Contrasting echogenicity in flexor digitorum profundus–flexor carpi ulnaris: A diagnostic ultrasound pattern in sporadic inclusion body myositis

Introduction: In this study we aimed to clarify whether muscle ultrasound (US) of the forearm can be used to differentiate between patients with sporadic inclusion body myositis (s‐IBM) and those with s‐IBM–mimicking diseases. Methods: We compared the echo intensity (EI) of the flexor digitorum profundus (FDP) muscle and the flexor carpi ulnaris (FCU) muscles in patients with s‐IBM (n = 6), polymyositis/dermatomyositis (PM/DM; n = 6), and amyotrophic lateral sclerosis (ALS; n = 6). Results: We identified EI abnormalities in 100% of patients with s‐IBM, 33% of those with PM/DM, and 33% of those with ALS. An “FDP–FCU echogenicity contrast,” a US pattern involving a higher EI in the FDP than in the FCU, was observed in all patients with s‐IBM, but in none of those with PM/DM or ALS. Conclusions: FDP–FCU echogenicity contrast in muscle US is a sensitive diagnostic indicator of s‐IBM. Muscle Nerve 49 : 745–748, 2014     

Electromyographs of the flexor digitorum profundus muscle are useful for the diagnosis of inclusion body myositis

Introduction: The frequent observation of high‐amplitude and long‐duration motor unit potentials (MUPs) in inclusion body myositis (IBM) is problematic, because it may lead to a misdiagnosis of amyotrophic lateral sclerosis (ALS). Objective: To document the diagnostic utility of EMG from the flexor digitorum profundus (FDP) muscle for IBM. Methods: Quantitative analyses of MUP parameters were performed in the FDP and biceps brachii (BB) muscles from 7 biopsy‐confirmed IBM patients. Results: In the FDP muscle, all MUP parameters were significantly decreased in IBM patients, which indicated the predominance of low‐amplitude and short‐duration MUPs in this muscle. In the BB muscle, most parameters were increased, suggesting the frequent contamination of high‐amplitude and long‐duration MUPs. Conclusions: Low‐amplitude MUPs in the FDP muscle indicate the presence of an advanced myopathy in this muscle that was extremely weak for all subjects. Examining the FDP muscle would reduce the chance of misdiagnosing IBM as ALS. Muscle Nerve 46: 181–186, 2012     

Peripheral nerve ultrasound in amyotrophic lateral sclerosis phenotypes

Introduction: In this study we sought to determine the cross‐sectional area (CSA) of peripheral nerves in patients with distinct subtypes of amyotrophic lateral sclerosis (ALS). Methods: Ulnar and median nerve ultrasound was performed in 78 ALS patients [classic, n = 21; upper motor neuron dominant (UMND), n = 14; lower motor neuron dominant (LMND), n = 20; bulbar, n = 15; primary lateral sclerosis (PLS), n = 8] and 18 matched healthy controls. Results: Compared with controls, ALS patients had significant, distally pronounced reductions of ulnar CSA (forearm/wrist level) across all disease groups, except for PLS. Median nerve CSA (forearm/wrist level) did not differ between controls and ALS. Conclusion: Ulnar nerve ultrasound in ALS subgroups revealed significant differences in distal CSA values, which suggests it has value as a marker of LMN involvement. Its potential was particularly evident in the UMND and PLS groups, which can be hard to separate clinically, yet their accurate separation has major prognostic implications. Muscle Nerve 51 :669–675, 2015     

A pilot study of neuromuscular ultrasound as a biomarker for amyotrophic lateral sclerosis

Introduction: This study explores the reliability and responsiveness of neuromuscular ultrasound in amyotrophic lateral sclerosis (ALS). Methods: Investigations were conducted with 10 healthy controls, 10 patients with ALS (single point in time), and 10 different patients with ALS (followed over 6 months; 4 completed follow-up). Ultrasound was used to measure the thickness of the geniohyoid, bilateral biceps/brachialis, bilateral tibialis anterior, and bilateral hemidiaphragms (at inspiration and expiration). Interrater and intrarater reliability and change in muscle thickness over 6 months were measured. Results: Interrater correlation coefficients ranged between 0.80 and 0.99 in healthy controls and between 0.78 and 0.97 in patients with ALS. Intrarater correlation coefficients ranged between 0.83 and 0.98 in healthy controls. The mean percentage decline in muscle thickness over 6 months was 20.25%. Discussion: Muscle ultrasound appears to be a reliable technique for measuring important muscles in patients with ALS. Larger studies with age-matched controls should be conducted to assess further the responsiveness of this biomarker in ALS. Muscle Nerve 59 :181–186, 2019     

Intermuscular coherence in amyotrophic lateral sclerosis: A preliminary assessment

Introduction: Simple laboratory tests of upper motor neuron involvement in amyotrophic lateral sclerosis (ALS) are not available. Intermuscular coherence has been shown to distinguish patients with primary lateral sclerosis, a pure upper motor neuron disorder, from normal subjects, suggesting it could be useful for assessing ALS. We aimed to determine whether intermuscular coherence can distinguish ALS patients from normal subjects. Methods: We measured biceps brachii and brachioradialis activity using surface electromyography while subjects held the elbow at flexion and the forearm in semipronation. Intermuscular coherence was calculated at between 20 and 40 Hz in 15 ALS patients and 15 normal subjects. Results: On average, intermuscular coherence was 3.8‐fold greater in normal subjects than in ALS patients (P < 0.01), and it distinguished ALS patients from normal subjects with a sensitivity of 87% and specificity of 87%. Conclusion: Intermuscular coherence measurement is a rapid, painless method that may detect upper motor neuron dysfunction in ALS. Muscle Nerve 55 : 862–868, 2017     

Further observations on forearm flexor weakness in inclusion body myositis

In order to further characterize and provide a possible mechanism for the asymmetrical involvement of forearm muscles in inclusion body myositis (IBM), we measured isometric hand and pinch grip strength, and forearm muscle girth on 15 IBM patients. Forearm muscle strength and girth were significantly greater on the dominant versus nondominant side: mean grip strength, 173.9 vs. 98.8 N; mean pinch strength, 47.6 vs. 29.7 N; and mean forearm girth, 22.5 vs. 19.9 cm. This observation may suggest a role for exercise in delaying the disease progression in IBM. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21:659–661, 1998.     

Magnetic resonance imaging pattern recognition in sporadic inclusion‐body myositis

Introduction: In sporadic inclusion‐body myositis (IBM), additional tools are needed to confirm the diagnosis, particularly in clinically atypical or pathologically unproven patients. The aims of this study were to define the pattern of muscle MRI in IBM and to assess its accuracy in differentiating IBM from other myopathies that overlap with it clinically or pathologically. Methods: Blind assessment was done on the scans of 17 definite IBM, 2 possible IBM, and 118 patients with other myopathies. Results: The diagnostic accuracy to detect definite IBM was 95% for the typical pattern (with 100% specificity) and 97% for both typical and consistent patterns (with 97% specificity). Conclusions: Muscle MRI is an accurate tool for diagnostic work‐up of suspected IBM patients and may be particularly helpful in patients with early disease or who lack the classical IBM pathology. Muscle Nerve 52 : 956–962, 2015     

Dynamic sonographic measurements at the carpal tunnel inlet: Reliability and reference values in healthy wrists

Introduction: Reliability and reference values are not well‐established for most dynamic sonographic measurements of the median nerve (MN) and flexor tendons that may be used for diagnosing carpal tunnel syndrome (CTS). Methods: Wrists of 20 healthy participants were imaged using ultrasound. Cines of the carpal tunnel inlet were acquired during hand motion. Based on shape and displacement measurements, intra‐ and interrater reliability and reference values were calculated. Results: Intraclass correlation coefficients (ICCs) for measurements of the MN and most flexor tendons were ≥0.51 for shape parameters and ≥0.71 for displacement parameters. During motion, the MN flattened with ulnar movement, tendons became more circular, and flexor tendons of corresponding fingers moved toward each other. Conclusion: Shape and displacement measurements of the MN and most flexor tendons had reliability results ranging from moderate to excellent. The reference values may be useful for the diagnosis of CTS. Muscle Nerve 48 : 525–531, 2013     

Quantifying disease progression in amyotrophic lateral sclerosis using peripheral nerve sonography

Introduction: In this study we investigated whether peripheral nerve sonography could be used as a biomarker to monitor disease progression in amyotrophic lateral sclerosis (ALS). Methods: In 37 patients, ulnar and median nerve cross‐sectional area (CSA) was determined in at least 2 ultrasound sessions; mean follow‐up was 14.5 months. Linear mixed‐effects models were conducted to analyze time effects on CSA. Results: Ulnar nerve CSA declined significantly at a monthly rate of –0.04 mm² (forearm) and –0.05 mm² (wrist); the decrease was more pronounced when baseline CSA was greater. To detect a 50% treatment effect on ulnar nerve CSA, 332 patients would need to be entered in a hypothetical randomized, controlled clinical trial. Time had no significant impact on median nerve CSA. Conclusions: Distal ulnar nerve ultrasound may be a useful biomarker to monitor disease progression in ALS, especially as hypothetical treatment effects on CSA seem to be detectable in manageable cohort sizes. Muscle Nerve 54 : 391–397, 2016     

Ultrasonographic assessment of longitudinal median nerve and hand flexor tendon dynamics in carpal tunnel syndrome

Introduction: Changes in subsynovial connective tissue (SSCT) in carpal tunnel syndrome (CTS) patients may result in altered dynamics; consequently, quantification of these dynamics might support objective diagnosis of CTS. Methods: We measured and compared longitudinal excursion of the flexor digitorum superficialis and profundus tendons, the median nerve, and the SSCT between the most and least affected hands of 51 CTS patients during extension‐to‐fist motion. Results: Median nerve and flexor digitorum superficialis tendon excursions in the most affected hands were smaller than in the least affected hands of the same patients, whereas the excursions of the flexor digitorum profundus were larger. Based on these excursions, logistic regression models classified between 67% and 86% of the hands correctly as having CTS. Conclusions: The altered hand dynamics in CTS patients may have implications for the pathophysiology and clinical evaluation of CTS, and ultrasound‐based classification models may further support the diagnosis of CTS. Muscle Nerve, 2012     

High‐resolution ultrasound visualization of the subcutaneous nerves of the forearm: A feasibility study in anatomic specimens

Introduction: The aim of this ultrasound‐anatomical study was to evaluate the ability of high‐resolution ultrasound (HRUS) to visualize and infiltrate small subcutaneous nerves of the forearm in anatomic specimens. Methods: Seven nonembalmed human bodies (4 men, 3 women; mean age at death, 60 years) were included in the study. Two investigators scanned the anatomic specimens using 15‐MHz and 18‐MHz HRUS transducers. The lateral, medial, and posterior antebrachial cutaneous nerves were scanned and interventionally marked with ink using HRUS‐guidance. Subsequently, dissections were performed to assess the anatomical correlation of HRUS findings. Results: All 3 nerves were identified consistently using HRUS. The precision of the ink‐markings was excellent, with good correlation with the small peripheral branches of all 3 nerves. Conclusions: HRUS can identify precisely the small subcutaneous nerves of the forearm and may aid in both diagnosis and therapy in cases of neuropathy. Muscle Nerve 49 : 676–679, 2014     

Median nerve ultrasound in diabetic peripheral neuropathy with and without carpal tunnel syndrome

Introduction: Median nerve ultrasound shows increased cross‐sectional area (CSA) in carpal tunnel syndrome (CTS) and diabetic peripheral neuropathy (PN). The role of ultrasound in diagnosing CTS superimposed on diabetic PN is unknown. The objective of this study is to evaluate ultrasound for diagnosis of CTS in diabetic PN. Methods: Prospective recruitment of diabetics with electrodiagnostically proven PN, subdivided into cases (with CTS) or controls (without CTS). The gold standard for CTS was clinical diagnosis. NCS were correlated with blinded median nerve CSA ultrasound measurements. Results: Eight cases (CTS) and eight controls (no CTS) were recruited. Nerve conduction studies (NCS): Median nerve distal latencies (antidromic sensory; palmar; lumbrical motor; and lumbrical motor to ulnar interosseous difference) were significantly prolonged in CTS cases. No ultrasound measurement (distal median CSA, wrist‐forearm ratio, wrist‐forearm difference) reached significance to detect CTS. Area under the curve was greatest for lumbrical distal latency by receiver operator characteristic analysis (0.85). Conclusions: In this pilot study, NCS may be superior to ultrasound for identification of superimposed CTS in diabetic PN patients, but larger numbers are needed for confirmation. Muscle Nerve 47: 437–439, 2013     

Inclusion‐body myositis presenting with facial diplegia

Introduction: The hallmark clinical presentation of inclusion‐body myositis (IBM) is slowly progressive weakness that characteristically affects the quadriceps and finger and wrist finger flexor muscles. Facial weakness can also occur, but it is typically mild and not a prominent finding. Methods: We describe the clinical features, laboratory investigations, and muscle biopsy findings in a 58‐year old man who presented with a 6‐year history of marked progressive symmetrical facial weakness. Examination also showed shoulder abduction and hip extensor weakness. Results: The patient's serum creatine kinase level was 655 U/L, and electromyography showed fibrillation potentials and myopathic motor unit potentials. A biopsy specimen of the left biceps muscle was pathognomonic for IBM. Conclusions: This patient did not have a typical presentation for IBM but rather fulfilled the pathological criteria for IBM. To our knowledge, facial diplegia has not been reported previously as a presenting manifestation of IBM. Muscle Nerve 49 : 287–289, 2014     

ULTRASOUND IN THE DIAGNOSIS AND MONITORING OF AMYOTROPHIC LATERAL SCLEROSIS: A REVIEW

Neuromuscular ultrasound is complementary to electrodiagnostic (EDx) testing and is useful in enhancing the diagnosis of mononeuropathies, peripheral nerve trauma, and demyelinating polyneuropathies. There is increasing interest in using ultrasound both to aid in the diagnosis of amyotrophic lateral sclerosis (ALS) and to monitor its progression. In this article we review the relevant literature on ultrasound in ALS. Ultrasound is more sensitive than EDx in identifying fasciculations in patients with ALS. It can detect decreased muscle thickness, increased muscle echointensity and echovariance, and reduced peripheral nerve size in these patients. Ultrasound is also a helpful tool in assessment of diaphragm function. Although additional studies are required to define the exact role of ultrasound in the evaluation and monitoring of ALS, it can improve the diagnostic yield in patients when ALS is suspected, but insufficiently supported, by clinical and EDx examinations. Muscle Nerve 60 : 114–123, 2019     

Differential involvement of forearm muscles in ALS does not relate to sonographic structural nerve alterations

Objective

We aimed to assess whether differential peripheral nerve involvement parallels dissociated forearm muscle weakness in amyotrophic lateral sclerosis (ALS).

Median nerve ultrasound as a screening tool in carpal tunnel syndrome: Correlation of cross‐sectional area measures with electrodiagnostic abnormality

Introduction: Sonographically measured median nerve cross‐sectional area (CSA) at the wrist is increased in patients with carpal tunnel syndrome (CTS). Ultrasound of the median nerve may be useful in screening for electrodiagnostic (EDx) abnormalities. Methods: EDx studies were performed on all participants. Sonographic evaluation of median nerve CSA at the wrist and in the forearm was performed by a physician blinded to the EDx results. Multivariate and receiver operating characteristic (ROC) analysis were used to assess the data. Results: Fifty control wrists and 192 symptomatic wrists were analyzed. Sensitivity of ultrasound in excluding EDx abnormality was 99% for CSA of 9 mm² and 97% for a wrist–forearm ratio (WFR) of 1.4. There was no clinically significant correlation between ultrasound parameters and EDx severity. Conclusions: Median nerve ultrasound is a highly sensitive screening tool for EDx abnormality, but it cannot determine severity. This may lead to changes in the current standards for evaluating CTS. Muscle Nerve, 2012     

Cytoplasmic 5′‐nucleotidase autoantibodies in inclusion body myositis: Isotypes and diagnostic utility

Introduction: Recent studies have identified circulating immunoglobulin (Ig) G autoantibodies against cytoplasmic 5′‐nucleotidase 1A (cN1A; NT5C1A) in patients with inclusion body myositis (IBM), whose detection provides for an IBM blood diagnostic test. Whether or not anti‐cN1A autoantibody isotypes other than IgG are present in IBM has not previously been reported. Methods: Plasma and serum samples from 205 patients (50 with and155 without IBM) were studied for the presence of IgM and IgA, in addition to IgG, anti‐cN1A autoantibodies using immunoblots and enzyme‐linked immunoassays (ELISAs). Results: IgM, IgA, and IgG anti‐cN1A autoantibodies were detected by ELISA with similar sensitivities (49–53%) and specificities (94–96%), but with differing patterns of autoantibody isotype presence. Combination assays of all 3 autoantibody levels improved diagnostic sensitivity to 76%. Conclusions: In addition to previously recognized IgG anti‐cN1A autoantibodies, IBM patients have circulating IgM and IgA anti‐cN1A autoantibodies. Differing patterns of these isotypes may be present and useful for diagnosis. Muscle Nerve 50 : 488–492, 2014     

Motor unit number index in the nasalis muscle in healthy subjects and patients with amyotrophic lateral sclerosis

Introduction: Motor unit number index (MUNIX) is a quick and feasible electrophysiological technique that estimates the number of motor neurons in limb muscles in healthy and amyotrophic lateral sclerosis (ALS) subjects. In this study we explored the feasibility, reliability, and differences of MUNIX in nasalis muscles in healthy subjects and ALS patients. Methods: MUNIX of the nasalis muscle of 50 healthy and 20 ALS subjects with bulbar involvement was compared. Functional impairment was evaluated by the ALS Functional Rating Scale—Revised and its bulbar subscore. Results: MUNIX was well tolerated and quickly performed. Bulbar ALS patients showed non‐significant lower nasalis MUNIX values and a lower functional bulbar subscore. Intra‐ and interrater reliability showed high intraclass correlation coefficients (ICCs) in healthy subjects (0.87) and ALS patients (0.92). Conclusion: MUNIX of the nasalis muscle is a reproducible method, but it showed no significant difference between healthy and bulbar ALS subjects and seems not to be a useful marker of disease progression in ALS. Muscle Nerve 54 : 733–737, 2016     

Fasciculations in nerve and muscle disorders – A prospective study of muscle ultrasound compared to electromyography

Objectives

We examined the clinical utility of muscle ultrasound (MUS) in detecting fasciculations in patients with nerve and muscle disorders (NMD) and investigated the impact on diagnostic sensitivity when combining electromyography (EMG) and MUS.

Newborn brachial plexus palsy: Evaluation of severity using quantitative ultrasound of muscle

Introduction: We studied ultrasound features of muscle after nerve injury. Methods: We evaluated ultrasound measurements of muscle thickness and backscatter in injured and contralateral uninjured elbow flexors of 51 children with newborn brachial plexus palsy (NBPP) and compared the results to elbow flexor function (Active Movement Scale), defined as normal, moderate, or severe. Results: Compared with uninjured limbs, muscle in injured arms was 15% thinner with severe impairment, 17% thicker with moderate impairment, and no different with normal function. Relative to uninjured limbs, moderately impaired muscle was thicker than both severely impaired and normal strength muscle. Backscatter was higher in injured than in uninjured limbs regardless of function. In 17 patients with sequential measures, muscle thickness, but not backscatter, increased with function over time. Conclusions: Muscle thickness differentiates moderate from severe impairment after NBPP and increases with recovery over time. Muscle backscatter identifies prior injury regardless of function. Muscle Nerve, 2013