A Flexible and Integrated System for the Remote Acquisition of Neuropsychological Data in Stroke Research

BACKGROUND

Neuropsychological testing is a central aspect of stroke research because it provides critical information about the cognitive-behavioral status of stroke survivors, as well as the diagnosis and treatment of stroke-related disorders. Standard neuropsychological methods rely upon face-to-face interactions between a patient and researcher, which creates geographic and logistical barriers that impede research progress and treatment advances.

INTRODUCTION

To overcome these barriers, we created a flexible and integrated system for the remote acquisition of neuropsychological data (RAND). The system we developed has a secure architecture that permits collaborative videoconferencing. The system supports shared audiovisual feeds that can provide continuous virtual interaction between a participant and researcher throughout a testing session. Shared presentation and computing controls can be used to deliver auditory and visual test items adapted from standard face-to-face materials or execute computer-based assessments. Spoken and manual responses can be acquired, and the components of the session can be recorded for offline data analysis.

MATERIALS AND METHODS

To evaluate its feasibility, our RAND system was used to administer a speech-language test battery to 16 stroke survivors with a variety of communication, sensory, and motor impairments. The sessions were initiated virtually without prior face-to-face instruction in the RAND technology or test battery.

RESULTS

Neuropsychological data were successfully acquired from all participants, including those with limited technology experience, and those with a communication, sensory, or motor impairment. Furthermore, participants indicated a high level of satisfaction with the RAND system and the remote assessment that it permits.

CONCLUSIONS

The results indicate the feasibility of using the RAND system for virtual home-based neuropsychological assessment without prior face-to-face contact between a participant and researcher. Because our RAND system architecture uses off-the-shelf technology and software, it can be duplicated without specialized expertise or equipment. In sum, our RAND system offers a readily available and promising alternative to face-to-face neuropsychological assessment in stroke research.

Resection of highly language-eloquent brain lesions based purely on rTMS language mapping without awake surgery

BACKGROUND

The resection of left-sided perisylvian brain lesions harbours the risk of postoperative language impairment. Therefore the individual patient's language distribution is investigated by intraoperative direct cortical stimulation (DCS) during awake surgery. Yet, not all patients qualify for awake surgery. Non-invasive language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) has frequently shown a high correlation in comparison with the results of DCS language mapping in terms of language-negative brain regions. The present study analyses the extent of resection (EOR) and functional outcome of patients who underwent left-sided perisylvian resection of brain lesions based purely on rTMS language mapping.

METHODS

Four patients with left-sided perisylvian brain lesions (two gliomas WHO III, one glioblastoma, one cavernous angioma) underwent rTMS language mapping prior to surgery. Data from rTMS language mapping and rTMS-based diffusion tensor imaging fibre tracking (DTI-FT) were transferred to the intraoperative neuronavigation system. Preoperatively, 5 days after surgery (POD5), and 3 months after surgery (POM3) clinical follow-up examinations were performed.

RESULTS

No patient suffered from a new surgery-related aphasia at POM3. Three patients underwent complete resection immediately, while one patient required a second rTMS-based resection some days later to achieve the final, complete resection.

CONCLUSIONS

The present study shows for the first time the feasibility of successfully resecting language-eloquent brain lesions based purely on the results of negative language maps provided by rTMS language mapping and rTMS-based DTI-FT. In very select cases, this technique can provide a rescue strategy with an optimal functional outcome and EOR when awake surgery is not feasible.

Five-year speech and language outcomes in children with cleft lip-palate

OBJECTIVE

To investigate 5-year speech and language outcomes in children with cleft lip/palate (CLP).

MATERIALS AND METHODS

Thirty-eight children aged 4-7 years and 8 months were recruited for this study. Speech abilities including articulation, resonance, voice, and intelligibility were assessed based on Thai Universal Parameters of Speech Outcomes. Language ability was assessed by the Language Screening Test.

RESULTS

The findings revealed that children with clefts had speech and language delay, abnormal understandability, resonance abnormality, and voice disturbance; articulation defects that were 8.33 (1.75, 22.47), 50.00 (32.92, 67.08), 36.11 (20.82, 53.78), 30.56 (16.35, 48.11), and 94.44 (81.34, 99.32).

CONCLUSIONS

Articulation errors were the most common speech and language defects in children with clefts, followed by abnormal understandability, resonance abnormality, and voice disturbance. These results should be of critical concern. Protocol reviewing and early intervention programs are needed for improved speech outcomes.

Executive functions in children with communication impairments, in relation to autistic symptomatology

Previous research has found that people with autism generate few novel responses in ideational fluency tasks, and it has been suggested this deficit is a specific correlate of stereotyped/repetitive behavior. We assessed generativity in children with pragmatic language impairment (PLI) who showed communicative abnormalities resembling those seen in autism. We compared four groups: high-functioning autism; PLI; specific language impairment; and control. Generativity was measured using two fluency tasks previously shown to be sensitive to autistic disorder. Correlational analysis revealed a significant relationship between the percentage of correct responses on the fluency tasks and measures of communicative abnormality. It is often assumed that pragmatic difficulties are caused by limitations of social cognition. This study suggests that difficulties in generating relevant ideas can be another cause of autistic-like communicative abnormalities.

Factors Influencing Choices of Contextualized Versus Traditional Practices With Children and Adolescents Who Have Traumatic Brain Injury

PURPOSE

This preliminary investigation examined speech-language pathologists' (SLPs') use of contextualized practices (i.e., functional, personally relevant, nonhierarchical, and collaborative) compared with traditional practices (i.e., clinical, generic, hierarchical, and expert driven) with school-age children and adolescents with traumatic brain injury (TBI).

METHODS

An electronic survey asked SLPs about their use of clinical activities described as more or less contextualized. Research questions focused on frequency of using contextualized practices and factors associated with their use or nonuse.

RESULTS

Seventy responses met criteria for analysis; 98% of these participants reported using at least 1 contextualized practice. Higher use of contextualized practices was associated with working in schools compared to health care settings, access to experts, and greater experience with TBI. Most frequently cited reasons for not using contextualized practices included not fitting the student and scheduling issues.

CONCLUSIONS

Factors associated with using contextualized practices suggest that access to experts and experience with TBI are critical components for facilitating contextualized practice recommendations. Reasons for not using certain contextualized practices highlight the need to address scheduling issues and to increase education about practices that may best meet the unique needs of students with TBI.

The role of the right hemisphere in semantic control: A case-series comparison of right and left hemisphere stroke

Semantic control processes guide conceptual retrieval so that we are able to focus on non-dominant associations and features when these are required for the task or context, yet the neural basis of semantic control is not fully understood. Neuroimaging studies have emphasised the role of left inferior frontal gyrus (IFG) in controlled retrieval, while neuropsychological investigations of semantic control deficits have almost exclusively focussed on patients with left-sided damage (e.g., patients with semantic aphasia, SA). Nevertheless, activation in fMRI during demanding semantic tasks typically extends to right IFG. To investigate the role of the right hemisphere (RH) in semantic control, we compared nine RH stroke patients with 21 left-hemisphere SA patients, 11 mild SA cases and 12 healthy, aged-matched controls on semantic and executive tasks, plus experimental tasks that manipulated semantic control in paradigms particularly sensitive to RH damage. RH patients had executive deficits to parallel SA patients but they performed well on standard semantic tests. Nevertheless, multimodal semantic control deficits were found in experimental tasks involving facial emotions and the 'summation' of meaning across multiple items. On these tasks, RH patients showed effects similar to those in SA cases - multimodal deficits that were sensitive to distractor strength and cues and miscues, plus increasingly poor performance in cyclical matching tasks which repeatedly probed the same set of concepts. Thus, despite striking differences in single-item comprehension, evidence presented here suggests semantic control is bilateral, and disruption of this component of semantic cognition can be seen following damage to either hemisphere.

The proportion of minimally verbal children with autism spectrum disorder in a community-based early intervention programme

BACKGROUND

Estimates of the proportion of children with autism spectrum disorder (ASD) who are minimally verbal vary from 25%to 35%. However, there is a lack of consensus in defining minimally verbal and few detailed reports of communication outcomes for these children following intervention. The aim of this study was to explore how minimally verbal children have been defined and to document the proportion of minimally verbal children in a group of children with ASD receiving a community based early intervention programme.

METHOD

A longitudinal cohort design was used to examine the proportion of children who met criteria for minimally verbal in 246 children with ASD when they entered and exited an early intervention programme.

RESULTS

Overall, 26.3% of the children in this study exited the programme using 'fewer than five spontaneous and functional words' and 36.4% exited not using 'two word phrases' as indicated by direct assessment. However, our findings were mixed depending on measures and definitions used, with parent report indicating that as many as 29.4% of children were not 'naming at least three objects' consistently, and 43.3% not using 'phrases with a noun and verb' consistently at exit. More than half of the children who entered the programme with minimal speech exited the programme with a similar language profile. A small percentage of children (1.2%-4.7%) regressed in their language level over time.

CONCLUSIONS

Despite advances in early intervention, and access to services at a younger age, around a quarter of individuals with ASD in this study exited early intervention with significant communication needs. Our findings are considered in relation to the literature and clinical implications, and future research directions are discussed.

A longitudinal investigation of childhood communication ability and adolescent psychotic experiences in a community sample

BACKGROUND

Some childhood speech and language impairments precede psychosis but it is not clear whether they also precede adolescent psychotic experiences and whether this association is specific to psychotic experiences.

METHODS

Pragmatic language and expressive speech and language (parent-assessed using the Children's Communication Checklist) at age 9 and psychotic experiences and depression at ages 12 and 18 were investigated in 7659 participants from the Avon Longitudinal Study of Parents and Children. Associations were investigated using multivariate modelling.

RESULTS

Poorer pragmatic language at 9years was associated with psychotic experiences at both ages (12years OR 1.22, 95% CI 1.11, 1.34; 18years OR 1.25, 95% CI 1.10, 1.41) but only with depression at 18years (OR 1.10, 95% CI 1.00, 1.22). Poorer expressive speech and language ability was not associated with psychotic experiences or depression at either age. There was evidence that pragmatic language was specifically associated with psychotic experiences at age 12 but no evidence that the strength of any of the associations changed over time.

CONCLUSIONS

Deficits in pragmatic language precede early and late adolescent psychotic experiences and early adolescent depression. Interventions aimed at helping children improve pragmatic language skills may reduce the incidence of adolescent psychopathology and associated psychological disorder and dysfunction later in life.

Consonant differentiation mediates the discrepancy between non-verbal and verbal abilities in children with ASD

BACKGROUND

Many children with autism spectrum disorder (ASD) demonstrate verbal communication disorders reflected in lower verbal than non-verbal abilities. The present study examined the extent to which this discrepancy is associated with atypical speech sound differentiation.

METHODS

Differences in the amplitude of auditory event-related potentials elicited by contrasting consonant-vowel syllables during a passive listening paradigm were used to assess speech sound differentiation in 24 children with ASD and 18 chronological age-matched children with typical development (TD), M age 6.90 years (SD = 1.39).

RESULTS

Results revealed that compared with TD peers, children with ASD showed reduced consonant differentiation in the 84- to 308-ms period. Brain responses indexing consonant differentiation were negatively related to the degree of discrepancy in non-verbal and verbal abilities and mediated the relationship between diagnostic group membership and the greater discrepancy.

CONCLUSIONS

We discuss the theoretical and clinical implications of the brain's response to speech sound contrasts possibly explaining the greater non-verbal versus language ability in children with ASD compared with that in typically developing children.

Assessment of cognition and language in the early diagnosis of autism spectrum disorder: usefulness of the Bayley Scales of infant and toddler development, third edition

BACKGROUND

The aim of this study was to test the usefulness of the Cognitive and Language scales Bayley-III in the early assessment of cognitive and language functions in the context of an autism spectrum disorder (ASD) diagnosis. This paper focuses on the application of the Bayley-III and studies the predictive value of the test result in children with ASD with different levels of verbal ability.

METHOD

A sample of 135 children (121 boys, 14 girls) with a confirmed ASD diagnosis at age 4 years were assessed with the Bayley-III before 42 months of age (m = 36.49, s = 4.46) and later with other rating scales of different psychological and psycholinguistic functions as part of a longitudinal study [McCarthy Scales of Children's Abilities (MSCA) (n = 48, 90% boys), Kaufman Assessment Battery for Children (K-ABC) (n = 38, 87% boys) or Illinois Test of Psycholinguistic Abilities (ITPA) (n = 44, 89% boys)]. Age assessment in months: MSCA (m = 48.80, s = 3.33), K-ABC (m = 51.80, s = 7.17) and ITPA (m = 54.48, s = 3.34).

RESULTS

Lower scores on the cognitive and language Bayley-III scales before 3.5 years of age predicted lower cognitive and oral language levels at 4 years of age. A significant correlation was found between the Cognitive Bayley-III Scale and the General Cognitive MSCA Scale, and with the Compound K-ABC Mental Processing. An association between the nonverbal cognitive level and oral language level acquired at 4 years of age was found.

CONCLUSIONS

The Bayley-III is a useful instrument in cognitive and language assessment of ASD.

[Dementia with motor and language disorders]

Memory is not the only core diagnostic criteria in Alzheimer's disease and many dementias are characterized by other cognitive deficits. Moreover dementias are often associated with multiple and complex motor signs. The first part of this reviewcovers parkinsonism in diffuse Lewy Body Disease and other neurodegenerative diseases, corticobasal syndrome, or motor deficit in the motoneurone disease-frontotemporal dementia spectrum. In the second part, primary progressive aphasia and its three variants including basic clinical evaluation are described. These complex clinical syndromes involving motor and language systems are important for the clinical practice since they are part of diagnostic criteria of several neurodegenerative diseases and can be considered as phenotypical markers of neurodegeneration.

Is semantic verbal fluency impairment explained by executive function deficits in schizophrenia?

OBJECTIVE

To investigate if verbal fluency impairment in schizophrenia reflects executive function deficits or results from degraded semantic store or inefficient search and retrieval strategies.

METHOD

Two groups were compared: 141 individuals with schizophrenia and 119 healthy age and education-matched controls. Both groups performed semantic and phonetic verbal fluency tasks. Performance was evaluated using three scores, based on 1) number of words generated; 2) number of clustered/related words; and 3) switching score. A fourth performance score based on the number of clusters was also measured.

RESULTS

SZ individuals produced fewer words than controls. After controlling for the total number of words produced, a difference was observed between the groups in the number of cluster-related words generated in the semantic task. In both groups, the number of words generated in the semantic task was higher than that generated in the phonemic task, although a significant group vs. fluency type interaction showed that subjects with schizophrenia had disproportionate semantic fluency impairment. Working memory was positively associated with increased production of words within clusters and inversely correlated with switching.

CONCLUSION

Semantic fluency impairment may be attributed to an inability (resulting from reduced cognitive control) to distinguish target signal from competing noise and to maintain cues for production of memory probes.

Abnormal Neural Oscillations in Schizophrenia Assessed by Spectral Power Ratio of MEG During Word Processing

This study investigated spectral power of neural oscillations associated with word processing in schizophrenia. Magnetoencephalography (MEG) data were acquired from 12 schizophrenia patients and 10 healthy controls during a visual word processing task. Two spectral power ratio (SPR) feature sets: the band power ratio (BPR) and the window power ratio (WPR) were extracted from MEG data in five frequency bands, four time windows of word processing, and at locations covering whole head. Cluster-based nonparametric permutation tests were employed to identify SPRs that show significant between-group difference. Machine learning based feature selection and classification techniques were then employed to select optimal combinations of the significant SPR features, and distinguish schizophrenia patients from healthy controls. We identified three BPR clusters and three WPR clusters that show significant oscillation power difference between groups. These include the theta/delta, alpha/delta and beta/delta BPRs during base-to-encode and encode time windows, and the beta band WPR from base to encode and from encode to post-encode windows. Based on two WPR and one BPR features combined, over 95% cross-validation classification accuracy was achieved using three different linear classifiers separately. These features may have potential as quantitative markers that discriminate schizophrenia patients and healthy controls; however, this needs further validation on larger samples.

Ability to solve riddles in patients with speech and language impairments after stroke

INTRODUCTION

Successful riddle solving requires recognition of the meaning of words, attention, concentration, memory, connectivity and analysis of riddle content, and sufficiently developed associative thinking.

OBJECTIVE

The aim of the study was to determine the ability to solve riddles in stroke patients who do or do not have speech and language disorders (SLDs), to determine the presence of SLDs in relation to the lesion localization, as well as to define the relationship between riddle-solving and functional impairment of a body side.

METHODS

The sample consisted of 88 patients. The data used included age, sex, educational level, time of stroke onset, presence of an SLD, lesion localization, and functional damage of the body side. The patients were presented with a task of solving 10 riddles.

RESULTS

A significant SLD was present in 38.60% of the patients. Brain lesions were found distributed at 46 different brain sites. Patients with different lesion localization had different success in solving riddles. Patients with perisylvian cortex brain lesions, or patients with Wernicke and global aphasia, had the poorest results. The group with SLDs had an average success of solved riddles of 26.76% (p = 0.000). The group with right-sided functional impairments had average success of 37.14%, and the group with functional impairments of the left side of the body 56.88% (p = 0.002).

CONCLUSION

Most patients with SLDs had a low ability of solving riddles. Most of the patients with left brain lesions and perisylvian cortex damage demonstrated lower ability in solving riddles in relation to patients with right hemisphere lesions.

Management of developmental speech and language disorders. Part 2: acquired conditions

Many children who present with these acquired impairments of communication have a clear preceding event such as an acquired brain injury from a road traffic accident. Children often respond differently in this situation to adult presentations. They may have a period of mutism when the prognosis might look poor and yet they subsequently make rapid progress and recover speech. They have greater potential for neural plasticity and language recovery, although they often have persisting difficulties in oral and written language. Alternatively, there may be a presentation with a paroxysmal event such as a seizure or a period of depressed consciousness, and the unusual behaviour that may accompany dysphasia and dysarthria may be misinterpreted in the child, whereas for the adult with the more common 'stroke-like' presentation, it would be immediately considered. Rarely the aphasia/dysphasia may itself be the paroxysmal event where actually recognising that the child's disrupted communication is the basis of any observed behaviours can be the greater challenge.

[Neuropsychological study in patients with Parkinson's disease: the effects of deep brain stimulation]

INTRODUCTION

Parkinson's disease (PD) is a disorder whose clinical manifestations are observed in the motor and neuropsychological domain and have an impact on the patient's quality of life. Several scientific studies evidence the effectiveness of deep brain stimulation as treatment for the motor symptoms, but further research is required on the neuropsychological symptoms.

AIM

To analyse the existence of significant differences in neuropsychological processes, such as attention, memory, language, visuoperception and the executive functions in patients with PD prior to and following deep brain stimulation.

PATIENTS AND METHODS

Our sample consisted of 20 patients of both sexes, aged 50-70 years, with PD, who were treated by healthcare service providers in Medellin. These subjects were administered the Continuous Performance Test and the Trail Making Test in order to assess attention, the Rey Complex Figure and Ardila memory tests to evaluate memory, the Boston and verbal fluency tests to assess language, the Rey Complex Figure Copy test for visuoperception, and the Wisconsin Card Sorting Test to appraise the executive functions.

RESULTS

There are significant differences between the scores before and after deep brain stimulation in patients with PD on attention and memory.

CONCLUSIONS

Knowledge of these findings is relevant for the neuropsychological therapy of patients with PD.

Formulaic Language in Parkinson's Disease and Alzheimer's Disease: Complementary Effects of Subcortical and Cortical Dysfunction

PURPOSE

The production of formulaic expressions (conversational speech formulas, pause fillers, idioms, and other fixed expressions) is excessive in the left hemisphere and deficient in the right hemisphere and in subcortical stroke. Speakers with Alzheimer's disease (AD), having functional basal ganglia, reveal abnormally high proportions of formulaic language. Persons with Parkinson's disease (PD), having dysfunctional basal ganglia, were predicted to show impoverished formulaic expressions in contrast to speakers with AD. This study compared participants with PD, participants with AD, and healthy control (HC) participants on protocols probing production and comprehension of formulaic expressions.

METHOD

Spontaneous speech samples were recorded from 16 individuals with PD, 12 individuals with AD, and 18 HC speakers. Structured tests were then administered as probes of comprehension.

RESULTS

The PD group had lower proportions of formulaic expressions compared with the AD and HC groups. Comprehension testing yielded opposite contrasts: participants with PD showed significantly higher performance compared with participants with AD and did not differ from HC participants.

CONCLUSIONS

The finding that PD produced lower proportions of formulaic expressions compared with AD and HC supports the view that subcortical nuclei modulate the production of formulaic expressions. Contrasting results on formal testing of comprehension, whereby participants with AD performed significantly worse than participants with PD and HC participants, indicate differential effects on procedural and declarative knowledge associated with these neurological conditions.

Alzheimer's disease and language impairments: social intervention and medical treatment

Communication is very important for people to be successfully integrated into social environment and make and maintain relationship. Particularly, language difficulties lead to social exclusion of the people affected with Alzheimer's disease (AD) and contribute to a significant decrease in the quality of their life and also have a big impact on their family members who in most cases become their caregivers who need to communicate with their loved ones in order to meet their needs. Therefore, the goal of this study is to describe language impairments in the individual phases of AD and discuss their improvement with respect to AD on the basis of literature review. The authors of this article use traditional research methods in order to achieve the goal set mentioned earlier. First, a method of literature review of available sources describing language impairments in the individual phases of AD is exploited. Second, to show how informal caregivers and relevant drugs can successfully intervene in the improvement of these language impairments, a method of comparison of different research studies exploring such social intervention and medical treatment is used.

[A case of pure alexia and foreign accent syndrome following acute encephalopathy in the presence of anti-glutamate receptor antibodies]

A 41-year-old right-handed woman presented abnormal behavior two weeks after suffering from headache and fever. Anti-glutamate receptor antibodies in the serum and cerebrospinal fluid were positive and we diagnosed anti-glutamate receptor antibody-related encephalopathy. The patient improved after administration of corticosteroid and was discharged without neurological deficit. After discharge, pure alexia and foreign accent syndrome-like language disturbance appeared consecutively. The serial fluorodeoxyglucose-positron emission tomography scans suggested that pure alexia and FAS-like language disturbance may have been caused by low function of the occipital lobes and the left frontal lobe, respectively. FAS has been linked to various lesions in the brain. The background mechanism may therefore be heterogeneous. On the other hand, patients with this syndrome recover spontaneously with our case. FAS may therefore be a temporal phenomenon resulting from imbalance in language processing rather than a specific deficit.

[Subtypes of mild cognitive impairment in Parkinson's disease and factors predicting its becoming dementia]

INTRODUCTION

Cognitive impairment may appear at the earliest stages in Parkinson's disease (PD). To assess the prevalence of mild cognitive impairment (MCI) and its different subtypes, as transitional stage, is complicated by the lack of consensus diagnostic criteria.

AIM

To review MCI in PD (MCI-PD), diagnostic criteria and predictive factors of conversion to dementia.

PATIENTS AND METHODS

Systematic review of articles published in Medline (PubMed) using the combination of keywords 'mild cognitive impairment' and 'Parkinson's disease'.

RESULTS

MCI-PD diagnostic criteria published by the Movement Disorders Society are an interesting tool for the diagnosis, in spite they are not validated. Its implementation has the following limitations: 1) the heterogeneity of cognitive deficits described in PD; 2) a variable evolution of cognitive symptoms in PD which difficult the identification of dementia predictors; 3) selection of the more appropriate neuropsychological tests and cut-off points; 4) patient characteristics, disease stage and type of antiparkinsonian treatment.

CONCLUSIONS

Neuropsychological subtypes, neuroimaging, biomarkers or limitation in some instrumental activities seem to be very sensitive for detecting patients with MCI-PD and increased risk of conversion to dementia.

Communication impairments in people with progressive supranuclear palsy: A tutorial

Progressive supranuclear palsy (PSP) is a progressive neurological condition, whose main features include supranuclear gaze palsy, frequent falls, bradykinesia, axial rigidity, cognitive decline and communication impairments. Even though communication impairments are early and prominent manifestations, there is a significant lack of research on the nature of these impairments in PSP and the role of speech-language pathologists (SLPs). This tutorial article aims to describe the communication impairments observed in people with PSP; provide clinical guidelines for SLPs when assessing motor speech, language and other communication impairments; and to present facilitation and compensation approaches to treatment for people with PSP. The predominant motor speech impairment is mixed dysarthria, but there is a lack of consensus about the classification of language impairments. The involvement of SLPs in the assessment and treatment of people with PSP should be early, on-going and in collaboration with other health professionals, with the primary focus of maintaining quality of life for these patients and their family members.

Language dysfunction

PURPOSE OF REVIEW

Language is a complex brain function requiring a number of cognitive processes and is commonly affected by both focal brain lesions and neurodegenerative disorders. This article reviews the neuroanatomic basis of language, assessment techniques of language function, and disorders affecting language.

RECENT FINDINGS

Recent functional imaging studies of language suggest that the classic connectionist models of language function may be incomplete. These studies and those analyzing how the primary progressive aphasias (PPAs) affect language function suggest that language processing is completed through large-scale distributed networks. The use of structured, standardized techniques allows for the diagnosis of focal brain lesions affecting language function as well as neurodegenerative and psychogenic causes of language dysfunction.

SUMMARY

By employing an accurate, neuroanatomically grounded language assessment technique, the neurologist can reach the correct diagnosis and implement the optimal management plan for patients with language disorders. Neurologists should also be aware of new information regarding the neural basis of language function as our understanding of the complex cognitive process of language continues to evolve.

Left-hemisphere lateralization for language and interhemispheric fiber tracking in patients with schizophrenia

BACKGROUND

It has been suggested that the degree of hemispheric specialization (HS) depends on the structural connectivity between the two hemispheres, that is to say the corpus callosum (CC). Studies, performed only on healthy participants, investigated this anatomo-functional relationship. Nevertheless, it has never been studied in schizophrenia. We therefore propose to study the anatomo-functional relationships between the integrity of interhemispheric connectivity and leftward functional lateralization for language in patients with schizophrenia compared with healthy participants, driven by a multimodal approach combining fMRI and DTI-based fiber tractography. We hypothesized that reduced leftward functional lateralization for language in patients with schizophrenia could be related to a callosal hypoconnectivity.

MATERIALS AND METHODS

Seventeen patients based on the DSM-IV, and 17 controls were included. The functional laterality index and interhemispheric diffusion values between homologue temporal regions, belonging to the language network, were individually extracted in order to study the anatomo-functional relationships.

RESULTS

In the patients, higher mean and radial diffusivity (RD) values (thicker myelin sheaths) were associated with less leftward lateralization. In contrast, the controls presented higher RD values and lower fractional anisotropy values (axonal loss) with more leftward lateralization.

CONCLUSIONS

Our study revealed a relationship between the CC and the HS for language, but did not provide evidence clarifying the direction of the relationship between callosal connectivity and functional lateralization for language. In particular, the present findings showed that the loss of integrity in interhemispheric callosal fibers was associated with reduced leftward cerebral dominance for language in patients with schizophrenia.

Can we improve structured sequence processing? Exploring the direct and indirect effects of computerized training using a mediational model

Recent research suggests that language acquisition may rely on domain-general learning abilities, such as structured sequence processing, which is the ability to extract, encode, and represent structured patterns in a temporal sequence. If structured sequence processing supports language, then it may be possible to improve language function by enhancing this foundational learning ability. The goal of the present study was to use a novel computerized training task as a means to better understand the relationship between structured sequence processing and language function. Participants first were assessed on pre-training tasks to provide baseline behavioral measures of structured sequence processing and language abilities. Participants were then quasi-randomly assigned to either a treatment group involving adaptive structured visuospatial sequence training, a treatment group involving adaptive non-structured visuospatial sequence training, or a control group. Following four days of sequence training, all participants were assessed with the same pre-training measures. Overall comparison of the post-training means revealed no group differences. However, in order to examine the potential relations between sequence training, structured sequence processing, and language ability, we used a mediation analysis that showed two competing effects. In the indirect effect, adaptive sequence training with structural regularities had a positive impact on structured sequence processing performance, which in turn had a positive impact on language processing. This finding not only identifies a potential novel intervention to treat language impairments but also may be the first demonstration that structured sequence processing can be improved and that this, in turn, has an impact on language processing. However, in the direct effect, adaptive sequence training with structural regularities had a direct negative impact on language processing. This unexpected finding suggests that adaptive training with structural regularities might potentially interfere with language processing. Taken together, these findings underscore the importance of pursuing designs that promote a better understanding of the mechanisms underlying training-related changes, so that regimens can be developed that help reduce these types of negative effects while simultaneously maximizing the benefits to outcome measures of interest.

Reversible splenium diffusion weighted MRI changes associated with hypoglycemia

Hypoglycemia can manifest as a stroke. MRI diffusion-weighted imaging is the most useful technique in diagnosing early ischemic injury. We report two cases of transient MRI lesions of the splenium of the corpus callosum related to hypoglycemia. Clinicians must be aware of such cases to avoid misdiagnosis.