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Objective: C8-dominant innervation of ulnar-innervated and T1-dominant innervation of median-innervated intrinsic hand muscles have been suggested, although less is known regarding forearm muscles. We aimed to determine myotomal innervation of the forearm muscles based on the clinical and electromyographial findings of patients with C8 or T1 lesions., Methods: Medical Research Council scale and EMG findings were retrospectively reviewed in 16 patients with C8 lesions (2 postmedian sternotomy C8 plexopathy and 14 C8 radiculopathy) and 9 patients with T1-dominant lesions (8 true neurogenic thoracic outlet syndrome and 1 T1 radiculopathy)., Results: Clinical and EMG findings revealed T1-dominant innervation of the flexor digitorum superficialis, flexor digitorum profundus of the index finger, abductor pollicis brevis, and flexor pollicis longus muscles, and C8-dominant innervation of the flexor carpi ulnaris, flexor digitorum profundus of the little finger, and digit extensors innervated by the posterior interosseous nerve. The first dorsal interosseous, and abductor digiti minimi muscles seem to be innervated by both C8 and T1 roots., Conclusions: C8-dominant innervation of ulnar-innervated muscles and T1-dominant innervation of median-innervated muscles are also evident for forearm flexor muscles., Significance: Such an additional evidence for myotomal innervation will improve localization in clinical as well as electrophysiological diagnoses., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Introduction: We describe a previously unreported pitfall, spread of the stimulus at the elbow to the radial nerve, in an antidromic sensory nerve conduction study of the lateral antebrachial cutaneous (LAC) nerve., Methods: Subjects consisted of 80 healthy volunteers, and both sides were examined for each subject. Besides routine recording of the LAC nerve, sensory nerve action potentials (SNAPs) of the radial nerve were recorded distally., Results: The spread phenomenon occurred in 73 of 160 arms (46%), and the SNAP amplitude increased due to contamination of the radial SNAP up to 6.7 times the genuine LAC SNAP. In 10 arms (6%), the spread started before the LAC SNAP was saturated, and the genuine LAC SNAP was unknown due to an anatomical variation in at least 1 arm., Conclusions: Without monitoring distal radial SNAPs, the spread phenomenon will remain unrecognized. This pitfall undermines the reliability of the test., (Copyright © 2013 Wiley Periodicals, Inc.)

Introduction: Far-field potentials (FFPs) from muscles other than the abductor digiti minimi (ADM) may interfere with motor unit number estimation (MUNE) from that muscle., Methods: We identified the origin of each surface motor unit potential (SMUP) during hypothenar MUNE using the multiple point stimulation method in 20 control subjects by recording from individual ulnar-innervated muscles with a common proximal reference (pref)., Results: ADM SMUPs comprised 39.0% of the accepted SMUPs, followed by those from the fourth dorsal interosseous muscle (14.0%), the fourth lumbrical muscle (9.2%), and the second and third palmar interosseous muscles (8.8% each). The percentage of ADM SMUPs varied from 18% to 73% of accepted SMUPs among individual subjects. Accepted non-ADM SMUPs were usually much smaller than ADM SMUPs, and many more non-ADM SMUPs were excluded due to their small size., Conclusions: A large contribution from non-ADM or non-hypothenar SMUPs obscures the meaning of the MUNE value., (© 2013 Wiley Periodicals, Inc.)

Introduction: The repetitive nerve stimulation (RNS) test in the trapezius muscle is used widely for the evaluation of myasthenia gravis. However, pseudofacilitation is often difficult to avoid in this muscle and may compromise the detection of small decremental responses. We have devised a new maneuver to reduce pseudofacilitation., Methods: Using our maneuver, the shoulder of a supine subject is elevated passively and is held firmly by the examiner. Four conventional maneuvers as well as ours were compared with regard to pseudofacilitation that was maximal at the second wave in 14 control subjects., Results: Pseudofacilitation at the second and fourth waves was the smallest using our maneuver. Up to 15% pseudofacilitation was observed using the other maneuvers., Conclusion: Pseudofacilitation in the trapezius muscle is mainly due to shortening of the muscle belly. It can be reduced greatly by shortening the muscle in advance., (Copyright © 2012 Wiley Periodicals, Inc.)

We present a patient who had adult-onset Still's disease (AOSD) complicated by thrombotic thrombocytopenic purpura (TTP) that resulted in retinal microangiopathy and rapidly fatal cerebral edema. The patient was a 37-year-old male who developed fever, eruption, arthritis and hepatic dysfunction, that, based on close examination, was diagnosed as AOSD. Despite treatment with corticosteroids, the patient developed acute visual field defect, neurological deterioration including convulsions and impaired consciousness, as well as acute renal failure that ultimately resulted in death. Pathological examination of autopsy specimens revealed multiple fibrin thrombi disseminated in small vessels of the brain and kidney, which was consistent with TTP, along with marked cerebral edema. Although TTP has rarely been reported in association with AOSD, awareness of the possible coexistence of these two diseases is important for diagnosis and treatment.

During the maternal-to-zygotic transition (MZT), maternal proteins in oocytes are degraded by the ubiquitin-proteasome system (UPS), and new proteins are synthesized from the zygotic genome. However, the specific mechanisms underlying the UPS at the MZT are not well understood. We identified a molecule named zygote-specific proteasome assembly chaperone (ZPAC) that is specifically expressed in mouse gonads, and expression of ZPAC was transiently increased at the mouse MZT. ZPAC formed a complex with Ump1 and associated with precursor forms of 20S proteasomes. Transcription of ZPAC genes was also under the control of an autoregulatory feedback mechanism for the compensation of reduced proteasome activity similar to Ump1 and 20S proteasome subunit gene expression. Knockdown of ZPAC in early embryos caused a significant reduction of proteasome activity and decrease in Ump1 and mature proteasomes, leading to accumulation of proteins that need to be degraded at the MZT and early developmental arrest. Therefore, a unique proteasome assembly pathway mediated by ZPAC is important for progression of the mouse MZT.

Objectives: To find the characteristic phenotypes of 3 different types of myasthenia gravis (MG)., Methods: The clinical and electrophysiological features among 15 cases of muscle-specific kinase antibody positive (MuSK Ab+) MG, 59 cases of double seronegative (DSN) MG, and 161 cases of acetylcholine receptor antibody (AChR Ab)+ MG in the University of Alabama at Birmingham were compared., Results: AChR Ab was positive in 69% of cases and MuSK Ab in 6% of cases. MuSK Ab+ MG was more common (14%) in African Americans compared with whites (4%). AChR Ab+ MG is characterized by male predominance, later onset, a fewer cases of ocular MG, and a higher association with thymoma. DSN-MG is characterized by a greater prevalence of ocular MG, milder forms of MG with less number of crisis, and fewer abnormalities in the repetitive nerve stimulation test. MuSK Ab+ MG is characterized by younger age at onset, severe and bulbar forms of MG, predominant faciobulbar neck weakness, and a poor response to edrophonium, anticholinesterase, and intravenous immunoglobulin. Long-term outcome showed no difference among 3 types of MG., Conclusions: AChR Ab+ MG and DSN-MG are similar, with the exception of less severity in the latter. MuSK Ab+ MG has distinct clinical and electrophysiological features.

Objective: To document the incidence and effects of a previously unreported pitfall during routine antidromic sensory nerve conduction study (SCS) of the ulnar nerve: the spread of the wrist stimulation to the dorsal ulnar cutaneous (DUC) branch., Methods: The subjects consisted of 20 healthy volunteers. An antidromic sensory nerve action potential (SNAP) was recorded over the proximal interphalangeal joint of the little finger, and the DUC response was monitored over the dorsum of hand to check for the occurrence of this spread., Results: The spread occurred in all subjects, which caused a 4-87% increase in the SNAP amplitude. The likelihood that this spread may occur during routine SCS varied among the subjects, and also within an individual subject depending on minute shifts of the stimulating site. Selective stimulation of the ulnar main trunk up to maximal intensity without spread to the DUC was not achieved despite every effort in two subjects., Conclusions: This spread phenomenon may occur frequently during routine antidromic SCS, but would not be recognized without monitoring the DUC response., Significance: This pitfall may interfere with the reproducibility of the SNAP amplitude, and also with the diagnosis of ulnar neuropathy at the wrist., (Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: The aim of this study is to establish reference values for single-fibre electromyography (SFEMG) using concentric needles in a prospective, multicentre study., Methods: Voluntary or stimulated SFEMG at the extensor digitorum communis (EDC) or frontalis (FRO) muscles was conducted in 56-63 of a total of 69 normal subjects below the age of 60years at six Japanese institutes. The cut-off values for mean consecutive difference (MCD) of individual potentials were calculated using +2.5 SD or 95% prediction limit (one-tail) of the upper 10th percentile MCD value for individual subjects., Results: The cut-off values for individual MCD (+2.5 SD) were 56.8μs for EDC-V (voluntary SFEMG for EDC), 58.8μs for EDC-S (stimulated SFEMG for EDC), 56.8μs for FRO-V (voluntary SFEMG for FRO) and 51.0μs for FRO-S (stimulated SFEMG for FRO). The false positive rates using these cut-off values were around 2%., Conclusions: The +2.5 SD and 95% prediction limit might be two optimal cut-off values, depending on the clinical question. The obtained reference values were larger than those reported previously using concentric needles, but might better coincide with conventional values., Significance: This is the first multicentre study reporting reference values for SFEMG using concentric needles. The way to determine cut-off values and the statistically correct definition of the percentile were discussed., (Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Introduction: In this investigation we report on the clinical utility of sensory nerve conduction studies of the medial femoral cutaneous (MFC) nerve., Methods: Sensory nerve conduction of the MFC nerve was assessed in 22 patients for whom this test was considered clinically necessary., Results: MFC nerve conduction was abnormal in 4 cases of MFC neuropathy. The most common cause was iatrogenic in 14 femoral neuropathy cases. MFC nerve conduction showed absent or low-amplitude sensory nerve action potential (SNAP) in 13 cases, with femoral motor nerve conduction abnormal in 5 cases. In 2 cases with acute lumbar plexopathy, the MFC SNAP was absent unilaterally. MFC nerve conduction was normal in 1 case with diabetic lumbar radiculopathy and in another case with postpolio syndrome., Conclusion: Assessment of MFC nerve conduction is extremely useful in the diagnosis of femoral neuropathy, medial femoral cutaneous neuropathy, and lumbar plexopathy., (Copyright © 2011 Wiley Periodicals, Inc.)

Introduction: The role of fasciculation potentials (FPs) in the diagnosis of amyotrophic lateral sclerosis (ALS) has been underrated. The Awaji algorithm has restored the value of FPs. Our aim was to test the diagnostic yield of the Awaji algorithm, with consideration of FPs., Methods: Subjects consisted of 139 consecutive ALS patients retrospectively enrolled over 5 years. At presentation we evaluated the diagnostic categories using the revised El Escorial Criteria (R-EEC) and the Awaji algorithm., Results: The percentage of patients classified as confirmed ALS, clinically probable (laboratory-supported), or higher was 43% using the R-EEC and 37% using the Awaji algorithm. Thirteen patients with upper motor neuron signs only in one body region showed a decrease in their category using the Awaji algorithm. FPs were observed in 89% of ALS patients and were frequent in proximal muscles., Conclusion: The sensitivity of the Awaji algorithm is lower than that of the R-EEC., (Copyright © 2011 Wiley Periodicals, Inc.)

Objective: To clarify the features of decremental responses following repetitive nerve stimulation in patients with motor neuron diseases (MNDs), in comparison with myasthenia gravis (MG)., Methods: The subjects consisted of 48 MND, 39 generalized MG and 19 ocular MG patients. Six muscles, both proximal and distal muscles, were tested., Results: Significant decrements (>5%) in at least one muscle were observed in 83% of the MND patients, and 74% and 47% of the generalized MG and ocular MG patients, respectively. Decrements were more frequently observed in the proximal muscles both in MND and MG patients (deltoid 76% and 62%, and trapezius 71% and 51% for MND and generalized MG, respectively), suggesting lower safety factors in neuromuscular transmission in those muscles. Decrements in the nasalis were rare in MND (8%) in comparison with generalized MG (54%)., Conclusions: Decremental responses were frequently observed in MND patients. There were small differences between MND and MG regarding the distribution and other features of decrements, such as the degree of the U-shape or the responses to different stimulus frequencies and to brief exercise., Significance: These results imply that the underlying mechanism regulating the decrements is common to MND and MG., (Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Introduction: The compound muscle action potential (CMAP) following ulnar nerve stimulation receives a considerable contribution from far-field potentials (FFPs), although their origin is not entirely clear. We investigated this issue using voluntary contractions., Methods: In 7 control subjects, we placed multiple recording electrodes over the motor points of ulnar-innervated muscles. We asked the subjects to perform a weak movement corresponding to the action of each muscle, and identified the single motor unit potentials (MUPs) from that muscle. We summed the MUPs from each individual muscle and reconstructed the CMAPs., Results: The reconstructed CMAPs coincided well with the actual ones. The N1, P1, and early N2 components of the FFPs were generated primarily by palmar, but also by dorsal, interosseous muscles. The abductor digiti minimi muscle usually generated positive-negative biphasic FFPs, and the negative FFP generated the late N2 component., Conclusions: These results should prompt a revision of the theory of FFP generation., (Copyright © 2010 Wiley Periodicals, Inc.)

Objective: To report the SFEMG findings in sporadic inclusion body myopathy (S-IBM)., Methods: We have analyzed the SFEMG data in 25 patients (mean age: 63; 16 males) with S-IBM which was diagnosed by the presence of classical rimmed vacuoles in the muscle biopsy together with clinical, laboratory, and electrophysiological findings., Results: All patients had fibrillations, positive sharp waves, and small-amplitude short-duration motor unit potentials (MUPs) in the needle EMG. High-amplitude MUPs were observed in eight (32%) patients, two of whom had long-duration MUPs. SFEMG was abnormal in 17 (68%) cases: mean "mean consecutive difference (MCD)" was increased beyond the age-adjusted normal limit in 16 cases, and more than 10% of potential pairs (PP) had MCD longer than the upper normal limit of an individual MCD in one case. Mean fiber density (FD) was 2.16, with maximum FD being 4.15. Increased FD was noted in 11 (44%) cases. In four cases, more than 10% of PP had blocking, but there was no neurogenic blocking in any PP. As expected, MCD increased linearly (r=0.85) with the percentage of PP beyond the normal upper limit., Conclusions: The SFEMG findings in S-IBM are typical of the classical pattern of myopathy., Significance: Our findings support the consensus that S-IBM is a myopathy.

We report a functional neuroimaging study of a 43-year-old woman with Nasu-Hakola disease (NHD). Regional cerebral blood flow (rCBF) images were measured with technetium-99m ethyl cysteinate dimer single photon emission computed tomography (SPECT). rCBF was decreased in the bilateral frontal lobes and thalamus. This finding was consistent with the known underlying neuropathology in patients with NHD. Brain SPECT is useful for demonstrating the pathophysiologic brain region in patients with NHD.

In this report, we describe a case of Neuro-Behçet's disease with early onset of bipolar mood disorder. A 53-year-old man with neuropathy including dysphasia and dyslalia developed bipolar mood disorder with anxiety, agitation, depressive mood, talkativeness, hyperkinesias, and appetite rise, and soon exhibited severe personality deterioration. Oral aphthae, cell proliferation and elevated IL-6 levels in spinal fluid, and the patient's clinical downhill course with remission and relapse in spite of good reaction to steroid preparation indicated the possibility of Neuro-Behçet's disease. Brain MRI showed clear swelling of the brain stem area, especially in the pons, in the active phase with low signal in T1-weighted images contrasting with clear high signal in T2-weighted images and FLAIR. At the time of remission, atrophy of the brain stem was shown. These findings were consistent with the view reported in recent years concerning the brain image of Neuro-Behçet's disease, which seemed to be useful for the differential diagnosis. This case manifested two outstanding clinical features. First, it showed bipolar mood swing or mixed state distinguishable from disinhibition or euphoria in deteriorated personality, which is common in this condition. A clear bipolar mood disorder has not been described until now in Neuro-Behçet's disease. Second, subclinical dysthymia or hypomanic phase occurred before clear onset of the disease. In Neuro-Behçet's disease, it is currently considered that psychiatric symptoms may appear in the early stage, but there is controversy as to whether they can precede the other symptoms. Our case indicated very early onset of psychiatric symptoms in this condition.