Normal EDX Research Articles

Ultrasound as a Complementary Tool to Electrodiagnostics in the Evaluation of Compressive Neuropathy of the Common Fibular Nerve

Background: Compressive neuropathy of the common fibular nerve (CFN) is increasingly recognized as an etiology for foot drop and falls. Electrodiagnostic (EDX) studies are widely used to evaluate this condition, but such tests are invasive and costly. As with carpal and cubital tunnel syndromes, there may be patients with characteristic symptoms of CFN compressive neuropathy but normal EDX studies in which ultrasound may aid in decision-making. Purpose: We sought to examine the association between ultrasound and nerve conduction studies (NCS) and electromyography (EMG) in the diagnosis of compressive neuropathy of the CFN. Methods: We performed a retrospective review identifying 104 patients who underwent CFN decompression from January 1, 2015, to June 30, 2023. Patients were included if they had both ultrasound and NCS/EMG prior to CFN decompression for compressive neuropathy and if they were older than 18 years at time of surgery. Patients were excluded if they had entrapment secondary to trauma, iatrogenic injury, or if they had had superficial fibular decompression alone without CFN decompression. After applying exclusion criteria, 17 patients remained in the cohort. Results: Mean ultrasound cross-sectional area and side-to-side (STS) ratios were significantly higher in those with abnormal compound muscle action potential (CMAP) amplitudes versus those with normal CMAP amplitudes. The probability of having an abnormal CMAP amplitude when STS ratio was abnormal was 18 times greater compared with those with normal STS ratio. With each unit increase in STS ratio, CMAP amplitude was reduced by 2.79 mV. Conclusions: This retrospective review found that ultrasound may provide complementary diagnostic information to EMG/NCS for compressive neuropathy of the CFN. Further study is needed to examine the relationship between ultrasound findings for CFN compressive neuropathy and results of surgical decompression.

Most Carpal Tunnel Releases Address Moderate or Severe Median Neuropathy.

The role of surgery in normal or very mild median neuropathy can be questioned given that surgery in the absence of pathophysiology may offer only nonspecific effects that can be achieved without surgery, which raises ethical concerns. It's also important to avoid misdiagnosis: given that mild median neuropathy is prevalent and generally well-accommodated, notable symptoms from mild median neuropathy can signal unhelpful thoughts and feelings of distress that are a more pressing health priority. We identified 38 studies that categorized electrodiagnostic (EDX) measured median neuropathy severity among people being evaluated for carpal tunnel syndrome. We converted the different EDX grades used into one general grading classification. The Kruskal-Wallis test was used to compare the ratio of moderate/severe to mild/normal EDX findings between tests ordered by a surgeon or a nonoperative clinician. The median (interquartile range) ratio of moderate/severe to mild/normal EDX findings of median neuropathy at the carpal tunnel was 1.2 (0.91 to 1.8) among tests ordered by nonoperative clinicians and 3.3 (1.5 to 5.3) among tests ordered by surgeons (P = .0023). Only 4.1% of the patients who had EDX testing ordered by a surgeon had no measurable neuropathy. There were zero patients with normal EDX findings in 10 of the 17 (59%) studies in surgeon practices and in 10 of the 21 (48%) in the practices of nonoperative clinicians. The observation that in case series documenting EDX severities of median neuropathy, surgeons are mostly treating and operating on moderate to severe pathophysiology, emphasizes that while mild median neuropathy is highly prevalent it is uncommonly considered for surgery. Level II, Prognostic study.

Rapid Functional Recovery After Thoracic Outlet Decompression in a Series of Adolescent Athletes With Chronic Atraumatic Shoulder-Girdle Pain, Scapular Winging/Dyskinesis, and Normal Electrodiagnostic Studies.

Spontaneous shoulder-girdle pain and scapular winging/dyskinesis can be caused by several neuromuscular disorders identifiable by electrodiagnostic studies (EDX). We describe a group of adolescent athletes with this clinical presentation but normal EDX, followed by later development of neurogenic thoracic outlet syndrome (NTOS). We identified patients referred for evaluation of NTOS that had a history of chronic atraumatic shoulder-girdle pain, scapular winging/dyskinesis, and normal EDX. Each was refractory to conservative management and underwent supraclavicular decompression and brachial plexus neurolysis for NTOS. Functional disability was quantified by Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores. There were 5 female patients with a mean age at symptom onset of 14.2 ± 0.4 years, including spontaneous severe pain in the shoulder, scapula, and arm, along with prominent scapular winging/dyskinesis, and normal EDX. Symptoms had persisted for 18.9 ± 4.0 months prior to referral, with pronounced upper extremity disability (mean QuickDASH, 54.6 ± 6.9). By 3 months after surgical treatment for NTOS, all 5 patients experienced near-complete symptom resolution, including scapular winging/dyskinesis, with markedly improved function (mean QuickDASH, 2.2 ± 1.3) and a return to normal activity. A subset of patients with chronic atraumatic shoulder-girdle pain, scapular winging/dyskinesis, and normal EDX may develop dynamic brachial plexus compression characteristic of NTOS, exhibiting an ischemic "Sunderland-zero" nerve conduction block for which surgical decompression can result in rapid and substantial clinical improvement. The presence of surgically treatable NTOS should be considered for selected patients with long-standing scapular winging/dyskinesis who fail conservative management.

A Three months Electrodiagnostic Follow-Up of Patients Suspected of having Ulnar Nerve Involvement at Elbow Level with Normal Conventional Electrodiagnostic Study at First Evaluation.

Compression of ulnar nerve at the elbow is the second most common peripheral neuropathy of the upper extremity. Due to the lack of the gold diagnostic standard for ulnar nerve involvement at elbow level (UNE) and the lack of sufficient study in this field, we decided to evaluate patients with symptoms of this disease who have normal conventional electrodiagnostic study (EDX) in first evaluation. In this cross-sectional study, 18 persons were selected from patients who were referred to the clinic of Physical Medicine and Rehabilitation. If conventional EDX was normal, compound nerve action potential (CNAP) test (peak latency and amplitude) was carried out. Patients with normal conventional EDX but abnormal ulnar CNAP included to our study. After 3 months, if they had not been treated for ulnar neuropathy, they were reexamined by conventional EDX plus ulnar CNAP measurement. In total, 18 patients (11 females, 7 males) aged 28-58 years old (mean = 40.11) were analyzed in this study. After 3 months, 14 patients (77.8%) demonstrated parameter changes consistent with UNE in conventional EDX. Based on the results of this study, ulnar CNAP has diagnostic value in patients with symptoms of UNE who have normal routine EDX. Therefore, ulnar CNAP should be taken into account for early diagnosis of ulnar neuropathy when routine electrodiagnostic tests are normal.

Electrodiagnostic referrals and neuromuscular disease pattern in East Africa: Experience from a tertiary hospital in Ethiopia

ObjectiveWe present a retrospective cross-sectional review of the electrodiagnostic (EDX) referral and diagnostic patterns in patients with suspected neuromuscular conditions at a tertiary hospital in Ethiopia. MethodsBetween 2016 and 2019, 313 patients were evaluated at the EDX lab in Tikur Anbessa Specialised Hospital, Addis Ababa, Ethiopia. In our patients, nerve conduction study and when appropriate needle electromyography was done. Demographic and clinical data were extracted from a digital registry. ResultsPolyneuropathy (19.8%), carpal tunnel syndrome (12.1%), and lumbosacral radiculopathy (9.9 %) were the top three reasons for EDX referral in Ethiopia. Among them, polyneuropathy was the most frequent electrodiagnosis, where diffuse axonal and demyelinating subtypes accounted for 54% and 18.8%, respectively. Guillain-Barre syndrome was suspected in 18 patients and 15 had EDX confirmed motor axon polyneuropathy while three patients had demyelinating variant. Although a quarter (26.2%) of the referrals had a normal EDX, abnormal test results were significantly associated with weakness (95% CI: 3.29–7.04, p < 0.001), bound to wheelchair (95% CI: 1.86–2.87, p = 0.01) and having a specific diagnosis at time of referral (95% CI: 2.53–4.68, p = 0.007). ConclusionsDiffuse and entrapment neuropathies were the main reasons for electrodiagnosis test referrals in Ethiopia. Also, motor axonal variant was the most common type of inflammatory polyneuropathy diagnosed with EDX. SignificanceProper patient evaluation and documentation significantly improves the diagnostic yield and cost-effectiveness of EDX testing in a resource-poor countries like Ethiopia. This might be achieved through educating medical students, residents, and other care providers on the basics of EDX and its indications for correct use in the clinical care.

Changes of clinical, neurophysiological and nerve ultrasound characteristics in CIDP over time: a 3-year follow-up.

To evaluate, in a prospective study, high-resolution ultrasound (HRUS) changes of nerve segments in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and their relationships with clinical and electrodiagnostic (EDX) characteristics. Twenty-three consecutive patients with CIDP were included in a 3-year follow-up (FU) study. Each patient underwent neurologic examination, EDX and HRUS study. HRUS was performed on median, ulnar and peroneal nerves, yielding a total of 319 scanned nerve segments. INCAT and MRC-sum scores, motor nerve conduction velocity (NCV), compound muscle action potential (cMAP) amplitude, and nerve cross-sectional area (NCSA) were collected at baseline and at FU end, and were used for statistical analysis. Twenty-two healthy individuals, matched to patients for age and BMI, served as controls. NCSA was higher in patients than in controls (p < 0.0001) and showed significant direct correlation with disease severity, and inverse correlation with NCV and cMAP amplitude, both at baseline and at FU end. Disease duration, clinical scores and EDX were predictors of NCSA enlargement at both time points. During FU, NCSA increased in 51% of nerve segments (p = 0.006), in correlation with INCAT increase and with NCV and cMAP reduction. Considering EDX changes in subgroups that reflect the different types of nerve damage, NCSA significantly increased in those nerve segments that from normal EDX switched to prevalent myelinopathic EDX characteristics. Peripheral nerve size tends to increase over time in patients with CIDP, in correlation with clinical and EDX changes, in particular in those nerve segments that undergo a predominantly demyelinating damage.

Association of Psychometric Indices and Normal Electrodiagnostic Studies in Referral for Suspected Carpal Tunnel Syndrome

The aim of this study was to investigate psychometric indices and their association with electrodiagnostic studies (EDX). A total of 100 patients referred for EDX testing of the upper limbs were prospectively enrolled. Demographic data, laboratory test results, referral physician specialty, main symptom, WHODAS 2.0-12 item version, Hospital Anxiety and Depression Scale (HADS), Boston Carpal Tunnel Questionnaire (BCTQ) and a Numeric Rating Scale (NRS) indicating the extent of their discomfort were collected. Normal EDX results were elicited from 56% of patients. Only the presence of numbness in the right hand, pain in the left hand and older age were significantly associated with an abnormal EDX result. The more depressed and anxious the patients were, the more they scored on psychometric scales. The large prevalence of normal EDX studies raises the issue of unnecessary referrals. A proportion of patients are referred only according to their reported symptoms. Psychological factors affect the way a person expresses physical discomfort, leading to unnecessary EDX referrals and inevitably with normal results.

Prevalence of denervation in the intrinsic foot muscles in patients with distal predominantly small fiber neuropathy

We aimed to evaluate the significance of electromyographic findings in the intrinsic foot muscles (IFMs) of patients with skin biopsy proven small fiber neuropathy (SFN). This was a single-center retrospective analysis of patients who underwent skin biopsy for intra-epidermal nerve fiber density (IENFD) measurement and electrodiagnostic (EDX) study for evaluation of polyneuropathy. A total of 1416 patents with normal lower extremity EDX studies proximal to the foot were included. Active denervation was seen in 16.1% of IFMs in patients with skin biopsy proven SFN and 4.1% of patients without SFN (P < .0001). Reinnervation changes without active denervation were observed in 30.4% of SFN patients and 23.8% of patients without SFN (P = .01). IENFD was lower in SFN patients with active denervation in IFMs than without (P < .0001). Evaluation of active denervation in the IFMs can reveal large fiber dysfunction in SFN patients with otherwise normal routine EDX findings.

Borderline Nerve Conduction Velocities for Median Neuropathy at the Carpal Tunnel

Patient knowledge of the frequency with which electrodiagnostic testing (EDx) for suspected median neuropathy at the carpal tunnel addresses nuance in the distinction between normal and abnormal neurophysiology might help them make an informed decision about whether or not to have this test. We reviewed a large set of consecutive EDx for possible carpal tunnel syndrome (CTS) and associated medical records to determine (1) the percentage of EDx measurements within 10% of threshold values; (2) discordance between clinician and EDx diagnosis of CTS using diagnostic performance characteristics; and (3) demographic and disease characteristics independently associated with EDx diagnosis of median neuropathy at the carpal tunnel. We retrospectively reviewed nerve conduction study (NCS) results of 537 consecutive patients evaluated for possible idiopathic median neuropathy at the carpal tunnel. We measured the number of patients within 10% of 3 NCS diagnostic thresholds; the diagnostic performance characteristics comparing clinician and EDx diagnosis; and patient and disease characteristics associated with EDx diagnosis of CTS. The 3 NCS parameters were within 10% of the threshold for diagnosis of median neuropathy at the carpal tunnel in 2.6% to 33% of patients. Overall, 76% of EDx results were interpreted as median neuropathy at the carpal tunnel, 19% as normal, and 5% as another diagnosis (eg, cervical radiculopathy). Patients with normal EDx were significantly younger, more likely not to report paresthesias/numbness, more likely to have prior normal EDx, and less likely to have had a previous contralateral carpal tunnel release. This data set reflecting management strategies for suspected CTS at a large institution confirms inherent diagnostic uncertainty, relatively strong concordance between clinician and EDx diagnosis, and the importance of focusing on paresthesia rather than pain. These findings support the use of clinical prediction rules and may help inform a patient's decision regarding whether or not to have EDx. Diagnostic III.

The usefulness of electrodiagnostic consultation in an outpatient clinic

The aim of this study was to record all patients referred to a private outpatient clinic for electrodiagnostic consultation during one calendar year.The demographic data of the patients, the specialty of the referring physicians, the referral diagnosis, the electromyographic (EMG) diagnosis and the concordance of referral and EMG diagnosis among all the referring physician’s specialties were recorded.There were one thousand patients (385 men and 615 women). 65.7% of the patients were referred from orthopedists and 22.4% from neurologists. EMG was normal in 498 patients (49.8%). Abnormal in 47.3% of the patients referred by orthopedists and 58.9% of those referred by neurologists. Carpal tunnel syndrome (CTS) was the most frequent electrophysiological diagnosis (26.8%), followed by polyneuropathy (8.9%), radiculopathy (7.1%) and mononeuropathy (4.6%).In this study electrodiagnostic consultation was abnormal in only half of the referred patients. The high proportion of normal EDX tests in this study denotes the need for more accurate clinical diagnosis in order to reduce the time spent and resources. The orthopedist is the initial physician to whom patients with neuromuscular symptoms are seen in the majority of cases. Neurologists seem to be more familiar with neuromuscular symptoms and diseases.

A prospective study of high resolution ultrasound in brachial plexopathies – Correlation with electrophysiological measurements

ObjectivesTo evaluate the diagnostic role of ultrasound in brachial plexopathies. MethodsWe included 59 healthy subjects (HS) and 42 patients consecutively referred with clinical suspicion of brachial plexopathy from October 2015 to May 2016. Patients underwent routine electrodiagnostic testing (EDx) as reference standard and a blinded standardised ultrasound examination of the brachial plexus as index test with cross-sectional area (CSA) as the ultrasound parameter of choice. ResultsSeventeen patients were diagnosed by EDx with brachial plexopathy, ten with mononeuropathies, and ten had normal EDx. Five had a cervical radiculopathy. In 11 (64%) out of the 17 patients with EDx diagnosed plexopathy, we found at least one abnormal level on ultrasound. Six (60%) out of ten normal EDx patients had a normal ultrasound examination at all levels. Ultrasound identified the same abnormal level(s) as EDx in eight (73%) of the 11 patients who had both abnormal EDx and ultrasound results. Mean CSA was higher in the plexopathy group compared to HS at the level of the C6 root (p = .022), the middle trunk (p = .027), and the medial cord (p = .003). ConclusionUltrasound examination showed abnormalities in patients with brachial plexopathies in good agreement with EDx. SignificanceUltrasound may be an important supplement to electrodiagnostics in evaluating brachial plexopathies.

Facing the challenges of electrodiagnostic studies in the very elderly (>80 years) population

ObjectiveStudies on electrodiagnostic (EDX) methods usually exclude the very elderly. This also holds true for studies of normal EDX values. We analyzed the outcome and diagnostic value of EDX and collected reference data in a large cohort of patients ≥80 years of age. MethodsReferral information, ICD-10 diagnoses and EDX data were retrieved from all patients ≥80 years of age referred for EDX studies at our department in 1995–2015. Normative data, including reference ranges, were obtained using the extrapolated norms (e-norms) method. Results1966 unique patients (2335 examinations) were included. Only 11% were considered to have normal findings. 66% had pathological EDX findings in accordance with the indication for referral. Carpal tunnel syndrome was by far the most common diagnosis. Normative data retrieved using e-norms were similar to those of reference values from healthy subjects regarding EMG multiMUP data, but typically provided a wider normality window when applied to nerve conduction parameters. ConclusionsEDX studies are valuable in the diagnostic work-up of very elderly patients. Using the e-norms method may be a useful alternative when obtaining reference values in this age group. SignificanceOur findings provide additional insights to the challenges of evaluating very elderly patients with neuromuscular disease and underline the importance of including this growing part of the patient population in EDX research.

The diagnostic accuracy of median nerve ultrasonography in elderly patients with carpal tunnel syndrome: sensitivity and specificity assessment.

BackgroundAccurate diagnosis of carpal tunnel syndrome (CTS), the most common entrapment neuropathy, and its differentiation from other diseases are essential, especially in older individuals with advanced symptoms and modified electrophysiological abnormalities. The current study was conducted to evaluate the diagnostic accuracy of ultrasonography (US), regarding sensitivity and specificity in the diagnosis of CTS in elderly patients.MethodsIndividuals with upper limb complaints and reference subjects were recruited from the Rofaydeh Hospital, Tehran, Iran, from June 2013 to October 2014 – (15 months). We evaluate case and control subjects for health status, demographics, clinical characteristics of CTS, median nerve physiology by electrodiagnostic tests, and anatomy by US. Median nerve cross-sectional area (CSA) at precanal, tunnel inlet, midcanal, tunnel outlet, and antecubital levels was measured applying US examination.ResultsOf the 723 complaining patients, we assessed 380 patients with CTS symptoms. Electrodiagnostic studies (EDX) confirmed the CTS diagnosis in 203 of these clinically diseased patients. A total of 103 patients (of the 113 reference subjects) had normal EDX in the reference group. Comparisons of wrists between the afflicted and reference subjects demonstrated the CSA at precanal, tunnel inlet, midcanal, and tunnel outlet levels being significantly more abundant in the diseased hands than in the nondiseased hands. CSA at the tunnel inlet and the inlet-to-antecubital CSA ratio with a threshold of 8.5 mm2 and 0.65 gave the best diagnostic accuracy with a sensitivity and specificity of 96.9 and 93.6% for the inlet CSA and 99 and 28% for the CSA ratio, respectively.ConclusionThe US as a noninvasive diagnostic method may serve for the investigation of CTS in elderly patients with excellent sensitivity and specificity.

Utilization of Electrodiagnostic Testing for Carpal Tunnel Syndrome by General Practitioners Prior to Hand Surgery Consultation.

Carpal tunnel syndrome (CTS) is the most common peripheral mononeuropathy and thus is frequently encountered by general practitioners (GPs). The aim of this study is to investigate the referral pattern of GPs with regard to electrodiagnostic (EDX) testing for suspected CTS prior to hand surgery consultation, as well as to investigate the results of EDX testing for suspected CTS when requested by GPs prior to evaluation by a hand surgeon. We retrospectively reviewed patients referred to our hand surgery clinic over a consecutive 2-year period for suspected CTS. A total of 403 patients were referred to our hand surgery clinic from January 1, 2016, to December 31, 2017. Of the 403, 295 (73.2%) were referred by GPs. GPs obtained prereferral EDX testing in 198 (67.1%) of these patients. EDX testing confirmed their diagnosis in 177 patients (89.4%). There were 21 patients (10.6%) identified with normal EDX testing and a more likely diagnosis reached based on clinical examination. GPs make up the majority of our referrals for CTS, and they obtain EDX testing prior to consultation in two-thirds of referrals. GPs appear to accurately utilize EDX testing to confirm their diagnosis prior to referral and have a low rate of normal testing where symptoms are more readily explained by an alternative diagnosis.

F99. Facing the challenges of electrodiagnostics in the very elderly

Introduction Although normal aging is known to influence most electrodiagnostic (EDX) parameters, few studies have focused on the difficulties concerning interpretation of EDX data in the very elderly population. Studies on EDX methods, such as nerve conduction studies and electromyography, usually exclude the very elderly (individuals ⩾ 80 years of age). This also holds true for studies of normal EDX values and the relationship between age and nerve conduction parameters. Therefore, we analyzed the outcome and diagnostic value of EDX and collected normative data in a large cohort consisting of patients ⩾ 80 years of age. Methods EDX data were extracted from studies of nerve conduction (amplitudes, conduction velocities, distal latencies, decrement), EMG (quantitative multiMUP data) and SFEMG (jitter values). Additionally, referral information and ICD-10 diagnoses were retrieved from all patients ⩾ 80 years of age referred for EDX studies at the department of Clinical Neurophysiology at Uppsala University Hospital from 1996 to 2015. Normative data, including reference ranges, were obtained using the extrapolated norms (e-norms) method and compared to current normal values at our department. Results A total of 1966 unique patients (2335 examinations) were included (59% female). The patients were born in 1900–1935 with an age span of 80.0–101.1 years at the time of their EDX evaluation. Only 255 examinations (11%) were considered to be without abnormal findings (ICD-10 diagnosis Z01.9). Sixty-six percent of patients had pathological EDX findings in accordance with the indication for referral. Data on specific disease groups are presented. Conclusion EDX studies offer great value in the diagnostic work-up of very elderly patients. Patients ⩾ 80 years are an increasing part of the population in many countries and pose challenges to the evaluating neurophysiologists given the difficulties in determining which parameters are affected by normal aging alone, and which are caused by disease states. Inclusion of healthy people to obtain reference values in this age group is challenging and hence using the extrapolated (e-norms) reference values may offer a good alternative.

Treatment outcome in patients with clinically defined carpal tunnel syndrome but normal electrodiagnostic test results: a randomized controlled trial

Little is known about treatment effect of carpal tunnel release in patients with clinically defined carpal tunnel syndrome (CTS), but normal electrodiagnostic test results (EDX). The aim of this study was to determine whether this category of patients will benefit from surgical treatment. 57 patients with clinically defined CTS and normal EDX were randomized for surgical treatment (n=39) or non-surgical treatment (n=18). A six-point scale for perceived improvement as well as the Boston Carpal Tunnel Questionnaire was completed at baseline and at follow-up after 6months. A significant improvement of complaints was reported by 70.0% of the surgically treated patients and 39.4% reported full recovery 6months after surgery. Furthermore, both Functional Status Score and Symptom Severity Score improved significantly more in the surgically treated group (p=0.036 and p<0.001, respectively). This study demonstrates that most patients with clinically defined CTS and normal EDX results will benefit from carpal tunnel release. Therefore, this group of CTS patients must not a priori be refrained from surgery.

Evaluation of the adequacy of requests for electrodiagnostic examination in a tertiary referral center

ObjectiveDiagnostic procedures are often overused in the attempt to substitute for the good clinical examination. The aim of this study was to evaluate the type and the accuracy of the referral diagnosis to our EMG lab, as well as the impact of electrodiagnostic (EDX) examination on the diagnosis of our patients. MethodsIn this prospective study all patients examined in the six months period in a single tertiary referral EMG lab were analyzed. All patients were tested in a uniform fashion and by the same neurologist, according to the referral diagnosis. ResultsEDX examination was performed in 570 patients. Most of the patients (43.9%) were referred with the diagnosis of polyneuropathy, lumbosacral (23.7%) or cervical (11.2%) radiculopathy and myasthenia gravis (11.6%). The outcome after EDX examination was: diagnosis confirmation in 49.6% of patients, new clinically relevant diagnosis in 16%, incidental diagnosis in 4% and normal EDX examination in 36.1% of patients. EDX examination confirmed referral diagnosis more often in patients referred by neuromuscular neurologists, while normal EDX finding was reported more often in patients referred by other neurologists. ConclusionThis study has confirmed the inappropriateness of a large number of referrals to EDX testing, especially made by the non-neuromuscular neurologists.

Lead Selenide Nanostructures Self-Assembled across Multiple Length Scales and Dimensions

A self-assembly approach to lead selenide (PbSe) structures that have organized across multiple length scales and multiple dimensions has been achieved. These structures consist of angstrom-scale 0D PbSe crystals, synthesized via a hot solution process, which have stacked into 1D nanorods via aligned dipoles. These 1D nanorods have arranged into nanoscale 2D sheets via directional short-ranged attraction. The nanoscale 2D sheets then further aligned into larger 2D microscale planes. In this study, the authors have characterized the PbSe structures via normal and cryo-TEM and EDX showing that this multiscale multidimensional self-assembled alignment is not due to drying effects. These PbSe structures hold promise for applications in advanced materials—particularly electronic technologies, where alignment can aid in device performance.

Nerve ultrasound identifies abnormalities in the posterior interosseous nerve in patients with proximal radial neuropathies.

The radial nerve and posterior interosseous nerve (PIN) are prone to injury at multiple sites. Electrodiagnostic (EDx) studies may only identify the most proximal lesion. Nerve ultrasound could augment EDx by visualizing additional pathology. This investigation was a retrospective examination of ultrasound and EDx from 26 patients evaluated for posterior cord/radial/PIN lesions. Eighteen of 26 patients had abnormalities on EDx (15 radial, 2 PIN, 1 posterior cord). Ultrasound identified 15 of 18 (83%) of the EDx abnormalities and provided additional diagnostic information. In 6 of 15 (40%) patients with EDx evidence of radial neuropathy, ultrasound identified both radial nerve enlargement and additional, unsuspected PIN enlargement (53% to 339% enlarged vs. unaffected side). Ultrasound also identified: nerve (dis)continuity at the trauma site (n = 8); and nerve tumor (n = 2; 1 with normal EDx). In radial neuropathy, ultrasound often augments EDx studies and identifies a second lesion in the PIN. Further studies are required to determine the etiology and significance of this additional distal pathology.

Diagnostic utility of somatosensory evoked potentials in chronic polyradiculopathy without electrodiagnostic signs of peripheral demyelination.

Diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) remains uncertain when nerve conduction studies (NCS) fail to show demyelination. We conducted a retrospective study of patients who presented with clinical criteria of CIDP in whom electrodiagnostic (EDx) criteria of definite or probable CIDP were missing [axonal sensorimotor neuropathy (n = 23), normal EDx with pure sensory presentation (n = 3)]. All patients received immunomodulatory treatment. Twenty-six patients were evaluated with somatosensory evoked potentials (SSEPs), MRI of spinal roots, cerebrospinal fluid analysis, and/or nerve biopsy. Diagnosis of CIDP was considered to be confirmed in patients who responded to immunotherapy. Twenty-two of 26 patients (85%) had SSEPs reflecting abnormal proximal conduction in sensory fibers, including 14 who had only clinical and SSEP data in favor of CIDP. SSEPs were abnormal in 16 of 20 responders (80%) to immunotherapy. SSEP recording contributes to the diagnosis of CIDP when nerve conduction studies fail to detect peripheral demyelination.