Prospective and retrospective studies of recovery in aphasia. Changes in cerebral blood flow and language functions

Automated Tractography for the Assessment of Aphasia in Acute Care Stroke Rehabilitation: A Case Series

Background

Aphasia is a common disorder among stroke patients. Assessment of aphasia is essential for scheduling appropriate rehabilitative treatment. Although this is conventionally accomplished using neuropsychological test batteries, these tests are not always accessible because of attention and/or consciousness disturbances during acute care. To overcome this issue, we have introduced a newly developed automated tractography known as XTRACT.

Cases

Diffusion-tensor images were acquired from three patients on days 10-14. Brain images were processed by XTRACT, which automatically extracts neural tracts using standardized protocols. Fractional anisotropy (FA) values were then bilaterally evaluated in the following neural tracts associated with aphasia: arcuate fasciculus, inferior fronto-occipital fasciculus, middle longitudinal fasciculus, inferior longitudinal fasciculus, and uncinate fasciculus. Case 1 had word-finding difficulty on admission. FA values in the lesioned left hemisphere were not decreased in all tracts and this patient fully recovered during acute care. Case 2 had reduced spontaneous speech and a low FA value in the left arcuate fasciculus. Rehabilitative treatment was scheduled to improve the verbal output of sentences and word recall. Case 3 could not complete the conventional aphasia test battery because of attention disturbance. He had low FA values in all tracts in the left hemisphere. Rehabilitative treatment was designed to focus on both speaking and auditory comprehension.

Discussion

Automated tractography enables quantitative assessment of the neural damage associated with aphasia, even in patients with attention and/or consciousness disturbances. This modality can aid in the assessment of aphasia and allows the planning of appropriate rehabilitative treatment.

Cerebral perfusion in post-stroke aphasia and its relationship to residual language abilities

Stroke alters blood flow to the brain resulting in damaged tissue and cell death. Moreover, the disruption of cerebral blood flow (perfusion) can be observed in areas surrounding and distal to the lesion. These structurally preserved but suboptimally perfused regions may also affect recovery. Thus, to better understand aphasia recovery, the relationship between cerebral perfusion and language needs to be systematically examined. In the current study, we aimed to evaluate (i) how stroke affects perfusion outside of lesioned areas in chronic aphasia and (ii) how perfusion in specific cortical areas and perilesional tissue relates to language outcomes in aphasia. We analysed perfusion data from a large sample of participants with chronic aphasia due to left hemisphere stroke (n = 43) and age-matched healthy controls (n = 25). We used anatomically defined regions of interest that covered the frontal, parietal, and temporal areas of the perisylvian cortex in both hemispheres, areas typically known to support language, along with several control regions not implicated in language processing. For the aphasia group, we also looked at three regions of interest in the perilesional tissue. We compared perfusion levels between the two groups and investigated the relationship between perfusion levels and language subtest scores while controlling for demographic and lesion variables. First, we observed that perfusion levels outside the lesioned areas were significantly reduced in frontal and parietal regions in the left hemisphere in people with aphasia compared to the control group, while no differences were observed for the right hemisphere regions. Second, we found that perfusion in the left temporal lobe (and most strongly in the posterior part of both superior and middle temporal gyri) and inferior parietal areas (supramarginal gyrus) was significantly related to residual expressive and receptive language abilities. In contrast, perfusion in the frontal regions did not show such a relationship; no relationship with language was also observed for perfusion levels in control areas and all right hemisphere regions. Third, perilesional perfusion was only marginally related to language production abilities. Cumulatively, the current findings demonstrate that blood flow is reduced beyond the lesion site in chronic aphasia and that hypoperfused neural tissue in critical temporoparietal language areas has a negative impact on behavioural outcomes. These results, using perfusion imaging, underscore the critical and general role that left hemisphere posterior temporal regions play in various expressive and receptive language abilities. Overall, the study highlights the importance of exploring perfusion measures in stroke.

Understanding recovery of language after stroke: insights from neurovascular MRI studies

Stroke causes a disruption in blood flow to the brain that can lead to profound language impairments. Understanding the mechanisms of language recovery after stroke is crucial for the prognosis and effective rehabilitation of people with aphasia. While the role of injured brain structures and disruptions in functional connectivity have been extensively explored, the relationship between neurovascular measures and language recovery in both early and later stages has not received sufficient attention in the field. Fully functioning healthy brain tissue requires oxygen and nutrients to be delivered promptly via its blood supply. Persistent decreases in blood flow after a stroke to the remaining non-lesioned tissue have been shown to contribute to poor language recovery. The goal of the current paper is to critically examine stroke studies looking at the relationship between different neurovascular measures and language deficits and mechanisms of language recovery via changes in neurovascular metrics. Measures of perfusion or cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) provide complementary approaches to understanding neurovascular mechanisms post stroke by capturing both cerebral metabolic demands and mechanical vascular properties. While CBF measures indicate the amount of blood delivered to a certain region and serve as a proxy for metabolic demands of that area, CVR indices reflect the ability of the vasculature to recruit blood flow in response to a shortage of oxygen, such as when one is holding their breath. Increases in CBF during recovery beyond the site of the lesion have been shown to promote language gains. Similarly, CVR changes, when collateral vessels are recruited to help reorganize the flow of blood in hypoperfused regions, have been related to functional recovery post stroke. In the current review, we highlight the main findings in the literature investigating neurovascular changes in stroke recovery with a particular emphasis on how language abilities can be affected by changes in CBF and CVR. We conclude by summarizing existing methodological challenges and knowledge gaps that need to be addressed in future work in this area, outlining a promising avenue of research.

Applicability of automated tractography during acute care stroke rehabilitation

[Purpose] To assess the clinical applicability of a novel automated tractography tool named XTRACT during acute stroke rehabilitation. [Participants and Methods] Three patients with left hemisphere stroke were sampled. Diffusion tensor images were acquired on the second week, and automated tractography was then applied. Tractography images and fractional anisotropy (FA) values in the corticospinal tract (CST) and arcuate fasciculus (AF) were assessed in relation to hemiparesis and aphasia. [Results] Patient 1 was nearly asymptomatic; FA in the left CST was 0.610 and that in the AF was 0.509. Patient 2 had severe hemiparesis and mild motor aphasia. Tractography images of the CST and AF were blurred; FA in the left CST was 0.295 and that in the AF was 0.304. Patient 3 showed no hemiparesis or aphasia at initial assessment. Tractography image of the CST was intact but that of the AF was less clear; FA in the left CST was 0.586 and that in the AF was 0.338. Considering the less clear images of the AF and lower FA value in Patients 2 and 3, further examinations for aphasia were performed, which revealed agraphia. [Conclusion] Visualization and quantification of neural fibers using automated tractography promoted planning acute care rehabilitative treatment in patients with stroke.

Structural Brain Network Correlated with Reading Impairment in Alzheimer's Disease

AIM

Alzheimer's disease (AD) is the most common age-related neurodegenerative disease and leads to dementia. AD is characterized by progressive declines in memory and, as the disease progresses, language dysfunction. Although it has been reported that AD patients show progressive aphasia, no study has examined the relationship between language functions estimated by the Standard Language Test for Aphasia (SLTA) and brain network connectivity in Japanese AD patients. If present, such a relationship would be of particular interest because Japanese speakers are accustomed to mingling ideography and phonography.

METHODS

22 Japanese patients with AD who underwent 1.5-tesla MRI scan and SLTA, the scale for speech and reading impairment, participated in this study. We computed brain network connectivity metrics such as degree, betweenness centrality, and clustering coefficient, and estimated their relationships with the subscores of SLTA.

RESULTS

There was a significant negative correlation between the score for "reading aloud Kanji words" and the clustering coefficient in the left inferior temporal region, bilateral hippocampal regions, and right parietotemporal region. We also found a significant negative correlation between the score for "auditory comprehension of words" and the clustering coefficient in the left prefrontal region. No significant relationship was found between the other SLTA scores and the network metrics.

CONCLUSIONS

Our data suggest relationships between reading impairments and regional brain network connectivity in Japanese patients with AD. The brain connectome may provide adjunct biological information that could improve our understanding of reading impairment.

Association between aphasia severity and brain network alterations after stroke assessed using the electroencephalographic phase synchrony index

Electroencephalographic synchrony can help assess brain network status; however, its usefulness has not yet been fully proven. We developed a clinically feasible method that combines the phase synchrony index (PSI) with resting-state 19-channel electroencephalography (EEG) to evaluate post-stroke motor impairment. In this study, we investigated whether our method could be applied to aphasia, a common post-stroke cognitive impairment. This study included 31 patients with subacute aphasia and 24 healthy controls. We assessed the expressive function of patients and calculated the PSIs of three motor language-related regions: frontofrontal, left frontotemporal, and right frontotemporal. Then, we evaluated post-stroke network alterations by comparing PSIs of the patients and controls and by analyzing the correlations between PSIs and aphasia scores. The frontofrontal PSI (beta band) was lower in patients than in controls and positively correlated with aphasia scores, whereas the right frontotemporal PSI (delta band) was higher in patients than in controls and negatively correlated with aphasia scores. Evaluation of artifacts suggests that this association is attributed to true synchrony rather than spurious synchrony. These findings suggest that post-stroke aphasia is associated with alternations of two different networks and point to the usefulness of EEG PSI in understanding the pathophysiology of aphasia.

Cerebral Microbleeds, Cerebrospinal Fluid, and Neuroimaging Markers in Clinical Subtypes of Alzheimer's Disease

Lobar cerebral microbleeds (CMBs) in Alzheimer's disease (AD) are associated with cerebral amyloid angiopathy (CAA) due to vascular amyloid beta (Aβ) deposits. However, the relationship between lobar CMBs and clinical subtypes of AD remains unknown. Here, we enrolled patients with early- and late-onset amnestic dominant AD, logopenic variant of primary progressive aphasia (lvPPA) and posterior cortical atrophy (PCA) who were compatible with the AD criteria. We then examined the levels of cerebrospinal fluid (CSF) biomarkers [Aβ1-42, Aβ1-40, Aβ1-38, phosphorylated tau 181 (P-Tau), total tau (T-Tau), neurofilament light chain (NFL), and chitinase 3-like 1 protein (YKL-40)], analyzed the number and localization of CMBs, and measured the cerebral blood flow (CBF) volume by ^99mTc-ethyl cysteinate dimer single photon emission computerized tomography (^99mTc ECD-SPECT), as well as the mean cortical standard uptake value ratio by ¹¹C-labeled Pittsburgh Compound B-positron emission tomography (¹¹C PiB-PET). Lobar CMBs in lvPPA were distributed in the temporal, frontal, and parietal lobes with the left side predominance, while the CBF volume in lvPPA significantly decreased in the left temporal area, where the number of lobar CMBs and the CBF volumes showed a significant inversely correlation. The CSF levels of NFL in lvPPA were significantly higher compared to the other AD subtypes and non-demented subjects. The numbers of lobar CMBs significantly increased the CSF levels of NFL in the total AD patients, additionally, among AD subtypes, the CSF levels of NFL in lvPPA predominantly were higher by increasing number of lobar CMBs. On the other hand, the CSF levels of Aβ1-38, Aβ1-40, Aβ1-42, P-Tau, and T-Tau were lower by increasing number of lobar CMBs in the total AD patients. These findings may suggest that aberrant brain hypoperfusion in lvPPA was derived from the brain atrophy due to neurodegeneration, and possibly may involve the aberrant microcirculation causing by lobar CMBs and cerebrovascular injuries, with the left side dominance, consequently leading to a clinical phenotype of logopenic variant.

Progressive amnestic cognitive impairment in a middle-aged patient with developmental language disorder: a case report

BACKGROUND

Developmental disorder and dementia in older adults have been considered unrelated clinical entities because their timing of diagnosis differs greatly; however, recent studies have suggested an association between them. This case describes a middle-aged patient with language disorder exhibiting progressive amnestic cognitive impairment.

CASE PRESENTATION

A 44-year-old Japanese man with long-term language dysfunction presented for his first-ever medical evaluation at age 36 years. Although his conversational ability had been impaired since childhood, he was able to graduate from secondary school and gain unskilled employment. At age 36 years, however, his workplace environment became more stressful, which led to behavioral problems that necessitated medical consultation. He consulted two psychiatrists in vain. At age 44 years, the third attending psychiatrist examined him in detail. The major component of his language disorder was amnestic cognitive impairment in the language domain as shown by logical memory subtests of the Wechsler Memory Scale-Revised. Magnetic resonance imaging showed normal findings for his age and no small vessel disease. Global cerebral hypoperfusion versus cerebellar blood flow was shown on (¹²³I) iodoamphetamine single-photon emission computed tomography, and amyloid-β deposition was negative on positron emission tomography with ¹¹C-Pittsburgh compound B. Pathologic tau accumulation was negative on ¹⁸F-THK5351 positron emission tomography imaging. Laboratory tests show no infections, no vitamin deficiencies, and no other diseases that may cause dementia. Clinical features, results of neurocognitive tests and neuroimaging studies showed no well-known neurodegenerative diseases. Collectively, he was diagnosed with language disorder based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Over a 2-year follow-up period, amnestic cognitive impairment in visual and language domains progressed in parallel with global cerebral hypoperfusion.

CONCLUSION

This case suggests a possible link between language disorder as defined by Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria and progressive amnestic cognitive impairment in middle age, which may ultimately lead to dementia, derived from a neurodegenerative disease.

The Landscape Montage Technique for diagnosing frontotemporal dementia starting as primary progressive aphasia: a case report

Background

The Landscape Montage Technique was originally developed by Hisao Nakai, a Japanese psychiatrist, to pursue the possibility and application of a psychotherapeutic approach using drawing for patients with schizophrenia. Drawing was initially adopted to evaluate patients with an impaired ability for verbal expression, particularly for the diagnosis and treatment of patients with schizophrenia. Since its development, the Landscape Montage Technique has been utilized in various clinical settings throughout Japan. This study aimed to evaluate the psychiatric conditions of a patient diagnosed as having primary progressive aphasia using the Landscape Montage Technique at a 3-year follow-up.

Case presentation

We present the case of a 64-year-old, right-handed Japanese woman initially diagnosed as having logopenic variant primary progressive aphasia or logopenic aphasia. At a 3-year follow-up, logopenic aphasia progressed to behavioral variant frontotemporal dementia or frontotemporal dementia. According to her husband, she began to have speech difficulties approximately 5 years before her first visit. The results of neurocognitive tests suggested mild cognitive impairment or early stages of dementia. Her clinical dementia rating score was 0.5, suggesting a diagnosis of mild cognitive impairment. She had a Raven’s Colored Progressive Matrices score of 31 out of 36, which indicated a nonverbal cognitive ability that was greater than the 90th percentile for her age. The Japanese Standard Language Test of Aphasia, which was performed at two points during the follow-up, indicated the possibility for a diagnosis of primary progressive aphasia given the progression of her aphasia. Based on her clinical symptoms and Japanese Standard Language Test of Aphasia results, a diagnosis of logopenic variant primary progressive aphasia was established. Magnetic resonance imaging revealed severe predominant left frontal and anterior temporal atrophy, as well as bilateral parietal atrophy. Amyloid beta deposition was negative. At the 3-year follow-up, logopenic variant primary progressive aphasia had progressed to behavioral variant frontotemporal dementia. However, the Landscape Montage Technique allowed for the diagnosis of behavioral variant frontotemporal dementia only 2 years after baseline.

Conclusions

The present study showed that the Landscape Montage Technique can be useful for diagnosing behavioral variant frontotemporal dementia that starts as logopenic variant primary progressive aphasia at earlier stages.

Resective Surgery for Double Epileptic Foci Overlapping Anterior and Posterior Language Areas: A Case of Epilepsy With Tuberous Sclerosis Complex

Tuberous sclerosis complex is a genetic systematic disorder characterized by hamartomas in multiple organs. Cortical tubers, the hamartomas in the cerebrum, cause multifocal refractory seizures. In certain cases, epileptic foci potentially involve language areas, and hence, extra- and intraoperative cortical mapping can help identify anterior and posterior areas, thus avoiding postsurgical language impairment. We report on a 21-year-old female with tuberous sclerosis complex experiencing refractory partial seizures due to two epileptic foci in the left hemisphere overlapping anterior and posterior language areas. To completely evaluate both language areas, we performed stepwise resections beginning from the anterior to the posterior epileptic focus. Although the patient presented with expressive aphasia following anterior resection, it was possible to conduct language tests during every resection. Postoperatively, she presented with expressive aphasia, comprehension deficits, left-right disorientations, and arithmetic deficits. The language dysfunctions almost disappeared at 5 weeks after the surgery and were completely resolved at 6 months after surgery. At postoperative 9 months, she was free from seizures.

Tau accumulation in two patients with frontotemporal lobe degeneration showing different types of aphasia using 18F-THK-5351 positron emission tomography: a case report

ABSTRACTTau deposits in Alzheimer's disease and corticobasal syndrome have been reported using 18F-THK-5351 positron emission tomography (PET). To our knowledge, our study is the first to demonstrate tau deposits in patients with frontotemporal lobe degeneration (FTLD), using 18F-THK-5351 PET. This case report presents two patients, both of whom showed positive Tau deposition using 18F-THK-5351 PET. One patient was diagnosed with semantic variant primary progressive aphasia (PPA) and the other diagnosed with logopenic variant PPA. Our results suggest an association in the pathology of Alzheimer's disease, corticobasal syndrome, and FTLD, and could plan more effective clinical care in advance.

Relationship between the change of language symptoms and the change of regional cerebral blood flow in the recovery process of two children with acquired aphasia

OBJECTIVE

This study aimed to investigate the relationship between the change of language symptoms and the change of regional cerebral blood flow (rCBF) in the recovery process of two children with acquired aphasia caused by infarctions from Moyamoya disease with an onset age of 8years.

METHODS

We compared the results for the Standard Language Test of Aphasia (SLTA) with rCBF changes in 7 language regions in the left hemisphere and their homologous regions in the right hemisphere at 4 time points from 3weeks for up to 5years after the onset of aphasia, while controlling for the effect of age.

RESULTS

In both cases, strong correlations were seen within a hemisphere between adjacent regions or regions that are connected by neuronal fibers, and between some language regions in the left hemisphere and their homologous regions in the right hemisphere. Conversely, there were differences between the two cases in the time course of rCBF changes during their recovery process.

CONCLUSION

Consistent with previous studies, the current study suggested that both hemispheres were involved in the long-term recovery of language symptoms in children with acquired aphasia. We suggest that the differences between both cases during their recovery process might be influenced by the brain states before aphasia, by which hemisphere was affected, and by the timing of the surgical revascularization procedure. However, the changes were observed in the data obtained for rCBF with strong correlations with the changes in language performance, so it is possible that rCBF could be used as a biomarker for language symptom changes.

Transcranial Direct Current Stimulation in Post-stroke Chronic Aphasia: The Impact of Baseline Severity and Task Specificity in a Pilot Sample

Emerging evidence suggests that transcranial direct current stimulation (tDCS) can improve aspects of language production in persons with chronic non-fluent aphasia due to left hemisphere stroke. However, to date, studies exploring factors that predict response to tDCS in this or any patient population remain sparse, as are studies that investigate the specific aspects of language performance that are most responsive to stimulation. The current study explored factors that could predict recovery of language fluency and which aspects of language fluency could be expected to improve with the identified factor(s). We report nine patients who demonstrated deficits in fluency as assessed using the Cookie Theft picture description task of the Boston Diagnostic Aphasia Examination. In the treatment condition, subjects received a 2.0 mA current through 5 cm × 5 cm electrodes for 20 min at a site previously shown to elicit a patient-dependent optimal response to tDCS. They were then tested 2-weeks and 2-months after treatment. In the sham condition, a subset of these subjects were tested on the same protocol with sham instead of real tDCS. The current study assessed language fluency improvements in measures of production at the word-level and sentence level, grammatical accuracy, and lexical selection as a function of baseline aphasia severity. A more severe baseline language profile was associated with larger improvements in fluency at the word-level after real tDCS but not sham stimulation. These improvements were maintained at the 2-week follow-up. The results suggest that for at least some outcome measures, baseline severity may be an important factor in predicting the response to tDCS in patients with chronic non-fluent aphasia. Moving forward, the ability to identify patient factors that can predict response could help refine strategies for the administration of therapeutic tDCS, focusing attention on those patients most likely to benefit from stimulation.

Non-invasive Brain Stimulation in the Treatment of Post-stroke and Neurodegenerative Aphasia: Parallels, Differences, and Lessons Learned

Numerous studies over the span of more than a decade have shown that non-invasive brain stimulation (NIBS) techniques, namely transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can facilitate language recovery for patients who have suffered from aphasia due to stroke. While stroke is the most common etiology of aphasia, neurodegenerative causes of language impairment—collectively termed primary progressive aphasia (PPA)—are increasingly being recognized as important clinical phenotypes in dementia. Very limited data now suggest that (NIBS) may have some benefit in treating PPAs. However, before applying the same approaches to patients with PPA as have previously been pursued in patients with post-stroke aphasia, it will be important for investigators to consider key similarities and differences between these aphasia etiologies that is likely to inform successful approaches to stimulation. While both post-stroke aphasia and the PPAs have clear overlaps in their clinical phenomenology, the mechanisms of injury and theorized neuroplastic changes associated with the two etiologies are notably different. Importantly, theories of plasticity in post-stroke aphasia are largely predicated on the notion that regions of the brain that had previously been uninvolved in language processing may take on new compensatory roles. PPAs, however, are characterized by slow distributed degeneration of cellular units within the language system; compensatory recruitment of brain regions to subserve language is not currently understood to be an important aspect of the condition. This review will survey differences in the mechanisms of language representation between the two etiologies of aphasia and evaluate properties that may define and limit the success of different neuromodulation approaches for these two disorders.

Functional Neuroimaging in Stroke Recovery and Neurorehabilitation: Conceptual Issues and Perspectives

Background

In stroke, functional neuroimaging has become a potent diagnostic tool; opened new insights into the pathophysiology of ischaemic damage in the human brain; and made possible the assessment of functional–structural relationships in postlesion recovery.

Summary of review

Here, we give a critical account on the potential and limitation of functional neuroimaging and discuss concepts related to the use of neuroimaging for exploring the neurobiological and neuroanatomical mechanisms of poststroke recovery and neurorehabilitation. We identify and provide evidence for five hypotheses that functional neuroimaging can provide new insights into: adaptation occurs at the level of functional brain systems; the brain–behaviour relationship varies with recovery and over time; functional neuroimaging can improve our ability to predict recovery and select individuals for rehabilitation; mechanisms of recovery reflect different pathophysiological phases; and brain adaptation may be modulated by experience and specific rehabilitation. The significance and application of this new evidence is discussed, and recommendations made for investigations in the field.

Conclusion

Functional neuroimaging is an important tool to explore the mechanisms underlying brain plasticity and, thereby, to guide clinical research in neurorehabilitation.

Efficacy of transcranial alternating current stimulation over bilateral mastoids (tACSbm) on enhancing recovery of subacute post-stroke patients

BACKGROUND AND AIMS

Transcranial alternating current stimulation (tACS) offers another method of non-invasive brain stimulation in post-stroke rehabilitation. Because it is not known if tACS over bilateral mastoids (tACS_bm) can promote the functional recovery in subacute post-stroke patients, we wish to learn the effect of tACS_bm on improving neurological function and intracranial hemodynamics of subacute post-stroke patients.

METHODS

Sixty subacute post-stroke patients (mean age: 65.4 ± 9.8 years), 15 to 60 days after the onset, were randomly assigned to receiving 15 sessions of usual rehabilitation program without (n = 30) or with tACS_bm (20 Hz and < 400 μA for 30-min; n = 30). The outcome measures included the NIH Stroke Scale (NIHSS) and measures of intracranial hemodynamics before and after treatment.

RESULTS

At the fifteenth session, when compared with the baseline, the mean NIHSS scores of the patients in the tACS_bm group had significantly a larger decrease [18.3 ± 2.6 vs. 10.8 ± 2.7; p < 0.001] than that of the control group [19.1 ± 2.7 vs. 13.0 ± 2.4] [F(1,54) = 4.29, p = 0.043]. After both the first and fifteenth sessions, compared with the control group, the mean blood flow velocity (MFVs) of the tACS_bm group had significantly larger increase in the MCA, ACA, and PCA (p < 0.001), the Gosling pulsatility index (PI) of the tACS_bm group had also significantly larger decline in the MCA, ACA, and PCA than that of the control group (p < 0.001). The best predictor of the changes in the NIHSS scores was the decline in the pulsatility index in the vascular territory of both lesional and non-lesional MCA measured by the end of the last treatment session.

CONCLUSIONS

tACS_bm appeared to be effective for enhancing patients' functional recovery and cerebral hemodynamics in the subacute phase. The extent of recovery seems to be associated with the decline of the resistance in vascular bed of the main cerebral arteries. The mechanisms behind this effect should be explored further through research.

Brain Perfusion in Corticobasal Syndrome with Progressive Aphasia

Background

Brain perfusion may differ between patients with corticobasal syndrome (CBS) with and without aphasia.

Methods

Twenty-six (9 males and 17 females; mean age 76 ± 5.3 years) patients with CBS were enrolled in the study. Brain MRI and single-photon emission computed tomography were performed in all subjects. Language was evaluated using the Standard Language Test of Aphasia. The patients were divided into two subgroups according to the presence or absence of progressive aphasia. Differences in the regional cerebral blood flow (rCBF) between the two groups were detected based on voxel-by-voxel group analysis using Statistical Parametric Mapping 8.

Results

All patients exhibited asymmetric motor symptoms and signs, including limb apraxia, bradykinesia, and akinetic rigidity. Of 26 patients, 9 had a clinically obvious language disturbance, characterized as nonfluent aphasia. Almost all CBS patients with aphasia exhibited cortical atrophy predominantly in the left frontal and temporal lobes with widening of the Sylvian fissure on MRI. The rCBF in the left middle frontal gyrus differed significantly between CBS patients with and without aphasia.

Conclusion

CBS patients with aphasia exhibit motor symptoms predominantly on the right side and cortical atrophy mainly in the left perisylvian cortices. In particular, left frontal dysfunction might be related to nonfluent aphasia in CBS.

Identifying Dysfunctional Cortex: Dissociable Effects of Stroke and Aging on Resting State Dynamics in MEG and fMRI

Spontaneous signals in neuroimaging data may provide information on cortical health in disease and aging, but the relative sensitivity of different approaches is unknown. In the present study, we compared different but complementary indicators of neural dynamics in resting-state MEG and BOLD fMRI, and their relationship with blood flow. Participants included patients with post-stroke aphasia, age-matched controls, and young adults. The complexity of brain activity at rest was quantified in MEG using spectral analysis and multiscale entropy (MSE) measures, whereas BOLD variability was quantified as the standard deviation (SDBOLD), mean squared successive difference (MSSD), and sample entropy of the BOLD time series. We sought to assess the utility of signal variability and complexity measures as markers of age-related changes in healthy adults and perilesional dysfunction in chronic stroke. The results indicate that reduced BOLD variability is a robust finding in aging, whereas MEG measures are more sensitive to the cortical abnormalities associated with stroke. Furthermore, reduced complexity of MEG signals in perilesional tissue were correlated with hypoperfusion as assessed with arterial spin labeling (ASL), while no such relationship was apparent with BOLD variability. These findings suggest that MEG signal complexity offers a sensitive index of neural dysfunction in perilesional tissue in chronic stroke, and that these effects are clearly distinguishable from those associated with healthy aging.

Brain plasticity in aphasic patients: intra- and inter-hemispheric reorganisation of the whole linguistic network probed by N150 and N350 components

The present study examined linguistic plastic reorganization of language through Evoked Potentials in a group of 17 non-fluent aphasic patients who had suffered left perisylvian focal lesions, and showed a good linguistic recovery. Language reorganisation was probed with three linguistic tasks (Phonological, Semantic, Orthographic), the early word recognition potential (N150) and the later phonological-related component (N350). Results showed the typical left-lateralised posterior N150 in healthy controls (source: left Fusiform Gyrus), that was bilateral (Semantic) or right sided (Phonological task) in patients (sources: right Inferior/Middle Temporal and Fusiform Gyri). As regards N350, controls revealed different intra- and inter-hemispheric linguistic activation across linguistic tasks, whereas patients exhibited greater activity in left intact sites, anterior and posterior to the damaged area, in all tasks (sources: Superior Frontal Gyri). A comprehensive neurofunctional model is presented, describing how complete intra- and inter-hemispheric reorganisation of the linguistic networks occurs after aphasic damage in the strategically dominant left perisylvian linguistic centres.

The importance of premotor cortex for supporting speech production after left capsular-putaminal damage

The left putamen is known to be important for speech production, but some patients with left putamen damage can produce speech remarkably well. We investigated the neural mechanisms that support this recovery by using a combination of techniques to identify the neural regions and pathways that compensate for loss of the left putamen during speech production. First, we used fMRI to identify the brain regions that were activated during reading aloud and picture naming in a patient with left putamen damage. This revealed that the patient had abnormally high activity in the left premotor cortex. Second, we used dynamic causal modeling of the patient's fMRI data to understand how this premotor activity influenced other speech production regions and whether the same neural pathway was used by our 24 neurologically normal control subjects. Third, we validated the compensatory relationship between putamen and premotor cortex by showing, in the control subjects, that lower connectivity through the putamen increased connectivity through premotor cortex. Finally, in a lesion-deficit analysis, we demonstrate the explanatory power of our fMRI results in new patients who had damage to the left putamen, left premotor cortex, or both. Those with damage to both had worse reading and naming scores. The results of our four-pronged approach therefore have clinical implications for predicting which patients are more or less likely to recover their speech after left putaminal damage.

CSF levels of Aβ1-38/Aβ1-40/Aβ1-42 and (11)C PiB-PET studies in three clinical variants of primary progressive aphasia and Alzheimer's disease

Primary progressive aphasia (PPA) is a cognitive syndrome characterized by progressive and isolated language impairments due to neurodegenerative diseases. Recently, an international group of experts published a Consensus Classification of the three PPA clinical variants (naPPA, svPPA and lvPPA). We analyzed 24 patients with PPA by cognitive functions, neuroimaging (MRI, (99 m)Tc ECD-SPECT, (11)C PiB-PET and FDG-PET) and cerebrospinal fluid (CSF) analysis (ptau-181, Aβ1-42, Aβ1-40 and Aβ1-38), to elucidate relationships between neuroimaging studies and biochemical findings in the three PPA clinical variants. Cognitive and speech functions were measured by mini-mental state examination and standard language test of aphasia. The patients with lvPPA showed significant decreases in CSF Aβ1-42 and ratios of Aβ1-42/Aβ1-40 and Aβ1-42/Aβ1-38, and significant increases in CSF ptau-181 and ratios of ptau-181/Aβ1-42 and ptau-181/Aβ1-38; these findings were similar to those of patients with Alzheimer's disease (AD). We observed a higher frequency of the ApoE ε4 allele in the lvPPA patients relative to the two other PPA variants. In (11)C PiB-PET of lvPPA patients, PiB positive findings were detected in cortices of frontal, temporal and parietal lobes and the posterior cingulate, where massive Aβ may accumulate due to AD. Our results of AD-CSF markers including Aβ1-38 and (11)C PiB-PET in the lvPPA patients demonstrate a common pathological mechanism with the occurrence of AD.

The longitudinal evolution of cerebral blood flow regulation after acute ischaemic stroke

BACKGROUND

Acute stroke is known to impair cerebral blood flow (CBF) regulation, but the longitudinal changes of these effects have been poorly reported. The main CBF regulatory mechanisms [cerebral autoregulation (CA) and neurovascular coupling (NVC)] were assessed over 3 months after acute ischaemic stroke.

METHODS

Recordings of CBF velocity (CBFv), blood pressure (BP), and end-tidal CO2 were performed during 5 min baseline and 1 min passive movement of the elbow. Stroke patients were assessed <72 h of stroke onset, and at 2 weeks, 1 and 3 months after stroke.

RESULTS

Fifteen acute stroke subjects underwent all 4 sessions and were compared to 22 control subjects. Baseline recordings revealed a significantly lower CBFv in the affected hemisphere within 72 h after stroke compared to controls (p = 0.02) and a reduction in CA index most marked at 2 weeks (p = 0.009). CBFv rise in response to passive arm movement was decreased bilaterally after stroke, particularly in the affected hemisphere (p < 0.01). Both alterations in CA and NVC returned to control levels during recovery.

CONCLUSION

The major novel finding of this study was that both CA and NVC regulatory mechanisms deteriorated initially following stroke onset, but returned to control levels during the recovery period. These findings are relevant to guide the timing of interventions to manipulate BP and potentially for the impact of intensive rehabilitation strategies that may precipitate acute physiological perturbations but require further exploration in a larger population that better reflects the heterogeneity of stroke. Further, they will also enable the potential influence of stroke subtype to be investigated.

Early sitting, standing, and walking in conjunction with contemporary Bobath approach for stroke patients with severe motor deficit

BACKGROUND

The commonly used therapeutic approach, the contemporary Bobath approach (CBA), is not sufficient to restore independent locomotion for individuals with severe motor deficit (SMD) after stroke. Therefore, we propose that the early sitting, standing, and walking in conjunction with the CBA (ECBA) be used to treat individuals with SMD after stroke.

OBJECTIVE

To investigate whether ECBA may enhance mobility and balance in subjects with SMD after stroke.

METHODS

Thirty-three men and 15 women, aged 60 to 74 years, with SMD after stroke were recruited for the study. CBA or ECBA was performed with the subjects 5 times per week in 50-minute sessions for 8 weeks. The Stroke Rehabilitation Assessment of Movement (STREAM) and the Berg Balance Scale were implemented before treatment and at 4 and 8 weeks after treatment, respectively.

RESULTS

The STREAM scores indicated that ECBA was more efficient than the CBA intervention for lower extremity mobility, F(1, 46) = 24.0, P < .001, and basic mobility, F(1, 46) = 102.6, P < .001. Overall STREAM scores were higher in the ECBA group, F(1, 46) =24.1, P < .001, after 8 weeks of therapy. Balance scores of the ECBA subjects were higher than those of the CBA subjects after 8 weeks of therapy, F(1, 46) = 73.1, P < .001. However, there was no difference in upper extremity mobility between the 2 groups.

CONCLUSION

ECBA is a valuable intervention to improve lower extremity mobility, basic mobility, and balance ability for individuals with SMD after stroke.

Right hand predominant constructional apraxia due to right hemisphere infarction without corpus callosum lesions

A 74-year-old right-handed woman without cognitive impairment suddenly developed nonfluent aphasia. Brain MRI showed acute infarction in the right frontal lobe and insula without involvement of the corpus callosum. A neurological examination demonstrated not only transcortical motor aphasia, but also ideomotor apraxia and right hand predominant constructional apraxia (CA). To date, right hand predominant CA has only been reported in patients with corpus callosum lesions. The right hand predominant CA observed in our patient may be associated with the failure to transfer information on the spatial structure from the right hemisphere to the motor cortex of the left hemisphere.

Cognitive control and its impact on recovery from aphasic stroke

Aphasic deficits are usually only interpreted in terms of domain-specific language processes. However, effective human communication and tests that probe this complex cognitive skill are also dependent on domain-general processes. In the clinical context, it is a pragmatic observation that impaired attention and executive functions interfere with the rehabilitation of aphasia. One system that is important in cognitive control is the salience network, which includes dorsal anterior cingulate cortex and adjacent cortex in the superior frontal gyrus (midline frontal cortex). This functional imaging study assessed domain-general activity in the midline frontal cortex, which was remote from the infarct, in relation to performance on a standard test of spoken language in 16 chronic aphasic patients both before and after a rehabilitation programme. During scanning, participants heard simple sentences, with each listening trial followed immediately by a trial in which they repeated back the previous sentence. Listening to sentences in the context of a listen–repeat task was expected to activate regions involved in both language-specific processes (speech perception and comprehension, verbal working memory and pre-articulatory rehearsal) and a number of task-specific processes (including attention to utterances and attempts to overcome pre-response conflict and decision uncertainty during impaired speech perception). To visualize the same system in healthy participants, sentences were presented to them as three-channel noise-vocoded speech, thereby impairing speech perception and assessing whether this evokes domain general cognitive systems. As expected, contrasting the more difficult task of perceiving and preparing to repeat noise-vocoded speech with the same task on clear speech demonstrated increased activity in the midline frontal cortex in the healthy participants. The same region was activated in the aphasic patients as they listened to standard (undistorted) sentences. Using a region of interest defined from the data on the healthy participants, data from the midline frontal cortex was obtained from the patients. Across the group and across different scanning sessions, activity correlated significantly with the patients’ communicative abilities. This correlation was not influenced by the sizes of the lesion or the patients’ chronological ages. This is the first study that has directly correlated activity in a domain general system, specifically the salience network, with residual language performance in post-stroke aphasia. It provides direct evidence in support of the clinical intuition that domain-general cognitive control is an essential factor contributing to the potential for recovery from aphasic stroke.

Brain activation during speech perception in a patient with a massive left hemisphere infarction

BACKGROUND

Little is known about the regions involved in recovery from global aphasia in patients with malignant infarction after decompressive hemicraniectomy. This study reports a case of brain activation during speech perception in a right-handed patient with a massive left hemispheric infarction.

METHODS

Decompressive hemicraniectomy was performed in a 20-year old woman with space-occupying infarction of the speech dominant hemisphere. Complete anterior, middle and part of the posterior cerebral artery territories of the left hemisphere, as well as posterior regions of the right middle cerebral artery territory, were affected. Neuropsychological testing and functional magnetic resonance imaging (fMRI) during speech perception were performed 10 months after stroke.

RESULTS

The patient was able to walk, go up and down stairs independently and perform simple tasks at home. She was also well able to match visually and orally presented words with their corresponding pictures, despite large bilateral lesions in the posterior regions. fMRI revealed strong activation of the left temporo-occipital and parieto-occipital areas. In the right hemisphere was observed a small area of activation in the posterior part of the superior and middle temporal gyrus.

CONCLUSIONS

In aphasic patients, the activation of posterior bilateral associative areas might be used to support language perception.

Cerebral blood flow response to neural activation after acute ischemic stroke: a failure of myogenic regulation?

We tested two hypotheses: (1) neurovascular coupling is impaired after acute ischemic stroke, (2) subcomponent analysis of cerebral blood flow velocity can reveal significant differences between acute ischemic stroke and healthy controls. This was explored through the comparison of nineteen acute ischemic stroke patients with healthy controls. Recordings of cerebral blood flow velocity, blood pressure and end-tidal CO2 were obtained during 60s of passive elbow flexion. Cerebral blood flow velocity changes were decomposed into standardized subcomponents describing the contributions of blood pressure (V BP), resistance area product (V RAP) and critical closing pressure (V CrCP). The passive paradigm led to a bilateral cerebral blood flow velocity increase in both groups, but in acute ischemic stroke the magnitude of change was significantly lower. Blood pressure increases were shown to be an important contributor to cerebral blood flow velocity response throughout the paradigm in both groups, with no significant difference between groups. The V CrCP contribution was not different between groups or hemispheres; its continuous rise during activation indicating a vasodilatory effect. On the other hand, the V RAP contribution showed significant differences (p = 0.03), thus suggesting myogenic impairment in acute ischemic stroke. Cerebral blood flow velocity responses to passive elbow flexion suggest an impairment of neurovascular coupling in acute ischemic stroke. Subcomponent analysis suggests an impairment of the myogenic pathways, giving a greater insight into the different mechanisms contributing to neurovascular coupling. Further research is needed to assess the clinical value of subcomponent analysis of neurovascular coupling and the natural history of such changes following acute ischemic stroke.

[Repetitive transcranial magnetic stimulation. A reasonable adjuvant therapeutic method in the treatment of post-stroke aphasia?]

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive, painless method used to stimulate areas of the brain through the intact skull by means of magnetic fields. Depending on the stimulation frequency, the effect on concurrent brain areas is either inhibiting or exciting. As a result, it should be possible to inhibit compensatory hyperactivation in certain brain areas or to temporarily enhance cortical excitability. Therefore, rTMS potentially represents an adjuvant treatment for aphasia. In this article, the literature regarding rTMS as a treatment for aphasia is reviewed and followed by a case report of a 79-year-old man who 3 years after stroke received rTMS (3 × 10 sessions) in combination with articulation therapy. Even though linguistic assessments did not show enhancements in language skills, the patient's family reported changes in communication patterns and behavior and explicitly asked to continue the rTMS treatment sessions. Reasons why no enhancements could be reported might be found in the type of language disorder (a comorbid speech disorder) or the stimulation protocol. Further studies are needed to evaluate the true potential of rTMS in the treatment of aphasia.

Motor development and motor resonance difficulties in autism: relevance to early intervention for language and communication skills

Research suggests that a sub-set of children with autism experience notable difficulties and delays in motor skills development, and that a large percentage of children with autism experience deficits in motor resonance. These motor-related deficiencies, which evidence suggests are present from a very early age, are likely to negatively affect social-communicative and language development in this population. Here, we review evidence for delayed, impaired, and atypical motor development in infants and children with autism. We then carefully review and examine the current language and communication-based intervention research that is relevant to motor and motor resonance (i.e., neural "mirroring" mechanisms activated when we observe the actions of others) deficits in children with autism. Finally, we describe research needs and future directions and developments for early interventions aimed at addressing the speech/language and social-communication development difficulties in autism from a motor-related perspective.

Nuclear medicine in cerebrovascular disease

Stroke and cerebrovascular diseases are major causes of mortality, morbidity, and disability. Nuclear Medicine, primarily via tomographic methods, has made significant contributions to the understanding of the hemodynamic and metabolic consequences of cerebrovascular diseases. In this review, the findings in acute, subacute, and chronic cerebrovascular diseases are described. Many of the pathophysiologic processes and consequences that follow stroke, including completed infarct core, adjacent penumbra, and diaschisis, have been investigated with Nuclear Medicine, and stroke outcome may be related to these phenomena. Additional topics included in this review are cerebrovascular reserve tests and multi-infarct dementia. Finally, Nuclear Medicine investigations of stroke recovery and cerebral plasticity appear to indicate that enhanced activity of preexisting networks, rather than substitution of function, represents the most important mechanism of improvement in chronic stroke rehabilitation.

Damage to the left ventral, arcuate fasciculus and superior longitudinal fasciculus-related pathways induces deficits in object naming, phonological language function and writing, respectively

The anatomic localization of brain functions can be characterized via diffusion tensor imaging in patients with brain tumors and neurological symptoms. The goal of the present study was to evaluate the function of the ventral, arcuate fasciculus (AF) and the superior longitudinal fasciculus (SLF)-related language pathways using these techniques by analyzing 9 patients treated in our hospital between 2007 and 2011. In cases 1-3, the left ventral pathways, namely, the inferior longitudinal fasciculus, uncinate fasciculus or inferior fronto-occipital fasciculus, were mainly damaged, and the common dysfunction experienced by these patients was a deficit in object naming. In cases 4-6, the left SLF was mainly damaged, and the common deficit was dysgraphia. In cases 7-9, the left AF was mainly damaged, and almost all language functions related to phonology were abnormal. These results suggest that the left ventral, AF and SLF-related pathways are closely related to visual, auditory and hand-related language function, respectively.

Neurocognitive brain response to transient impairment of Wernicke's area

This study examined how the brain system adapts and reconfigures its information processing capabilities to maintain cognitive performance after a key cortical center [left posterior superior temporal gyrus (LSTGp)] is temporarily impaired during the performance of a language comprehension task. By applying repetitive transcranial magnetic stimulation (rTMS) to LSTGp and concurrently assessing the brain response with functional magnetic resonance imaging, we found that adaptation consisted of 1) increased synchronization between compensating regions coupled with a decrease in synchronization within the primary language network and 2) a decrease in activation at the rTMS site as well as in distal regions, followed by their recovery. The compensatory synchronization included 3 centers: The contralateral homolog (RSTGp) of the area receiving rTMS, areas adjacent to the rTMS site, and a region involved in discourse monitoring (medial frontal gyrus). This approach reveals some principles of network-level adaptation to trauma with potential application to traumatic brain injury, stroke, and seizure.

Different clinical phenotypes in siblings with a presenilin-1 P264L mutation

BACKGROUND

Mutations in the presenilin-1 gene (PSEN1) have been identified in autosomal dominant early-onset cases of Alzheimer's disease (AD).

AIMS

To investigate different clinical phenotypes of siblings possessing the same heterozygous P264L mutation in the PSEN1 gene.

METHODS

We evaluated clinical features, neuroimaging results, and neuropsychological examinations. The PSEN1 gene and other dementia-related gene mutations were screened.

RESULTS

We clinically diagnosed the proband as atypical AD with frontotemporal dementia features and diagnosed the elder brother of the proband as typical AD, based on neuropsychological symptoms and a brain imaging examination including amyloid imaging data. A heterozygous P264L mutation in the PSEN1 gene was identified in both siblings.

CONCLUSION

This study is one of few reports of AD siblings possessing the same mutation but exhibiting different clinical phenotypes in a Japanese family possessing a P264L mutation in the PSEN1 gene. The current results suggest that unknown modifiers, including both genetic and epigenetic factors, may alter the pathological and clinical phenotypes of a genetically predetermined disease.

Post-stroke aphasia prognosis: a review of patient-related and stroke-related factors

RATIONALE, AIMS AND OBJECTIVES

Recovery of language function in individuals with post-stroke aphasia is associated with a variety of patient and stroke-related indices. Amidst a complex interaction of a multitude of variables, clinicians are faced with the arduous challenge of predicting aphasia recovery patterns and subsequently, long-term outcomes in these individuals. Unfortunately, predictive factors are highly variable making prognosis of aphasia recovery difficult. Therefore, the objective of this review was to assess the influence of patient-related and stroke-related factors on language recovery in individuals with post-stroke aphasia.

METHODS

We completed a literature review to assess and identify evidence-based patient and stroke-related variables shown to be influential in aphasia recovery.

RESULTS

A range of patient-related (gender, handedness, age, education, socio-economic status and intelligence) and stroke-related indices (initial severity, lesion site and lesion size) were identified as potential influential factors to post-stroke aphasia recovery. Initial severity of aphasia emerged as the factor most predictive of long-term aphasia recovery. Other influential factors of post-stroke language recovery included lesion site and size.

CONCLUSIONS

Stroke-related factors, including aphasia severity, lesion site and lesion size, appear most critical to post-stroke aphasia recovery. The findings presented in this review offer clinicians an evidenced-based framework to assist in prediction of post-stroke aphasia recovery patterns and subsequent long-term functional communication outcomes.

Effects of covert and overt paradigms in clinical language fMRI

RATIONALE AND OBJECTIVES

The aim of this study was to assess the intrasubject and intersubject reproducibility of functional magnetic resonance imaging (fMRI) language paradigms on language localization and lateralization.

MATERIALS AND METHODS

Fourteen healthy volunteers were enrolled prospectively and underwent language fMRI using visually triggered covert and overt sentence generation (SG) and word generation (WG) paradigms. Semiautomated analysis of all functional data was performed using Brain Voyager on an individual basis. Regions of interest for Broca's area, Wernicke's area, and their contralateral homologues were drawn. The Euclidean coordinates of the center of gravidity (x, y, and z) of the respective blood oxygenation level-dependent (BOLD) activation cluster, and the correlation of the measured hemodynamic response to the applied reference function (r), relative BOLD signal change as BOLD signal characteristics were measured in each region of interest. Regional lateralization indexes were calculated for Broca's area, Wernicke's area, and their contralateral homologues separately. Wilcoxon's signed-rank test was applied for statistical comparisons (P values < .05 were considered significant). Ten of the 14 volunteers had three repeated measurements to test intrasession reproducibility and intersession reproducibility.

RESULTS

Overall activation rates for the four paradigms were 89% for covert SG, 82% for overt SG, 89% for covert WG, and 100% for overt WG. When comparing covert and overt paradigms, language localization was significantly different in 17% (Euclidean coordinates) and 19% (BOLD signal characteristics), respectively. Language lateralization was significantly different in 75%. Intrasubject and intersubject reproducibility was excellent, with 3.3% significant differences among all five parameters for language localization and 0% significant differences for language lateralization using covert paradigms.

CONCLUSIONS

Covert language paradigms (SG and WG) provided highly robust and reproducible localization and lateralization of essential language centers for scans performed on the same and different days. Their overt counterparts achieved confirmatory localization but lower lateralization capabilities. Reference data for presurgical application are provided.

Familial semantic dementia with P301L mutation in the Tau gene

BACKGROUND/AIMS

Semantic dementia (SD) is a clinical subclassification of frontotemporal lobar degeneration. Patients with 'pure SD' present with semantic memory impairment preceding the frontal symptoms, and there have been no reports of familial cases.

METHODS

We evaluated the clinical features of, and performed neuropsychological examinations on, the proband and two affected family members. Then we performed neuroimaging and genetic analysis of MAPT and other dementia-related genes in the proband.

RESULTS

All three cases had semantic memory impairment with loss of word meanings as the primary early symptom. We diagnosed all cases as pure SD and identified a P301L mutation in the MAPT gene of the proband.

CONCLUSION

Although the P301L mutation identified here has been previously described as pathogenic for frontotemporal dementia with parkinsonism-17 (FTDP-17), the proband and his two affected relatives showed different clinical symptoms from those of typical FTDP-17 cases who carry the P301L mutation. Pathologically, pure SD usually shows a TAR DNA-binding protein proteinopathy, but the molecular understanding of SD is not well established. Although our cases were clinically pure SD, the proband has a tau gene mutation, which would lead to tauopathy. These findings suggest that reconsideration of the molecular understanding of SD is warranted.

Non-invasive brain stimulation enhances the effects of melodic intonation therapy

Research has suggested that a fronto-temporal network in the right hemisphere may be responsible for mediating melodic intonation therapy's (MIT) positive effects on speech recovery. We investigated the potential for a non-invasive brain stimulation technique, transcranial direct current stimulation (tDCS), to augment the benefits of MIT in patients with non-fluent aphasia by modulating neural activity in the brain during treatment with MIT. The polarity of the current applied to the scalp determines the effects of tDCS on the underlying tissue: anodal-tDCS increases excitability, whereas cathodal tDCS decreases excitability. We applied anodal-tDCS to the posterior inferior frontal gyrus of the right hemisphere, an area that has been shown both to contribute to singing through the mapping of sounds to articulatory actions and to serve as a key region in the process of recovery from aphasia, particularly in patients with large left hemisphere lesions. The stimulation was applied while patients were treated with MIT by a trained therapist. Six patients with moderate to severe non-fluent aphasia underwent three consecutive days of anodal-tDCS + MIT, and an equivalent series of sham-tDCS + MIT. The two treatment series were separated by 1 week, and the order in which the treatments were administered was randomized. Compared to the effects of sham-tDCS + MIT, anodal-tDCS + MIT led to significant improvements in fluency of speech. These results support the hypothesis that, as the brain seeks to reorganize and compensate for damage to left hemisphere language centers, combining anodal-tDCS with MIT may further recovery from post-stroke aphasia by enhancing activity in a right hemisphere sensorimotor network for articulation.

The use of non-invasive brain stimulation techniques to facilitate recovery from post-stroke aphasia

Aphasia is a common symptom after left hemispheric stroke. Neuroimaging techniques over the last 10-15 years have described two general trends: Patients with small left hemisphere strokes tend to recruit perilesional areas, while patients with large left hemisphere lesions recruit mainly homotopic regions in the right hemisphere. Non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been employed to facilitate recovery by stimulating lesional and contralesional regions. The majority of these brain stimulation studies have attempted to block homotopic regions in the right posterior inferior frontal gyrus (IFG) to affect a presumed disinhibited right IFG (triangular portion). Other studies have used anodal or excitatory tDCS to stimulate the contralesional (right) fronto-temporal region or parts of the intact left IFG and perilesional regions to improve speech-motor output. It remains unclear whether the interhemispheric disinhibition model, which is the basis for motor cortex stimulation studies, also applies to the language system. Future studies could address a number of issues, including: the effect of lesion location on current density distribution, timing of the intervention with regard to stroke onset, whether brain stimulation should be combined with behavioral therapy, and whether multiple brain sites should be stimulated. A better understanding of the predictors of recovery from natural outcome studies would also help to inform study design, and the selection of clinically meaningful outcome measures in future studies.

Does long term use of piracetam improve speech disturbances due to ischemic cerebrovascular diseases?

Aphasia causes significant disability and handicap among stroke survivors. Language therapy is recommended for aphasic patients, but not always available. Piracetam, an old drug with novel properties, has been shown to have mild beneficial effects on post-stroke aphasia. In the current study, we investigated the effects of 6 months treatment with piracetam on aphasia following stroke. Thirty patients with first-ever ischemic strokes and related aphasia were enrolled in the study. The scores for the National Institutes of Health Stroke Scale (NIHSS), Barthel Index (BI), modified Rankin Scale (mRS), and Gülhane Aphasia Test were recorded. The patients were scheduled randomly to receive either 4.8 g piracetam daily or placebo treatment for 6 months. At the end of 24 weeks, clinical assessments and aphasia tests were repeated. The level of improvement in the clinical parameters and aphasia scores was compared between the two groups. All patients had large lesions and severe aphasia. No significant difference was observed between the piracetam and placebo groups regarding the improvements in the NIHSS, BI and mRS scores at the end of the treatment. The improvements observed in spontaneous speech, reading fluency, auditory comprehension, reading comprehension, repetition, and naming were not significantly different in the piracetam and placebo groups, the difference reached significance only for auditory comprehension in favor of piracetam at the end of the treatment. Piracetam is well-tolerated in patients with post-stroke aphasia. Piracetam taken orally in a daily dose of 4.8 g for 6 months has no clear beneficial effect on post-stroke language disorders.

Ambient experience in restitutive treatment of aphasia

One of the greatest challenges to language rehabilitation is reconciling the fact that the same therapeutic intervention, provided to different individuals with similar types of stroke-induced aphasia, may result in divergent outcomes. In this paper, the authors reviewed existing literature to identify relevant ambient factors – those outside the control of the clinician – that may potentially influence functional language recovery in aphasia and response to treatment. The goal was to develop a clinical history-taking tool to assist clinicians in gathering information germane to each individual's unique circumstances and environment, elements that may have previously been underestimated, to provide a complete inventory of potentially potent prognostic factors. First, two of the authors, speech–language pathologists experienced in aphasia rehabilitation, identified and categorized factors that seemed likely to influence aphasia outcomes. Then, a wide range of literature was reviewed in an effort to identify factors empirically found to be potent influences on aphasia recovery. Where studies relating these factors to aphasia were not found, relevant research from allied fields that examined recovery from brain injury is reported. Moreover, some factors thought to be potentially potent have yet to be examined. Finally, the ambient factors supported by evidence were categorized as facilitators or barriers to functional improvement, and the Ambient Influences on Outcome Checklist (AOC) was developed, including only those factors shown to be potent in the recovery process. It is hoped that this checklist can be used to more broadly assess potential prognostic influences in aphasia restitution, as well as spawn further research.

From singing to speaking: facilitating recovery from nonfluent aphasia

It has been reported for more than 100 years that patients with severe nonfluent aphasia are better at singing lyrics than they are at speaking the same words. This observation led to the development of melodic intonation therapy (MIT). However, the efficacy of this therapy has yet to be substantiated in a randomized controlled trial. Furthermore, its underlying neural mechanisms remain unclear. The two unique components of MIT are the intonation of words and simple phrases using a melodic contour that follows the prosody of speech and the rhythmic tapping of the left hand that accompanies the production of each syllable and serves as a catalyst for fluency. Research has shown that both components are capable of engaging fronto-temporal regions in the right hemisphere, thereby making MIT particularly well suited for patients with large left hemisphere lesions who also suffer from nonfluent aphasia. Recovery from aphasia can happen in two ways: either through the recruitment of perilesional brain regions in the affected hemisphere, with variable recruitment of right-hemispheric regions if the lesion is small, or through the recruitment of homologous language and speech-motor regions in the unaffected hemisphere if the lesion of the affected hemisphere is extensive. Treatment-associated neural changes in patients undergoing MIT indicate that the unique engagement of right-hemispheric structures (e.g., the superior temporal lobe, primary sensorimotor, premotor and inferior frontal gyrus regions) and changes in the connections across these brain regions may be responsible for its therapeutic effect.

Damage of left temporal lobe resulting in conversion of speech to Sutra, a Buddhist prayer stored in the right hemisphere

The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed conversion of speech to Sutra, a Buddhist prayer, which was stored in the right hemisphere according to the Wada test. After surgery, relative improvement in the speech disorder was observed, and frequency of speech production of simple normal words with normal phonology increased. These observations indicate that damage to left temporal lobe resulted in conversion of speech to Sutra, and that Sutra was stored in this patient's right hemisphere.

Deficits in the left inferior longitudinal fasciculus results in impairments in object naming

The functional characteristics of the left inferior longitudinal fasciculus (ILF) remain unclear. The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed marked deterioration in object naming ability after invasion of the tumor into the medial region of the left posterior (middle and inferior) temporal lobe just beside the atrium of the lateral ventricle. Diffusion tensor imaging showed possible interruption of the left ILF after invasion of tumor at this site. By contrast, the left superior longitudinal fasciculus (SLF) remained intact after invasion of tumor, and the inferior fronto-occipital fasciculus (IFOF) was already disrupted prior to tumor invasion. These observations indicate that intact ILF function may be required for object naming ability.