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Introduction/Aims The aim of the study was to determine the association between the virtual Myasthenia Gravis Impairment Index (vMGII) with other patient‐reported outcomes (PROs) of myasthenia gravis (MG) and its usefulness in telephone consultations with MG patients. Methods This was a retrospective case series in which vMGII score along with virtual Single Simple Question (vSSQ), virtual Patient‐Acceptable Symptom State PASS (vPASS) response, and patient disease status based on Myathenia Gravis Foundation of America postintervention status were collected during telephone consultation along with the MGII, SSQ, and PASS responses during the preceding in‐person clinic visits. Results In 214 patients, the mean difference of vMGII between the vPASS “Yes” and “No” groups was −14.2 ± 1.4 (95% confidence interval, −16.9 to −11.3; P

Introduction Several studies of patients with polyneuropathy failed to show differences between patients with and without pain. In the current study, we aimed to explore the association between neuropathic symptoms, mainly pain, and polyneuropathy characteristics. Methods A prospective cross-sectional study recruiting 151 patients with non-diabetic polyneuropathy was performed between November 2016 and May 2017. 38 patients with chronic inflammatory demyelinating neuropathy were excluded. Patients underwent clinical, electrophysiological and functional assessments of their polyneuropathy. Polyneuropathy characteristics were compared depending on the presence and severity of neuropathic symptoms. Results The presence and the severity of weakness were associated with a more severe neuropathy as measured by clinical, electrophysiological and functional assessments, while the presence of pain was associated with higher sural amplitudes, and the severity of pain showed a curvilinear association with neuropathy severity. Discussion Our study shows a novel finding of a curvilinear association between pain and polyneuropathy severity. This article is protected by copyright. All rights reserved.

Introduction A single and simple question, namely "What percentage of normal (PoNL) do you feel regarding your disease?" is feasible and valid in myasthenia gravis. In this study, we aimed to determine the validity of this question in patients with nondiabetic polyneuropathy. Methods Clinical, electrophysiological, and functional and disability assessments were performed in 151 patients with nondiabetic polyneuropathy. One hundred forty patient answers were recorded for the PoNL question, and these were included in the current study. Results The PoNL correlated moderately with functional and disability scales. Discussion "What PoNL do you feel?" is a simple, quick, and valid question, which correlates moderately with functional and disability scales in nondiabetic polyneuropathy, and it may be incorporated in polyneuropathy assessment.

INTRODUCTION Elevated creatine kinase (CK) level was redefined by the European Federation of Neurological Societies)EFNS(as 1.5 times the upper limit of normal. In the current study we sought to determine the sensitivity and specificity of CK testing for the diagnosis of neuromuscular disorders. METHODS Demographics and CK levels were retrospectively extracted from an electronic database for 234 patients with neuromuscular disorders. Sensitivity, specificity, and likelihood ratios and the area under curve were determined for each diagnosis and different cutoff CK values. RESULTS Using the EFNS cutoff values significantly reduced CK test sensitivity. Creatine kinase values >1000 IU/L showed a high likelihood (11.04) for myopathies and a low likelihood for polyneuropathies (0). DISCUSSION European Federation of Neurological Societies cutoff values significantly reduce CK sensitivity for diagnosing neuromuscular disorders. While low CK values cannot exclude a neuromuscular disease, values >1000 IU/L are associated with a high likelihood of myopathy.

INTRODUCTION Patients with myasthenia gravis often experience fatigue, but its effect on quality of life (QoL) is underestimated, and fatigue is rarely measured in clinical trials. METHODS Two hundred fifty-seven myasthenic patients completed the Neuro-QoL-Fatigue and measures of disease severity and QoL. We studied the relationship between fatigue and clinical and demographic variables. Finally, we studied the responsiveness of the Neuro-QoL-Fatigue in 95 patients receiving treatments for myasthenia and estimated the minimal important difference (MID). RESULTS Fatigue correlated with greater disease severity (r = 0.52-0.69, P

Introduction Monoclonal gammopathy has been reported in several polyneuropathies. In this study, we sought to explore the frequency and characteristics of monoclonal gammopathy in patients with diabetic sensorimotor polyneuropathy (DSP). Methods Patients with type 1 and type 2 diabetes mellitus (DM 1, DM 2) and controls without diabetes were evaluated between November 2008 and December 2013. Results Fifty controls, 66 patients with DM 1, and 106 patients with DM 2 were included, with average ages of 43 ± 18, 45 ± 17, and 65 ± 10 years, respectively; the frequency of monoclonal gammopathy was 0%, 8%, and 15%, respectively. In patients with DSP, the frequency of monoclonal gammopathy increased to 14% in DM 1 and 21% in DM 2; the most common monoclonal proteins were immunoglobulin (Ig) M and IgG, respectively. Discussion DSP might be associated with a high frequency of monoclonal gammopathy, with different characteristics in DM 1 and in DM 2. Muscle Nerve 57: 1018-1021, 2018.

Patients with chronic inflammatory demyelinating polyneuropathy (CIDP) often require long-term intravenous immunoglobulin (IVIG) maintenance therapy. Subcutaneous immunoglobulin (SCIG) offers an alternative administration option with anticipated improvements in patient quality of life, convenience, and flexibility. To evaluate IgPro20 (SCIG) as a maintenance treatment in CIDP. A randomized, double-blind trial in CIDP patients (n=172) investigated 0.2 and 0.4 g/kg weekly doses of IgPro20 versus placebo. The primary outcome was percentage of patients with CIDP relapse/withdrawal during 24-weeks of treatment determined by Inflammatory Neuropathy Cause and Treatment score. Secondary endpoints included grip strength and patient satisfaction. Both IgPro20 doses significantly reduced rate of CIDP relapse/withdrawal versus placebo. Grip strength remained stable with Hizentra®, but deteriorated with placebo. Most subjects preferred SCIG over IVIG. Local reactions, reported in 33% of IgPro20-treated patients, were mild or moderate in intensity. IgPro20 is efficacious and well-tolerated as maintenance treatment in CIDP. This article is protected by copyright. All rights reserved

Introduction: Assessing myasthenia gravis (MG) can be challenging, and multiple scales are available to evaluate disease severity. We evaluated the utility of a single simple question, namely “what percentage of normal do you feel regarding your MG, 0-100% normal”, as part of the MG evaluation. Methods: A retrospective chart review of patients attending the neuromuscular clinic from 01/2014 to 12/2015 was performed. Responses were correlated with symptoms and signs, QMGS (quantitative myasthenia gravis score), MGII (myasthenia gravis impairment index), and MG-QOL15 (myasthenia gravis quality of life). Results: The total cohort included 169 patients. The percentage of normal correlated strongly with limb muscle weakness and MG scales, moderately with bulbar and respiratory symptoms, and weakly with ocular manifestations. Discussion: The question “what percentage of normal do you feel regarding your MG”, is a feasible and valid question, and can be incorporated easily into routine clinical evaluation. This article is protected by copyright. All rights reserved.

Introduction Electrophysiological studies play an important role in the diagnosis of myasthenia gravis (MG). The objectives of this study was to explore the correlation of jitter and decrement with various clinical symptoms and signs and disease severity. Methods We performed a retrospective chart review of 75 MG patients who attended the neuromuscular clinic from April 2013 to May 2014. We compared clinical characteristics between patients with high jitter (>100 µs) and decrement (>10%), and patients with lower values to explore the correlations and optimal thresholds of jitter and decrement for different clinical features. Results High jitter and decrement values were associated with more severe disease, manifested by more frequent symptomatic bulbar and limb muscle weakness, more frequent ocular and limb muscle weakness on examination, higher quantitative MG score, and generalized disease. Conclusions The yield of the electrophysiological assessment in MG extends beyond disease diagnosis and correlates with disease severity and the presence of generalized disease. Muscle Nerve 56: 445–448, 2017

Introduction Repetitive nerve stimulation (RNS) showing ≥ 10% decrement is considered the cutoff for myasthenia gravis (MG), but this has never been validated. The objective of this study was to find an optimal validated cutoff value for decrement on RNS. Methods We performed retrospective chart review of patients who had electrophysiological assessment for possible MG from 2013 to 2015. Results A total of 122 patients with MG and 182 controls were identified. RNS sensitivities for generalized and ocular MG using the traditional ≥10% cutoff value were 46% and 15%, respectively, for frontalis recordings, and 35% and 19%, respectively, for nasalis recordings. Using a decrement cutoff value of 7% for frontalis and 8% for nasalis increased the sensitivities by 6-11%, with specificities of 95-96%. Conclusions For RNS in facial muscles, we suggest a cutoff value of 7-8%, which increases test sensitivity by 6-11%, while preserving high specificity for the diagnosis of MG. Muscle Nerve, 2016 Muscle Nerve 55: 166-170, 2017.

Introduction High-resolution ultrasound (HRU) is used in the diagnosis of peripheral neuropathies. There are conflicting data regarding HRU findings in patients with diabetic sensorimotor polyneuropathy (DSP). Our purpose in this study was to measure nerve cross-sectional areas (CSAs) in patients with diabetes, with and without DSP. Methods We performed a prospective peripheral nerve HRU study of 100 diabetic subjects, assessed the CSA at predefined sites, and compared the results with those of 100 normal subjects. We evaluated the use of individual CSA values and various summary scores for diagnosis of DSP. Results Diabetic subjects had higher CSA values than healthy volunteers, and those with DSP had higher CSA values. Three or more enlarged CSA sites predicted DSP with 64% sensitivity and 77% specificity. Conclusions Peripheral nerves are enlarged diffusely in diabetic patients, including sites not susceptible to bony compression. The number of enlarged CSA values can help predict the presence of DSP. Muscle Nerve, 2016 Muscle Nerve 55: 171-178, 2017.

Introduction The MG-QOL15 is a validated, health-related quality of life (HRQOL) measure for myasthenia gravis (MG). Widespread use of the scale gave us the opportunity to further analyze its clinimetric properties. Methods We first performed Rasch analysis on >1,300 15-item Myasthenia Gravis Quality of Life scale (MG-QOL15) completed surveys. Results were discussed during a conference call with specialists and biostatisticians. We decided to revise 3 items and prospectively evaluate the revised scale (MG-QOL15r) using either 3, 4, or 5 responses. Rasch analysis was then performed on >1,300 MG-QOL15r scales. Results The MGQOL15r performed slightly better than the MG-QOL15. The 3-response option MG-QOL15r demonstrated better clinimetric properties than the 4- or 5-option scales. Relative distributions of item and person location estimates showed good coverage of disease severity. Conclusions The MG-QOL15r is now the preferred HRQOL instrument for MG because of improved clinimetrics and ease of use. This revision does not negate previous studies or interpretations of results using the MG-QOL15. Muscle Nerve 54: 1015-1022, 2016.

INTRODUCTION Subcutaneous immunoglobulin (SCIg) has been used for treatment of immune neuropathies. METHODS We evaluated the safety and efficacy of 1.53:1 SCIg to intravenous immunoglobulin (IVIg) in individuals receiving

Introduction: High-resolution ultrasonography (HRU) is a novel method that provides morphological information about peripheral nerves. We aimed to determine reference values for nerve cross-sectional area (CSA) on HRU. Methods: One hundred healthy volunteers had HRU of median, radial, ulnar, fibular, tibial, sural, and superficial fibular nerves at defined sites. The CSA was measured and the effects of age, gender, and body mass index (BMI) were evaluated. Results: CSA values in healthy subjects are described. CSA is larger in lower limb motor nerves than in sensory nerves at similar sites, and the CSA tends to be symmetrical. The strongest effect on CSA was for age, although gender and BMI had some effects. Conclusions: This study provides normative values for HRU, and it suggests that further research with age- and gender-specific distributions must be a key priority in the development of HRU for use as a diagnostic test for peripheral nerve diseases. Muscle Nerve 53: 538–544, 2016

Introduction: Generic health-related quality-of-life (HRQOL) patient-reported outcome measures have been used in patients with chronic immune-mediated polyneuropathies. We have created a disease-specific HRQOL instrument. Methods: The chronic acquired polyneuropathy patient-reported index (CAP-PRI) was developed and validated in multiple steps. Items were initially generated through patient and specialist input. The performance of the preliminary 20 items was analyzed via a prospective, 5-center study involving chronic immune-mediated polyneuropathy patients. Results: Data analysis suggested modification to a 15-item scale with 3 response categories rather than 5. The final CAP-PRI was validated in another prospective, 5-center study. The CAP-PRI appeared to be a unidimensional outcome measure that fit the Rasch model in our multicenter cohort. It correlated appropriately with outcome measures commonly used in this patient population. Conclusions: The CAP-PRI is a simple disease-specific HRQOL measure that appears to be useful for clinical care and possibly also for clinical trials. Muscle Nerve 54: 9-17, 2016.

Introduction Myasthenia gravis (MG) exacerbations may be treated with intravenous immunoglobulin (IVIg) or plasma exchange (PLEX), which have equivalent effectiveness. This cost-minimization analysis compared IVIg with PLEX for treatment of patients with MG exacerbation. Methods We combined the Ontario-based health cost data with clinical data from a randomized clinical trial. Analyses were undertaken from the perspective of a public healthcare insurer and from the perspective of a tertiary university hospital payer. Results PLEX was less costly than IVIg among patients with a body mass index (BMI) > 15.7 kg/m2, from the perspective of the public healthcare insurer (P 15.7 kg/m2, from the perspective of a public healthcare insurer. Muscle Nerve, 2015

Introduction: Electrodiagnostic studies (EDX) are not performed routinely before treatment suspension in CIDP, and no data exist regarding their value in predicting clinical relapse. Methods: Serial EDX (baseline and after IGIV-C therapy) were analyzed from subjects in the ICE clinical trial who responded to IGIV-C treatment and were subsequently re-randomized to placebo in an extension phase. Comparisons were made between subjects who relapsed and those who did not. Results: A total of 55% (6/11) of the Relapse group had an increase in total number of demyelinating findings (DF) versus 8% (1/13) in the No Relapse group (P = 0.023). In the Relapse group, 100% had ≥1 new DF and 73% (8/11) had ≥4 new DF versus 60% (8/13) and 8% (1/13), respectively, in the No Relapse group. Conclusions: An increased total number of DF or the occurrence of ≥4 new DF may indicate a higher risk of clinical relapse after treatment cessation in IGIV-C-responsive patients. Muscle Nerve 52: 498–502, 2015

Introduction: The minimal clinically important difference (MCID) is the smallest outcome change that has clinical significance. Its use has not been established in the study of myasthenia gravis (MG). Methods: Patients from a published intravenous immunoglobulin (IVIg) vs. placebo study were studied. One anchor-based and 3 distribution-based techniques were used to identify quantitative myasthenia gravis score (QMGS), repetitive nerve stimulation (RNS), and single-fiber electromyography (SFEMG) MCID cut-offs. Patients with a change-score exceeding MCID cut-offs were compared. Results: MCID cut-offs were below a QMGS change of 3.0. Anchor-based and 1 × SEM cut-offs showed 58.3% vs. 30.7% responders (P = 0.017), ½ SD 54.2% vs. 19.2% responders (P = 0.018), and effect size 0.519 vs. 0.164 (P = 0.011) in IVIg vs. placebo. Anchor-based (P = 0.73) and effect-size (P = 0.41) MCID cut-offs did not show a difference between IVIg and placebo. MCID methods did not produce meaningful RNS cut-offs. Conclusions: QMGS MCID values provide clinically relevant information and are recommended in MG trials. MCID analysis shows that improvement in MG patients treated with IVIg reflects clinically meaningful changes. Muscle Nerve 49: 661–665, 2014

Introduction: Plasma exchange (PLEX) is effective in myasthenia gravis (MG), but there are concerns about its safety. Methods: We collected data prospectively from 42 patients randomized to PLEX treatment in a comparison study with intravenous immunoglobulin (IVIg). Detailed information on the PLEX treatment methodology and adverse events are reported. Results: Forty of 42 patients completed PLEX. Ninety percent were treated in an outpatient setting. Fifty-five percent had no complications, and 45% had mild–moderate reactions that did not require stopping treatment; the majority were citrate reactions and peripheral vascular issues that were easily treated. Fifty-seven percent of patients responded to treatment, and 83% completed PLEX via peripheral venous access. Two patients had severe adverse events: 1 related and 1 unrelated to PLEX. Comorbid disease and age did not predict reactions. Conclusion: PLEX is safe, effective, and well tolerated in patients with MG. Our results do not raise concerns about the safety of PLEX in patients with moderate–severe MG. Muscle Nerve 47: 510–514, 2013

Introduction: Factors determining response to intravenous immunoglobulin (IVIg) and plasmapheresis in myasthenia gravis (MG) have not been evaluated systematically. Methods: This study included patients treated with IVIg (n = 63) or plasmapheresis (n = 42) from two trials evaluating IVIg vs. placebo or plasmapheresis in MG. Response was defined as improvement in the quantitative myasthenia gravis score (QMGS) of ≥3.5 points at day 14. Baseline clinical, electrophysiological, and immunological factors were analyzed as predictors. Results: Baseline QMGS, acetylcholine receptor antibody (AChRAb) positivity, single-fiber electromyography (SFEMG) jitter, and percent abnormal pairs and percent blocking pairs were higher in responders than in non-responders. Using multivariate logistic regression, the odds ratio for response was 13.0 (1.01–381.5) in QMGS 11–17 and 15.3 (1.34–414.3) in QMGS >17 compared with QMGS

Data are lacking on correlations between changes in nerve conduction (NC) studies and treatment response in chronic inflammatory demyelinating polyneuropathy (CIDP). This report examined data from a randomized, double-blind trial of immune globulin intravenous, 10% caprylate/chromatography purified (IGIV-C [Gamunex]; n = 59) versus placebo (n = 58) every 3 weeks for up to 24 weeks in CIDP. Motor NC results and clinical measures were assessed at baseline and endpoint/week 24. Improvement from baseline in adjusted inflammatory neuropathy cause and treatment score correlated with improvement in proximally evoked compound muscle action potential (CMAP) amplitudes (r = -0.53; P < 0.001) of all nerves tested and with improvement in CMAP amplitude of the most severely affected motor nerve (r = -0.36; P < 0.001). Correlations were observed between improvement in averaged CMAP amplitudes and dominant-hand grip strength (r = 0.44; P < 0.001) and Medical Research Council sum score (r = 0.38; P < 0.001). Overall, the change in electrophysiologic measures of NC in CIDP correlated with clinical response to treatment.

Introduction: The relationship between sleep and neuromuscular fatigue is understood poorly. The goal of this study was to evaluate the effects of napping on quantitative measures of neuromuscular fatigue in patients with myasthenia gravis (MG). Methods: Eight patients with mild to moderate MG were recruited. Patients underwent maintenance of wakefulness tests (MWT) and multiple sleep latency tests (MSLT). The Quantitative Myasthenia Gravis Score (QMGS) was measured before nap and after each nap to examine the effects of napping and sleep on neuromuscular weakness. Results: Results showed that QMGS improves only after naps where patients slept more than 5 min but not where patients did not sleep or slept less than 5 min. Conclusions: Daytime napping mitigates neuromuscular fatigue in patients with MG, especially if patients slept for more than 5 min. Muscle Nerve 48:816–818, 2013

Occasional cases of peripheral neuropathy have been reported in classic mycosis fungoides. A rare variant of mycosis fungoides is the granulomatous form. We describe the occurrence of myopathy and peripheral neuropathy in a young woman who had skin lesions since the age of 12 years. At the age of 20 years they were diagnosed as granulomatous mycosis fungoides. The skin lesions resolved with interferon therapy and radiation. She then presented with cardiac and pulmonary symptoms and signs that were initially thought to be due to sarcoidosis or systemic vasculitis. A nerve and muscle biopsy showed granulomatous mycosis fungoides. To our knowledge, involvement of muscle and nerve by granulomatous mycosis fungoides has not been reported previously. Early reports suggested a favorable prognosis for the granulomatous subtype of mycosis fungoides. Based on a literature review and the course in our case, however, granulomatous mycosis fungoides seems to be an indicator of aggressive disease and ultimately a poor prognosis.

Identifying patients with diabetic peripheral neuropathy (DPN) amenable to therapy is a challenge. To determine whether the amplitude of the sural sensory nerve action potential (sural SNAP) reflects the severity of DPN, an analysis was performed on 205 patients with DPN, identified by an abnormal vibration detection threshold (VDT), who were enrolled in a multinational clinical trial investigating ruboxistaurin (RBX) mesylate. Nerve conduction velocity and response amplitude and latency were measured and compared. VDT was significantly lower in those with preserved sural SNAPs (n = 128) than in those in whom they were absent (n = 77; 21.5 vs. 22.7 JND units, P = 0.002). Thus, preserved sural SNAP denoted less severe DPN. Logistic regression analyses evaluating baseline characteristics, HbA1c, and baseline symptom scores identified only DPN duration as a factor that might contribute to the presence of sural SNAP (P = 0.004; OR = 0.896). For patients with abnormal VDT, preserved sural SNAP identifies a patient population with less severe DPN who may respond to therapeutic intervention in clinical trials. Muscle Nerve, 2005

Nerve conduction studies (NCS) in diabetic sensorimotor polyneuropathy (DSP) are sensitive, noninvasive, and associated with small coefficients of variation, and correlate well with underlying peripheral nerve morphological change. For these reasons, the current reference standard for DSP involves multivariate instruments that emphasize NCS results. However, the interside symmetry of NCS findings in different stages of DSP are unknown, although requirement for symmetry has been suggested in clinical trials of DSP. We therefore aimed to determine the degree of symmetry of NCS findings in DSP of differing severity stages. A cohort of diabetic patients, including patients without neuropathy and those with mild to severe DSP, was studied. We also studied a series of nondiabetic, healthy subjects. A variation of stratified sampling by means of a clinical neuropathy score ensured that a broad spectrum of neuropathy was studied. A total of 478 subjects was ascertained; patient accrual was discontinued when the smallest clinical group consisted of 50 subjects. Nerve conduction studies were conducted prospectively and in a blinded fashion using surface recordings, averaging for sensory action potentials, control of limb temperature, and standardized techniques. Median and ulnar motor and sensory, peroneal and tibial motor, and sural NCS were performed. Interside symmetry, independent of neuropathy severity, was observed for all investigated nerves, except for the median sensory nerve action potential amplitude, which was lower on the right side. These results confirm that abnormal NCS findings consistent with DSP are reliably symmetrical with the exception of the amplitude of the median sensory nerve action potential. Thus, unilateral evaluation of NCS in DSP is sufficient as a reference standard in clinical trials. We also conclude that great degrees of asymmetry in NCS results are reason to question inclusion of DSP patients in clinical trials.

We performed upper- and lower-limb sympathetic skin responses (SSRs) in a series of 337 diabetic patients with and without peripheral polyneuropathy and 38 reference subjects. We did not find any correlations between SSRs and symptoms of pain or autonomic dysfunction. The SSR correlated more strongly with vibration perception threshold (VPT) and sural nerve amplitude than with cooling detection threshold (CDT) or clinical symptoms. We conclude that current limitations inherent in SSR testing preclude its use as a reliable and consistent index of the autonomic dysfunction commonly encountered in diabetic patients.

Electrophysiological testing remains an important efficacy parameter in clinical neuropathy trials. The quality of nerve conduction studies in reported trials varies greatly, and may be responsible for negative results. We report the utilization of an expert core lab for electrophysiological testing. With the core lab, the variability of repeat testing is comparable to that of a single, excellent laboratory. Motor conduction velocities demonstrated a coefficient of variation of 3% and sensory conduction velocities 4% across 60 study sites. The distal motor evoked potential amplitudes varied by 13% at the ankle, and 10% at the wrist. The sensory potential amplitudes varied by 16% at the ankle, and 11% at the wrist in 60 sites. The overall monitoring rate in all submitted nerve conduction tracings was 36.6%. Our results show that an expert core lab can improve the electrophysiological quality of clinical trial data with the potential to show small changes in nerve conduction velocities and in both motor and sensory potential amplitudes.

Repetitive stimulation of the facial nerve is commonly performed in cases of suspected myasthenia gravis (MG) because bulbar weakness is often present, but the most sensitive facial muscle is unknown. We compared the sensitivity of repetitive nerve stimulation (RNS) to the frontalis and nasalis muscles in 244 patients with suspected MG. We found no difference in sensitivity of RNS when recording from these muscles in both ocular and generalized MG. In addition, we confirmed the low sensitivity of RNS for ocular (18%) or generalized (47%) MG. The specificity of facial RNS for both muscles was 100% and, in certain circumstances, may obviate the need for further diagnostic testing.

In this study we examined the value of single-fiber electromyography (SFEMG) in assessing the degree of reinnervation in diabetic patients with clinical neuropathy. Relationships between reinnervation and the degree of metabolic control, and/or duration of diabetes were examined. Thirty-six insulin-dependent diabetics and 54 non-insulin-dependent diabetics underwent SFEMG examination of the tibialis anterior muscle, as well as conventional nerve conduction studies of the upper and lower limbs. All patients examined exhibited some abnormality of SFEMG even in the presence of normal nerve conduction studies found in 18% of patients. In diabetic patients, the jitter in the tibialis anterior muscle correlated positively with glycosylated hemoglobin; whereas lower limb nerve conduction studies did not correlate with this measure of diabetic control. These data suggest that SFEMG is a sensitive measure of nerve function and reinnervation and that it may reflect the dynamic changes in metabolic status in diabetic patients.

A 21-year-old woman had myasthenic symptoms since birth that responded poorly to anticholinesterase therapy. Tests for acetylcholine receptor (AChR) antibodies were negative. An intercostal muscle specimen was obtained to investigate the character of the neuromuscular transmission defect. There were no immune deposits at the endplates. The quantal content of the endplate potential was normal. Miniature endplate potentials and currents were very small, but the number of AChR per endplate was normal. On electron microscopy, the synaptic vesicles were of normal size, the junctional folds were intact, and the density and distribution of AChR on the folds was normal. The kinetic properties of AChR were studied by analysis of acetylcholine (ACh)-induced current noise. The mean single channel conductance was normal. The noise power spectrum was abnormal, containing two components of different time course. This could result from an abnormal interaction of ACh with AChR, or from two populations of AChR at the endplate. The second possibility is unlikely because if two populations of AChR were present at the endplate, then both would have to have low conductance to explain the small miniature endplate current, but the average conductance of the channels that did open was normal. © 1993 John Wiley & Sons, Inc.

We reviewed results of immunotherapy in patients with demyelinating motor neuropathy (DMN), and found that patients over 50 years of age at onset responded poorly, and younger patients responded variably to intervention. We suggest that patients with DMN be given a guarded prognosis, particularly if >50 years of age at onset.