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Sung Ho Jang - One of the best experts on this subject based on the ideXlab platform.

  • injury of the Arcuate Fasciculus in the dominant hemisphere in patients with mild traumatic brain injury a retrospective cross sectional study
    Medicine, 2016
    Co-Authors: Sung Ho Jang, Ah Young Lee, So Min Shin
    Abstract:

    Little is known about injury of the Arcuate Fasciculus (AF) in patients with mild traumatic brain injury (TBI). We investigated injury of the AF in the dominant hemisphere in patients with mild TBI, using diffusion tensor tractography (DTT). We recruited 25 patients with injury of the left AF among 64 right-handed consecutive patients with mild TBI and 20 normal control subjects. DTTs of the left AF were reconstructed, and fractional anisotropy (FA), apparent diffusion coefficient (ADC), and fiber number of the AF were measured. Among 64 consecutive patients, 25 (39%) patients showed injury of the left AF. The patient group showed lower FA value and fiber number with higher ADC value than the control group (P 2 language symptoms in 6 (24.0%) patients. We found that a significant number (39%) of patients with mild TBI had injury of the AF in the dominant hemisphere and these patients had mild language deficit. These results suggest that DTT could provide useful information in detecting injury of the AF and evaluation of the AF using DTT would be necessary even in the case of a patient with mild TBI who complains of mild language deficit.

  • recovery of injured Arcuate Fasciculus in the dominant hemisphere in a patient with an intracerebral hemorrhage
    American Journal of Physical Medicine & Rehabilitation, 2014
    Co-Authors: Sung Ho Jang, Han Do Lee
    Abstract:

    This study reports on a patient with an intracerebral hemorrhage who showed recovery of an injured Arcuate Fasciculus (AF) in the dominant hemisphere, using follow-up diffusion tensor tractography. A 43-year-old right-handed man presented with severe aphasia and hemiparesis resulting from a spontaneous intracerebral hemorrhage in the left parietotemporal lobes. The patient showed severe aphasia at 1 month after onset, with an aphasia quotient of 5% on the Korean-Western Aphasia Battery. He underwent comprehensive rehabilitative therapy until 22 months after onset and his aphasia showed improvement, with an aphasia quotient of 58% on the Korean-Western Aphasia Battery. On 1-month diffusion tensor tractography, only the thin ascending part of the left AF from the Wernicke area remained. In contrast, on 16-month diffusion tensor tractography, the injured left AF was thickened and elongated to around the left Broca area; however, discontinuation of the left AF was observed around the left Broca area, and this continuation was elongated to the left Broca area on 22-month diffusion tensor tractography. This study reports on a patient who showed recovery from injury of the left AF along with improvement of aphasia. Recovery of the injured AF in the dominant hemisphere appears to be one of the mechanisms for recovery from aphasia.

  • relation between aphasia and Arcuate Fasciculus in chronic stroke patients
    BMC Neurology, 2014
    Co-Authors: Hyung Jun Tak, Sung Ho Jang
    Abstract:

    The role of the Arcuate Fasciculus (AF) in the dominant hemisphere in stroke patients with aphasia has not been clearly elucidated. We investigated the relation between language function and diffusion tensor tractography (DTT) findings for the left AF in chronic stroke patients with aphasia. Twenty five consecutive right-handed stroke patients with aphasia following lesions in the left hemisphere were recruited for this study. The aphasia quotient (AQ) of Korean-Western Aphasia Battery was used for assessment of language function. We measured values of fractional anisotropy (FA), apparent diffusion coefficient (ADC), voxel number of the left AF. We classified patients into three groups: type A - the left AF was not reconstructed, type B - the left AF was discontinued between Wernicke’s and Broca’s areas, and type C – the left AF was preserved around the stroke lesion. Moderate positive correlation was observed between AQ and voxel number of the left AF (r = 0.471, p   0.05) and ADC values (r = -0.286, p > 0.05). Significant differences in AQ scores were observed between the three types (p < 0.05); the AQ score of type C was higher than those of type A and B, and that of type B was also higher than that of type A (p < 0.05). According to our findings, the remaining volume of the left AF, irrespective of directionality and diffusivity, showed moderate positive correlation with language function in chronic stroke patients with aphasia. Discontinuation or non-construction of the left AF was also an important factor for language function.

  • diffusion tensor imaging studies on Arcuate Fasciculus in stroke patients a review
    Frontiers in Human Neuroscience, 2013
    Co-Authors: Sung Ho Jang
    Abstract:

    Aphasia is one of the most common and devastating sequelae of stroke. The Arcuate Fasciculus (AF), an important neural tract for language function, connects Broca's and Wernicke's areas. In this review article, previous diffusion tensor imaging (DTI) studies on the AF in stroke patients were reviewed with regard to the usefulness for diagnosis (seven studies), prediction of prognosis (two studies), and recovery of aphasia (three studies). Although scant studies on this topic have been conducted in stroke patients, DTI for the AF appears to provide useful information on the presence or severity of injury of the AF, prognosis prediction of aphasia, and recovery mechanisms of aphasia in stroke patients. Therefore, further DTI studies on these topics should be encouraged, especially studies on prognosis prediction and recovery mechanisms of aphasia. In addition, research on other neural tracts known to be involved in aphasia as well as the AF in both hemispheres should be encouraged.

  • excellent recovery of aphasia in a patient with complete injury of the Arcuate Fasciculus in the dominant hemisphere
    NeuroRehabilitation, 2011
    Co-Authors: Hyeok Gyu Kwon, Sung Ho Jang
    Abstract:

    Abstract The Arcuate Fasciculus (AF) is the neural tract that connects Wernicke's area and Broca's area. The main role of the AF is speech repetition; therefore, injury to the AF typically causes conduction aphasia. We report on a patient who showed excellent recovery of aphasia despite complete injury of the AF due to a cerebral infarct. A 54-year-old, right-handed male presented with aphasia and right hemiparesis. Brain MRI showed an infarct in the left centrum semiovale and corona radiata. Diffusion tensor tractography for the AF was reconstructed using DTI-studio software. The Korean-Western Aphasia Battery (K-WAB) was used for measurement of language function. On K-WAB at 1 week after onset, his aphasia type was compatible with global aphasia (aphasia quotient: 12‰, fluency: 5‰, comprehension: 24‰, repetition: 15‰, and naming: 31‰). The patient underwent rehabilitative therapy, including language therapy and medication, which is known to facilitate recovery from aphasia, for a period of 24 months. His aphasia had improved to a nearly normal state at 30 months after onset; aphasia quotient: 93‰ (fluency: 91‰, comprehension: 92‰, repetition: 85‰, and naming: 96‰). The left AF showed a complete disruption on 27-month diffusion tensor tractography. Findings from this study suggest the possibility that aphasia might show good recovery, even in cases of severe injury of the AF.

Gottfried Schlaug - One of the best experts on this subject based on the ideXlab platform.

  • apraxia of speech involves lesions of dorsal Arcuate Fasciculus and insula in patients with aphasia
    Neurology: Clinical Practice, 2020
    Co-Authors: Karen Chenausky, Andrea Norton, Sebastien Paquette, Gottfried Schlaug
    Abstract:

    Objective To determine the contributions of apraxia of speech (AOS) and anomia to conversational dysfluency. Methods In this observational study of 52 patients with chronic aphasia, 47 with concomitant AOS, fluency was quantified using correct information units per minute (CIUs/min) from propositional speech tasks. Videos of patients performing conversational, how-to and picture-description tasks, word and sentence repetition, and diadochokinetic tasks were used to diagnose AOS using the Apraxia of Speech Rating Scale (ASRS). Anomia was quantified by patients9 scores on the 30 even-numbered items from the Boston Naming Test (BNT). Results Together, ASRS and BNT scores accounted for 51.4% of the total variance in CIUs/min; the ASRS score accounted for the majority of that variance. The BNT score was associated with lesions in the left superior temporal gyrus, left inferior frontal gyrus, and large parts of the insula. The global ASRS score was associated with lesions in the left dorsal Arcuate Fasciculus (AF), pre- and post-central gyri, and both banks of the central sulcus of the insula. The ASRS score for the primary distinguishing features of AOS (no overlap with features of aphasia) was associated with less AF and more insular involvement. Only ∼27% of this apraxia-specific lesion overlapped with lesions associated with the BNT score. Lesions associated with AOS had minimal overlap with the frontal aslant tract (FAT) ( Conclusions Results are consistent with previous findings identifying lesions of the insula and AF in patients with AOS, damage to both of which may create dysfluency in patients with aphasia.

  • atypical hemispheric asymmetry in the Arcuate Fasciculus of completely nonverbal children with autism
    Annals of the New York Academy of Sciences, 2012
    Co-Authors: Catherine Y Wan, Sarah Marchina, Andrea Norton, Gottfried Schlaug
    Abstract:

    Despite the fact that as many as 25% of the children diagnosed with autism spectrum disorders are nonverbal, surprisingly little research has been conducted on this population. In particular, the mechanisms that underlie their absence of speech remain unknown. Using diffusion tensor imaging, we compared the structure of a language-related white matter tract (the Arcuate Fasciculus, AF) in five completely nonverbal children with autism to that of typically developing children. We found that, as a group, the nonverbal children did not show the expected left–right AF asymmetry—rather, four of the five nonverbal children actually showed the reversed pattern. It is possible that this unusual pattern of asymmetry may underlie some of the severe language deficits commonly found in autism, particularly in children whose speech fails to develop. Furthermore, novel interventions (such as auditory-motor mapping training) designed to engage brain regions that are connected via the AF may have important clinical potential for facilitating expressive language in nonverbal children with autism.

  • impairment of speech production predicted by lesion load of the left Arcuate Fasciculus
    Stroke, 2011
    Co-Authors: Sarah Marchina, Lin L Zhu, Andrea Norton, Lauryn Zipse, Catherine Y Wan, Gottfried Schlaug
    Abstract:

    Background and Purpose—Previous studies have suggested that patients' potential for poststroke language recovery is related to lesion size; however, lesion location may also be of importance, particularly when fiber tracts that are critical to the sensorimotor mapping of sounds for articulation (eg, the Arcuate Fasciculus) have been damaged. In this study, we tested the hypothesis that lesion loads of the Arcuate Fasciculus (ie, volume of Arcuate Fasciculus that is affected by a patient's lesion) and of 2 other tracts involved in language processing (the extreme capsule and the uncinate Fasciculus) are inversely related to the severity of speech production impairments in patients with stroke with aphasia. Methods—Thirty patients with chronic stroke with residual impairments in speech production underwent high-resolution anatomic MRI and a battery of cognitive and language tests. Impairment was assessed using 3 functional measures of spontaneous speech (eg, rate, informativeness, and overall efficiency) as...

  • effects of practice and experience on the Arcuate Fasciculus comparing singers instrumentalists and non musicians
    Frontiers in Psychology, 2011
    Co-Authors: Gus F Halwani, Gottfried Schlaug, Psyche Loui, Theodor Ruber
    Abstract:

    Structure and function of the human brain are affected by training in both linguistic and musical domains. Individuals with intensive vocal musical training provide a useful model for investigating neural adaptations of learning in the vocal-motor domain and can be compared with learning in a more general musical domain. Here we confirm general differences in macrostructure (tract volume) and microstructure (fractional anisotropy (FA)) of the Arcuate Fasciculus (AF), a prominent white-matter tract connecting temporal and frontal brain regions, between singers, instrumentalists, and non-musicians. Both groups of musicians differed from non-musicians in having larger tract volume and higher FA values of the right and left AF. The AF was then subdivided in a dorsal (superior) branch connecting the superior temporal gyrus and the inferior frontal gyrus (STG IFG), and ventral (inferior) branch connecting the middle temporal gyrus and the inferior frontal gyrus (MTG IFG). Relative to instrumental musicians, singers had a larger tract volume but lower FA values in the left dorsal AF (STG IFG), and a similar trend in the left ventral AF (MTG IFG). This between-group comparison controls for the general effects of musical training, although FA was still higher in singers compared to non-musicians. Both musician groups had higher tract volumes in the right dorsal and ventral tracts compared to non-musicians, but did not show a significant difference between each other. Furthermore, in the singers’ group, FA in the left dorsal branch of the AF was inversely correlated with the number of years of participants’ vocal training. Our findings suggest that long-term vocal-motor training might lead to an increase in volume and microstructural complexity of specific white matter tracts connecting regions that are fundamental to sound perception, production, and its feedforward and feedback control which can be differentiated from a more general musician effect.

Antoin D De Weijer - One of the best experts on this subject based on the ideXlab platform.

  • the Arcuate Fasciculus in auditory verbal hallucinations a meta analysis of diffusion tensor imaging studies
    Schizophrenia Research, 2014
    Co-Authors: Pierre Alexis Geoffroy, Antoin D De Weijer, Josselin Houenou, Alain Duhamel, Ali Amad, Branislava Curcicblake, David Edmund Johannes Linden, Pierre Thomas, Renaud Jardri
    Abstract:

    Auditory-verbal hallucinations (AVHs) are associated with an impaired connectivity of large-scale networks. To examine the relationship between white-matter integrity and AVHs, we conducted a meta-analysis of diffusion-tensor-imaging studies that compared patients with schizophrenia and AVHs with matched healthy controls (HCs). Five studies were retained gathering 256 DTI data points, divided into AVHs (n=106) and HCs (n=150). The meta-analysis demonstrated a reduced fractional anisotropy in the left Arcuate Fasciculus (AF) of hallucinators (hg= -0.42; CI[-0.69,-0.16]; p<10(-3)). The current meta-analysis confirmed disruptions of white matter integrity in the left AF bundle of schizophrenia patients with AVHs.

  • aberrations in the Arcuate Fasciculus are associated with auditory verbal hallucinations in psychotic and in non psychotic individuals
    Human Brain Mapping, 2011
    Co-Authors: Antoin D De Weijer, Sebastiaan F W Neggers, Kelly M J Diederen, Rene C W Mandl, Rene S Kahn, Hilleke Hulshoff E Pol, Iris E C Sommer
    Abstract:

    The pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the Arcuate Fasciculus, the major tract connecting frontal and temporo-parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and studied a group of non-psychotic individuals with AVH as well as patients with AVH and non-hallucinating matched controls. We compared tract integrity of the Arcuate fasiculus and of three other control tracts, between 35 non-psychotic individuals with AVH, 35 schizophrenia patients with AVH, and 36 controls using diffusion tensor imaging and magnetization transfer imaging. Both groups with AVH showed an increase in magnetization transfer ratio (MTR) in the Arcuate Fasciculus, but not in the other control tracts. In addition, a general decrease in fractional anisotropy (FA) for almost all bundles was observed in the patient group, but not in the non-psychotic individuals with AVH. As increased MTR in the Arcuate Fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible. Decreases in FA, on the other hand, seem to be related to other disease processes of schizophrenia.

  • microstructural alterations of the Arcuate Fasciculus in schizophrenia patients with frequent auditory verbal hallucinations
    Schizophrenia Research, 2011
    Co-Authors: Antoin D De Weijer, Sebastiaan F W Neggers, Kelly M J Diederen, Rene C W Mandl, Rene S Kahn, Hilleke Hulshoff E Pol, Iris E C Sommer
    Abstract:

    Abstract Auditory verbal hallucinations (AVH) is a common and stressful symptom of schizophrenia. Disrupted connectivity between frontal and temporo-parietal language areas, giving rise to the misattribution of inner speech, is speculated to underlie this phenomenon. Disrupted connectivity should be reflected in the microstructure of the Arcuate fasciculi (AF); the main connection between frontal and temporo-parietal language areas. In this study we compared microstructural properties of the AF and three other fiber tracts (cortical spinal tract, cingulum and uncinate Fasciculus), between 44 schizophrenia patients with chronic severe hallucinations and 42 control subjects using diffusion tensor imaging (DTI) and magnetic transfer imaging (MTI). The DTI scans were used to compute fractional anisotropy (FA) and to reconstruct the fiber bundles of interest, while the MTI scans were used to compute magnetic transfer ratio (MTR) values. The patient group showed a general decrease in FA for all bundles. In the Arcuate Fasciculus this decreased FA was coupled to a significant increase in MTR values. A correlation was found between mean MTR values in both Arcuate fasciculi and the severity of positive symptoms. The combination of decreased FA and increased MTR values observed in the Arcuate fasciculi in patients suggests increased free water concentrations, probably caused by degraded integrity of the axons or the supportive glia cells. This suggests that disintegrated fiber integrity in the connection between frontal and temporo-parietal language areas in the schizophrenia patients is associated with their liability for auditory verbal hallucinations.

Iris E C Sommer - One of the best experts on this subject based on the ideXlab platform.

  • aberrations in the Arcuate Fasciculus are associated with auditory verbal hallucinations in psychotic and in non psychotic individuals
    Human Brain Mapping, 2011
    Co-Authors: Antoin D De Weijer, Sebastiaan F W Neggers, Kelly M J Diederen, Rene C W Mandl, Rene S Kahn, Hilleke Hulshoff E Pol, Iris E C Sommer
    Abstract:

    The pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the Arcuate Fasciculus, the major tract connecting frontal and temporo-parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and studied a group of non-psychotic individuals with AVH as well as patients with AVH and non-hallucinating matched controls. We compared tract integrity of the Arcuate fasiculus and of three other control tracts, between 35 non-psychotic individuals with AVH, 35 schizophrenia patients with AVH, and 36 controls using diffusion tensor imaging and magnetization transfer imaging. Both groups with AVH showed an increase in magnetization transfer ratio (MTR) in the Arcuate Fasciculus, but not in the other control tracts. In addition, a general decrease in fractional anisotropy (FA) for almost all bundles was observed in the patient group, but not in the non-psychotic individuals with AVH. As increased MTR in the Arcuate Fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible. Decreases in FA, on the other hand, seem to be related to other disease processes of schizophrenia.

  • microstructural alterations of the Arcuate Fasciculus in schizophrenia patients with frequent auditory verbal hallucinations
    Schizophrenia Research, 2011
    Co-Authors: Antoin D De Weijer, Sebastiaan F W Neggers, Kelly M J Diederen, Rene C W Mandl, Rene S Kahn, Hilleke Hulshoff E Pol, Iris E C Sommer
    Abstract:

    Abstract Auditory verbal hallucinations (AVH) is a common and stressful symptom of schizophrenia. Disrupted connectivity between frontal and temporo-parietal language areas, giving rise to the misattribution of inner speech, is speculated to underlie this phenomenon. Disrupted connectivity should be reflected in the microstructure of the Arcuate fasciculi (AF); the main connection between frontal and temporo-parietal language areas. In this study we compared microstructural properties of the AF and three other fiber tracts (cortical spinal tract, cingulum and uncinate Fasciculus), between 44 schizophrenia patients with chronic severe hallucinations and 42 control subjects using diffusion tensor imaging (DTI) and magnetic transfer imaging (MTI). The DTI scans were used to compute fractional anisotropy (FA) and to reconstruct the fiber bundles of interest, while the MTI scans were used to compute magnetic transfer ratio (MTR) values. The patient group showed a general decrease in FA for all bundles. In the Arcuate Fasciculus this decreased FA was coupled to a significant increase in MTR values. A correlation was found between mean MTR values in both Arcuate fasciculi and the severity of positive symptoms. The combination of decreased FA and increased MTR values observed in the Arcuate fasciculi in patients suggests increased free water concentrations, probably caused by degraded integrity of the axons or the supportive glia cells. This suggests that disintegrated fiber integrity in the connection between frontal and temporo-parietal language areas in the schizophrenia patients is associated with their liability for auditory verbal hallucinations.

Harry T Chugani - One of the best experts on this subject based on the ideXlab platform.

  • relationship between genotype and Arcuate Fasciculus morphology in six young children with global developmental delay preliminary dti stuy
    Journal of Magnetic Resonance Imaging, 2016
    Co-Authors: Jeong-won Jeong, Michael E Behen, Senthil K Sundaram, Harry T Chugani
    Abstract:

    PURPOSE To investigate whether different genetic mutations observed in children with global developmental delay (GD) are associated with unique patterns of the Arcuate Fasciculus dysmorphology. MATERIALS AND METHODS Six children with GD (age: 36.8 ± 14.1 months, 5 boys) having mutations in MID1, CDK4, SFRP1, EN2, RXRG-GLRB, or MECP2, and five children with typical development (TD, age: 38.5 ± 20.5 months, 4 boys) underwent a 3 Tesla MRI including diffusion weighted imaging (DWI). Five language pathway segments in the left hemisphere, "C1 : Broca's to Wernicke's area," "C2 : Broca's to premotor area," "C3 : premotor to Wernicke's area," "C4 : Wernicke's to inferior parietal area," and "C5 : premotor to inferior parietal area" were objectively identified using the DWI "maximum a posteriori probability" classifier. RESULTS Affinity propagation clustering analysis found that three Arcuate pathway segments, C1,2,4 , of MID1, CDK4, EN2, and MECP2 had a similar pattern of volume ratio while those of SFRP1 and RXRG-GLRB had a heterogeneous pattern of volume ratio (net similarity = -0.01). Using receiver operating characteristic curve analysis, the fiber ratios of C1,2,4 showed a high probability to discriminate between GD and TD, yielding an accuracy of 0.91, 0.91, 1.00, respectively. The fiber volumes of C1 and C4 showed a strong correlation with expressive language (R2  = 0.6019; P-value = 0.033) and receptive language (R2  = 0.6379; P-value = 0.028), respectively. CONCLUSION The findings of the present study provide preliminary evidence to suggest that different segments of the Arcuate Fasciculus are formed under the regulation of different genes which, when mutated, may result in developmental delay. J. Magn. Reson. Imaging 2016;44:1504-1512.

  • reorganization of the right Arcuate Fasciculus following left Arcuate Fasciculus resection in children with intractable epilepsy
    Journal of Child Neurology, 2011
    Co-Authors: Dhruman D Goradia, Csaba Juhász, Harry T Chugani, Rajkumar Munian Govindan, Michael E Behen, Sandeep Sood
    Abstract:

    The authors evaluated postsurgical reorganization of the Arcuate Fasciculus longitudinally using diffusion tensor imaging in 10 children with intractable epilepsy, whose resections included the left Arcuate Fasciculus. Evaluation of fractional anisotropy before and after surgery (mean follow-up: 7.5 months) showed a significant increase (P = .002) in the right Arcuate Fasciculus during follow-up. There was marked enlargement of the right Arcuate Fasciculus postsurgically in 8 patients. The change in right Arcuate Fasciculus fractional anisotropy values showed a positive correlation with interval between resection and postsurgical magnetic resonance imaging (MRI) (P = .044). Comparison of 10 age-matched controls to patients pre- and postsurgery showed significantly reduced presurgery fractional anisotropy in the left (P = .018) and right (P = .036) Arcuate Fasciculus and no difference in postsurgery fractional anisotropy in the right Arcuate Fasciculus (P = .399) in patients. These findings suggest a compensatory reorganization in the right Arcuate Fasciculus in children with intractable epilepsy following left Arcuate Fasciculus resection.

  • Arcuate Fasciculus and speech in congenital bilateral perisylvian syndrome
    Pediatric Neurology, 2011
    Co-Authors: Anita S D Saporta, Rajkumar Munian Govindan, Ashok Kumar, Senthil K Sundaram, Harry T Chugani
    Abstract:

    Standard magnetic resonance imaging can diagnose congenital bilateral perisylvian polymicrogyria, but is limited in explaining the heterogeneous clinical spectrum of the related congenital bilateral perisylvian syndrome, characterized by pseudobulbar dysfunction, developmental delay, and epilepsy. We analyzed Arcuate fasciculi using diffusion tensor imaging, a major language tract in the perisylvian region interconnecting the Broca and Wernicke areas, and at high risk of becoming developmentally affected in this condition. Six patients with congenital bilateral perisylvian syndrome underwent diffusion tensor imaging and were evaluated. The Arcuate Fasciculus was manually isolated, using tractography. The tract was identified in three patients who had developed speech, and whose values for various diffusion parameters were similar to those in age-matched controls (patients/controls means: fractional anisotropy, 0.50/0.52; apparent diffusion coefficient, 0.0022/0.0022 mm 2 /second; P = ns for both). However, in three patients with severe impairment and no speech development, the Arcuate Fasciculus could not be identified by fiber-tracking. In this small series, the absence of Arcuate fasciculi on diffusion tensor imaging correlated with a more severe phenotype, which cannot be appreciated via structural magnetic resonance imaging alone.

  • absence of Arcuate Fasciculus in children with global developmental delay of unknown etiology a diffusion tensor imaging study
    The Journal of Pediatrics, 2008
    Co-Authors: Senthil K Sundaram, Michael E Behen, Lalitha Sivaswamy, Malek I Makki, Harry T Chugani
    Abstract:

    Objective To investigate cortical association tracts using diffusion tensor imaging (DTI) in children with global developmental delay of unknown etiology. Study design We performed DTI in 20 patients (age range: 18-83 months, mean: 45 ± 16 months, 12 males) with a history of global developmental delay and 10 typically developing children (age range: 26-99 months, mean: 54 ± 24 months, 5 males). DTI tractography was performed to isolate major cortical association tracts. Results In 9 out of 20 patients, Arcuate Fasciculus (AF) was absent bilaterally and in another 2 patients, it was absent in left hemisphere. In contrast, AF was present bilaterally in all typically developing children. Fractional Anisotropy (FA) of inferior longitudinal Fasciculus (ILF) was asymmetric in the control group but not in the developmental delay group ( P = .04). FA was significantly reduced in right ILF in developmentally delayed children compared with controls ( P = .03). FA of other association tracts was not different between patients and controls ( P = NS). The apparent diffusion coefficient (ADC) showed no asymmetry for these tracts in controls or developmentally delayed children ( P = NS). Conclusions DTI can be used to identify absence of AF and inadequate maturation of ILF in children with global developmental delay of unknown etiology.