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Many reports have shown improvements in motor symptoms after repetitive transcranial magnetic stimulation (rTMS). However, the best stimulation area in the brain has not currently been determined. We assessed the effects of high-frequency rTMS (HF-rTMS) on the motor and mood disturbances in Parkinson’s disease (PD) patients and attempted to determine whether the primary motor area (M1), the supplementary motor area (SMA), and the dorsolateral prefrontal cortex (DLPFC) were the best treatment targets. In this randomized, double-blind crossover design study, we investigated the efficacy of 3 consecutive days of HF-rTMS over the M1, SMA, and DLPFC and compared these HF-rTMS to sham stimulations. We used motor and non-motor scales to evaluate the parkinsonian symptoms. The changes in the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III) scores after the application of HF-rTMS over the M1 and SMA were significantly greater than those after the sham stimulation. However, after the application of HF-rTMS over the DLPFC, the UPDRS-III scores were similar to those after the sham stimulation. No significant improvements were demonstrated in the mood disturbances after the stimulations over any of the targets. In conclusion, the application of HF-rTMS over the M1 and SMA significantly improved the motor symptoms in the PD patients but did not alter the mood disturbances. [ABSTRACT FROM AUTHOR]

Background: In neuroendovascular therapy, the effect of arterial stiffness on postprocedural cerebral thromboembolism is unknown. In this observational study, we examined the relationship between cerebral thromboembolism after carotid artery stenting and arterial stiffness.Methods: From April 2015 to February 2017, we enrolled consecutive patients undergoing scheduled carotid artery stenting in our institution. In all patients, preprocedural brachial-ankle pulse wave velocity was used to assess arterial stiffness, whereas the number of new cerebral ischemic lesions on diffusion-weighted magnetic resonance imaging was assessed after treatment. We also analyzed patient data and details of procedures in patients with carotid artery stenting.Results: Twenty-one patients completed the study. The mean brachial-ankle pulse wave velocity was 1879 cm/s. There was no association of cerebral thromboembolisms with age, unstable plaque, protection device, or type of stent. However, the brachial-ankle pulse wave velocity was an independent predictor of cerebral thromboembolisms (P = .0017).Conclusions: Brachial-ankle pulse wave velocity is predictive of silent cerebral embolisms on diffusion-weighted magnetic resonance imaging after carotid artery stenting. [ABSTRACT FROM AUTHOR]

Background: Ischemic stroke is one form of cancer-associated thrombosis that can greatly worsen a patient's performance status. The present investigation aimed to elucidate the characteristic distribution pattern(s) of cryptogenic stroke lesions using a voxel-based lesion-mapping technique and examine the differences in clinical manifestations between cryptogenic and conventional strokes in patients with advanced cancer.Methods: Data from 43 patients with advanced cancer who developed acute ischemic stroke were retrospectively collected. Stroke etiology was grouped into either cryptogenic or conventional stroke etiology according to the ASCO stroke score. Clinical data were reviewed, and voxel-based lesion mapping using diffusion-weighted imaging (DWI) was performed to visualize the cross-patient spatial distribution of the lesions.Results: Of the 43 patients, 25 were classified as having cryptogenic stroke etiology and 18 were classified as having conventional stroke etiology. Median survival time of patients from stroke onset was 96 days for cryptogenic stroke etiology and 570 days for conventional stroke etiology (P = .01). D-dimer of patients was significantly higher in cryptogenic stoke etiology than in conventional stroke etiology (P = .006). Voxel-based lesion mapping showed that DWI hyperintense lesions accumulated at cortical and internal watershed areas of the cerebrum and at the vascular border zone of the superior cerebellar and posterior inferior cerebellar arteries at the cerebellum.Conclusions: Voxel-based lesion mapping for cryptogenic stroke in patients with advanced cancer showed that lesions accumulated at vascular border zones within the brain both at the cerebrum and at the cerebellum, but not at perforating arterial territories. [ABSTRACT FROM AUTHOR]

To elucidate the pituitary function of Japanese patients after aneurysmal subarachnoid hemorrhage (aSAH) and implicative factors related to growth hormone deficiency (GHD) after aSAH. We evaluated basal pituitary hormone levels among 59 consecutive aSAH patients with a modified Rankin Scale (mRS) ⩽4 at 3 months after aSAH onset. Patients with low insulin-like growth factor 1 (IGF-1) SD score (SDS) or who seemed to develop pituitary dysfunction underwent provocative endocrine testing during a period of 3–36 months after SAH onset. The relationship between IGF-1 SDS and clinical factors of the patients such as severity of SAH, aneurysm location, and treatment modalities, were assessed. Six patients (10.2%) demonstrated their IGF-1 SDS less than −2. Multiple logistic regression analyses revealed that patients who underwent surgical clipping had a significantly lower IGF-1 SDS (<−1 SD) than patients who underwent endovascular embolization with an odds ratio of 5.83 ( p = 0.032). Thirty-three patients took provocative tests and five (15.6%) patients were identified as having GHD. The mean IGF-1 SDS of these five GHD patients was 0.08 SD. The aneurysms in all GHD patients were located in internal carotid artery (ICA) or anterior cerebral artery (ACA). To the best of our knowledge, this is the first report describing the prevalence of GHD in Japanese patients after aSAH, and it was not as high as that of previous European studies. We recommend that screening pituitary dysfunction for aSAH survivors with their aneurysms located in ICA or ACA. [ABSTRACT FROM AUTHOR]

Background: We evaluated the clinical outcomes of malignant middle cerebral artery (MCA) infarction (MMI) and determined an infarcted brain volume (BV) threshold value for accurate MMI prediction in elderly patients.Methods: We analyzed 69 consecutive patients (mean, 75.6 ± 11.7) with internal carotid artery or MCA infarction within 48 hours from onset. Diffusion-weighted high-intensity volume (DHV) and BV were measured in all patients. The percentage of DHV within BV (DHV/BV ratio) was calculated to standardize the DHV difference for each individual BV. Patients were stratified based upon their MMI status and age, compared with the following: (1) MMI versus non-MMI groups and (2) age ≥75 years group versus age <75 years group, based on DHV values, DHV/BV ratio, Glasgow Coma Scale (GCS) scores on admission, and modified Rankin Scale (mRS) scores at 3 months after onset.Results: The MMI group (n = 14) showed significantly larger DHV values (P < .001), larger DHV/BV ratios (P < .001), lower GCS scores on admission (P < .01), and higher mRS scores at 3 months (P < .001) than the non-MMI group. The DHV threshold value predicting MMI was 102 cm(3) (sensitivity 85%, specificity 91%, P < .01) and DHV/BV threshold ratio was 7.8% (sensitivity 86%, specificity 87%, P < .01). Both the age ≥75 years group and the age <75 years group with MMI showed equally poor outcomes (mRS 5.7 ± .7 versus 5.3 ± 1.3).Conclusions: DHV and DHV/BV can provide reliable information for MMI prediction in elderly patients. [ABSTRACT FROM AUTHOR]

Although proatlas segmentation abnormalities as developmental remnants around the foramen magnum have been reported in postmortem studies, they are rarely documented in a clinical setting. This report details the clinical and radiological characteristics of a rare case of proatlas segmentation abnormalities with clinical onset during the seventh decade of life. This case was suspected to have a familial factor. We also review the literature regarding this condition. [ABSTRACT FROM AUTHOR]

Abstract: Background: Repetitive transcranial magnetic stimulation (rTMS) has been reported to be clinically effective for treating motor symptoms in Parkinson's disease (PD). Few studies have been performed reporting the effects of rTMS on non-motor symptoms such as depression and apathy in PD. Objective: We assessed the effects of high-frequency (HF) rTMS over the primary motor (M1) foot area on motor symptoms, depression and apathy scales, and sensory symptoms in PD. Methods: We investigated the efficacy of 3 consecutive days of HF-rTMS over the M1 foot area in 21 patients with PD using a randomized, double-blind cross-over trial compared with sham stimulation. Motor effects were evaluated using the Unified Parkinson's Disease Rating Scale part III (UPDRS-III), the self-assessment motor score, the visual analog scale (VAS), the 10-m walking test, and finger tapping. Non-motor effects were analyzed using the Montgomery Asberg Depression Rating Scale, the Apathy Scale, and quantitative sensory testing. Results: HF-rTMS significantly improved UPDRS-III (P < 0.001), VAS (P < 0.001), the walking test (P = 0.014), self-assessment motor score (P = 0.010), and finger tapping measurement (P < 0.05) compared to sham stimulation. In contrast, no significant improvement was observed in depression and apathy scales. Consecutive days of rTMS did not significantly increase the improvement in motor symptoms. There were no adverse effects following rTMS on patients with PD. Conclusions: We confirmed that HF-rTMS over the M1 foot area significantly improved motor symptoms in patients with PD. In addition, daily repeated stimulation was not significantly more effective than a single session of stimulation, but may be effective for maintaining the improvement in motor symptoms in patients with PD. [Copyright &y& Elsevier]

Objective: Though a cortical visual prosthesis is a promising method for treating severe visual disturbances, long-term blindness is known to depress visual cortex activity. We examined the use of repetitive transcranial magnetic stimulation (rTMS) with a navigation system as a direct functional assessment tool for the visual cortex. Methods: We performed rTMS of the occipital cortex at three different stimulus frequencies (1 Hz, 5 Hz, and 20 Hz), on five stimulus targets around the calcarine fissure in 10 healthy subjects and 3 patients with visual impairment. Results: In the subjects with normal vision, phosphenes were mostly induced in the visual hemifield contralateral to the stimulation site, and stimulation on the targets inferior to the calcarine fissure predominantly induced phosphenes in the upper visual hemifield. High-frequency stimulation induced larger and complicated-shaped phosphenes at higher rates. The phosphenes induced rate and spatial distribution were altered in the blind patients. Conclusions: The rTMS has the ability to directly assess the regional visual function of the occipital cortex both in normal-sighted subjects and blind patients. Precise targeting with a navigation system appropriately stimulated the lingual gyri, which contributed to consistently inducing the phosphenes in the upper visual fields. Atypical representation of the phosphenes in patients with visual impairment suggests the alteration of regional cortical excitations and spatial representation due to the cortical reorganization after the loss of visual inputs. [ABSTRACT FROM AUTHOR]

Abstract: Background: Conventional laminectomy is a simple procedure that provides adequate decompression in cases of lumbar spinal canal stenosis. However, with this surgical modality, important posterior osteoligamentous elements necessary for spinal stability are lost; and it is often accompanied by damage to the facet joint. Bilateral interlaminar fenestration and unroofing of the intervertebral foramen to achieve decompression of the nerve roots by using a unilateral microsurgical approach in lumbar spinal canal stenosis are less invasive compared with conventional laminectomy. Methods: We carried out bilateral interlaminar fenestration and unroofing of the intervertebral foramen to decompress the stenosed nerve roots under a microscope by using a unilateral approach. In particular, we performed the decompression of the contralateral nerve root with this surgical method by using a Caspar retractor. Surgery was performed on 47 patients (18 women and 29 men; 29-85 years; median age, 62 years). All cases were with single-level lumbar spinal canal stenosis and bilateral radiculopathy. Results: The mean preoperative NCOS was 29.8 (range, 8-48). The mean NCOS after a postoperative period of 3 months was 79.9 (range, 32-100). After a postoperative period of 2 years, the mean NCOS increased to 83.2 (range, 32-100). The satisfaction measures indicated that the procedure was “very successful” in 45 cases, providing “almost complete relief”; “fairly successful” in one case, providing “a good deal of relief”; and “not very successful” in another case, affording “only a little relief.” Conclusions: This unilateral, minimally invasive decompression provided satisfactory results. [Copyright &y& Elsevier]

The synthetic aperture magnetometry (SAM) is a spatially selective beamformer, which transforms neuromagnetic signals into units of dipole moment on a per-voxel basis. We applied this technique to demonstrate the tomographic distribution of the power calculated from the spontaneous magnetoencephalogram (MEG) activities in a patient with a focal cerebral ischemia.The distribution of spontaneous MEG activity was affected by the changes in the regional cerebral blood flow (rCBF) and also by the presence of magnetic resonance image (MRI)-documented lesion. The present study for the first time demonstrated the altered patterns in the tomography of spontaneous MEG activity at different frequency bands, i.e. delta, alpha and beta bands, in a stroke patient which may elucidate an important implication in the pathoneurophysiology associated with cerebral ischemia. [Copyright &y& Elsevier]

Abstract: Brain abscess formation is a rare complication of intracranial endovascular treatment. To our knowledge, all previous reports of brain abscess formation have been associated with treatments involving the introduction of foreign materials. A 75-year-old man was admitted to hospital for acute stroke. Cerebral angiography revealed occlusion of the left middle cerebral artery (MCA) at the origin of the M2 segment. Intra-arterial thrombolytic therapy was administered but a hemorrhagic event occurred during this process. A brain CT scan revealed a hematoma extending from the left basal ganglia to the left frontal lobe and expansion of the infarct in the left MCA territory. A brain abscess at the hemorrhagic site developed 3 months after symptom onset. This is the first report of a patient with brain abscess formation following intra-arterial thrombolytic treatment. It is important to ensure aseptic technique during endovascular procedures irrespective of the involvement of foreign materials. [Copyright &y& Elsevier]

Abstract: Numerous procedures have been reported for reconstruction of the bony defect around the sphenoid ridge after a frontotemporal craniotomy. However, it is still often difficult to restore the defect because of the complex curvature. Here we describe a simple cranial reconstruction method using hydroxyapatite cement and gelatin sponges. This procedure has been used on six patients, and satisfactory reconstruction was confirmed in all with postoperative three-dimensional CT scans. Using this technique, the bony defect was completely reconstructed with an appropriate thickness and curvature. [ABSTRACT FROM AUTHOR]

Locked-in syndrome (LIS) usually occurs as a result of pontine lesions and has been classified into various categories on the basis of neurologic conditions, of which transient total mesencephalic LIS is extremely rare. A 53-year-old man presented with bilateral ptosis followed by a total locked-in state. In the clinical course, the patient successfully recovered with only left slight hemiparesis and skew deviation remaining. Magnetic resonance imaging revealed multiple ischemic lesions caused by thrombosis at the top of basilar artery, including the bilateral cerebral peduncles, tegmentum of the midbrain, and the right cerebellar hemisphere. Antecedent bilateral ptosis before the locked-in state may be related to ischemia in the central caudal nucleus of the oculomotor nuclei. We should pay attention to this easily missed condition during the treatment of ischemic stroke involving the basilar artery. [Copyright &y& Elsevier]

Background: To examine the strength and tolerance of the fibrin glue sealant in a situation of extended transsphenoidal surgery. The withstand pressure of fibrin glue sealant was measured using a simple sellar reconstruction model. Methods: A 15-mm diameter hole at the bottom of a 51-cm high cylinder was covered with a Gore-Tex (Gore-Tex, Tokyo, Japan) sheet. A small plate was placed on the center for a brief fixation, and 3 mL of fibrin glue was applied over the entire bottom. Then water was gradually filled in five cylinders, and the water level at leakage was measured as withstand pressures at 10 minutes and 24 hours after sealant application. The stability of the sealant under pressures of 20 and 30 cm H2O for 12 hours was also examined. Results: The median initial withstand pressure at 10 minutes was 32 cm H2O (n = 5), and was significantly increased to 47.5 cm H2O after 24 hours (n = 4). In four of five cylinders, fibrin glue sealants were stable against a pressure of 20 cm H2O for 12 hours and 30 cm H2O for the next 12 hours. Conclusions: The withstand pressure of simple fibrin glue sealant without other biological reactions could be estimated to be more than 20 cm H2O after application, and increased to more than 40 cm H2O after 24hours. These data are practical for neurosurgeons to comprehend the strength and limit of fibrin glue sealant and suggests the importance to control the intracranial pressure to less than 20 cm H2O, especially for the first 12 to 24 hours. [ABSTRACT FROM AUTHOR]

We examined the effect of the pathology of Alzheimer's disease (AD) on improvement of clinical symptoms after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH). Forty-four iNPH patients were classified into 18 patients with (iNPH/AD +) and 26 patients without (iNPH/AD −) combination with low amyloid β42 and high total tau in cerebrospinal fluid (CSF). We compared improvements after lumbo-peritoneal shunt surgery (LPS) between the two groups in Timed Up & Go Test, 10-m reciprocating walking test, Digit Symbol Substitution Test, attention test, delayed recall test, Mini-Mental State Examination, iNPH grading scale, Neuropsychiatric Inventory, Zarit Burden Interview, and other evaluations. Three months after LPS, gait, urination, overall cognition, psychomotor speed, attention, and neuropsychiatric symptoms significantly improved in both groups, but the improvement in delayed recall and reduction of caregiver burden were significantly greater in iNPH/AD − than iNPH/AD +. In addition, improvement in delayed recall score after LPS was significantly and negatively correlated with the probability of AD as judged by amyloid β42 and total tau levels in CSF. Three months after LPS, almost all of the triad symptoms decreased in iNPH patients with and without AD pathology but memory improved only in iNPH patients without AD pathology. [ABSTRACT FROM AUTHOR]

Background When it comes to evacuating intracranial hemorrhagic lesions in patients with traumatic brain injury (TBI), neurosurgeons perform either a craniotomy or a decompressive craniectomy (DC). The aim of the present study was to estimate the impact of DC on outcomes in elderly patients. Methods This retrospective cohort study, conducted in a neurosurgical institute in Japan from April 2009 to June 2014, included 91 consecutive patients with TBI (aged 60 years or older) who underwent evacuation of intracranial hemorrhagic lesions. Patients were divided into 2 groups: craniotomy only or DC. We set the primary endpoint as an unfavorable outcome (death or vegetative state), as evaluated on the Glasgow Outcome Scale at 6 months after injury. The secondary endpoints included existence of delayed hemorrhage and occurrence of hydrocephalus requiring shunt placement. The inverse probability of treatment weighting method was used to develop a propensity model to adjust for baseline imbalances between groups. Results The DC group exhibited greater severity both in clinical and computed tomography findings according to baseline characteristics. After we adjusted for these differences by inverse probability of treatment weighting using the propensity score, DC was significantly associated with unfavorable outcomes (adjusted odds ratio, 8.00; 95% confidential interval, 2.30–27.84; P = 0.002) and delayed hemorrhage (adjusted odds ratio, 13.42; 95% confidential interval, 1.52–118.89; P = 0.022). There was no significant difference in the occurrence of hydrocephalus requiring shunt placement. Conclusions DC in conjunction with evacuation of intracranial hemorrhagic lesions was associated with worse functional outcome in elderly patients with TBI. [ABSTRACT FROM AUTHOR]

Introduction Patients with idiopathic normal pressure hydrocephalus (iNPH) have neuropsychiatric symptoms that could affect patients' quality of life and caregiver burden. In this study, we assessed the effect of lumbo-peritoneal (L-P) shunt surgery on neuropsychiatric symptoms and the association between neuropsychiatric symptoms and caregiver burden after L-P shunt surgery. Methods We recruited 22 iNPH patients who had L-P shunt surgery and who were followed up for 3 months after surgery. Neuropsychiatric symptoms and caregiver burden were evaluated with the Neuropsychiatric Inventory (NPI) and Zarit Burden Interview (ZBI), respectively, before and 3 months after surgery. We evaluated the changes of NPI and ZBI and the association between the changes in these 2 scores and the triad symptoms. Results NPI total, apathy, and depression scores significantly decreased after surgery. The improvement in NPI total, apathy, disinhibition, and irritability scores after surgery were significantly and positively associated with improvement in ZBI score after surgery. Improvement in NPI apathy score was significantly associated with improvement in Frontal Assessment Battery score after surgery. Conclusion L-P shunt surgery was effective in reducing not only the triad symptoms but also the neuropsychiatric symptoms, and the improved neuropsychiatric symptoms might decrease caregiver burden for iNPH patients. [ABSTRACT FROM AUTHOR]

Abstract: A brain machine interface (BMI) provides the possibility of controlling such external devices as prosthetic arms for patients with severe motor dysfunction using their own brain signals. However, there have been few studies investigating the decoding accuracy for multiclasses of useful unilateral upper limb movements using non-invasive measurements. We investigated the decoding accuracy for classifying three types of unilateral upper limb movements using single-trial magnetoencephalography (MEG) signals. Neuromagnetic activities were recorded in 9 healthy subjects performing 3 types of right upper limb movements: hand grasping, pinching, and elbow flexion. A support vector machine was used to classify the single-trial MEG signals. The movement types were predicted with an average accuracy of 66±10% (chance level: 33.3%) using neuromagnetic activity during a 400-ms interval (−200ms to 200ms from movement onsets). To explore the time-dependency of the decoding accuracy, we also examined the time course of decoding accuracy in 50-ms sliding windows from −500ms to 500ms. Decoding accuracies significantly increased and peaked once before (50.1±4.9%) and twice after (58.5±7.5% and 64.4±7.6%) movement onsets in all subjects. Significant variability in the decoding features in the first peak was evident in the channels over the parietal area and in the second and third peaks in the channels over the sensorimotor area. Our results indicate that the three types of unilateral upper limb movement can be inferred with high accuracy by detecting differences in movement-related brain activity in the parietal and sensorimotor areas. [Copyright &y& Elsevier]

Abstract: C-Jun N-terminal kinase (JNK) mediates neuronal death in response to stress and injury in the CNS and peripheral nervous system. Here, we show that JNK also regulates retrograde axonal degeneration (axonal dieback) after spinal cord injury (SCI) in mice. Activated phospho-JNK was highly expressed in damaged corticospinal tract (CST) axons after thoracic SCI by hemisection. Local administration of SP600125, a JNK inhibitor, prevented accumulation of amyloid-β precursor protein and retraction of the severed CST axons as well as preserved the axonal arbors rostral to the injury site. The treatment with SP600125 also improved functional recovery of the hindlimbs, assessed by Basso mouse scale open-field scores and the grid-walking test. In Jnk1 −/− and Jnk3 −/− mice, we observed prevention of axonal degeneration and enhancement of motor recovery after SCI. These results indicate that both JNK1 and JNK3 induce axonal degeneration and limit motor recovery after SCI. Thus, a JNK inhibitor may be a suitable therapeutic agent for SCI. [Copyright &y& Elsevier]

Abstract: Alpha rhythm is one of the most prominent electromagnetic changes in the brain, and electroencephalography (EEG) alpha reactivity disturbance may sometimes represent an early sign of cerebral dysfunction. Although magnetoencephalography (MEG) has a better spatial resolution than EEG, it has not extensively been used to explore alpha-power change deficits in schizophrenia as a possible neurophysiological marker of the disease. The purpose of this study was to use MEG to identify abnormalities in alpha synchronization induced by eye-closing in schizophrenia patients compared to healthy controls, and to investigate whether alpha reactivity deficits correlate with clinical features of the disorder. MEG data were recorded in 22 schizophrenia patients and 20 age- and gender-matched controls during eyes-open/eyes-closed resting states. Cortical sources of event-related synchronization (ERS) were estimated using multiple source beamformer, and BrainVoyager was used for statistic group analysis. A significant decrease in ERS in the upper alpha band (10–13Hz) was found in the left posterior temporal region in schizophrenia patients relative to controls, and this activity showed correlation with visual memory scores. This upper alpha ERS deficit may indicate left temporal dysfunction and visual-information processing impairment in schizophrenia, and upon further confirmation it might represent a neurophysiological state marker of the disorder. [Copyright &y& Elsevier]

Abstract: Although recent studies have shown that cell transplantation is effective in promoting regeneration of the central nervous system (CNS) of adult mammals, functional recovery has been reported to be limited. In vitro models of axonal outgrowth assays are often used as easy methods for screening cells for transplantation but often fail to reflect the physiological conditions of in vivo CNS injury models. In order to bridge the gap between in vitro and in vivo models, we have established a new organotypic co-culture system comprising cortical tissue and a Matrigel containing several cell types that are candidates for transplantation therapy for CNS injury. In this model, cells transplanted in a Matrigel produce a three-dimensional architecture, with axons elongating from the cortex in the Matrigel. The ability of the transplanted cells to promote axonal growth was examined quantitatively by assessing axonal number and length. Moreover, we observed site-specific rearrangement of transplanted cells and interactions between axons and cells, including several cortical cells that migrated into the gel. These results indicate that our co-culture system can provide a useful assay for transplanted cells prior to in vivo screening. [Copyright &y& Elsevier]

Abstract: The mu rhythm is regarded as a physiological indicator of the human mirror neuron system (MNS). The dysfunctional MNS hypothesis in patients with autistic spectrum disorder (ASD) has often been tested using EEG and MEG, targeting mu rhythm suppression during action observation/execution, although with controversial results. We explored neural activity related to the MNS in patients with ASD, focusing on power increase in the beta frequency band after observation and execution of movements, known as post-movement beta rebound (PMBR). Multiple source beamformer (MSBF) and BrainVoyager QX were used for MEG source imaging and statistical group analysis, respectively. Seven patients with ASD and ten normal subjects participated in this study. During the MEG recordings, the subjects were asked to observe and later execute object-related hand actions performed by an experimenter. We found that both groups exhibited pronounced PMBR exceeding 20% when observing and executing actions with a similar topographic distribution of maximal activity. However, significantly reduced PMBR was found only during the observation condition in the patients relative to controls in cortical regions within the MNS, namely the sensorimotor area, premotor cortex and superior temporal gyrus. Reduced PMBR during the observation condition was also found in the medial prefrontal cortex. These results support the notion of a dysfunctional execution/observation matching system related to MNS impairment in patients with ASD, and the feasibility of using MEG to detect neural activity, in particular PMBR abnormalities, as an index of MNS dysfunction during performance of motor or cognitive tasks. [Copyright &y& Elsevier]