Different Types Of Neuropathy Research Articles

Normative Data and Quantile Regression Analysis of the Sural-to-Radial Nerve Amplitude Ratio.

The aim of this study was to establish normative data for the sural-to-radial nerve amplitude ratio (SRAR) and develop a quantile regression model for individualized cutoff values. A cohort of 68 healthy individuals (36 female participants) aged 20 to 59 years was recruited. Sensory nerve conduction studies were conducted to measure sural and radial sensory nerve action potential amplitudes. Quantile regression analysis was used to determine the fifth percentile of SRAR after adjusting for age, sex, and other demographic variables. This study found significant differences in body height and weight between the sexes, with radial sensory nerve action potential being higher in female participants. The sural-to-radial nerve amplitude ratio was negatively correlated with age (r = -0.3, p = 0.007) and showed significant sex differences. The final regression equation, SRAR = 0.519 - 0.006 × age + 0.046 × sex (1 = male, 0 = female), was developed for the fifth percentile cutoff, accounting for age and sex. This study establishes normative SRAR data and introduces a novel quantile regression approach to determine individualized cutoff values. Age and sex are critical factors for SRAR variation, necessitating tailored diagnostic criteria for neuropathy assessment. This model enhances diagnostic accuracy and potentially reduces misdiagnosis in clinical settings. Further research is recommended to validate the clinical applicability of SRAR across different types of neuropathies.

Paraproteinemic neuropathies.

The diagnostic evaluation of a peripheral neuropathy includes testing for the presence of monoclonal gammopathy, which can be found in about 10% of patients with peripheral neuropathy. Our role, as physicians, is to determine whether the neuropathy is directly related to the gammopathy or whether the co-occurrence of these two disorders is purely coincidental. The evaluating physician needs to be familiar with the different types of neuropathies associated with monoclonal gammopathies, their clinical and electrodiagnostic characteristics, and their appropriate diagnostic evaluation and management. Testing for monoclonal protein disorders includes serum protein electrophoresis (SPEP) and immunofixation of blood, and in some cases of urine, as well as measurement of free light chains and quantitative immunoglobulins. Specific antibody testing is directed by paraprotein type and neuropathy phenotype. Patients with abnormal free light chains in association with sensory and autonomic neuropathy should be evaluated for AL amyloidosis. When a lambda monoclonal protein is identified together with a clinical phenotype of chronic inflammatory demyelinating neuropathy (CIDP), a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes (POEMS) syndrome should be considered. Patients with IgM paraprotein associated neuropathy should be assessed for distal acquired demyelinating sensorimotor (DADS) neuropathy, with or without anti myelin associated glycoprotein (MAG) antibody or CANOMAD syndrome. In many cases, a monoclonal gammopathy of uncertain significance (MGUS) is incidental and unrelated to the neuropathy. Collaboration with oncology is critical in evaluating patients with monoclonal proteins to assess for underlying plasma cell neoplasms or B cell lymphomas.

Cross-sectional study investigating the association between inflammatory biomarkers and neuropathy in adolescents with type 1 diabetes

ObjectivesThe aims of this study were to investigate circulating levels of inflammatory markers in adolescents with type 1 diabetes with and without different types of neuropathies and evaluate the association...

Peripheral neuropathies associated with DNA repair disorders.

Repair of genomic DNA is a fundamental housekeeping process that quietly maintains the health of our genomes. The consequences of a genetic defect affecting a component of this delicate mechanism are quite harmful, characterized by a cascade of premature aging that injures a variety of organs, including the nervous system. One part of the nervous system that is impaired in certain DNA repair disorders is the peripheral nerve. Chronic motor, sensory, and sensorimotor polyneuropathies have all been observed in affected individuals, with specific physiologies associated with different categories of DNA repair disorders. Cockayne syndrome has classically been linked to demyelinating polyneuropathies, whereas xeroderma pigmentosum has long been associated with axonal polyneuropathies. Three additional recessive DNA repair disorders are associated with neuropathies, including trichothiodystrophy, Werner syndrome, and ataxia-telangiectasia. Although plausible biological explanations exist for why the peripheral nerves are specifically vulnerable to impairments of DNA repair, specific mechanisms such as oxidative stress remain largely unexplored in this context, and bear further study. It is also unclear why different DNA repair disorders manifest with different types of neuropathy, and why neuropathy is not universally present in those diseases. Longitudinal physiological monitoring of these neuropathies with serial electrodiagnostic studies may provide valuable noninvasive outcome data in the context of future natural history studies, and thus the responses of these neuropathies may become sentinel outcome measures for future clinical trials of treatments currently in development such as adeno-associated virus gene replacement therapies.

Clinical presentations and electromyographical aspects in toxic neuropathies

Objectives Peripheral nerves are likely to be damaged by a wide array of toxins and medications causing different types of neuropathies mainly affecting distal nerves. Toxic neuropathies are often misdiagnosed due to the lack of available specific evidence. However, they can be suspected through clinical examination and electrodiagnostic features. We aimed to determine the pattern of clinical and electroneuromyographic disorder in toxic neuropathies. Methods A retrospective study was carried out on patients who had history of neurotoxin exposure and diagnosed with toxic neuropathy. All cases underwent detailed neurological examination and appropriate investigations needed to exclude other causes of neuropathy, as well as electrophysiological studies (EMG). Results Over the 21 patients we selected: 9 were alcoholic, 4 glue-sniffing addicts, 2 received medication with metronidazole and 3 had chemotherapy. Two had a professional exposure to N-Hexane and 1 did a suicide attempt with organophosphate. Neurological examination showed motor deficit predominating in distal limbs (61.9%), areflexia (85.7%) amyotrophy (19%) as well as proprioceptive ataxia (42.8%) and hypoesthesia (33.3%). Electrophysiological studies showed a symmetric sensorial dominant sensory-motor axonal type polyneuropathy (90%) with greater involvement of lower extremities (100%). Therefore, demyelinating features were detected in 40% with increased distal and F wave latencies (35%), decreased motor and sensory nerve conduction velocities (40%), motor conduction block (15%) and temporal dispersion (5%) defining the polyradiculoneuropathy electromyographic criteria (20%). Denervation signs were revealed in 30%. Most of patients (57.14%) regained their sensory and motor capacities within few months. Conclusion Peripheral neuropathies secondary to toxins are increasingly considered but can be difficult to definitively diagnose especially when it presents with a subacute severe form mimicking Guillain-Barre syndrome. Yet, detecting the syndromic presentation and a history of toxin exposure can facilitate prompt and accurate diagnosis.

Early commitment of cardiovascular autonomic modulation in Brazilian patients with congenital generalized lipodystrophy

BackgroundMetabolic abnormalities in congenital generalized lipodystrophy (CGL) are associated with microvascular complications. However, the evaluation of different types of neuropathy in these patients, including the commitment of cardiovascular autonomic modulation, is scarce. The objective of the present study was to determine the prevalence of cardiovascular autonomic neuropathy (CAN) in patients with CGL compared with individuals with type 1 diabetes and healthy subjects.MethodsTen patients with CGL, 20 patients with type 1 diabetes and 20 healthy subjects were included in the study. Controls were paired 1:2 for age, gender, BMI and pubertal stage. Heart rate variability (HRV) was analyzed using cardiovascular autonomic reflex tests, including postural hypotension test, Valsalva (VAL), respiratory (E/I) and orthostatic (30/15) coefficients, and spectral analysis of the HRV, determining very low (VLF), low (LF) and high (HF) frequencies components. The diagnosis of CAN was defined as the presence of at least two altered tests.ResultsCAN was detected in 40% of the CGL patients, 5% in type 1 diabetes patients and was absent in healthy individuals (p < 0.05). We observed a significant reduction in the E/I, VLF, LF and HF in CGL cases vs. type 1 diabetes and healthy individuals and lower levels of 30/15 and VAL in CGL vs. healthy individuals. A significant positive correlation was observed between leptin and 30/15 coefficient (r = 0.396; p = 0.036) after adjusting for insulin resistance and triglycerides. Autonomic cardiovascular tests were associated with HbA1c, HOMA-IR, triglycerides and albumin/creatinine ratio in CGL cases.ConclusionsWe observed a high prevalence of CAN in young patients with CGL, suggesting that insulin resistance, hypertriglyceridemia and hypoleptinemia, may have been involved in early CAN development. Additional studies are needed to evaluate the role of leptinemia in the physiopathogenesis of the condition.

Severe Muscle Weakness Needing Intubation in AIDS Patient

SESSION TITLE: Critical Care 3 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Flaccid paralysis has myriad of differential diagnoses ranging from different types of neuropathies, myopathies and neuromuscular disorders. HIV is now a chronic disease with the advent of highly active anti retroviral therapy (HAART) such that several HIV related complications are now evident. HIV myopathy is a rare condition that can manifest at any stage of HIV irrespective of the CD4 count. We present a case of HIV associated myopathy in a patient who presented with about 2-3 day history of generalized weakness. CASE PRESENTATION: A 41-year-old woman with HIV/AIDS who was non compliant with HAART presented with flaccid paralysis which progressed to respiratory failure requiring intubation and mechanical ventilation. Her CD4 count was 6/mcL with 75000 HIV RNA copies/ml. Cerebrospinal fluid analysis was negative for albumin-cytological dissociation. MRI brain and spine were negative for progressive multifocal leukoencephalopathy. MRI of bilateral lower extremities showed intramuscular edema. EMG/NCS was inconclusive in view of obesity and severe edema. Creatine kinase and aldolase were mildly elevated. Left quadriceps femoris biopsy was suggestive of occlusive small arteriopathy consistent with vasculitis, and severe myofiber atrophy. ANA, ANCA, CMV PCR, HTLV I/II were negative. She had similar presentation a year ago where she responded to steroids which were tapered over 8 months ago. She was diagnosed with AIDS at that time and started on HAART, however, patient was non compliant with treatment. This time however, she had minimal response to steroids and antiretroviral therapy. She had ATN and subsequent renal failure from multiple medications. Given her poor prognosis, comfort measures were initiated and patient passed away shortly after extubation. DISCUSSION: Neuromuscular disorders associated with HIV include neuropathies such as distal symmetric polyneuropathy, acute and chronic inflammatory demyelinating neuropathy, mononeuropathy, radiculopathy, etc., and myopathies.1 Muscle disorders in HIV could be from the virus itself resulting in HIV myopathy, which is similar in picture to autoimmune polymyositis; drug induced myopathy from HAART such as zidovudine which is a mitochondrial disorder; HIV wasting syndrome; myopathy from opportunistic infections such as CMV, etc. The biggest case series with HIV induced polymyositis had remission in 80% of patients at 9 month follow up.2 However this result has not been replicated and HIV myopathy is thought to have variable steroid response. CONCLUSIONS: HIV myopathy is a rare manifestation with variable prognosis and response to steroids. Immunosuppressive therapy is used with caution due to toxicity. Reference #1: Robinson-Papp J, Simpson DM. Neuromuscular diseases associated with HIV-1 infection. Muscle Nerve. 2009;40:1043-1053. Reference #2: Johnson RW, Williams FM, Kazi S, Dimachkie MM, Reveille JD. Human immunodeficiency virus-associated polymyositis: a longitudinal study of outcome. Arthritis Rheum. 2003;49:172-178. DISCLOSURE: The following authors have nothing to disclose: Pooja Gurram, Vikas Koppurapu, Krishna Siva Sai Kakkera, Kevin Davis, Swathi Subramany, Rajani Jagana No Product/Research Disclosure Information

Neuropathy-specific alterations in a Mexican population of diabetic patients

BackgroundNeuropathy is one of the major complications of type 2 diabetes mellitus. Our first aim was to determine the clinical characteristics of a population of diabetic patients with different types of neuropathy. Our next goal was to characterize the cytokine profile (IL-6 and IL-10), nerve growth factor (NGF) and circulating cell-adhesion molecules in these patients. Finally, we aimed to compare the renal function among the groups of neuropathic patients.MethodsIn a cross-sectional study, we included 217 diabetic patients classified in three groups: sensory polyneuropathy with hypoesthesia (DShP) or hyperesthesia (DSHP), and motor neuropathy (DMN). Two control groups were included: one of 26 diabetic non-neuropathic patients (DNN), and the other of 375 non-diabetic (ND) healthy subjects. The participants were attending to the Mexican Institute of Social Security.ResultsThe circulating levels of NGF were significantly lower in diabetic patients, compared to healthy subjects. The range of IL-6 and IL-10 levels in neuropathic patients was higher than the control groups; however, several samples yielded null measurements. Neuropathic patients also showed increased circulating levels of the adhesion molecules ICAM, VCAM, and E-Selectin, compared to the ND group. Moreover, neuropathic patients showed reduced glomerular filtration rates compared to healthy subjects (82–103 ml/min per 1.73 m2, data as range from 25th–75th percentiles), especially in the group with DMN (45–76 ml/min per 1.73 m2).ConclusionsSome particular alterations in neuropathic patients included -but were not limited to- changes in circulating NGF, cell adhesion molecules, inflammation, and the worsening of the renal function. This study supports the need for further clinical surveillance and interventions considering a neuropathy-related basis.

Characterization of conformation-specific, human-derived monoclonal antibodies against TTR aggregates with potential for diagnostic and therapeutic use

Misfolding and aggregation of transthyretin (TTR) is the basic pathophysiological mechanism of hereditary and wild type TTR amyloid (ATTR) amyloidosis. Polyneuropathy and/or cardiomyopathy with heart failure dominates the clinical presentation of the disease. Conformational changes of the TTR protein structure produce toxic intermediates that introduce cell death and ultimately loss of organ function. Reliable and early diagnosis of ATTR amyloidosis are, however, difficult to obtain based on the patients’ clinical presentation, since different types of neuropathies or cardiomyopathies often exhibit similar clinical findings, especially early after onset of disease. Since misfolded TTR aggregates constitutes an early phase of amyloid formation, availability of a diagnostic tests able to detect misfolded TTR aggregates either biochemically or by imaging techniques would facilitate a correct and early diagnosis of ATTR amyloidosis. By comprehensive genetic sequence analyses of the human immune repertoire for TTR-specific memory B-cells, we cloned and recombinantly expressed human-derived monoclonal antibodies, which specifically bind with high affinity and selectivity to misfolded TTR but not physiological TTR tetramers. These antibodies specifically detect ATTR deposits in ATTR amyloidosis patients’ biopsies and TTR aggregates in corresponding tissues from TTR transgenic mouse-models. The selectivity of the human antibodies for misfolded TTR is driven by their targeting of cryptic or conformational epitopes which are exposed in misfolded and/or aggregated wild type as well as mutant TTR. These conformation-specific, human-derived monoclonal antibodies are promising candidates for diagnostic use, and for the development of disease-modifying therapies for TTR amyloidosis by targeting and facilitating the removal of disease-causing TTR aggregates.

Analyzing Relationship Between Monoclonal Gammopathy of Undetermined Significance (MGUS) with Different Types of Neuropathy: An Observational Study.

To analyze multiple variables, including immunoglobulin subtypes in patients with monoclonal gammopathy of undetermined significance (MGUS) and different types of neuropathy. This was a retrospective, single center study done in a tertiary care hospital in the United States. The data was collected for years 2001-2011. Inclusion criteria were the presence of MGUS and neuropathy. Exclusion criteria were the presence of other factors such as diabetes, vitamin B12 deficiency, alcoholism etc. which can cause neuropathy. Patients with IgM MGUS were compared with patients having Non-IgM MGUS. A total of 281 patients were analyzed in this study. The average age at the time of diagnosis of MGUS and neuropathy was 68years. The most common type of neuropathy was sensorimotor peripheral neuropathy (46%). The most common location of neuropathy was the lower extremities (68%). Among our patients, 52% had their neuropathy symptoms for 1-5years before presenting to the clinic. When IgM MGUS was compared with Non-IgM MGUS, a statistically significant difference was found in terms of race (White vs. Others, OR 4.43, 95% CI 2.13, 9.19, p<0.001) and survival status (OR 1.98, 95% CI 1.01, 3.90, p=0.046). Patients with MGUS are prone to develop different types of neuropathies. Caucasians are more likely to have IgM MGUS as compared to other races. IgM MGUS is generally related to worse outcomes as compared to Non-IgM MGUS. Medical therapies, including gabapentin and pregabalin are effective treatments and the response rate can be as high as 80-90% with these medications.

Peripheral Neuropathy Due to Vitamin Deficiency, Toxins, and Medications

Peripheral neuropathies secondary to vitamin deficiencies, medications, or toxins are frequently considered but can be difficult to definitively diagnose. Accurate diagnosis is important since these conditions are often treatable and preventable. This article reviews the key features of different types of neuropathies caused by these etiologies and provides a comprehensive list of specific agents that must be kept in mind. While most agents that cause peripheral neuropathy have been known for years, newly developed medications that cause peripheral neuropathy are discussed. Peripheral nerves are susceptible to damage by a wide array of toxins, medications, and vitamin deficiencies. It is important to consider these etiologies when approaching patients with a variety of neuropathic presentations; additionally, etiologic clues may be provided by other systemic symptoms. While length-dependent sensorimotor axonal peripheral neuropathy is the most common presentation, several examples present in a subacute severe fashion, mimicking Guillain-Barré syndrome.

Afferent control of walking: Are there distinct deficits associated to loss of fibres of different diameter?

ObjectivesTo compare the gait pattern in patients affected by different types of neuropathy. MethodsWe recruited healthy subjects (HS, n=38), patients with Charcot–Marie–Tooth disease type 1A (CMT1A) (n=10) and patients with diabetic neuropathy (DNP) (n=12). Neuropathy impairment score and neuropathy score were assessed. Body sway during quiet stance, and spatio-temporal gait parameters were recorded. ResultsMost patients had reduced or absent tendon-tap reflexes. Strength of foot dorsiflexor muscles (p<0.05) and conduction velocity (CV) of leg nerves (p<0.0001) were more impaired in CMT1A than DNP, whereas joint-position sense was more affected (p<0.05) in DNP. Body sway while standing was larger in DNP compared to CMT1A and HS (p<0.01 and p<0.0001 respectively). During gait, the distribution of foot sole contact pressure was abnormal in CMT1A (p<0.05) but not in DNP. Velocity and step length were decreased, and foot yaw angle at foot flat increased, in DNP with respect to CMT1A and HS (both variables, p<0.001). Gait velocity and step length were decreased (p<0.005) also in CMT1A, but to a smaller extent than in DNP, so that the difference between patient groups was significant (p<0.0005). Duration of the double support was protracted in DNP compared to CMT1A and HS (p<0.0005). For DNP only, velocity of gait and duration of single support were correlated (p<0.05) both to sway path and lower limb muscle strength. ConclusionsChanges in both body sway and stance phase of gait were larger in DNP than CMT1A, indicating more impaired static and dynamic control of balance when neuropathy affects the small in addition to the large afferent fibres. Diminished somatosensory input from the smaller fibres rather than muscle weakness or foot deformity plays a critical role in the modulation of the support phase of gait. SignificanceThe analysis of balance and gait in patients with neuropathy can offer a tool for understanding the nature and functional impact of the neuropathy and should be included in their functional evaluation.

Translational nociceptor research as guide to human pain perceptions and pathophysiology

Microneurography is a method for recording single unit action potentials with microelectrodes from the nerves of awake cooperating humans. Although this method is now in use since almost 40 years, its potency has been strengthened by the recent technical developments. A great progress was the discovery that different functional groups of nociceptors are characterized by a distinctly different post-excitatory slowing of their conduction velocities. Microneurography is now powerful enough to analyze the nerve activity pattern of enigmatic sensations such as pruritus. Furthermore, it is the only method providing direct insight in the changes which human nerves undergo with aging. Recently, reliable recordings from patients suffering from painful neuropathies came into reach. It has been shown that different types of neuropathies are characterized by different patterns of abnormal nociceptor functions. Although some of them are characterized by abnormal spontaneous activity in C-nociceptors, others show mainly signs of denervation. Microneurography is, therefore, a tool for translational studies on human nociceptor functions by linking direct animal studies on experimental neuropathies with human diseases.

Comparison of Oxaliplatin- and Cisplatin-Induced Painful Peripheral Neuropathy in the Rat

Although platinum-based cancer chemotherapies produce painful peripheral neuropathy as dose-limiting side effects, there are important differences in the pain syndromes produced by members of this class of drugs. In the rat, cisplatin-induced hyperalgesia has latency to onset of 24 to 48 hours, is maximal by 72 to 96 hours, and is attenuated by inhibitors of caspase signaling but not by inhibitors of the mitochondrial electron transport chain (mETC) and antioxidants. In contrast, oxaliplatin-induced mechanical hyperalgesia is already present by 5 minutes and peaks by 20 minutes. Whereas oxaliplatin hyperalgesia persists for weeks, starting around day 10 to 15, its severity decreases to a lower 2nd plateau level. The rapid-onset 1st plateau in oxaliplatin-induced hyperalgesia was characterized by prominent cold allodynia and in contrast to cisplatin was attenuated by inhibitors of the mETC and antioxidants but not inhibitors of caspase signaling. However, tested later during the 2nd plateau, it was characterized by less intense hyperalgesia and no cold allodynia and was attenuated by inhibitors of caspase signaling as well as by inhibitors of the mETC and by antioxidants. The findings of this study distinguish between the neuropathic pain syndromes produced by members of a single chemical class of anticancer drugs and suggest that the underlying mechanisms of various forms of peripheral neuropathy may be different. Further, it defines the need for selective therapy for different types of neuropathy.

Miller Fisher Variant of Guillain—Barré Syndrome Requiring a Cardiac Pacemaker in a Patient on Tacrolimus after Liver Transplantation

To report a case of Miller Fisher syndrome (MFS), a variant of Guillain-Barre syndrome (GBS) necessitating the placement of a permanent cardiac pacemaker in a patient on tacrolimus after a cadaveric orthotopic liver transplantation. A 46-year-old African American male, who had been receiving tacrolimus 4 mg/day orally for the preceding 6 months, developed a Miller Fisher variant of GBS (severe ataxia, ophthalmoplegia, areflexia). He developed symptomatic sinus pauses requiring a cardiac pacemaker. He improved substantially after cessation of tacrolimus and initiation of intravenous immunoglobulin therapy. The patient was not rechallenged with tacrolimus due to the clinical/ethical gravity of this probable adverse effect. Although different types of neuropathies have been reported with the use of tacrolimus, to the best of our knowledge, this is the first case report of a Miller Fisher variant of GBS severe enough to cause dysautonomia requiring a cardiac pacemaker associated with the use of this drug. Causality assessment using the Naranjo probability scale revealed the adverse drug event was probable. Tacrolimus was probably associated with a Miller Fisher variant of GBS necessitating the placement of a permanent cardiac pacemaker in this patient. MFS needs to be considered a potentially life-threatening adverse effect of tacrolimus therapy.

Neuromuscular complications in HIV.

HIV affects many organs of the body, including the nervous system. As a result, a series of neurologic complications have created challenges for scientists and clinicians alike. Among these, HIV-associated neuropathy and myopathy may occur at all stages of the disease process. Of the neuropathies, distal symmetrical polyneuropathy is the most common form. The pathogenesis of primary HIV neuropathy is unknown. Other types of neuropathy seen in HIV-infected subjects include toxic neuropathy, inflammatory demyelinating polyneuropathy, progressive polyradiculopathy, and mononeuritis multiplex. In this review, we present the clinical manifestations, pathogenesis, diagnosis, and management of different types of neuropathy in HIV infection. Myopathy, another complication of HIV, is not associated with any particular stage of immunosuppression. Symptoms include symmetrical weakness of the proximal muscles in the extremities. Serum creatine kinase levels are often moderately elevated. Electromyography and muscle biopsy are helpful tests for diagnosis. Treatment of HIV myopathy includes corticosteroids, nonsteroidal anti-inflammatory agents, and intravenous immunoglobulin.

Heart-rate variability for discrimination of different types of neuropathy in patients with insulin-dependent diabetes mellitus

It has been shown that patients with insulin-dependent diabetes mellitus (IDDM) may reveal abnormal alterations in heart-rate variability (HRV) due to autonomic neuropathy. This study was performed to prove whether heart-rate variability can be used to stratify diabetic patients with different types of neuropathy. 48 patients with IDDM (age 17-64 yr) underwent standard function tests to assess autonomic and peripheral neuropathy. According to the results of these tests they were divided into 4 groups: Group 1: 18 patients without autonomic or peripheral neuropathy. Group 2: 13 patients with peripheral neuropathy. Group 3: 7 patients with autonomic neuropathy. Group 4: 9 patients with autonomic and peripheral neuropathy. HRV was measured by continuous 24-hours monitoring and time domain parameters were calculated. The results were compared with sex and age-matched healthy controls according to the individual characteristics of the groups and among each subgroup. Our results showed that in Group 1 there was a significant difference of time domain parameters indicative of parasympathetic influence, i.e. rMSSD and pNN50 in comparison to the control subjects (p = 0.002, p = 0.008). These results depended on the duration of diabetes; a subgroup of patients with a duration of IDDM of less than 2 years had no significant differences of HRV values. Group 2 showed the same significant differences. Group 3 and 4 showed significant differences in all measured time domain variables (SDNN, SDANN, SDNN index, rMSSD and pNN50) in comparison to the control subjects (p < 0.04). A comparison of group 1 with group 2 offered significant differences in rMSSD and pNN50 (p = 0.004, p = 0.003). Comparing group 1 with group 3 and 4, all HRV parameters showed significant differences (p < 0.03). In conclusion, HRV is able to distinguish between patients with different types of neuropathy depending on the involvement of parasympathetic or more sympathetic influenced parameters. Furthermore, this method is able to unmask early manifestations of neurological disorders prior to their detection by neurological function tests.

Slowly conducting, low-threshold components of sensory nerve potentials in peripheral neuropathy: a microneurographic study.

By recording the averaged potential from a microelectrode inserted into the nerve, small late components of the sensory nerve action potential can be analyzed. We studied the thresholds of the late components in median nerves of 15 normal subjects and 37 patients with peripheral neuropathies. Under normal conditions, the late components reflected the activities of small myelinated fibers which had high thresholds. In the patients with peripheral neuropathies, a part of the late components often had abnormally low thresholds, occasionally the lowest. The presence of low-threshold, late components was related to the pathologies of the different types of neuropathy and correlated with the numbers of regenerating clusters in sural nerve biopsies. These slowly conducting, low-threshold components may originate from regenerating or remyelinating fibers, and therefore should have prognostic value.

Motor Nerve Conduction Studies

Motor nerve conduction studies are reviewed. The principles of electrode placement, stimulus intensity, algorithms for measurement of parameters, causes of variability, reference values, and reporting are discussed. A rigorous standardization of methods has several advantages. The sensitivity of each method is increased without loss of specificity. In addition, reference values obtained in one laboratory can be used in other laboratories as well. Pathophysiological interpretation of findings in different types of neuropathies is also presented.

AAEM minimonograph #41: Neuromuscular diseases associated with HIV‐1 infection

Neuromuscular diseases occur in as many as 50% of patients infected with human immunodeficiency virus type 1 (HIV-1). All forms of neuromuscular disease have been reported, including axonal neuropathy, demyelinating neuropathy, mononeuropathy multiplex, polyradiculitis, ALS-like syndromes, disorders of neuromuscular transmission, myopathy, and toxic neuropathies due to medication side effects. Neuromuscular disease is often the presenting manifestation of HIV-1 infection. Infection with cytomegalovirus (CMV) is associated with different types of neuropathy including mononeuritis multiplex and polyradiculopathy. There is effective treatment for many of the associated disorders including chronic inflammatory demyelinating neuropathy, CMV-mediated neuropathies, and myopathy. Treatment of CMV-mediated mononeuropathy multiplex may be life saving. The different neuromuscular syndromes associated with different stages of HIV-1 infection may be due, in part, to different levels of immunocompetence.