Palsy of Both the Tibial Nerve and Common Peroneal Nerve Caused by a Ganglion Cyst in the Popliteal Area.

A ganglion cyst is a benign mass consisting of high-viscosity mucinous fluid. It can originate from the sheath of a tendon, peripheral nerve, or joint capsule. Compressive neuropathy caused by a ganglion cyst is rarely reported, with the majority of documented cases involving peroneal nerve palsy. To date, cases demonstrating both peroneal and tibial nerve palsies resulting from a ganglion cyst forming on a branch of the sciatic nerve have not been reported. In this paper, we present the case of a 74-year-old man visiting an outpatient clinic complaining of left-sided foot drop and sensory loss in the lower extremity, a lack of strength in his left leg, and a decrease in sensation in the leg for the past month without any history of trauma. Ankle dorsiflexion and great toe extension strength on the left side were Grade I. Ankle plantar flexion and great toe flexion were Grade II. We suspected peroneal and tibial nerve palsy and performed a screening ultrasound, which is inexpensive and rapid. In the operative field, several cysts were discovered, originating at the site where the sciatic nerve splits into peroneal and tibial nerves. After successful surgical decompression and a series of rehabilitation procedures, the patient's neurological symptoms improved. There was no recurrence.

Changes in Gait Characteristics of Stroke Patients with Foot Drop after the Combination Treatment of Foot Drop Stimulator and Moving Treadmill Training.

Objective: To study the changes in gait characteristics of stroke patients with foot drop after the combination treatment of foot drop stimulator and moving treadmill training and thus provide a basis for the improvement in a foot drop gait after stroke. Methods: Sixty patients with hemiplegia and foot drop caused by stroke were randomly divided into two groups of 30: the test group and the control group. Both groups received basic rehabilitation training. On this basis, the test group received the combination treatment of foot drop stimulator and moving treadmill training. The control group received foot drop stimulator training. Both groups received consecutive treatment for 3 weeks, five times a week, and every single time lasted for 30 minutes. Before and after the treatment, a gait watch three-dimensional gait analysis system was used to measure and record the maximum angles of flexion of the affected side's hip, knee, and ankle; the pace; the step length asymmetry; the iEMG of the tibialis anterior muscle; the functional ambulation category; and Ashworth's modified spasticity classification of the gastrocnemius. Results: After treatment, in the two groups, the maximum angles of flexion of the affected side's hip, knee, and ankle improved, the pace increased, the step length asymmetry decreased, the iEMG of the tibialis anterior muscle increased, the functional ambulation category improved, and Ashworth's modified spasticity classification of the gastrocnemius decreased, but the above changes in the test group were better than those in the control group. The difference is statistically significant (p < 0.05). Conclusions: The combination treatment of the foot drop stimulator and moving treadmill can significantly improve stroke patients' foot gait and promote the normalization of hip flexion, knee flexion, and ankle flexion. It can increase the pace, significantly reduce the step length asymmetry, reduce the muscle tone of the gastrocnemius, and improve walking function.

Characterization of mononeuropathy of the lateral cutaneous nerve of the calf.

INTRODUCTION/AIMS: Isolated injuries to the lateral cutaneous nerve of the calf (LCNC) branch of the common peroneal nerve can cause obscure chronic posterolateral knee and upper calf pain and sensory symptoms. Routine examination and electrodiagnostic testing do not detect them because the LCNC has no motor distribution and it is not interrogated by the typical peroneal nerve conduction study. There are only about 10 prior cases, thus scant physician awareness, so most LCNC injuries remain misdiagnosed or undiagnosed, hindering care. METHODS: We extracted pertinent records from seven patients with unexplained posterolateral knee/calf pain, six labeled as complex regional pain syndrome, to investigate for mononeuropathies. Patients were asked to outline their skin area with abnormal responses to pin self-examination independently. Three underwent an LCNC-specific electrodiagnostic study, and two had skin-biopsy epidermal innervation measured. Cadaver dissection of the posterior knee nerves helped identify potential entrapment sites. RESULTS: Initiating events included knee surgery (three), bracing (one), extensive kneeling (one), and other knee trauma. All pin-outlines included the published LCNC neurotome. One oftwo LCNC-specific electrodiagnostic studies revealed unilaterally absent potentials. Longitudinal, controlled skin biopsies documented profound LCNC-neurotome denervation then re-innervation contemporaneous with symptom recovery. Cadaver dissection identified the LCNC traversing through the dense fascia of the proximolateral gastrocnemius muscle insertion. DISCUSSION: Isolated LCNC mononeuropathy can cause unexplained posterolateral knee/calf pain syndromes. This series characterizes presentations and supports patient pin-mappings as a sensitive, globally available, low-cost diagnostic aid. Improved recognition may facilitate more rapid, accurate diagnosis and, thus, optimize management and improve outcomes.

Large Mitochondrial DNA Deletions in HIV Sensory Neuropathy.

OBJECTIVE: The primary objective of this study was to evaluate the correlation of large mitochondrial DNA (mtDNA) deletions in skin samples of people with HIV (PWH) with measures of neuropathy and prior exposure to therapy. We hypothesized that deletions would be associated with neuropathy. As secondary objectives, we determined the correlation of deletion burden with demographic data and neuropathy measures. METHODS: In this retrospective cohort study, we measured the accumulation of large mtDNA deletions in skin biopsies from PWH recruited as part of the AIDS Clinical Trials Group (ACTG). Our cohort includes individuals with and without sensory neuropathy, as well as individuals with normal or abnormal skin biopsies. Skin biopsies, sural and peroneal nerve conduction studies, total neuropathy score, and deletion burden scores were measured, along with baseline demographic data such as age, CD4+ cell count, viral counts, and prior nucleoside reverse transcriptase inhibitor exposures. RESULTS: Sixty-seven PWH were enrolled in the study. The mean age of the cohort (n = 67) was 44 years (SD 6.8, range 32-65 years), and 9 participants were female. The mean CD4+ T-cell count was 168 cells/mm3 (SD 97 cells/mm3, range 1-416 cells/mm3) and mean viral load was 51,129 copies/mL (SD 114,586 copies/mL, range 147-657,775 copies/mL). We determined that there was a correlation between the total mtDNA deletion and intraepidermal nerve fiber density (IENFD) (r = -0.344, p = 0.04) and sural nerve amplitude (r = -0.359, p = 0.004). CONCLUSIONS: Both IENFD and sural nerve amplitude statistically correlate with mitochondrial mutation burden in PWH, specifically in those with HIV-associated sensory neuropathy as assessed by skin biopsy.

Lumbosacral plexopathy due to pelvic hematoma after extracorporeal membrane oxygenation: A case report.

RATIONALE: Peripheral nerve injury related to vascular complications associated with extracorporeal membrane oxygenation (ECMO) is perhaps underappreciated. Compared to the well-described central nervous system complications of ECMO, brachial plexopathy and lumbosacral plexopathy have rarely been reported. We report this case to heighten awareness of lumbosacral plexus injury due to pelvic hematoma formation after ECMO. PATIENT CONCERNS: A 53-year-old woman developed a large pelvic hematoma with significant mass effect on intrapelvic structures after receiving lifesaving venoarterial ECMO for cardiogenic shock following a cardiac arrest. During her hospital course, she developed bilateral foot drop that was attributed to critical illness. Her lack of neurological recovery after 6 months prompted referral to neuromuscular medicine for consultation. DIAGNOSIS: The patient was retrospectively diagnosed with bilateral lumbosacral plexopathy due to the large pelvic hematoma. INTERVENTION: Electromyography/nerve conduction study (EMG/NCS) obtained at the time of referral to neuromuscular medicine localized her neurological deficits to the bilateral lumbosacral plexus and demonstrated no volitional motor unit action potentials in her lower leg muscles. OUTCOMES: The patient had minimal recovery of strength at the level of the ankles but was ambulatory with solid ankle-foot orthoses due to spared proximal lower extremity strength. Unfortunately, the absence of any volitionally activated motor unit action potentials in her lower leg muscles on EMG performed 6 months after the initial injury was a poor prognostic indicator for successful reinnervation and future neurological recovery. LESSONS: Neurological deficits occurring during the course of administration of ECMO require accurate localization. Neurology consultation and/or EMG/NCS may be useful if localization is not clear. Lesions localizing to the lumbosacral plexus should prompt radiographic evaluation with computed tomography of the abdomen and pelvis. Hemostasis of a retroperitoneal hematoma may be achieved with embolization. However, if neurological deficits do not improve, surgical consultation for hematoma evacuation may be warranted.

Recovery of foot drop in chronic inflammatory demyelinating polyneuropathy (CIDP).

INTRODUCTION/AIMS: Foot drop is common in chronic inflammatory demyelinating polyneuropathy (CIDP), but its prognosis is uncertain. METHODS: CIDP patients with less than anti-gravity strength (<3/5 power) of ankle dorsiflexion (ADF) on Medical Research Council manual muscle testing on presentation at our center were identified by retrospective review. After initiation of standard treatment, ADF power was serially tabulated, and predictors of recovery were determined. RESULTS: Of the 27 identified patients, ADF power at presentation was <3/5 in 48/54 legs. At 1 y after treatment, ADF power improved to >/= 3/5 in 17/27 patients in one (N = 6) or both (N = 11) legs. On multi-variate analysis, predictors of recovery of ADF power were tibialis anterior compound muscle action potential amplitude at presentation, shorter disease duration, and female gender. DISCUSSION: Foot drop improves to anti-gravity power in most treated CIDP patients depending in part on the severity of fibular motor axon loss at onset of treatment.

A rare case of parasagittal meningioma causing isolated foot drop: case report and review of the literature.

Foot drop represents a very common reason for a neurologist referral and is often first seen in emergency departments or by a general practitioner. This condition is defined as weakness of ankle dorsiflexion (mainly through tibialis anterior muscle weakness). The most common causes include lower motor neuron lesion, with L4-L5 radiculopathy and peroneal neuropathy being the most frequent ones. Classical diagnostic pathway includes a thorough medical history, detailed neurological examination, radiological studies (MRI of the lumbosacral spine), EMG and nerve conduction studies, and a battery of laboratory tests. The absence of abnormal radiological and neurophysiological findings when searching for the most common causes of foot drop, should raise a red flag and broaden the diagnostic yield for central nervous system pathology (upper motor neuron, UMN) as a possible cause of foot drop. Central causes of isolated foot drop are very rare, with less than 20 cases reported in literature so far, and seven of them being a meningioma. We present a case of a 79-year-old female patient with an isolated foot drop (with no UMN signs on the initial examination) and parasagittal meningioma. Central causes of foot drop should be suspected when foot drop is associated with UMN signs on examination (hyperreflexia of the patellar or ankle jerk and extensor plantar reflex) and when standard diagnostic work-up (MRI of the lumbar spine, EMG and NCS, standard laboratory screening for most common causes of foot drop) is negative or inconclusive. Although very rare, central lesions present a far more serious cause of foot drop and require a more urgent diagnostic work up and a potential neurosurgical referral and treatment. Keeping in mind the possible central causes of foot drop would eliminate unnecessary diagnostic work up and avoid delayed diagnosis and treatment.

Proximal fibular nerve conduction studies to tibialis anterior: Optimal E2 (reference electrode) placement.

BACKGROUND: Several E2 (reference electrode) positions are described for fibular (peroneal) nerve conduction studies to tibialis anterior (TA). METHODS: This study compared the contribution of different E2 sites to the TA motor response, using remote referential recordings and different bipolar montages. RESULTS: The medial knee contributes minimal electrical activity to the bipolar TA recordings, whereas tibial, ankle, and toe references resulted in very similar, moderate amplitude contributions consistent with far field potentials. These observations were very similar in controls and in patients with lower leg symptoms and signs. CONCLUSIONS: Standard montages using distal leg or foot E2 sites result in lower amplitudes with distortion arising from the E2 electrode, compared with the TA-Knee montage. Optimal measurement of the TA motor response is achieved using a medial knee reference, without compromising measures of fibular nerve conduction across the knee.

Nicolau Syndrome, Masquerader of Postinjection Sciatic Nerve Injury: Case Report and Review of Literature.

BACKGROUND: Sciatic nerve injury after inadvertent intramuscular gluteal injection is a well-described entity. We have presented a case of a rare and probably underdiagnosed pathological entity, Nicolau syndrome, which can be confused with injection palsy. CASE DESCRIPTION: We report the case of a 13-year-old boy who had presented with foot drop and urinary and fecal incontinence after an intramuscular injection of benzathine penicillin in the left gluteal region. On examination, the patient had multiple ecchymoses over the left gluteal region and back of the thigh, mild swelling of the left lower limb, and left foot drop. Meticulous examination also revealed a subtle weakness of the opposite limb. Nerve conduction studies revealed axonopathy involving multiple bilateral lower limb nerves. These unusual neurological-dermatological signs and electrophysiological findings raised the concern for an alternative pathology, which was later diagnosed as Nicolau syndrome. The patient experienced clinical and electrophysiological recovery after a course of oral steroids and physiotherapy during the next few months. CONCLUSIONS: Before diagnosing injection sciatic nerve injury, the possibility of medically treatable Nicolau syndrome should be considered. Neurosurgeons' familiarity with this pathology and a timely diagnosis is essential to plan appropriate treatment strategies.

Identifying Common Peroneal Neuropathy before Foot Drop.

BACKGROUND: Common peroneal neuropathy shares the same pathophysiology as carpal tunnel syndrome. However, management is often delayed because of the traditional misconception of recognizing foot drop as the defining symptom for diagnosis. The authors believe recognizing common peroneal neuropathy before foot drop can relieve pain and help improve quality of life. METHODS: One hundred eighty-five patients who underwent surgical common peroneal neuropathy decompression between 2011 and 2017 were included. The mean follow-up time was 249 ± 28 days. Patients were classified into two stages of severity based on clinical presentation: pre-foot drop and overt foot drop. Demographics, presenting symptoms, clinical signs, electrodiagnostic studies and response to surgery were compared between these two groups. Multivariate regression analysis was used to identify variables that predicted outcome following surgery. RESULTS: Overt foot drop patients presented with significantly lower preoperative motor function (percentage of patients with Medical Research Council grade ≤ 1: overt foot drop, 90 percent; pre-foot drop, 0 percent; p < 0.001). Pre-foot drop patients presented with a significantly higher preoperative pain visual analogue scale score (pre-foot drop, 6.2 ± 0.2; overt foot drop, 4.6 ± 0.3; p < 0.001) and normal electrodiagnostic studies (pre-foot drop, 31.4 percent; overt foot drop, 0.1 percent). Postoperatively, both groups of patients showed significant improvement in quality-of-life score (pre-foot drop, 2.6 ± 0.3; overt foot drop, 2.7 ± 0.3). Patients with obesity or a traumatic cause for common peroneal neuropathy were less likely to have improvements in quality of life after surgical decompression. CONCLUSION: Increased recognition of common peroneal neuropathy can aid early management, relieve pain, and improve quality of life. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

(Cost-)effectiveness of lower extremity nerve decompression surgery in subjects with diabetes: the DeCompression (DECO) trial-study protocol for a randomised controlled trial.

INTRODUCTION: The peripheral nerves of patients with diabetes are often pathologically swollen, which results in entrapment at places of anatomical narrowing. This results in nerve dysfunction. Surgical treatment of compression neuropathies in the lower extremities (lower extremity nerve decompression (LEND)) results in relief of symptoms and gain in peripheral nerve function, which may lead to less sensory loss (short term) and less associated detrimental effects including foot ulceration and amputations, and lower costs (long term). The aim of the DeCompression trial is to evaluate the effectiveness and (cost-)effectiveness of surgical decompression of compressed lower extremity nerves (LEND surgery) compared with patients treated with conventional (non-surgical) care. METHODS AND ANALYSIS: A stratified randomised (1 to 1) controlled trial comparing LEND surgery (intervention) with conventional non-surgical care (control strategy) in subjects with diabetes with problems of neuropathy due to compression neuropathies in the lower extremity. Randomisation is stratified for participating hospital (n=11) and gender. Patients and controls have the same follow-up at 1.5, 3, 6, 9, 12, 18, 24 and 48 months. Participants (n=344) will be recruited in 12 months and enrolled in all affiliated hospitals in which they receive both the intervention or conventional non-surgical care and follow-up. Outcome assessors are blinded to group assignment. PRIMARY OUTCOME: disease-specific quality of life (Norfolk Quality of Life Questionnaire-Diabetic Neuropathy). SECONDARY OUTCOMES: health-related quality of life (EuroQoL 5-dimension 5-level (EQ-5D5L), 36-item Short Form (SF-36)), plantar sensation (Rotterdam Diabetic Foot Test Battery), incidence of ulcerations/amputations, resource use and productivity loss (Medical Cost Questionnaire, Productivity Cost Questionnaire) during follow-up. The incremental cost-effectiveness ratio will be estimated on the basis of the collected empirical data and a cost-utility model. ETHICS AND DISSEMINATION: Ethics approval has been granted by the Medical Research Ethics Committee of Utrecht University Medical Center (reference: NL68312.041.19v5, protocol number: 19-335/M). Dissemination of results will be via journal articles and presentations at national and international conferences. TRIAL REGISTRATION NUMBER: NetherlandsTrial Registry NL7664.

Application value of conventional ultrasound and real-time shear wave elastography in patients with type 2 diabetic polyneuropathy.

PURPOSE: To explore the application value of conventional ultrasound and real-time shear wave elastography (SWE) to the tibial nerve (TN) and the common peroneal nerve (CPN) in diabetic peripheral neuropathy (DPN). MATERIALS AND METHODS: Thirty-three healthy volunteers, 33 diabetic patients without DPN, and 30 diabetic patients with DPN were enrolled in this study. The anteroposterior diameter (APD), the cross-sectional area (CSA), and the perimeter of the TN and the CPN were measured by conventional ultrasound, and the stiffness of the nerves was measured by SWE. RESULTS: The conventional ultrasound parameters and stiffness of the TN in patients with DPN were significantly larger than those of the other two groups (P < 0.01). The conventional ultrasound parameters of the CPN were significantly higher in patients with DPN than in the other two groups (P < 0.01).The patients with DPN demonstrated a greater stiffness of the CPN compared to the control group (P < 0.05). The comparison of all parameters for the left and right TNs and CPNs among the three groups showed no significant difference. The area under the curve (AUC) of TN stiffness for the diagnosis of DPN was significantly greater than that of conventional ultrasound parameters. CONCLUSION: The conventional ultrasound parameters and the stiffness of the TN and the CPN were significantly higher in patients with DPN. The stiffness of the TN could better diagnose DPN than conventional ultrasound parameters. In short, conventional ultrasound and SWE of nerves are of good application value in the diagnosis of DPN.

Isolated Nerve Grafting for a Young Patient with a Complete Common Peroneal Nerve Palsy Following a Traumatic Knee Dislocation: A case report.

BACKGROUND: Common peroneal nerve (CPN) injury following a knee dislocation is a serious problem, and an optimal treatment is yet to be established. We report a case of complete CPN palsy following a knee dislocation treated with sural nerve grafting. CASE: A 19-year-old man suffered a knee injury during a hurdle race. Diagnosis in a previous hospital revealed a complex ligament injury with CPN palsy. Ten weeks following injury, he was admitted to our institution because of a lack of neurological improvement. Considering the grade 0 results obtained in the manual muscle test (MMT) of tibialis anterior (TA) and extensor hallucis longus (EHL), the patient was diagnosed with complete neurotmesis of CPN, and surgery was performed. Operative findings revealed CPN discontinuity and an extended nerve defect length of 15 cm; therefore, sural nerve grafting was performed to repair the CPN injury. One year postoperatively, a grade 1 result from MMT of TA and EHL indicated a gradual neurological recovery. Three years postoperatively, MMT of TA and EHL showed significant improvement to grade 4+ and grade 4, respectively, and he could walk and jog without a knee brace. DISCUSSION: Nerve graft length of >6 cm has shown limited success, and their efficacy for the treatment of CPN palsy following knee dislocations is controversial. However, young patients with complete CPN lesion are more likely to recover regardless of the length of nerve injury. Therefore, in such cases, nerve grafting can be considered as one of the treatments for complete CPN lesion following knee dislocations.

Proteomic analysis of synaptic protein turnover in the anterior cingulate cortex after nerve injury.

Synaptic proteins play an important role for the regulation of synaptic plasticity. Numerous studies have identified and revealed individual synaptic protein functions using protein overexpression or deletion. In neuropathic pain nociceptive stimuli conveyed from the periphery repetitively stimulate neurons in the central nerve system, brain and spinal cord. Neuronal activities change the turnover (synthesis and degradation) rate of synaptic proteins. Thus, the analysis of synaptic protein turnover rather than just expression level change is critical for studying the role of synaptic proteins in synaptic plasticity. Here, we analyzed synaptosomal proteome in the anterior cingulate cortex (ACC) to identify protein turnover rate changes caused by peripheral nerve injury. Whereas PKCγ levels were not altered, we found that the protein's turnover rate decreased after peripheral nerve injury. Our results suggest that postsynaptic PKCγ synthesized by neuronal activities in the ACC is translocated to the postsynaptic membrane with an extended half-life.

Great toe drop following knee ligament reconstruction: A case report.

Case Description: A 17-year-old male post anterior cruciate ligament reconstruction complained of the inability to extend his great toe immediately following surgery. Background: Neurological injuries following knee arthroscopy have been reported to occur between 0.6%-2.5%. The most commonly injured nerves are the saphenous and common fibular nerve (CFN). Great toe-drop secondary to isolated denervation of the extensor hallucis longus (EHL), has only been reported one time in the literature. This report describes a case of isolated denervation of the EHL following knee cruciate ligament reconstruction. A detailed description of the anatomy of the CFN is reviewed as well as how electroneuromyographic (EMG/NCS) testing can assist in the diagnosis, prognosis, and intervention of this type of injury. Outcomes: EHL paralysis did not functionally limit the patient from participating in a post-surgical rehabilitation regime. The patient successfully completed his ACL reconstruction rehabilitation and was released to return to sporting activities 9 months postsurgery. Twelve months post-surgery, the patient regained full great toe extension and strength. Discussion: It is important to note that physical therapists can identify the need for, refer, and in some instances perform EMG/NCS testing on patients with neuromuscular disorders. Isolated injury of the CFN branch that innervates the EHL is extremely rare. Understanding the anatomy of the CFN and its branches is critical for the physical therapist when performing an examination and interpreting the findings. It is also important to understand the potential causes and management approaches following this type of injury.

Foot drop following primary total hip arthroplasty.

INTRODUCTION: Foot drop is a potentially debilitating complication following injury to the sciatic nerve during primary total hip arthroplasty (THA). The aim of this study was to determine the incidence, risk factors and outcome of this complication within one large surgical practice. METHODS: We analysed the records of 10,624 primary THAs carried out between January 1993 and November 2017 using a posterior approach. All were under the care of the senior author. RESULTS: Overall, there were 47 cases (0.44%) of foot drop, but over time the incidence dropped from 0.6% to 0.3% (p = 0.033). Preoperative protrusio acetabulae (p < 0.001), female sex (p < 0.001) and junior grade of surgeon (p < 0.009) were all significant risk factors. In this series, dysplasia was not a risk factor. 1 year postoperatively, 25 (53.2%) had complete recovery, 12 (25.5%) had ongoing sensory deficit but normal power, and 10 (21.3%) had a residual sensory-motor deficit. CONCLUSION: Take home message:- In this series, protrusio acetabulae, female sex and junior grade of surgeon were significant risk factors for foot drop following primary THA.

Muscle velocity recovery cycles in neurogenic muscles.

OBJECTIVE: To examine muscle membrane properties in neurogenic muscles using Muscle Velocity Recovery Cycles (MVRCs). METHODS: Forty-seven patients referred to Nerve Conduction Studies (NCS) and Electromyography (EMG) for peroneal nerve entrapment neuropathy were prospectively included. The patients were categorized as peroneal nerve entrapment neuropathy across knee (n = 22), L5-radiculapathy (n = 10), normal NCS/EMG (n = 9) and other disorders (n = 6) using NCS/EMG and neuroimaging results. Strength in anterior tibial muscle was measured by Medical Council Scale (MRC) and disease duration was recorded. In addition to conventional NCS/EMG, all subjects were examined with MVRCs in anterior tibial muscle. This provided parameters of muscle relative refractory period (MRRP) and early supernormality (ESN) and late supernormality (LSN). The results were compared with 29 age-matched healthy control subjects. RESULTS: MRRP was prolonged and ESN and LSN were reduced in neurogenic muscles. MRRP, ESN and LSN correlated to MRC and incidence of spontaneous activity but not to motor unit potential parameters or disease duration. CONCLUSIONS: MVRC changes provide in vivo evidence of depolarization in intact human muscle fibres that could underlie reduced muscle excitability and hence weakness in neurogenic muscles. SIGNIFICANCE: MVRCs appear to be a useful technique for revealing disease mechanism in a broad range of neuromuscular diseases.