Effect of Oral Apraxia on Dysphagia in Patients with Subacute Stroke.

Aim of this study was to investigate the effect of post-stroke oral apraxia on dysphagia in patients with subacute stroke. We retrospectively analyzed the clinical data of 130 supratentorial stroke patients from January 2015 to February 2021 who underwent a formal limb and oral apraxia test and videofluoroscopic swallowing study (VFSS), and we compared the patients in two groups: the apraxia and non-apraxia (oral apraxia score > 45 and ≤ 45 points, respectively). All the patients participated in the standardized testing battery. The test variables were videofluoroscopic dysphagia scale (VDS), oral transit time (OTT), pharyngeal delay time (PDT), pharyngeal transit time, and penetration-aspiration scale (PAS); we conducted multivariable regression analysis with those parameters to confirm the significance of oral apraxia as a clinical determinant of post-stroke dysphagia. The mean oral apraxia scores were 38.4 and 47.6 points in the apraxia and non-apraxia groups, respectively (p < 0.001). The apraxia group had a higher proportion of delayed OTT for the 2-mL-thick liquid than the non-apraxia group (17.6% and 4.2%, respectively; p = 0.011). Oral apraxia was a significant determinant of VDS (p < 0.001), delayed OTT of 2-mL-thick liquids (p = 0.028), delayed PDT of cup drinking for thin liquid (p = 0.044), and PAS scores (p = 0.003). The presence of oral apraxia was significantly associated with dysphagia, especially with the VFSS parameters of the oral phase (thick liquid), pharyngeal phase (cup drinking for thin liquid) of swallowing, and increased risk of aspiration in subacute stroke patients. Thus, a formal assessment of oral apraxia is needed for stroke patients with dysphagia.

Design and Evaluation of Korean Electropalatography (K-EPG).

Recently, the development of medical rehabilitation technology has resulted in an increased interest in speech therapy equipment. In particular, research on articulation therapy for communication disorders is being actively conducted. The existing methods for the diagnosis and treatment of speech disorders, such as traditional tactile perception tests and methods based on the empirical judgment of speech therapists, have many limitations. Moreover, the position and contact force of the tongue are key factors in speech disorders with regards to articulation. This is a very important factor in the distinction of Korean characters such as lax, tense and aspirated consonants. In this study, we proposed a Korean-electropalatography (EPG) system to easily measure and monitor the position and contact force of the tongue during articulation treatment and diagnosis. In our proposed K-EPG system, a sensor was fabricated using an AgCl electrode and biocompatible silicon. Furthermore, the measured signal was analyzed by implementing a bio-signal processing module and monitoring program. In particular, the bio-signal was measured by inserting the device into the palate of an experimental healthy test group (four subjects). Through these experiments, we confirmed that our K-EPG system could be applied to clinical treatment in speech therapy.

Reduced axial diffusivity and increased mode and T2 signals in cerebral white matter of chronic obstructive pulmonary disease using tract-based spatial statistics.

PURPOSE: Chronic obstructive pulmonary disease (COPD) is considered to be a multi-systemic disease involving pathological changes in the brain. This study investigated how diffusion tensor imaging (DTI) parameters in patients with non-hypoxemic COPD differ from those in controls. Moreover, we tried to examine whether the mode of anisotropy (MO) reflects early changes in white matter (WM) integrity in COPD. METHODS: DT images were obtained from 13 male COPD patients and 13 age- and sex-matched healthy controls. Raw DT images were processed using an automated tract-based spatial statistics (TBSS) pipeline. DTI scalars of fractional anisotropy (FA); axial, radial, and mean diffusivities (AD, RD, and MD, respectively); MO; and raw T2 signal (S0) were statistically compared between COPD patients and controls. TBSS methods were used for analysis. RESULTS: In patients with COPD, decreased AD was observed in the temporal stem (TS), corticospinal tract (CST), thalamus, subiculum, crus cerebri, and midbrain. Increased MO values were found in the corpus callosum, CST, internal capsule, cerebellar peduncle (CP), and medial lemniscus (ML). Additionally, increased S0 was found in the TS, CP, pons, and cerebellar tonsil (threshold-free cluster enhancement to a family-wise error rate of p < 0.05). CONCLUSION: The results revealed decreased AD and increased MO scalars in COPD patients compared with the controls, although there were no differences in FA, RD, and MD scalars. Decreased AD and increased MO scalars may reflect early changes in WM integrity in COPD patients.

Changes in the regional shape and volume of subcortical nuclei in patients with tinnitus comorbid with mild hearing loss.

PURPOSE: Tinnitus, the perception of sound without an external source, is a prevalent disease, but its underlying mechanism has not been fully elucidated. Recent studies have suggested the involvement of subcortical nuclei in tinnitus generation. We investigated changes in the local shape and volume of subcortical nuclei in relation to tinnitus. METHODS: The participants included 53 patients with tinnitus and 52 age- and gender-matched normal controls. Individual 3D T1-weighted structural images were obtained using 3-T magnetic resonance imaging. Surface-based vertex analysis (SVA) was performed with automated segmentation of the bilateral caudate nuclei, putamina, nucleus accumbens, thalami, pallidum, hippocampi, amygdalae, and brainstem. The scalar distances from the mean surface and volumes of 15 nuclei were compared between the tinnitus and control groups and correlated with tinnitus handicap score (THI) and tinnitus duration. RESULTS: SVA revealed regional contractions in the accessory basal and lateral nuclei of the right amygdala and expansions in the left medial and right ventral posterior nuclei and lateral dorsal nucleus of both thalami. The surface distances of the right nucleus accumbens were positively correlated with tinnitus duration, while those of the left nucleus accumbens and left hippocampus were negatively correlated with THI. CONCLUSION: Regional atrophy of the amygdala may indicate self-modulation of emotional response regulation to diminish tinnitus-related emotional distress. Thalamic regional expansion may signify dysfunctional auditory gating in the thalamus, where inhibition of the tinnitus signal at the thalamus level is disrupted due to abnormal changes in the limbic system, ultimately leading to the tinnitus percept.

Sonography of Carpal Tunnel Syndrome According to Pathophysiologic Type: Conduction Block Versus Axonal Degeneration.

OBJECTIVES: The purpose of this study was to investigate sonographic findings according to the pathophysiologic type in patients with carpal tunnel syndrome. METHODS: We retrospectively reviewed the records of 80 patients (148 hands) with carpal tunnel syndrome. Patients were classified into 3 groups according to electrophysiologic findings: (1) conduction block and conduction delay; (2) axonal degeneration; and (3) mixed. We used sonographic evaluations to assess the cross-sectional area at the distal wrist crease and the distal forearm and the wrist-to-forearm ratio of the median nerve. RESULTS: Patients with axonal degeneration had significantly larger cross-sectional areas and wrist-to-forearm ratios than those with a conduction block (P < .05). The increased wrist-to-forearm ratio correlated with a reduced amplitude of the sensory nerve action potential, which reflects the degree of axonal degeneration. CONCLUSIONS: The cross-sectional area and wrist-to-forearm ratio were associated with the pathophysiologic type of carpal tunnel syndrome, with larger nerve swellings seen in patients with axonal degeneration compared with those with demyelinating lesions. In addition to helping in the localization of the nerve lesion, sonography may indicate the type of nerve lesion.

Recovery of language function in Korean-Japanese crossed bilingual aphasia following right basal ganglia hemorrhage.

Few studies have investigated language recovery patterns and the mechanisms of crossed bilingual aphasia following a subcortical stroke. In particular, Korean-Japanese crossed bilingual aphasia has not been reported. A 47-year-old, right-handed man was diagnosed with an extensive right basal ganglia hemorrhage. He was bilingual, fluent in both Korean and Japanese. After his stroke, the patient presented with crossed aphasia. We investigated changes in the Korean (L1) and Japanese (L2) language recovery patterns. Both Korean and Japanese versions of the Western Aphasia Battery (WAB) were completed one month after the stroke, and functional magnetic resonance imaging (fMRI) was performed using picture-naming tasks. The WAB showed a paradoxical pattern of bilingual aphasia, with an aphasia quotient (AQ) of 32 for Korean and 50.6 for Japanese, with Broca's aphasia. The patient scored better in the Japanese version of all domains of the tests. The fMRI study showed left lateralized activation in both language tasks, especially in the inferior frontal gyrus. After six months of language therapy targeting L1, the Korean-WAB score improved significantly, while the Japanese-WAB score showed slight improvement. In this case, the subcortical lesion contributed to crossed bilingual aphasia more highly affecting L1 due to loss of the cortico-subcortical control mechanism in the dominant hemisphere. The paradoxical pattern of bilingual aphasia disappeared after lengthy language therapy targeting L1, and the therapy effect did not transfer to L2. Language recovery in L1 might have been accomplished by reintegrating language networks, including the contralesional language homologue area in the left hemisphere.

Neural substrates of lower extremity motor, balance, and gait function after supratentorial stroke using voxel-based lesion symptom mapping.

INTRODUCTION: Stroke impairs motor, balance, and gait function and influences activities of daily living. Understanding the relationship between brain lesions and deficits can help clinicians set goals during rehabilitation. We sought to elucidate the neural substrates of lower extremity motor, balance, and ambulation function using voxel-based lesion symptom mapping (VLSM) in supratentorial stroke patients. METHODS: We retrospectively screened patients who met the following criteria: first-ever stroke, supratentorial lesion, and available brain magnetic resonance imaging (MRI) data. MRIs of 133 stroke patients were selected for VLSM analysis. We generated statistical maps of lesions related to lower extremity motor (lower extremity Fugl-Meyer assessment, LEFM), balance (Berg Balance Scale, BBS), and gait (Functional Ambulation Category, FAC) using VLSM. RESULTS: VLSM revealed that lower LEFM scores were associated with damage to the bilateral basal ganglia, insula, internal capsule, and subgyral white matter adjacent to the corona radiata. The lesions were more widely distributed in the left than in the right hemisphere, representing motor and praxis function necessary for performing tasks. However, no associations between lesion maps and balance and gait function were established. CONCLUSION: Motor impairment of the lower extremities was associated with lesions in the basal ganglia, insula, internal capsule, and white matter adjacent to the corona radiata. However, VLSM revealed no specific lesion locations with regard to balance and gait function. This might be because balance and gait are complex skills that require spatial and temporal integration of sensory input and execution of movement patterns. For more accurate prediction, factors other than lesion location need to be investigated.

Erratum: Inpatient Stroke Rehabilitation Outcomes in Korea Derived from the Korean Brain Rehabilitation Centers' Online Database System for the Years 2007 to 2011.

[This corrects the article on p. 644 in vol. 30, PMID: 25931798.].

Inpatient stroke rehabilitation outcomes in Korea derived from the Korean Brain Rehabilitation Centers' online database system for the years 2007 to 2011.

The purpose of this report was to provide information for patients receiving inpatient rehabilitation after stroke and to identify the possible factors influencing functional outcome after inpatient rehabilitation. Stroke patients (n = 5,212) who were discharged from the Departments of Rehabilitation Medicine (RM) of university hospitals and rehabilitation hospitals from 2007 through 2011 were participants. Prevalence, age, transfer time after onset, length of stay (LOS), functional status at admission and discharge were analyzed. In all stroke subjects, cerebral infarctions (67%) were more common than hemorrhages. Cerebral infarctions in the middle cerebral artery territory were most common, while the basal ganglia and cerebral cortex were the most common areas for hemorrhagic stroke. The LOS decreased from 45 to 28 days. Transfer time after onset decreased from 44 to 30 days. Shorter transfer time after onset was correlated with better discharge functional status and shorter LOS. Initial functional status was correlated with discharge functional status. In ischemic stroke subtypes, cerebellar and brainstem strokes predicted better outcomes, while strokes with more than one territory predicted poorer outcomes with more disabilities. In hemorrhagic stroke subtypes, initial and discharge functional status was the lowest for cortical hemorrhages and highest for brainstem hemorrhages. This report shows that LOS and transfer time after onset has been decreased over time and initial functional status and shorter transfer after onset are predictors of better functional outcome at discharge.

Effectiveness of Non-invasive Brain Stimulation in Dysphagia Subsequent to Stroke: A Systemic Review and Meta-analysis.

The objective of this study is to assess the efficacy and safety of non-invasive brain stimulation (NIBS) in patients with dysphagia subsequent to stroke. A systematic search of the literature published by Medline (January 1, 1976 through June 21, 2013), EMBASE (January 1, 1985 through June 21, 2013), and the Cochrane Library (January 1, 1987 through June 21, 2013) was conducted for all relevant articles related to NIBS, dysphagia, and cerebrovascular disorders (CVD). Two reviewers (S.N.Y and S.B.P) independently evaluated the eligibility of retrieved data according to the selection criteria and assessed methodological quality of the studies using the 'assessing risk of bias' table recommended in the Cochrane Handbook for Systematic Reviews of Interventions (version 5.0.2). Six randomized controlled trials (59 intervention groups and 55 placebo groups) were identified as addressing the use of NIBS for dysphagia after CVD and were included in the meta-analysis. The function scale score improvement of dysphagia in patients treated with NIBS was statistically significant compared with that of patients who underwent sham stimulation (standardized mean difference = 1.08, 95 % confidence intervals = 0.29-1.88, p = 0.008; I (2) = 72 %). A subgroup analysis based on the type of intervention (three repetitive transcranial magnetic stimulation (rTMS) studies and three transcranial direct current stimulation (tDCS) studies) revealed a statistically significant beneficial effect of NIBS compared with sham stimulation in the rTMS group, but not in the tDCS group. When the results were examined based on intervention site (ipsilesional vs. contralesional site stimulation), no statistically significant difference was noted between two groups. No complications of NIBS were reported in this analysis.

Explainable artificial intelligence on safe balance and its major determinants in stroke patients.

This study develops explainable artificial intelligence for predicting safe balance using hospital data, including clinical, neurophysiological, and diffusion tensor imaging properties. Retrospective data from 92 first-time stroke patients from January 2016 to June 2023 was analysed. The dependent variables were independent mobility scores, i.e., Berg Balance Scales with 0 (45 or below) vs. 1 (above 45) measured after three and six months, respectively. Twenty-nine predictors were included. Random forest variable importance was employed for identifying significant predictors of the Berg Balance Scale and testing its associations with the predictors, including Berg Balance Scale after one month and corticospinal tract diffusion tensor imaging properties. Shapley Additive Explanation values were calculated to analyse the directions of these associations. The random forest registered a higher or similar area under the curve compared to logistic regression, i.e., 91% vs. 87% (Berg Balance Scale after three months), 92% vs. 92% (Berg Balance Scale after six months). Based on random forest variable importance values and rankings: (1) Berg Balance Scale after three months has strong associations with Berg Balance Scale after one month, Fugl-Meyer assessment scale, ipsilesional corticospinal tract fractional anisotropy, fractional anisotropy laterality index and age; (2) Berg Balance Scale after six months has strong relationships with Fugl-Meyer assessment scale, Berg Balance Scale after one month, ankle plantar flexion muscle strength, knee extension muscle strength and hip flexion muscle strength. These associations were positive in the SHAP summary plots. Including Berg Balance Scale after one month, Fugl-Meyer assessment scale or ipsilesional corticospinal tract fractional anisotropy in the random forest will increase the probability of Berg Balance Scale after three months being above 45 by 0.11, 0.08, or 0.08. In conclusion, safe balance after stroke strongly correlates with its initial motor function, Fugl-Meyer assessment scale, and ipsilesional corticospinal tract fractional anisotropy. Diffusion tensor imaging information aids in developing explainable artificial intelligence for predicting safe balance after stroke.

Gerstmann Syndrome as a Disconnection Syndrome: A Single Case Diffusion Tensor Imaging Study.

Gerstmann syndrome (GS) is a rare syndrome that occurs when there is a lesion of the dominant inferior parietal lobule (IPL), causing agraphia, acalculia, finger agnosia, and right-left disorientation. A 49-year-old right-handed male was diagnosed as GS after left parieto-occipital lobe hemorrhage. The patient showed mild anomic aphasia with agraphia in the language test and the neuropsychological test revealed acalculia, impaired right-left discrimination, and finger agnosia. In diffusion tensor tractography, the tracts of left superior longitudinal fasciculus (SLF), middle longitudinal fasciculus, U-fibers and posterior corpus callosum (CC) were disrupted around the left IPL. In addition, fractional anisotropy (FA) values were markedly decreased in left SLF, and posterior CC when compared to twelve healthy control subjects. Our clinical and neuroimaging findings support that GS is a disconnection syndrome caused by lesion in the white matter pathway surrounding IPL. In future, more studies of the correlation between the white matter disconnection and the development of GS including high quality imaging technique are needed.

Predictors of manual dexterity at 3 and 6 months after stroke: integration of clinical, neurophysiological, and neuroimaging factors.

This retrospective study aimed to predict dexterity at 3 and 6 months post-stroke by integrating clinical, neurophysiological, and neuroimaging factors. We included 126 patients with first-ever, unilateral, and supratentorial stroke. Demographic, stroke characteristics, and initial clinical assessment variables [Mini-mental state examination and Fugl-Meyer Assessment Upper Extremity (FMA-UE)] were evaluated 2 weeks after stroke. Dexterity, measured using the Manual Function Test (MFT) hand subscore, was the primary outcome. The neurophysiological variables, upper limb somatosensory evoked potential (SEP) and motor evoked potential (MEP), were assessed 2 weeks post-stroke. The neuroimaging variable, fractional anisotropy (FA) of the corticospinal tract (CST), was assessed 3 weeks post-stroke. Multiple regression analysis revealed significant predictors for improved dexterity at 3 and 6 months post-stroke, including younger age, higher FMA-UE score, presence of waveforms in the SEP and MEP, and higher FA values in the CST (adjusted R 2  = 0.776, P  < 0.001 at 3 months; adjusted R 2  = 0.668, P  < 0.001 at 6 months; where MEP, SEP, and FA accounted together for an additional 0.079 and 0.166 of variance beyond age and FMA-UE, respectively). Subgroup analysis was conducted by categorizing the participants based on their initial hand function: those with no hand function (MFT hand subscore = 0) (N = 60) and those with a score >0 (N = 51). Initial FMA-UE was a primary predictive factor regardless of the time point or initial severity, whereas the presence of MEP was a significant predictor only in the group with no initial hand dexterity.

Clinical efficacy of overground powered exoskeleton for gait training in patients with subacute stroke: A randomized controlled pilot trial.

BACKGROUND: To investigate the efficacy and usefulness of 12 sessions of overground robot-assisted gait training (RAGT) in subacute stroke patients. METHODS: In this pilot study, 17 subacute stroke survivors were randomly assigned to the intervention (n = 9) and control (n = 8) groups. In addition to the conventional stroke neurorehabilitation program, the intervention group received 30 minutes of overground exoskeletal RAGT, while the control group received 30 minutes of conventional gait training by a physiotherapist. All interventions were performed in 12 sessions (3 times/week for 4 weeks). The primary aim was to assess ambulation ability using the functional ambulation category (FAC). The 10-m walk test, Berg Balance Scale, timed-up-and-go Timed-up-and-go, Fugl-Meyer assessment of lower extremity, pulmonary function test, the Korean version of the modified Barthel index, and Euro quality of life-5 dimensions (EQ-5D) were assessed. All outcomes were evaluated both before and after the intervention. RESULTS: The Berg Balance Scale, Korean version of the modified Barthel index, and EQ-5D scores (P < .05) improved significantly in both groups. Only those in the RAGT group improved significantly in the FAC, timed-up-and-go, and 10-m walk test (P < .05). In the FAC and EQ-5D, the intervention group showed greater improvement than the control group (P < .05). CONCLUSION: We found that 4 weeks of overground RAGT combined with conventional training may improve walking independence and quality of life in patients with subacute stroke.

Short-term and long-term predictors of balance function in stroke patients: a 6-month follow-up study.

We aimed to determine early predictors of balance function (Berg Balance Scale, BBS) at 3 and 6 months after stroke using clinical, neurophysiological, and neuroimaging variables. Seventy-nine patients with hemiparesis after a stroke were included. Demographics, stroke characteristics, and clinical variables [Mini-Mental State Examination, BBS, strength in the hemiparetic hip, knee, and ankle muscles, and Fugl-Meyer Assessment Lower Extremity (FMA-LE)] were evaluated 2 weeks post-stroke, on average. Somatosensory-evoked potentials (SEP) from both tibial nerves and diffusion tensor imaging data were collected respectively within 3 weeks and 4 weeks post-onset to calculate the SEP amplitude ratio and the laterality index of fractional anisotropy of the corticospinal tract. In multiple linear regression analysis, younger age, higher FMA-LE score, and stronger hemiparetic hip extensors were independent predictors of higher BBS at 3 months post-stroke (adjusted R2 = 0.563, P < 0.001). At 6 months post-stroke, significant predictors of higher BBS were younger age, higher FMA-LE, stronger hemiparetic hip extensors, and larger SEP amplitude ratio (adjusted R2 = 0.552, P < 0.001), although the incremental contribution of the latter was rather small ( R2 = 0.019). We conclude that age and the initial motor impairment of the affected lower limb can inform the state of balance function at 3 and 6 months after stroke.

Clinical Practice Guideline for Stroke Rehabilitation in Korea-Part 1: Rehabilitation for Motor Function (2022).

This clinical practice guideline (CPG) is the fourth edition of the Korean guideline for stroke rehabilitation, which was last updated in 2016. The development approach has been changed from a consensus-based approach to an evidence-based approach using the Grading of Recommendations Assessment Development and Evaluation (GRADE) method. This change ensures that the guidelines are based on the latest and strongest evidence available. The aim is to provide the most accurate and effective guidance to stroke rehabilitation teams, and to improve the outcomes for stroke patients in Korea. Fifty-five specialists in stroke rehabilitation and one CPG development methodology expert participated in this development. The scope of the previous clinical guidelines was very extensive, making it difficult to revise at once. Therefore, it was decided that the scope of this revised CPG would be limited to Part 1: Rehabilitation for Motor Function. The key questions were selected by considering the preferences of the target population and referring to foreign guidelines for stroke rehabilitation, and the recommendations were completed through systematic literature review and the GRADE method. The draft recommendations, which were agreed upon through an official consensus process, were refined after evaluation by a public hearing and external expert evaluation.

Korean Brain Rehabilitation Registry for rehabilitation of persons with brain disorders: annual report in 2009.

This first annual report provides a description of patients discharged from rehabilitation facilities in Korea based on secondary data analysis of Korean Brain Rehabilitation Registry V1.0 subscribed in 2009. The analysis included 1,697 records of patients with brain disorders including stroke, traumatic brain injury, brain tumor and other disorders from 24 rehabilitation facilities across Korea. The data comprised 1,380 cases of stroke, 104 cases of brain injury, 55 cases of brain tumor, and 58 cases of other brain diseases. The functional status of each patient was measured using the Korean version of the Modified Barthel Index (KMBI). The average change in the KMBI score was 15.9 for all patients in the inpatient rehabilitation facility. The average length of stay for inpatient rehabilitation was 36.9 days. The transfer rates to other hospitals were high, being 62.4% when all patients were considered. Patients with brain disorders of Korea in 2009 and measurable functional improvement was observed in patients. However, relatively high percentages of patients were not discharged to the community after inpatient rehabilitation. Based on the results of this study, consecutive reports of the status of rehabilitation need to be conducted in order to provide useful information to many practitioners.

The Relationship Between Visuoconstructive Abilities and Language Performance in Patients With Aphasia After Stroke.

This study aimed to investigate the visuoconstructive abilities and the relationship between visuoconstructive function and language performance in aphasic patients. Right-handed 24 aphasic patients (males 14, females 10) with at least 3 months post-stroke and 32 age-matched healthy controls participated in this study. Visuoconstructive function was assessed by 3 levels of task difficulty: simple (drawing objects), intermediate (clock drawing), and complex (copy subtest of Rey complex figure test and block construction). Aphasic patients were divided into 3 sub-groups (mild, moderate to severe, and very severe group) according to severity of aphasia and compared with the control group, respectively. We analyzed the relation all levels of visuoconstructive tasks to aphasia quotient (AQ) and sub-domain scores of K-WAB. Moderate to severe aphasia group demonstrated no significant differences in scores of simple drawing objects compared to controls, but clock drawing, Rey complex figure copy and block design showed significantly decreased scores. Very severe group showed significantly lower scores in all levels of visuoconstructive tasks than the control. Correlation between all levels of visuoconstructive tasks except drawing objects and AQ were found to be statistically significant. Among the tasks, the clock drawing test revealed the highest correlation with language performance. Visuoconstructive abilities varied according to the severity of aphasia and the level of visuoconstructive tasks. Therefore, a thorough individual assessment of visuoconstructive function is needed to plan and predict the treatment and prognosis of aphasia and the clock drawing test may be a useful screening tool to evaluate this function.

Structural Changes in the Arcuate Fasciculus and Recovery of Post-stroke Aphasia: A 6-Month Follow-up Study using Diffusion Tensor Imaging.

BACKGROUND: Temporal changes in the structural connectivity of major language tracts after stroke and their contribution to aphasia recovery are unclear. OBJECTIVE: To investigate longitudinal arcuate fasciculus (AF) integrity changes and their relationship with post-stroke aphasia recovery using diffusion tensor imaging (DTI). METHODS: Thirty-five patients with aphasia due to first-ever left hemispheric stroke underwent the Korean version of the Western Aphasia Battery and DTI at 1- and 6-month post stroke onset. Fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) of both AF tracts were analyzed to evaluate the temporal changes in tract integrity and determine the correlation between changes (Δ; follow-up - initial) in DTI parameters and language scores. RESULTS: At 6 months post-stroke, the mean FA decreased, and mean MD and RD increased in both hemispheres; however, compared with mean AD observed after 1 month, the mean observed at 6 months increased only in the left hemisphere (P < .05). ΔFA of the left AF and proportional change in the aphasia quotient showed a significant positive correlation (r = 0.365, P = .031). No correlation was found between changes in the right AF parameters and language score. The group with increased FA in the left AF showed more significant language improvement than the group with decreased FA. CONCLUSIONS: During the subacute stage, the integrity of AF decreased in both hemispheres in patients with aphasia, and the change in structural connectivity of the left AF was associated with language improvement.

Language systems from lesion-symptom mapping in aphasia: A meta-analysis of voxel-based lesion mapping studies.

BACKGROUND: Aphasia is one of the most common causes of post-stroke disabilities. As the symptoms and impact of post-stroke aphasia are heterogeneous, it is important to understand how topographical lesion heterogeneity in patients with aphasia is associated with different domains of language impairments. Here, we aim to provide a comprehensive overview of neuroanatomical basis in post-stroke aphasia through coordinate based meta-analysis of voxel-based lesion-symptom mapping studies. METHODS: We performed a meta-analysis of lesion-symptom mapping studies in post-stroke aphasia. We obtained coordinate-based structural neuroimaging data for 2,007 individuals with aphasia from 25 studies that met predefined inclusion criteria. RESULTS: Overall, our results revealed that the distinctive patterns of lesions in aphasia are associated with different language functions and tasks. Damage to the insular-motor areas impaired speech with preserved comprehension and a similar pattern was observed when the lesion covered the insular-motor and inferior parietal lobule. Lesions in the frontal area severely impaired speaking with relatively good comprehension. The repetition-selective deficits only arise from lesions involving the posterior superior temporal gyrus. Damage in the anterior-to-posterior temporal cortex was associated with semantic deficits. CONCLUSION: The association patterns of lesion topography and specific language deficits provide key insights into the specific underlying language pathways. Our meta-analysis results strongly support the dual pathway model of language processing, capturing the link between the different symptom complexes of aphasias and the different underlying location of damage.