Tomihiro Imai

Health-related quality-of-life and treatment targets in myasthenia gravis.

Introduction: The aim of this study was to determine factors affecting health‐related quality of life (HRQOL) and to propose appropriate treatment targets for patients with myasthenia gravis (MG). Methods: We evaluated 640 consecutive patients with MG seen at 11 neurological centers. Two‐year follow‐up data were obtained for 282 patients. Correlations between detailed clinical factors and the Japanese version of the 15‐item MG‐specific QOL scale score were analyzed. Results: In a cross‐sectional analysis of 640 MG patients, multivariate regression revealed that disease severity, as evaluated by the MG Composite (P < 0.0001), total dose of oral prednisolone during the last year (P = 0.002), and Cushingoid appearance index (P = 0.0004), showed significant negative effects on HRQOL, but the quantitative MG score and current prednisolone dose did not. Conclusions: Achieving minimal manifestations (MM) status or better with prednisolone ≤5 mg/day was found to exert a major positive impact on HRQOL in both the cross‐sectional and 2‐year follow‐up patient samples and can be recommended as a treatment target. Muscle Nerve 50: 493–500, 2014

Non-invasive positive pressure ventilation for laryngeal contraction disorder during sleep in multiple system atrophy

We examined the usefulness of non-invasive positive pressure ventilation (NPPV) in the management of nocturnal laryngeal stridor associated with vocal cord dysfunction in five cases of multiple system atrophy (MSA). First, the patients were investigated during sleep induced by a minimal dose of propofol. Laryngoscopy showed paradoxical vocal cord movement resulting in inspiratory stridor. Electromyographic (EMG) study revealed synchronized bursts in the thyroarytenoid muscles and diaphragm in every inspiratory phase whenever the stridor emerged. NPPV was initiated after paradoxical movement was recognized with laryngoscopy. The NPPV mask was equipped with an additional channel for laryngoscopic monitoring. The optimal pressure for treatment was determined according to laryngoscopic and EMG findings. Next, NPPV was applied to natural sleep using the conditions determined in propofol-induced sleep. In all cases, NPPV eliminated nocturnal stridor and oxygen desaturation during natural sleep. Laryngoscopic observation during induced sleep is recommended as a useful procedure to titrate the optimal pressure for NPPV therapy. Since central hypoventilation progresses in the course of MSA, the choice of NPPV rather than continuous positive airway pressure should be encouraged to treat laryngeal contraction disorder associated with MSA.

Reference values for voluntary and stimulated single-fibre EMG using concentric needle electrodes: A multicentre prospective study

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.

Clinical features and treatment status of adult myasthenia gravis in Japan

Myasthenia gravis (MG) is classified as early‐onset MG (EOMG; age at onset ≤49 years), late‐onset MG (LOMG; age at onset ≥50 years) or thymoma‐associated MG (TAMG) (E‐L‐T classification). To clarify the characteristics of each group in the E‐L‐T classification in Japan, we carried out multicenter analyses of MG.

Study of urinary mandelic acid concentration and peripheral nerve conduction among styrene workers

The relationship between exposure to styrene and nerve conduction velocities was investigated in 32 workers occupationally exposed to styrene. There was a dose-dependent relationship between urinary mandelic acid and ulnar and peroneal motor distal latencies (MDLs). The ulnar and peroneal MDLs of subgroup B (urinary mandelic acid > or = 250 mg/l) were significantly longer than those of subgroup A (urinary mandelic acid < 250 mg/l)(p < 0.05), and the referent group (p < 0.03). After adjusting confounding factors, urinary mandelic acid had a significant positive relationship with ulnar and peroneal MDL. Our study suggests that a low level of styrene, below the 50 ppm exposure limit of the American Conference of Governmental Industrial Hygienists (ACGIH), involves the risk of inducing adverse effects on the peripheral nervous system. The study also indicated that motor distal latency is a sensitive parameter of toxic peripheral neuropathy.

Oral corticosteroid therapy and present disease status in myasthenia gravis

Introduction: The aim of this study was to elucidate the effectiveness of oral prednisolone (PSL) according to dosing regimen in 472 patients with myasthenia gravis (MG). Methods: We compared the clinical characteristics and PSL treatment between 226 patients who achieved minimal manifestations (MM) or better and 246 patients who remained improved (I) or worsened, according to the MG Foundation of America postintervention status. Results: Achievement of MM or better at peak PSL dose (odds ratio 12.25, P < 0.0001) and combined use of plasma exchange/plasmapheresis (PE/PP) and/or intravenous immunoglobulin (IVIg) (odds ratio 1.92, P = 0.04) were associated positively, and total PSL dose during the past year (odds ratio 0.17, P = 0.03) was associated negatively with present MM or better status. Conclusions: Higher PSL dose and longer PSL treatment do not ensure better outcome. In the absence of a good response, the PSL dose should be decreased by combining with modalities such as PE/PP or IVIg. Muscle Nerve 51:692–696, 2015

Cervical dural arteriovenous malformation presenting with right-sided occipitalgia: Before and after successful treatment by embolization

SYNOPSIS

Single nucleotide polymorphisms and functional analysis of MxA promoter region in multiple sclerosis

OBJECTIVE Interferons (IFNs)-inducible myxovirus resistance protein A (MxA) has recently been used as an indirect marker of neutralizing antibody against IFN in patients with multiple sclerosis (MS). On the other hand, MxA inhibits the replication of viruses by means of modifying cellular function, including apoptotic pathway. Our objective is to investigate the genetic and pathological role of MxA in patients with MS. METHODS We examined SNPs of MxA promoter region in 67 patients with MS. Moreover, to elucidate the functional roles of SNPs, we conducted Luciferase assay with pGL3-basic vector including patient-derived or artificially mutated MxA promoter region. RESULTS A significantly higher frequency of the haplotype with -88T and -123A, which correlates with over-expression of MxA, was observed in MS. Moreover, we elucidated novel findings showing that nt -88 played a leading part with type I IFNs and that nt -123 played the same role independently without type I IFNs, respectively. CONCLUSION SNPs on MxA promoter region may play an important role in the pathophysiology of MS and provide a novel strategy for the therapeutic resolutions of MS.

Entrapment neuropathy of the palmar cutaneous branch of the median nerve in carpal tunnel syndrome

OBJECTIVE The aim of this study is to elucidate the significance of electrophysiological data of the palmar cutaneous branch of the median nerve (PCBm) in the diagnosis entrapment of the PCBm concomitant with carpal tunnel syndrome (CTS). MATERIALS AND METHODS Clinical and electrophysiological studies were conducted for abnormal sensation of the thenar eminence in eight CTS patients. Sensory nerve action potentials (SNAPs) of the PCBm were recorded from bipolar surface electrodes over the forearm using an orthodromic method. The preoperative SNAP evaluation was compared with the operative findings. RESULTS The eight patients were divided into two groups based on the characteristics of SNAPs of the PCBm; five patients had normal SNAPs of the PCBm and three patients had delayed or absent SNAPs. Open surgery confirmed entrapment of the PCBm in one patient in the first group and all patients in the latter group. CONCLUSIONS Although clinical symptoms were not always reliable to diagnose entrapment of the PCBm in CTS, electrophysiological study of the PCBm was highly sensitive (75%) and entirely specific (100%) to demonstrate the entrapment of the PCBm preoperatively.

Synovial chondromatosis presenting with cervical radiculopathy: a case report.

Study Design. A case report is presented. Objectives. To report a case of synovial chondromatosis of a cervical facet joint and describe the appearance with magnetic resonance imaging and computed tomography myelography. Summary of Background Data. Synovial chondromatosis is an uncommon disorder characterized by the presence of multiple cartilaginous or osteocartilaginous nodules in the synovium of a joint space. Synovial chondromatosis in the cervical facet joint is rare. Method. A 52-year-old woman experienced the sudden onset of severe pain in the dorsal shoulder girdle and in the ulnar side of her right arm and forearm. This refractory pain only responded to an epidural nerve root block. Neurologic examination showed right nerve root signs that ranged from the C7 to Th1 segments of the spinal cord. Radiologic and electrophysiological examinations were carried out. Result. A mass was found in the right facet joint between C7 and Th1 with magnetic resonance imaging and computed tomography myelography. These investigations clearly indicated the location, size, and extent of the lesion accompanying the irregularity of the joint and osteolytic change. Somatosensory-evoked potentials with right ulnar nerve stimulation indicated a significant conduction block in the lower right cervical nerve roots. After surgical removal of this lesion, the neurologic symptoms markedly improved. The histopathology diagnosed synovial chondromatosis. Conclusion. Synovial chondromatosis should be included in the differential diagnosis of radiculopathies of unknown etiology.