澁谷 和幹

INTRODUCTION: This study explored potential diagnostic markers of nerve ultrasound in differentiating amyotrophic lateral sclerosis (ALS) from mimic disorders. METHODS: Ultrasound of the median, ulnar, and tibial nerves was conducted in 53 patients with ALS, 32 patients with ALS-mimic disorders, and 30 controls. Nerve cross-sectional area (CSA) and distal-proximal ratios were calculated. RESULTS: The median nerve CSA in the upper arm was decreased (7.9 ± 1.3 mm2 vs. 9.0 ± 1.4 mm2 , P < 0.05), and the median nerve wrist-upper arm ratio was increased in ALS patients compared with controls (1.3 ± 0.4 vs. 1.1 ± 0.2; P < 0.01). In differentiating ALS from mimic presentations, assessment of median nerve CSA in the upper arm and comparison of a median and ulnar nerve CSA distal-proximal ratio provide diagnostic potential. DISCUSSION: Assessment of nerve CSA combined with calculation of nerve CSA distal-proximal ratio provides a useful marker to aid in the diagnosis of ALS. Muscle Nerve 58:777-783, 2018.

OBJECTIVE: To assess the cerebral blood flow (CBF) in patients with diabetic neuropathic pain, and its changes after duloxetine therapy. METHODS: Using iodine-123-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (IMP-SPECT), we performed a cross-sectional study of 44 patients with diabetes, and compared CBF in those with (n = 24) and without neuropathic pain (n = 20). In patients with neuropathic pain, we also longitudinally assessed changes in CBF 3 months after treatment with duloxetine. RESULTS: IMP-SPECT with voxel-based analyses showed a significant increase in cerebral blood flow in the right anterior cingulate cortex and a decrease in the left ventral striatum in patients with neuropathic pain, compared with those without pain. After duloxetine treatment, volume of interest analyses revealed a decrease in cerebral blood flow in the anterior cingulate cortex in patients with significant pain relief but not in non-responders. Furthermore, voxel-based whole brain correlation analyses demonstrated that greater baseline CBF in the anterior cingulate cortex was associated with better pain relief on the numerical rating scale. CONCLUSIONS: Our results suggest that the development of neuropathic pain is associated with increased activity in the anterior cingulate cortex, and greater baseline activation of this region may predict treatment responsiveness to pharmacological intervention. TRIAL REGISTRATION NUMBER: UMIN000017130;Results.

AIM: To investigate whether primary lateral sclerosis (PLS) represents part of the amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD) spectrum of diseases. METHODS: Comprehensive assessment was taken on 21 patients with PLS and results were compared to patients diagnosed with pure motor ALS (n = 27) and ALS-FTD (n = 12). Clinical features, Addenbrooke's Cognitive Examination (ACE) scores, Motor Neuron Disease Behaviour (Mind-B) scores, motor disability on the ALS functional rating scale (ALSFRS) and survival times were documented. Motor cortex excitability was evaluated using transcranial magnetic stimulation (TMS). RESULTS: Global cognition was impaired in PLS (mean total ACE score 82.5 ± 13.6), similar to ALS-FTD (mean total ACE score 76.3 ± 7.7, p > 0.05) while behavioural impairments were not prominent. TMS revealed that resting motor threshold (RMT) was significantly higher in PLS (75.5 ± 6.2) compared ALS-FTD (50.1 ± 7.2, p < 0.001) and ALS (62.3 ± 12.6, p = 0.046). Average short-interval intracortical inhibition (SICI) was similar in all three patient groups. The mean survival time was longest in PLS (217.4 ± 22.4 months) and shortest in ALS-FTD (38.5 ± 4.5 months, p = 0.002). Bulbar onset disease (β = - 0.45, p = 0.007) and RMT (β = 0.54, p = 0.001) were independent predictors of global cognition while motor scores (β = 0.47, p = 0.036) and SICI (β = 0.58, p = 0.006) were significantly associated with ALSFRS. CONCLUSION: The cognitive profile in PLS resembles ALS-FTD, without prominent behavioural disturbances. A higher RMT in PLS than ALS and ALS-FTD is consistent with differential cortical motor neuronal abnormalities and more severe involvement of corticospinal axons while SICI, indicative of inhibitory interneuronal dysfunction was comparable with ALS and ALS-FTD. Overall, while these findings support the notion that PLS lies on the ALS-FTD spectrum, the mechanisms underlying slow disease progression are likely to be distinct in PLS.

OBJECTIVE: To elucidate differences in the distribution and firing frequency of fasciculations between peripheral nerve hyperexcitability syndromes and amyotrophic lateral sclerosis (ALS) and to explore the generator site of fasciculations. METHODS: Ultrasound of 14 preselected muscles was performed in patients with peripheral hyperexcitability and ALS. The distribution and firing frequency of fasciculations were calculated. Cortical excitability assessment was also done by threshold tracking transcranial magnetic stimulation. RESULTS: In total, 518 muscles from 37 peripheral hyperexcitability patients and 756 muscles from 54 ALS patients were examined. Regarding the detection rate, 74% of muscles in ALS patients demonstrated fasciculations, compared with 34% of muscles in peripheral hyperexcitability patients (P < 0.001). The number of unique repeating focal muscle fasciculation movements per muscle and firing frequency of individual fasciculations in ALS were both significantly higher than those in peripheral hyperexcitability (P < 0.001). Furthermore, cortical silent period duration negatively correlated with the number and firing frequency of fasciculations in ALS (P < 0.05). A similar relationship was not evident in peripheral hyperexcitability. CONCLUSIONS: In ALS patients, fasciculations were more widespread, greater in number and higher in firing frequency than in peripheral hyperexcitability patients. SIGNIFICANCE: A significant proportion of fasciculations in ALS may be influenced by changes in central excitability.

INTRODUCTION: This study seeks to elucidate the optimal scan time to detect fasciculations by using ultrasound in the diagnosis of amyotrophic lateral sclerosis (ALS). METHODS: The intervals between fasciculations were recorded from tongue, abdominal, and limb muscles in ALS patients, incorporating assessment of the cumulative probability of 2 fasciculations occurring. RESULTS: From prospective studies of 228 muscles from 19 ALS patients, fasciculations were detectable in 68% of patients. The longest interfasciculation interval recorded was 81.4 s in the hand muscle. The cumulative probability of 2 fasciculations occurring was calculated as ≥0.9 in all muscles during a period of 60 s. DISCUSSION: A definition of 2 or more fasciculations occurring during a scan time of 60 s reliably allowed detection of fasciculations in ALS. Muscle Nerve, 2017.

OBJECTIVE: The aim of the present study was to elucidate the pattern of change in bulbar muscles using ultrasound in patients diagnosed with amyotrophic lateral sclerosis (ALS). METHODS: Changes in the mylohyoid and geniohyoid muscle complex (mylohyoid-geniohyoid-muscle-complex) thickness were recorded while swallowing 5 ml of water using M-mode ultrasound in 30 ALS patients compared to 20 healthy controls. The ratio of mylohyoid-geniohyoid-muscle-complex thickness as determined by the maximum thickness of mylohyoid-geniohyoid-muscle-complex during swallowing divided by thickness at rest, was compared between ALS patients and controls, with the correlation between thickness ratio, echogenicity and clinical parameters assessed. RESULTS: Overall, the thickness ratio in ALS patients was 1.39 ± 0.23 (mean ± SD) compared to 1.55 ± 0.17 in controls (p < 0.05). In sub-analysis, the thickness ratio was significantly decreased in ALS patients with bulbar-onset disease compared to those with limb-onset disease (p < 0.01) and controls (p < 0.01). Thickness ratio negatively correlated with the severity of upper motor neuron involvement in the bulbar region (p < 0.05). CONCLUSIONS: Bulbar muscle ultrasound represents a novel method to detect impaired mobility and thereby provides an objective assessment of upper motor neuron involvement in the bulbar region of ALS patients.

INTRODUCTION: Threshold tracking paired-pulse transcranial magnetic stimulation (TTTMS) examines cortical function and is useful for diagnosis of motor neuron disorders. Differences in cortical function have been identified between dominant and non-dominant limbs using constant stimulus methods, but they remain unclear, potentially due to methodological differences. In this study we aimed to clarify differences in cortical function between dominant and non-dominant limbs using TTTMS. METHODS: Single-pulse TMS, TTTMS, and nerve conduction studies were performed in 25 healthy, right-handed participants by recording from the abductor pollicis brevis muscle. RESULTS: There were no side-to-side differences observed in resting motor threshold, motor evoked potential (MEP) amplitude, MEP latency, central motor conduction time, cortical silent period, short-interval intracortical inhibition and facilitation, compound muscle action potential (CMAP) amplitude, CMAP latency, F-wave latency, or neurophysiological index. CONCLUSIONS: These findings suggest that, when using TTTMS, there are no differences in cortical function between dominant and non-dominant hemispheres. Muscle Nerve 55: 424-427, 2017.

Introduction: Motor neuron hyperexcitability appears linked to the process of neurodegeneration in amyotrophic lateral sclerosis (ALS). As such, therapies that inhibit neuronal hyperexcitability may prove effective in arresting the progression of ALS.Area covered: We searched MEDLINE and ClinicalTrials.gov and selected randomised controlled trials that covered neuroprotective therapy. Riluzole has been established to reduce neuronal hyperexcitability. More recently, initial studies of Na+ channel blockers (mexiletine and flecainide) have been trialled. Separately, a trial of a K+ channel activator (retigabine) is underway, while edaravone is currently being considered for licensing by drug approval agencies based on a hypothesis that the elimination of free radicals may lead to protection of motor neurones.Expert commentary: Initial clinical trials with Na+ channel blockers have not yet established efficacy in ALS. Currently, retigabine is under evaluation as a potential therapy. Edaravone has recently been approved as a new therapeutic option for ALS in Japan.

OBJECTIVE: To study the relationship between cortical function and survival in amyotrophic lateral sclerosis (ALS). METHODS: A total of 216 referrals were screened, and participants with familial ALS or an inexcitable cortex were excluded. Clinical measures and phenotyping from 169 patients with sporadic ALS were combined with an assessment of cortical function using threshold tracking transcranial magnetic stimulation with indices including short interval intracortical inhibition (SICI). Peripheral nerve studies were collected, incorporating compound muscle action potential amplitude. Clinical prognostic factors were recorded longitudinally, including ALS Functional Rating Scale-Revised (ALSFRS-R). RESULTS: Compared to 109 healthy controls, 169 patients had reduced SICI (p < 0.0001). In survival analysis, 105 patients progressed to death with an estimated median survival time of 37 months. In patients with less than 2 years disease duration (n = 140), those with bulbar onset (p = 0.017), rapid vital capacity (VC) decline (p < 0.0001), rapid ALSFRS-R decline (p < 0.0001), and reduced averaged SICI (p = 0.047) had a poorer prognosis. Multivariate analysis identified rapid VC decline (p < 0.0001), rapid ALSFRS-R decline (p = 0.0060), and reduced averaged SICI (p = 0.011) as factors independently associated with a shorter survival. CONCLUSIONS: Cortical dysfunction appears to be a prognostic marker in patients with ALS within 2 years of disease onset, such that patients with reduced averaged SICI, indicative of intracortical hyperexcitability, demonstrated a worse prognosis.

Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS), suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP) amplitude (index of motor neuronal loss) and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44), ALS patients (n = 140) had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p &lt; 0.05), greater threshold changes in depolarizing threshold electrotonus (p &lt; 0.05) and depolarizing current threshold relationship (i.e. less accommodation; (p &lt; 0.05), greater superexcitability (a measure of fast potassium current; p &lt; 0.05) and reduced late subexcitability (a measure of slow potassium current; p &lt; 0.05), suggesting increased persistent sodium currents and decreased potassium currents. The reduced potassium currents were found even in the patient subgroups with normal CMAP (&gt; 5mV). Regression analyses showed that SDTC (R = -0.22) and depolarizing threshold electrotonus (R = -0.22) increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS.

Objective: Recently, the utility of threshold tracking paired-pulse transcranial magnetic stimulation (TTTMS), to measure changes in cortical excitabilitability, has been established for diagnostic purposes across a range of neurological diseases. However, the impact of healthy aging on the GABA-ergic intracortical inhibitory system remains unclear. To improve the clinical applicability, TTTMS was performed across an age spectrum. Methods: TTTMS, single-pulse TMS and nerve conduction studies (NCS) were performed in 113 healthy subjects aged between 20 and 83 years (57 male and 56 female). Results: Prolonged motor evoked potential (MEP) latency, increased central motor conduction time, decreased compound muscle action potential (CMAP) amplitude, prolonged F-wave latency and decreased neurophysiological index (NI), calculated from CMAP amplitude, latency and F-wave frequency, were observed as subjects aged. In contrast, short interval intracortical inhibition (SICI) and facilitation did not change. Compared to females, males exhibited a reduced SICI and NI along with longer MEP, CMAP with prolonged F-wave latencies. Multivariate analyses revealed similar results. Conclusion: Utilizing clinically applicable TTTMS protocols, findings suggest that GABA mediated intracortical inhibition may be greater in females but does not significantly change with age. Significance: These findings may better inform the interpretation of diagnostic TTTMS studies in the clinical setting. (C) 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Background: Calciphylaxis is a syndrome consisting of vascular calcification, thrombosis, and skin necrosis. The syndrome develops often in chronic hemodialysis patients. However, there have been several case reports on calciphylaxis in patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome, a systemic disease associated with plasma cell dyscrasia and upregulation of vascular endothelial growth factor (VEGF). Methods: In 76 POEMS patients and 86 age- and gender-matched disease controls, we studied abnormal small vessel calcification by computed tomography (CT) of the soft tissues. Clinical and laboratory profiles were compared between POEMS patients with and without calciphylaxis. Histological examination was performed in six autopsy cases. Results: Small vessel calcification on CT was found in 17 % of POEMS patients and in none of the controls (P &lt; 0.001). Autopsy confirmed calciphylaxis in 2 (33 %) patients. Among POEMS patients, higher disease activity, including more severe neuropathy and ascites, higher serum levels of interleukin-6, and lower serum albumin levels, was associated with the development of calciphylaxis. Serum levels of creatinine, calcium, and phosphate were not related to the presence of calciphylaxis. Conclusions: Calciphylaxis is often present in patients with POEMS syndrome. Upregulation of multiple inflammatory cytokines such as VEGF and interleukin-6 may contribute to the development of calciphylaxis, by entirely different mechanism from that in chronic dialysis. POEMS syndrome should be recognized as a potential cause of calciphylaxis.

Objective: POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome is a rare cause of demyelinating neuropathy with upregulation of vascular endothelial growth factor (VEGF). This study aimed to elucidate axonal excitability properties and their relation to VEGF levels and nerve edema in POEMS neuropathy. Methods: Axonal excitability measurement and nerve ultrasound were performed in the median nerve of 33 patients with POEMS syndrome. Serum VEGF levels were measured by ELISA. Results: Compared with normal subjects (n = 87), POEMS patients showed longer strength-duration time constant, fanning-out of threshold electrotonus curves, and greater threshold changes in a hyperpolarizing current-threshold relationship. Nerve ultrasound showed significant enlargement in POEMS patients. Serum VEGF levels and the extent of nerve edema partly correlated with nerve conduction slowing, as well as persistent sodium currents and inward rectification. Conclusions: In POEMS syndrome, patterns of changes in excitability properties could suggest increased persistent sodium currents, and impaired potassium and inward rectifying channels. The findings were not consistent with depolarization due to nerve edema and compression ischemia. Significance: In addition to demyelination, nerve edema induced by upregulated VEGF, and upregulated inflammatory cytokines could modulate profiles of POEMS neuropathy. (C) 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

To identify the target molecules of chronic inflammatory demyelinating polyneuropathy (CIDP), we used proteomic-based approach in the extracted proteins from porcine cauda equina. Two of 31 CIDP patients had markedly elevated serum autoantibodies against vinculin, a cell adhesion protein. Both of the patients with anti-vinculin antibodies had similar clinical manifestation, which are compatible with those of "typical" CIDP. Immunocytochemistry showed that vinculin was stained at the myelin sheath of the sciatic nerves by serum samples. Our results suggest that vinculin is a possible immunological target molecule in a subpopulation of typical CIDP patients. (C) 2015 Elsevier B.V. All rights reserved.

Objective: The duration of the distal compound muscle action potential (DCMAP) is a useful index to detect demyelination in the distal nerve segments. However in published electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), the cut-off values of DCMAP duration are defined using an EMG low frequency filter of only 20. Hz. We aimed to provide widely-available reference data using several low cut filters. Methods: In 13 Japanese and European tertiary centers, DCMAP duration data using 2, 5, 10, and 20. Hz low frequency filters were prospectively collected from 147 normal controls, 59 patients with typical CIDP, and 100 with diabetic polyneuropathy. Optimal cut-off values were calculated with receiver-operating characteristic curves, offering 100% specificity versus normal controls. Results: The higher low frequency filter was associated with significantly shorter DCMAP duration in all groups. For CIDP diagnosis, the calculated cut-off values had a sensitivity ranging from 51% to 66%, and a specificity versus diabetic neuropathy from 96% to 98%. Conclusions: Our results show that DCMAP duration is largely dependent on low frequency filter settings, but is a useful index for CIDP diagnosis when the cut-off values are properly determined at each filter setting. Significance: Our data provide the systematic reference values of DCMAP duration for CIDP diagnosis available for most EMG laboratories.

Fasciculations are characteristic features of amyotrophic lateral sclerosis (ALS), and suggest motor nerve hyperexcitability. Recent reports have shown that an increase in persistent nodal sodium current is associated with shorter survival in ALS patients. This objective of this trial is to study the efficacy and safety of mexiletine, a sodium channel blocker, for ALS. Sixty eligible participants were randomly allocated (1:1) to riluzole 100 mg or riluzole plus mexiletine 300 mg. The primary endpoint was change in the revised ALS functional rating scale (ALSFRS-R) scores during six months. We also monitored strength-duration time constant (SDTC, a measure of persistent sodium current) in median motor axons. Results showed that during six months of treatment, changes in the ALSFRS-R score and SDTC were -7.0 +/- 7.1 and -0.04 +/- 0.1, respectively, in the riluzole group and -6.9 +/- 6.4 and 0.04 +/- 0.1, respectively, in the mexiletine group (p = 0.96 and 0.049). Adverse events amounted 20% in the riluzole and 33% in the mexiletine groups. In conclusion, the results suggest that daily 300 mg mexiletine has no effects on axonal sodium current and ALSFRS-R deterioration in ALS. We have to attempt another trial using a higher dose of mexiletine or other agents to suppress sodium currents and ALS progression in the future.

To study distribution and patterns of nerve hypertrophy in chronic inflammatory demyelinating polyneuropathy (CIDP), magnetic resonance neurography with 3-dimensional reconstruction of short tau inversion recovery images was performed in 33 patients. This technique clearly showed longitudinal morphological changes from the cervical roots to the nerve trunks in the proximal arm. Nerve enlargement was detected in 88% of the patients. According to the clinical subtype of CIDP, typical CIDP patients showed symmetric and root-dominant hypertrophy, whereas Lewis-Sumner syndrome patients had multifocal fusiform hypertrophy in the nerve trunks. The patterns of nerve hypertrophy presumably reflect the different pathophysiology of each CIDP subtype. Ann Neurol 2014.

Purpose:In current electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy, the cutoff values of distal compound muscle action potential (DCMAP) duration are defined using electromyogram low-cut filter setting of 20 Hz. We aimed to assess effects of low-cut filter on DCMAP duration (10 vs. 20 Hz).Methods:We prospectively measured DCMAP duration in 130 normal controls and 42 patients, fulfilling diagnostic criteria for typical chronic inflammatory demyelinating polyneuropathy by European Federation of Neurological Societies/Peripheral Nerve Society.Results:Distal compound muscle action potential duration was significantly shortened with 20-Hz than 10-Hz filtering. When the cutoff values were defined as the upper limit of normal (ULN, mean + 2.5SD), the sensitivity/specificity was 67%/95% in 10-Hz recordings, and 69%/95% in 20-Hz recordings. This diagnostic accuracy was similar to that defined by receiver operating characteristic analyses.Conclusions:Distal compound muscle action potential duration significantly affected by the low-cut electromyogram filter setting, but with at least 10 and 20 Hz, the diagnostic accuracy is similar.

We examined the phosphorylated 43-kDa TAR DNA-binding protein (pTDP-43) inclusions as well as neuronal loss in full-length spinal cords and five selected regions of the central nervous system from 36 patients with amyotrophic lateral sclerosis (ALS) and 10 age-matched normal controls. The most severe neuronal loss and pTDP-43 lesions were seen in lamina IX motor nuclei columns 4, 6, and 8 of lower cervical segments and in columns 9-11 of lumbosacral segments. Severity of pTDP-43 pathology and neuronal loss correlated closely with gray and white matter oligodendroglial involvement and was linked to onset of disease, with severe involvement of columns 4, 6, and 8 of upper extremity onset cases and severe involvement of columns of 9, 10, and 11 in cases with lower extremity onset. Severe TDP-43 lesions and neuronal loss were observed in stage 4 cases and sometimes included Onuf's nucleus. Notably, three cases displayed pTDP-43 aggregates in the midbrain oculomotor nucleus, which we had not seen previously even in cases with advanced (i.e., stage 4) pathology. pTDP-43 aggregates were observed in neurons of Clarke's column in 30.6 % of cases but rarely in the intermediolateral nucleus (IML). Gray matter oligodendroglial pTDP-43 inclusions were present in areas devoid of neuronal pTDP-43 aggregates and neuronal loss. Taken together, our findings indicate that (1) the dorsolateral motor nuclei columns of the cervical and lumbosacral anterior horn may be the earliest foci of pTDP-43 pathology in the spinal cord, (2) gray matter oligodendroglial involvement is an early event in the ALS disease process that possibly heralds subsequent involvement of neurons by pTDP-43 pathology, and (3) in some very advanced cases, there is oculomotor nucleus involvement, which may constitute an additional neuropathological stage (designated here as stage 5) of pTDP-43 pathology in ALS.

Hereditary spastic paraplegia (HSP) is one of the most genetically heterogeneous neurodegenerative disorders characterized by progressive spasticity and pyramidal weakness of lower limbs. Because 430 causative genes have been identified, screening of multiple genes is required for establishing molecular diagnosis of individual patients with HSP. To elucidate molecular epidemiology of HSP in the Japanese population, we have conducted mutational analyses of 16 causative genes of HSP (L1CAM, PLP1, ATL1, SPAST, CYP7B1, NIPA1, SPG7, KIAA0196, KIF5A, HSPD1, BSCL2, SPG11, SPG20, SPG21, REEP1 and ZFYVE27) using resequencing microarrays, array-based comparative genomic hybridization and Sanger sequencing. The mutational analysis of 129 Japanese patients revealed 49 mutations in 46 patients, 32 of which were novel. Molecular diagnosis was accomplished for 67.3% (33/49) of autosomal dominant HSP patients. Even among sporadic HSP patients, mutations were identified in 11.1% (7/63) of them. The present study elucidated the molecular epidemiology of HSP in the Japanese population and further broadened the mutational and clinical spectra of HSP.

Objective: Bortezomib is a proteasome inhibitor with high efficacy for multiple myeloma but with severe peripheral neurotoxicity, leading to dose modification and severe neurological disability. This study aimed to investigate the pathophysiology of bortezomib-induced neuropathy. Methods: Threshold tracking was used to assess the excitability of sensory and motor axons. Measurements were sequentially performed before and after bortezomib treatment in nine patients with newly diagnosed multiple myeloma. Results: In total, 67% of patients finally developed symptomatic neuropathy. Changes in sensory axonal excitability indices readily occurred after the first course of administration. Patterns of changes in excitability indices suggest membrane depolarization (decreased superexcitability, P &lt; 0.001; decreased depolarizing threshold electrotonus 90-100 ms, P = 0.02). Abnormalities in nerve conduction parameters suggestive of axonal degeneration appeared after the second course of treatment. Conclusions: Bortezomib induces a depolarizing shift in resting membrane potential prior to the development of neuropathy. Membrane depolarization could be associated with impairment of electrogenic Na+-K+-ATPase-dependent pump caused by toxic effects of bortezomib on mitochondria. Significance: Axonal depolarization and hyperexcitability might enhance neurodegeneration in bortezomib-induced neuropathy. (C) 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Objective To investigate whether or not the lesions in sporadic amyotrophic lateral sclerosis (ALS) originate from a single focal onset site and spread contiguously by prion-like cell-to-cell propagation in the rostrocaudal direction along the spinal cord, as has been hypothesised (the 'single seed and simple propagation' hypothesis). Methods Subjects included 36 patients with sporadic ALS and initial symptoms in the bulbar, respiratory or upper limb regions. Abnormal spontaneous activities in needle electromyography (nEMG)-that is, fibrillation potentials, positive sharp waves (Fib/PSWs) or fasciculation potentials (FPs)-were compared among the unilateral muscles innervated by different spinal segments, especially between the T10 and L5 paraspinal muscles, and between the vastus medialis and biceps femoris. Axon length and the proportion of muscle fibre types, which are both related to motoneuronal vulnerability in ALS, are similar in the paired muscles. Results Fourteen of 36 patients showed a non-contiguous distribution of nEMG abnormalities from the onset site, with skipping of intermediate segments. In eight of them, the non-contiguous pattern was evident between paired muscles with the same motoneuronal vulnerability. The non-contiguously affected lumbosacral lesions involved motoneuron columns horizontally or radially proximate to one another, appearing to form a cluster in four of the eight patients. FPs, known to precede Fib/PSWs, were shown more frequently than Fib/PSWs in all the lumbosacral segments but L5, suggesting that 2nd hits occur at L5 and then spread to other lumbosacral segments. Conclusions In sporadic ALS, the distribution of lower motoneuron involvement cannot be explained by the 'single seed and simple propagation' hypothesis alone. We propose a 'multifocal hits and local propagation' hypothesis instead.

Objective No clinically effective treatment for promoting peripheral axonal regeneration has yet been established. Several experimental studies in vitro and in vivo have shown that a high dose of methylcobalamin (MeCbl), an analogue of vitamin B12, promotes axonal growth in peripheral nerve injury. We herein assessed the safety and efficacy of an ultra-high dose MeCbl treatment for patients with peripheral neuropathy and chronic axonal degeneration. Methods Fourteen patients with immune-mediated or hereditary neuropathy in the chronic progressive or stable phase were enrolled. MeCbl, 25 mg/day for 10 days followed by monthly 25 mg for 5 months, was intravenously administered. The patients were evaluated before and 1 year following treatment. The primary endpoints were safety and improvement in the Medical Research Council (MRC) sum score in at least two muscles of the 20 muscles. This trial is registered with the University Hospital Medical Information Network (UMIN) Center in Japan under the ID: UMIN000009359. Results There were no adverse effects in twelve of the patients, whereas treatment was discontinued in two patients who had seborrheic dermatitis at 3 months and respiratory tract infection at 2 months, respectively. Therefore, twelve patients were evaluated for the primary outcomes; the MRC sum score was improved in seven of the patients and unchanged or worsened in the remaining five patients. Conclusion Intravenous ultra-high dose MeCbl treatment is a safe and potentially efficacious therapy for patients with peripheral neuropathy and chronic axonal degeneration.

広範な線維束性収縮は筋萎縮性側索硬化症（ALS）を特徴づける症状であり，神経原性筋萎縮を呈する疾患の中でALSにほぼ特異的な所見である．線維束性収縮の多くは下位運動ニューロン軸索遠位部起源であり，軸索の機能障害・興奮性増大を基盤としている．ALSの皮質および下位運動ニューロンおよび軸索の興奮性を評価した研究では，興奮性増大の所見が報告されており，これが運動神経細胞死とかかわっていると推測されている．これらの所見に基づいて，運動ニューロンおよび軸索の興奮性を抑制することにより，ALSの病態進行を抑制できるかを検討するため，メキシレチン塩酸塩をもちいた臨床試験が実施されている．

Objective Vascular endothelial growth factor (VEGF) plays an essential role in the pathophysiology of polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome. Anti-VEGF antibody (bevacizumab) appears to be an attractive therapeutic option. The aim of this study is to investigate the effects of bevacizumab for patients with POEMS syndrome. Methods We reported six POEMS patients treated with bevacizumab and reviewed the literature. Results The serum VEGF levels decreased immediately after bevacizumab administration in all six patients. However, four patients had entirely no clinical response, and two of them died. The remaining two showed improvement that could be explained by combined treatments. We also reviewed the literature and found 11 patients treated with bevacizumab; of these, only one was treated with bevacizumab alone. 10 had combined treatments, and four died without any response. Conclusions Both our experience and the literature suggest ambiguous effects of bevacizumab; inhibition of VEGF alone may be insufficient because multiple cytokines are upregulated, or aberrant neo-vascularization may have already fully developed in the advanced stage of POEMS syndrome.

Background In amyotrophic lateral sclerosis (ALS), muscle wasting preferentially affects the abductor pollicis brevis (APB) and first dorsal interosseous over the abductor digit minimi (ADM), and this is termed split hand'. Previous axonal excitability studies have suggested increased nodal persistent sodium current and reduced potassium current in motor axons in ALS, but the extent of excitability changes in APB and ADM axons in ALS has never been compared. Objective To elucidate the peripheral axonal pathophysiology of split hand. Methods In both APB and ADM motor axons of 21 patients with ALS and 17 age-matched normal controls, threshold tracking was used to measure excitability indices such as strength-duration time constant (SDTC; a measure of persistent sodium current) and threshold electrotonus. Results In normal controls, SDTC was significantly longer for APB than ADM axons, suggesting that axonal excitability is physiologically higher in APB axons. Compared with normal controls, patients with ALS had longer SDTC and greater threshold changes in depolarising threshold electrotonus in both APB and ADM axons. Furthermore, the difference in extent of SDTC prolongation between normal subjects and patients with ALS was greater in APB than ADM axons. Conclusions APB axons have physiologically higher excitability than ADM axons, and, in ALS, the hyperexcitability is more prominent in APB axons. Although cortical mechanisms would also be involved, more prominent hyperexcitability of APB axons may contribute to development of split hand, and the altered axonal properties are possibly associated with motor neuronal death in ALS.

Objectives: To clarify whether patients with spinal muscular atrophy (SMA) or spinal and bulbar muscular atrophy (SBMA) suffer disabling muscle fatigue, and whether activity-dependent conduction block (ADCB) contributes to their fatigue. ADCB is usually caused by reduced safety factor for impulse transmission in demyelinating diseases, whereas markedly increased axonal branching associated with collateral sprouting may reduce the safety factor in chronic lower motor neuron disorders. Methods: We assessed the fatigue severity scale (FSS) in 22 patients with SMA/SBMA, and in 100 disease controls (multiple sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy (CIDP), and axonal neuropathy). We then performed stimulated-single fibre electromyography (s-SFEMG) in the extensor digitorum communis (EDC) muscle of 21 SMA/SBMA patients, 6 CIDP patients, and 10 normal subjects. Results: The FSS score was the highest in SMA/SBMA patients [4.9 +/- 1.1 (mean +/- SD)], with 81% of them complaining of disabling fatigue, compared with normal controls (3.5 +/- 1.0), whereas patients with multiple sclerosis (4.3 +/- 1.6), myasthenia gravis (4.0 +/- 1.6) or CIDP (4.3 +/- 1.4) also showed higher FSS score. When 2000 stimuli were delivered at 20 Hz in s-SFEMG, conduction block of single motor axons developed in 46% of patients with SMA/SBMA, and 40% of CIDP patients, but in none of the normal controls. Conclusion: SMA/SBMA patients frequently suffer from disabling fatigue presumably caused by ADCB induced by voluntary activity. Significance: ADCB could be the mechanism for muscle fatigue in chronic lower motor neuron diseases. (C) 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.