Ulnar neuropathy.

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

Carpal tunnel syndrome.

Median neuropathy at the wrist, commonly referred to as carpal tunnel syndrome (CTS), is the most common entrapment neuropathy. It is caused by chronic compression of the median nerve at the wrist within the space-limited carpal tunnel. Risk factors that contribute to the etiology of compression include female gender, obesity, work-related factors, and underlying medical conditions, such as hypothyroidism, pregnancy, and amyloidosis. The diagnosis is made on clinical grounds, although these can be confounded by anatomical variations. Electrodiagnostic studies, which are specific and sensitive in diagnosing CTS, support the diagnosis; however, a subgroup may present with normal results. The advent of imaging techniques, including ultrasound and MRI, further assists the diagnostic process. The management of CTS is divided into the nonsurgical approaches that include hand therapy, splinting and corticosteroid injection, and surgical decompression of the carpal tunnel. Although several surgical techniques have been developed, no one method is more effective than the other. Each of these management approaches are effective at providing symptom relief and are utilized at different severities of the condition. There is, however, a lack of consensus on standardized diagnostic criteria, as well as when and to whom to refer patients for surgery.

Successful Management of Acute Streptococcal Meningoencephalitis Complicated by Bilateral Third-Nerve Palsies, Wall-Eyed Bilateral Internuclear Ophthalmoplegia, Blindness, and Deafness: Case Report.

Introduction: Streptococcal meningoencephalitis (SME) is a rare, and frequently lethal, acute infection, and inflammation of the central nervous system parenchyma, with associated meningeal involvement. Bacterial meningoencephalitis is generally associated with high rates of morbidity and mortality, despite available antimicrobial and corticosteroid treatments. While Streptococcus pneumoniae is well recognised to cause bacterial meningitis, direct extension into the central nervous system parenchyma is rare. Case Presentation: A previously well 49-year-old man presented with sudden onset severe headache, fevers, neck stiffness, and reduced consciousness. The manifestations of SME in this patient were bilateral pupil-involving third-nerve palsies, wall-eyed bilateral internuclear ophthalmoplegia (WEBINO), bilateral blindness, bilateral deafness, a right lower motor neuron facial palsy, and upper motor neuron signs in his limbs. Initially, a partial response to high dose intravenous antibiotics occurred, but with administration of intravenous corticosteroids, further substantial resolution of the patient's neurological and neuro-ophthalmological deficits occurred. Conclusion: This case highlights the benefit of multidisciplinary diagnostic and therapeutic interventions in a case of SME complicated by bilateral pupil-involving third-nerve palsies, WEBINO, bilateral blindness, bilateral deafness, a right lower motor neuron facial palsy, and upper motor neuron signs. It appears to be the first reported case of SME with this rare collection of neuro-ophthalmological abnormalities.

Electrodiagnostic studies and new diagnostic modalities for evaluation of peripheral nerve disorders.

Electrodiagnostic studies (EDx) are frequently performed in the diagnostic evaluation of peripheral nerve disorders. There is increasing interest in the use of newer, alternative diagnostic modalities, in particular imaging, either to complement or replace established EDx protocols. However, the evidence to support this approach has not been expansively reviewed. In this paper, diagnostic performance data from studies of EDx and other diagnostic modalities in common peripheral nerve disorders have been analyzed and described, with a focus on radiculopathy, plexopathy, compressive neuropathies, and the important neuropathy subtypes of Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), vasculitic neuropathy and diabetic neuropathy. Overall EDx retains its place as a primary diagnostic modality in the evaluated peripheral nerve disorders. Magnetic resonance imaging and ultrasound have developed important complementary diagnostic roles in compressive and traumatic neuropathies and atypical CIDP, but their value is more limited in other neuropathy subtypes. Identification of hourglass constriction in nerves of patients with neuralgic amyotrophy may have therapeutic implications. Investigation of radiculopathy is confounded by poor correlation between clinical features and imaging findings and the lack of a diagnostic gold standard. There is a need to enhance the literature on the utility of these newer diagnostic modalities.

Axonal excitability as an early biomarker of nerve involvement in hereditary transthyretin amyloidosis.

OBJECTIVES: The treatment of hereditary transthyretin amyloidosis polyneuropathy (ATTRv-PN) has been revolutionised by genetic therapies, with dramatic improvements in patient outcomes. Whilst the optimal timing of treatment initiation remains unknown, early treatment is desirable. Consequently, the aim of the study was to develop biomarkers of early nerve dysfunction in ATTRv-PN. METHODS: Ulnar motor and sensory axonal excitability studies were prospectively undertaken on 22 patients with pathogenic hereditary transthyretin amyloid (ATTRv) gene variants, 12 with large fibre neuropathy (LF+) and 10 without (LF-), with results compared to age- and sex-matched healthy controls. RESULTS: In motor axons we identified a continuum of change from healthy controls, to LF- and LF+ ATTRv with progressive reduction in hyperpolarising threshold electrotonus (TEh40(10-20 ms): p = 0.04, TEh40(20-40 ms): p = 0.01 and TEh40(90-10 ms): p = 0.01), suggestive of membrane depolarisation. In sensory axons lower levels of subexcitability were observed on single (SubEx) and double pulse (SubEx2) recovery cycle testing in LF+ (SubEx: p = 0.015, SubEx2: p = 0.015, RC(2-1): p = 0.04) suggesting reduced nodal slow potassium conductance, which promotes sensory hyperexcitability, paraesthesia and pain. There were no differences in sensory or motor excitability parameters when comparing different ATTRv variants. CONCLUSIONS: These progressive changes seen across the disease spectrum in ATTRv-PN suggest that axonal excitability has utility to identify early and progressive nerve dysfunction in ATTRv, regardless of genotype. SIGNIFICANCE: Axonal excitability is a promising early biomarker of nerve dysfunction in ATTRv-PN.

Advances in diagnosis and management of distal sensory polyneuropathies.

Distal sensory polyneuropathy (DSP) is characterised by length-dependent, sensory-predominant symptoms and signs, including potentially disabling symmetric chronic pain, tingling and poor balance. Some patients also have or develop dysautonomia or motor involvement depending on whether large myelinated or small fibres are predominantly affected. Although highly prevalent, diagnosis and management can be challenging. While classic diabetes and toxic causes are well-recognised, there are increasingly diverse associations, including with dysimmune, rheumatological and neurodegenerative conditions. Approximately half of cases are initially considered idiopathic despite thorough evaluation, but often, the causes emerge later as new symptoms develop or testing advances, for instance with genetic approaches. Improving and standardising DSP metrics, as already accomplished for motor neuropathies, would permit in-clinic longitudinal tracking of natural history and treatment responses. Standardising phenotyping could advance research and facilitate trials of potential therapies, which lag so far. This review updates on recent advances and summarises current evidence for specific treatments.

Muscle ultrasound in hereditary muscle disease.

In this review we summarise the key techniques of muscle ultrasound as they apply to hereditary muscle disease. We review the diagnostic utility of muscle ultrasound including its role in guiding electromyography and muscle biopsy sampling. We summarize the different patterns of sonographic muscle involvement in the major categories of genetic muscle disorders and discuss the limitations of the technique. We hope to encourage others to adopt ultrasound in their care for patients with hereditary muscle diseases.

Traumatic peripheral nerve injuries: diagnosis and management.

PURPOSE OF REVIEW: To review advances in the diagnostic evaluation and management of traumatic peripheral nerve injuries. RECENT FINDINGS: Serial multimodal assessment of peripheral nerve injuries facilitates assessment of spontaneous axonal regeneration and selection of appropriate patients for early surgical intervention. Novel surgical and rehabilitative approaches have been developed to complement established strategies, particularly in the area of nerve grafting, targeted rehabilitation strategies and interventions to promote nerve regeneration. However, several management challenges remain, including incomplete reinnervation, traumatic neuroma development, maladaptive central remodeling and management of fatigue, which compromise functional recovery. SUMMARY: Innovative approaches to the assessment and treatment of peripheral nerve injuries hold promise in improving the degree of functional recovery; however, this remains a complex and evolving area.

Prospective analysis of stroke recognition, stroke risk factors, thrombolysis rates and outcomes in Indigenous Australians from a large rural referral hospital.

BACKGROUND: Cardiovascular disease is the most common cause of death and disability in indigenous communities but limited prospective data exist about stroke. AIMS: To estimate the difference in stroke recognition, risk factors, treatment rates and outcomes between indigenous and non-indigenous peoples admitted to the Wagga Wagga Rural Referral Hospital (WWRRH) over a 5-year period with a suspected acute stroke. METHODS: All suspected strokes presenting to the 33 peripheral hospitals within the Murrumbidgee Local Health District (MLHD) were transferred to the WWRRH and prospectively assessed over a 5-year period from 1 January 2012 to 31 December 2017. Actions at stroke onset, risks factors, stroke type, treatment and outcomes were analysed. RESULTS: A total of 1843 patients were included. Of these, 45 (2.5%) patients were indigenous. Only 26.6% of indigenous and 34% of non-indigenous patients knew of the face, arm, speech, time (FAST) acronym. Indigenous patients were younger (mean age 62.0 years vs 74.4 years) and more likely to have diabetes (risk difference (RD) 22.3% (95% CI: 3%, 41.7%)), dyslipidaemia (RD 19.4% (95% CI: 21.%, 36.7%)), and be ever smokers (RD 24.9% (95% CI: 9.5%, 40.3%)). Stroke types were similar except lacunar infarcts were more common (19.2% vs 8.4%). Treatment rates and outcomes were similar between the two groups. CONCLUSIONS: Indigenous Australians with stroke are a decade younger and have a higher prevalence of important, modifiable stroke-risk factors. Delayed presentation to hospital is more common, due in part to stroke symptoms being underrecognised. When admitted to a specialised stroke unit, treatment rates and outcomes are comparable.

Review Article "Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date".

Neuromuscular ultrasound is rapidly becoming incorporated into clinical practice as a standard tool in the assessment of peripheral nerve diseases. Ultrasound complements clinical phenotyping and electrodiagnostic evaluation, providing critical structural anatomical information to enhance diagnosis and identify structural pathology. This review article examines the evidence supporting neuromuscular ultrasound in the diagnosis of compressive mononeuropathies, traumatic nerve injury, generalised peripheral neuropathy and motor neuron disease. Extending the sonographic evaluation of nerves beyond simple morphological measurements has the potential to improve diagnostics in peripheral neuropathy, as well as advancing the understanding of pathological mechanisms, which in turn will promote precise therapies and improve therapeutic outcomes.

Objectively Assessing Sports Concussion Utilizing Visual Evoked Potentials.

A portable system capable of measuring steady-state visual-evoked potentials (SSVEP) was developed to provide an objective, quantifiable method of electroencephalogram (EEG) testing following a traumatic event. In this study, the portable system was used on 65 healthy rugby players throughout a season to determine whether SSVEP are a reliable electrophysiological biomarker for concussion. Preceding the competition season, all players underwent a baseline SSVEP assessment. During the season, players were re-tested within 72 h of a match for either test-retest reliability or post-injury assessment. In the case of a medically diagnosed concussion, players were reassessed again once deemed recovered by a physician. The SSVEP system consisted of a smartphone housed in a VR-frame delivering a 15 Hz flicker stimulus, while a wireless EEG headset recorded occipital activity. Players were instructed to stare at the screen's fixation point while remaining seated and quiet. Electrodes were arranged according to the 10-20 EEG-positioning nomenclature, with O1-O2 being the recording channels while P1-P2 the references and bias, respectively. All EEG data was processed using a Butterworth bandpass filter, Fourier transformation, and normalization to convert data for frequency analysis. Players SSVEP responses were quantified into a signal-to-noise ratio (SNR), with 15 Hz being the desired signal, and summarized into respective study groups for comparison. Concussed players were seen to have a significantly lower SNR compared to their baseline; however, post-recovery, their SNR was not significantly different from the baseline. Test-retest indicated high device reliability for the portable system. An improved portable SSVEP system was also validated against an established EEG amplifier to ensure the investigative design is capable of obtaining research quality EEG measurements. This is the first study to identify differences in SSVEP responses in amateur athletes following a concussion and indicates the potential for SSVEP as an aid in concussion assessment and management.

Asymptomatic common extensor tendon pathology in patients with carpal tunnel syndrome.

INTRODUCTION/AIMS: Carpal tunnel syndrome (CTS) and lateral epicondylitis are both highly prevalent conditions. Our objective was to determine the prevalence of B-mode ultrasound abnormalities of the common extensor tendon (CET) in patients with CTS and establish the relationship between CET stiffness, as measured by shear wave elastography (SWE) and CTS severity. METHODS: Patients without symptoms or signs of lateral epicondylitis were recruited from referrals to a neurophysiology laboratory for possible CTS. These patients were examined for clinical features of CTS before undergoing electrodiagnostic testing followed by an ultrasound examination, consisting of B-mode, power Doppler, and SWE. RESULTS: Thirty-nine limbs with clinically diagnosed CTS and 20 control limbs were included. Of the CTS limbs, 61.5% had sonographically abnormal CET compared with 35% of the controls. The mean CET sonographic abnormality score was higher in CTS patients compared with controls (P = .006). CTS patients with sonographically abnormal CET had more severe CTS by electrophysiological criteria. The mean CET stiffness in CTS patients was lower than in controls (P = .033). DISCUSSION: Sonographic abnormalities of the CET are common in CTS patients with no clinical evidence of lateral epicondylitis and may relate to common pathogenetic mechanisms. These findings suggest that isolated ultrasound abnormalities in the CET are not diagnostically useful in patients presenting with upper limb pain unless there are clinical features of lateral epicondylitis.

Corrigendum: Steady-State Visual-Evoked Potentials as a Biomarker for Concussion: A Pilot Study.

[This corrects the article DOI: 10.3389/fnins.2020.00171.].

Current and future applications of ultrasound imaging in peripheral nerve disorders.

Neuromuscular ultrasound (NMUS) is a rapidly evolving technique used in neuromuscular medicine to provide complimentary information to standard electrodiagnostic studies. NMUS provides a dynamic, real time assessment of anatomy which can alter both diagnostic and management pathways in peripheral nerve disorders. This review describes the current and future techniques used in NMUS and details the applications and developments in the diagnosis and monitoring of compressive, hereditary, immune-mediated and axonal peripheral nerve disorders, and motor neuron diseases. Technological advances have allowed the increased utilisation of ultrasound for management of peripheral nerve disorders; however, several practical considerations need to be taken into account to facilitate the widespread uptake of this technique.

Steady-State Visual-Evoked Potentials as a Biomarker for Concussion: A Pilot Study.

A variety of assessment tools are currently available to help clinicians assess Sports Related Concussion (SRC). Currently, the most widely available tools are neither objective nor portable, and are therefore not ideal for assessment at the site and time of a suspected injury. A portable system was developed to deliver a measurement of the steady-state visual-evoked potential (SSVEP). This system involved a smartphone housed in a Google Cardboard frame, which delivered a 15-Hz flicker visual stimulus while an electroencephalography (EEG) headset recorded EEG signals. Sixty-five rugby union players were tested during their regular season and were stratified into healthy, concussed, and recovered groups based on clinical examination. Their SSVEP response was quantified into a signal-to-noise ratio (SNR). The SNRs of players in each study group were summarized. Additionally, the SNRs of individual players who had baseline, post-injury, and post-recovery readings were analyzed. Sixty-five participants completed a baseline evaluation to measure their SSVEP. Twelve of these participants sustained a medically diagnosed concussion and completed SSVEP re-testing within 72 h. Eight concussed players received follow-up SSVEP testing after recovery. Concussed participants had a lower SNR [2.20 (2.04-2.38)] when compared to their baseline [4.54 (3.79-5.10)]. When clinically recovered, participant SNR was not significantly different to their baseline [4.82 (4.13-5.18)]. The baseline SNRs of the players who experienced a concussion during the season were not different to those of players who did not experience a concussion [4.80 (4.07-5.68)]. This is the first study to identify differences in SSVEP responses in male amateur rugby union players with and without concussion. It is also the first SSVEP demonstration for concussion evaluation at point-of-care. SSVEPs are significantly attenuated in the presence of concussion in these male athletes. Individuals returned to their baseline SSVEP following clinical recovery from the concussive injury. The use of SSVEPs has the potential to be a supplemental aid for the assessment and management of concussion.