvian areas due to a stroke and presented with verbal short-term memory (STM) deficits. He occasionally could not recall even a single syllable that he had heard one second before. A study of mismatch negativity using magnetoencephalography suggested that the duration of auditory sensory (echoic) memory traces was reduced on the affected side of the brain. His maximum digit span was four with auditory presentation (equivalent to the 1st percentile for normal subjects), whereas it was up to six with visual presentation (almost within the normal range). He simply showed partial recall in the digit span task, and there was no self correction or incorrect reproduction. From these findings, reduced echoic memory was thought to have affected his verbal short-term retention. Thus, the impairment of verbal short-term memory observed in this patient was “pure auditory” unlike previously reported patients with deficits of the phonological short-term store (STS), which is the next higher-order memory system. We report this case to present physiological and behavioral data suggesting impaired short-term storage of verbal information, and to demonstrate the influence of deterioration of echoic memory on verbal STM.

Evidence for a Specific Impairment of Serial Order Short‐term Memory in Dyslexic Children

In order to better understand the nature of verbal short-term memory (STM) deficits in dyslexic children, the present study used the distinction between item and serial order retention capacities in STM tasks. According to recent STM models, storage of verbal item information depends very directly upon the richness of underlying phonological and semantic representations. On the other hand, storage of serial order information appears to reflect a language-independent system. Hence, if there is a fundamental STM deficit in dyslexia that is not to be explained only by the poor phonological processing abilities that characterize dyslexia, then difficulties in serial order STM should also be observed in dyslexic children. We administered tasks maximizing either serial order or item retention capacities to dyslexic children and reading age (RA) and chronological age (CA) matched controls. Dyslexic children performed significantly poorer than the CA controls on the item STM measure. Furthermore, the dyslexic group obtained inferior performance than both CA and RA control groups on the serial order STM measure. These findings highlight a severe impairment of STM for serial order information in dyslexia that cannot be reduced to a phonological processing impairment. Implications of serial order retention deficits for reading acquisition and dyslexia are discussed.

Dissociating short-term memory and language impairment: The importance of item and serial order information

Background: Selective verbal short-term memory (STM) deficits are rare, and when they appear, they are often associated with a history of aphasia, raising doubts about the selectivity of these deficits. Recent models of STM consider that STM for item information depends on activation of the language system, and hence item STM deficits should be associated with language impairment. By contrast, STM for order information is considered to recruit a specific system, distinct from the language system: this system could be impaired in patients with language-independent STM deficits. Aims: We demonstrate here the power of the item–order distinction to separate STM and language impairments in two brain-damaged cases with STM impairment and a history of aphasia. Methods & Procedures: Recognition and recall STM tasks, maximising STM for either item or order information were administered to patients MB and CG. Outcomes & Results: Patient MB showed mild phonological impairment. As predicted, associated STM deficits were characterised by poor item STM but preserved order STM. On the other hand, patient CG showed no residual language deficits. His STM deficit was characterised by poor order STM but perfectly preserved item STM. Conclusions: This study presents the first double dissociation between item and order STM deficits, and demonstrates the necessity of this distinction for understanding and assessing STM impairment in patients with and without aphasia.

Language and verbal short-term memory skills in children with Down syndrome: A meta-analytic review

This study presents a meta-analytic review of language and verbal short-term memory skills in children with Down syndrome. The study examines the profile of strengths and weaknesses in children with Down syndrome compared to typically developing children matched for nonverbal mental age. The findings show that children with Down syndrome have broad language deficits (that are not restricted to measures of expressive language) and associated verbal short-term memory deficits. The profile of language skills in children with Down syndrome shows similarities to that seen in children with Specific Language Impairment. The practical and theoretical implications of these findings are discussed.

Using visual strategies to support verbal comprehension in an adolescent with Down syndrome

It has been frequently reported that children with Down syndrome have deficits in verbal short-term memory while having relatively good performance in visual short-term memory tasks. Such verbal deficits have a detrimental effect on various high-level cognitive processes, most notably language comprehension. In this study, we report the case of an adolescent with Down syndrome whose verbal short-term memory and comprehension capacities are impaired. Noting that his visual memory remained relatively well preserved, we developed a remediation strategy based on his visual abilities to support his verbal memory deficit. This remediation led to significant improvements in verbal short-term memories of story and thematic units as well as in overall story comprehension. These results are consistent with recent findings suggesting that deficits in verbal short-term memory can be compensated by efficient visual memory abilities.

Searching for the Hebb effect in Down syndrome: evidence for a dissociation between verbal short‐term memory and domain‐general learning of serial order

The Hebb effect is a form of repetition-driven long-term learning that is thought to provide an analogue for the processes involved in new word learning. Other evidence suggests that verbal short-term memory also constrains now vocabulary acquisition, but if the Hebb effect is independent of short-term memory, then it may be possible to demonstrate its preservation in a sample of individuals with Down syndrome, who typically show a verbal short-term memory deficit alongside surprising relative strengths in vocabulary. In two experiments, individuals both with and without Down syndrome (matched for receptive vocabulary) completed immediate serial recall tasks incorporating a Hebb repetition paradigm in either verbal or visuospatial conditions. Both groups demonstrated equivalent benefit from Hebb repetition, despite individuals with Down syndrome showing significantly lower verbal short-term memory spans. The resultant Hebb effect was equivalent across verbal and visuospatial domains. These studies suggest that the Hebb effect is essentially preserved within Down syndrome, implying that explicit verbal short-term memory is dissociable from potentially more implicit Hebb learning. The relative strength in receptive vocabulary observed in Down syndrome may therefore be supported by largely intact long-term as opposed to short-term serial order learning. This in turn may have implications for teaching methods and interventions that present new phonological material to individuals with Down syndrome.