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Hertz P, Bril V, Orszag A, Ahmed A, Ng E, Nwe P, Ngo M, Perkins BA. Reproducibility of in vivo corneal confocal microscopy as a novel screening test for early diabetic sensorimotor polyneuropathy. Diabet Med 2011; 28:1253-60. [PMID: 21434993 DOI: 10.1111/j.1464-5491.2011.03299.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AIM With the goal of identifying a valid biomarker of early diabetic sensorimotor polyneuropathy, we aimed to identify the most reliable in vivo corneal confocal microscopy (CCM) parameter for detection of abnormality of small nerve fibre morphology. METHODS Cross-sectional examination of 46 subjects (26 with Type 1 diabetes and 20 healthy volunteers) examined by corneal confocal microscopy for intra- and interobserver reproducibility by the intraclass correlation coefficient method. Corneal nerve fibre density, nerve branch density, nerve fibre length and tortuosity were measured on the same day that subjects underwent clinical and electrophysiological examination. RESULTS The 26 subjects with Type 1 diabetes had mean age and diabetes duration 42.8 ± 16.9 and 22.7 ± 16.4 years, respectively. Twelve of those subjects (46%) did not meet criteria for diabetic sensorimotor polyneuropathy, while five (19%) had mild, three (12%) had moderate and six (23%) had severe diabetic sensorimotor polyneuropathy. None of the healthy volunteers (mean age 41.4 ± 17.3 years) had polyneuropathy. Re-examination of selected corneal confocal microscopy images or sets of 40 images yielded very good to excellent intraclass correlation coefficients for all parameters. However, only one parameter (corneal nerve fibre length) emerged with consistently very good reproducibility using a clinically relevant 'study-level' protocol of subject re-examination (intra-observer intraclass correlation coefficient 0.72; interobserver intraclass correlation coefficient 0.73). Despite no differences in intraclass correlation coefficient between subgroups, corneal nerve fibre length was significantly lower (14.76 vs. 16.15 mm/mm(2), P = 0.04) in those with diabetes. CONCLUSIONS Development of corneal confocal microscopy may need to focus on the measurement of corneal nerve fibre length, as it appears to have superior reliability in comparison with other parameters, and as evidence exists for its potential as a clinical biomarker of early diabetic sensorimotor polyneuropathy.
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Barth D, Nabavi Nouri M, Ng E, Nwe P, Bril V. Comparison of IVIg and PLEX in patients with myasthenia gravis. Neurology 2011; 76:2017-23. [PMID: 21562253 PMCID: PMC3109880 DOI: 10.1212/wnl.0b013e31821e5505] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 02/18/2011] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Both IV immunoglobulin (IVIg) and plasma exchange (PLEX) are immunomodulatory treatments used to treat patients with myasthenia gravis (MG), but the choice of which treatment to administer to patients is limited due to lack of evidence from adequately powered, masked, randomized, standardized trials. METHODS We randomized 84 patients with moderate to severe MG defined as a Quantitative Myasthenia Gravis Score for disease severity (QMGS) of >10.5 and worsening weakness to IVIg (Gamunex®, Talecris Biotherapeutics) 1 g/kg/day for 2 consecutive days or PLEX (Caridian Spectra) 1.0 plasma volume exchanges for 5 exchanges. The patients were evaluated at day 14 after treatment for the primary efficacy parameter of change in QMGS and secondary clinical and electrophysiologic parameters and were followed for a total of 60 days. RESULTS Both IVIg and PLEX reduced the QMGS, and IVIg was comparable to PLEX in efficacy. The dropout rate was the same for both treatment arms and both treatments were well-tolerated. The presence of acetylcholine receptor antibodies and greater baseline disease severity predicted a better response to therapy. The postintervention status revealed that the same proportion of patients improved with treatment: 69% on IVIg and 65% on PLEX. The duration of improvement was similar with both treatments. CONCLUSIONS IVIg has comparable efficacy to PLEX in the treatment of patients with moderate to severe MG. Both treatments are well-tolerated, and the duration of effect is comparable. Either treatment may be offered to patients depending on availability of resources. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that IVIg and PLEX have comparable efficacy and are equally tolerated in adult patients with moderate to severe MG within 2 weeks of treatment.
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Bril V, England J, Franklin GM, Backonja M, Cohen J, Del Toro D, Feldman E, Iverson DJ, Perkins B, Russell JW, Zochodne D. Evidence-based guideline: Treatment of painful diabetic neuropathy: report of the American Academy of Neurology, the American Association of Neuromuscular and Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation. Neurology 2011; 76:1758-65. [PMID: 21482920 DOI: 10.1212/wnl.0b013e3182166ebe] [Citation(s) in RCA: 344] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To develop a scientifically sound and clinically relevant evidence-based guideline for the treatment of painful diabetic neuropathy (PDN). METHODS We performed a systematic review of the literature from 1960 to August 2008 and classified the studies according to the American Academy of Neurology classification of evidence scheme for a therapeutic article, and recommendations were linked to the strength of the evidence. The basic question asked was: "What is the efficacy of a given treatment (pharmacologic: anticonvulsants, antidepressants, opioids, others; and nonpharmacologic: electrical stimulation, magnetic field treatment, low-intensity laser treatment, Reiki massage, others) to reduce pain and improve physical function and quality of life (QOL) in patients with PDN?" RESULTS AND RECOMMENDATIONS Pregabalin is established as effective and should be offered for relief of PDN (Level A). Venlafaxine, duloxetine, amitriptyline, gabapentin, valproate, opioids (morphine sulfate, tramadol, and oxycodone controlled-release), and capsaicin are probably effective and should be considered for treatment of PDN (Level B). Other treatments have less robust evidence or the evidence is negative. Effective treatments for PDN are available, but many have side effects that limit their usefulness, and few studies have sufficient information on treatment effects on function and QOL.
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Perkins BA, Dholasania A, Buchanan RA, Bril V. Short-term metabolic change is associated with improvement in measures of diabetic neuropathy: a 1-year placebo cohort analysis. Diabet Med 2010; 27:1271-9. [PMID: 20950385 DOI: 10.1111/j.1464-5491.2010.03110.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AIMS Randomized clinical trials have frequently shown improvement in diabetic sensorimotor polyneuropathy in placebo-treated participants, counter to the prevailing concept that it deteriorates with time. We aimed to determine the variables associated with this paradoxical nerve function improvement. METHODS Participants with diabetic sensorimotor polyneuropathy randomized to placebo in a multi-centre, double-blind study were evaluated for the primary outcome of 1-year change in the summed sensory nerve conduction velocity of the bilateral sural and non-dominant median nerves. Association with clinical and biochemical variables measured at 13 time points were examined. RESULTS The 134 participants had mild to moderate diabetic sensorimotor polyneuropathy of 4.6 years' duration and mean 1-year improvement of 2.0 ± 8.0 m/s. Primary outcome measures were available for 122 participants (91%). In multivariate analyses, the change in HbA(1c) and serum triglycerides from baseline to 2 months demonstrated the strongest association, even independent of baseline and end-of-study levels. According to quintiles of change, we determined thresholds: participants with salutary improvement in HbA(1c) (exceeding a drop of -0.8%) or whose triglycerides did not increase (by 0.32 mmol/l or more) experienced significant improvement (2.9 m/s), while those with salutary levels of both these variables had an exaggerated improvement (5.1 m/s). In comparison, those with non-salutary changes in both variables experienced a loss of -4.9 m/s (ANOVA P=0.0014). CONCLUSIONS In mild to moderate diabetic sensorimotor polyneuropathy, short-term improvements in glycaemic control and serum triglyceride levels have an independent, additive and durable effect on restoration of nerve function.
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Merkies I, Bril V, Dalakas MC, Deng C, Donofrio P, Hanna K, Hartung HP, Hughes RA, Latov N, van Doorn PA. Health-related quality-of-life improvements in CIDP with immune globulin IV 10%: The ICE Study. Neurology 2009; 72:1337-44. [DOI: 10.1212/wnl.0b013e3181a0fd80] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Bril V, Tomioka S, Buchanan RA, Perkins BA. Reliability and validity of the modified Toronto Clinical Neuropathy Score in diabetic sensorimotor polyneuropathy. Diabet Med 2009; 26:240-6. [PMID: 19317818 PMCID: PMC2871179 DOI: 10.1111/j.1464-5491.2009.02667.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
INTRODUCTION A reliable and valid clinical tool to capture symptoms and signs of diabetic sensorimotor polyneuropathy (DSP) for use in clinical research trials is urgently needed. The validated Toronto Clinical Neuropathy Score (TCNS) was modified to improve sensitivity to early DSP changes. We aimed to assess the reproducibility of this modified tool, the mTCNS and to determine its validity relative to the precursor TCNS. METHODS Sixty-five patients (six Type 1, 59 Type 2 diabetes) with diabetes duration 13 +/- 8 years were accrued from four study sites and examined on 2 days for internal consistency and inter- and intra-rater reliability of the mTCNS. In the absence of a single quantitative gold-standard measure for DSP, results of the mTCNS were compared with the precursor TCNS for the purpose of estimating validity. RESULTS Internal consistency of the two domains within the mTCNS was good (Cronbach's alpha 0.78). Very good inter-rater reliability for the mTCNS was demonstrated by an intra-class correlation coefficient for the mTCNS of 0.87 (95% confidence interval, 0.79-0.91), which was similar in magnitude to that of the TCNS (0.83; 95% confidence interval, 0.75-0.89). Intra-rater reliability testing of the mTCNS showed moderate to good correlation for individual symptoms and sensory tests (Cohen's kappa values of 0.54-0.73). The mTCNS shared moderate correlation with the precursor TCNS (Pearson correlation coefficient, 0.58). DISCUSSION The mTCNS, a clinical score with higher face validity for tracking mild to moderate DSP, has sufficient reliability and validity relative to its precursor TCNS for use in clinical research.
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Bril V. W16 Neurophysiology and clinical trials. Clin Neurophysiol 2006. [DOI: 10.1016/j.clinph.2006.07.084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Bril V, Zinman L. FC1.2 Comparison of electrophysiological studies and clinical evaluation as measures of treatment response in patients with myasthenia gravis. Clin Neurophysiol 2006. [DOI: 10.1016/j.clinph.2006.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zinman LH, Sutton D, Ng E, Nwe P, Ngo M, Bril V. A pilot study to compare the use of the Excorim staphylococcal protein immunoadsorption system and IVIG in chronic inflammatory demyelinating polyneuropathy. Transfus Apher Sci 2005; 33:317-24. [PMID: 16239123 DOI: 10.1016/j.transci.2005.07.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Accepted: 07/30/2005] [Indexed: 10/25/2022]
Abstract
Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune mediated neuropathy responding to immunomodulation with IVIG or plasma exchange (PE). We tested the efficacy and safety of selective immunoglobulin removal by Excorim immunoadsorption (IA) in a pilot trial in CIDP patients randomized to monthly IA or IVIG treatments for 6 months. Response rates at 2 and 6 months were greater with IA due to longer disease duration and greater disability at baseline in the patients receiving IVIG. IA appears to be a safe and efficacious therapy for patients with CIDP, but an appropriately powered clinical trial with stratification for disease duration is required.
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Olaleye D, Perkins BA, Bril V. Evaluation of three screening tests and a risk assessment model for diagnosing peripheral neuropathy in the diabetes clinic. J Peripher Nerv Syst 2002. [DOI: 10.1046/j.1529-8027.2002.02011_11.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bril V. STATUS OF CURRENT CLINICAL TRIALS IN DIABETIC POLYNEUROPATHY. J Peripher Nerv Syst 2002. [DOI: 10.1046/j.1529-8027.2002.2008_5.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Olaleye D, Perkins BA, Bril V. Evaluation of three screening tests and a risk assessment model for diagnosing peripheral neuropathy in the diabetes clinic. Diabetes Res Clin Pract 2001; 54:115-28. [PMID: 11640995 DOI: 10.1016/s0168-8227(01)00278-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE with the aim of evaluating predictive power, three simple screening tests as alternates to nerve conduction tests for diagnosing diabetic peripheral neuropathy (DPN) were investigated. Results of the screening tests, along with the subjects' demographic and clinical characteristics, were planned as the variables for the development of a risk assessment tool for predicting DPN. DESIGN this is a cross-sectional multi-group comparison study. The study utilized a predictive model derived from one subset of the study population, and prospectively tested in the other subset to predict the presence of neuropathy. SETTING Diabetic Neuropathy Research Clinic of the Toronto General Hospital and University Health Network in Toronto, Ontario, Canada from June 1998 to August 1999. SAMPLE POPULATION data come from 478 subjects consisting of non-diabetic reference subjects, and patients with type 1 and type 2 diabetes mellitus. OUTCOMES MEASURES nerve conduction studies (NCS) comprised the primary defined outcome. The three screening sensory tests examined in the study were the Semmes-Weinstein 10 g monofilament examination (SWME), superficial pain sensation, and vibration by the on-off method. RESULTS the three screening tests are significantly and positively correlated with NCS. An increase in the number of insensate responses in the screening test is associated with an increase in the abnormal NCS score. The strength of the association between NCS and each sensory test was greater when the neuropathy severity stage of the subject was added to the model. Both the SWME and vibration by the on-off method tests demonstrated sufficient statistical power to differentiate non-diabetic control subjects from subjects with diabetes, as well as to differentiate subjects with diabetes with and without neuropathy. These two tests, when compared with NCS, also demonstrated acceptable diagnostic performance characteristics in terms of high sensitivity and specificity, total number of correctly predicted cases, and receiver-operating characteristic curves. CONCLUSION this data, through the development of a model involving training and validation sets, demonstrates that the knowledge of clinical risk factors alters the interpretation of sensory tests for DPN. This finding lends further support to the validity of simple sensory testing maneuvers in the conditional diagnosis of DPN. We recommend annual screening with either the SWME or vibration by the on-off method in the primary care and diabetes clinics.
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Apfel SC, Asbury AK, Bril V, Burns TM, Campbell JN, Chalk CH, Dyck PJ, Dyck PJ, Feldman EL, Fields HL, Grant IA, Griffin JW, Klein CJ, Lindblom U, Litchy WJ, Low PA, Melanson M, Mendell JR, Merren MD, O'Brien PC, Rendell M, Rizza RA, Service FJ, Thomas PK, Walk D, Wang AK, Wessel K, Windebank AJ, Ziegler D, Zochodne DW. Positive neuropathic sensory symptoms as endpoints in diabetic neuropathy trials. J Neurol Sci 2001; 189:3-5. [PMID: 11596565 DOI: 10.1016/s0022-510x(01)00584-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bril V. Do case series have a role in an evidence-based medical culture? Can J Neurol Sci 2001; 28:189-90. [PMID: 11513336 DOI: 10.1017/s0317167100001323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Peripheral polyneuropathy is the most frequent complication of diabetic mellitus. In spite of many clinical trials of different specific interventions for diabetic polyneuropathy, intensive glycemic control remains the only effective specific therapy currently available for this troublesome complication. This systematic overview reports the status of current clinical trials in diabetic polyneuropathy with an emphasis on those interventions directed towards specific pathophysiological derangements. A discussion of clinical trials of agents directed towards relieving painful symptoms of diabetic polyneuropathy concludes this overview.
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Perkins BA, Greene DA, Bril V. Glycemic control is related to the morphological severity of diabetic sensorimotor polyneuropathy. Diabetes Care 2001; 24:748-52. [PMID: 11315842 DOI: 10.2337/diacare.24.4.748] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The aim of the current study was to determine the independent clinical risk factors for predicting morphological severity of distal diabetic sensorimotor polynecuropathy (DSP) as determined by fiber density (FD) on sural nerve biopsy. RESEARCH DESIGN AND METHODS A total of 89 patients with both type 1 and type 2 diabetes, ascertained from a large therapeutic randomized clinical trial, were included in this observational cohort study. Morphological severity of DSP was expressed as the myelinated FD in the sural nerve biopsy General linear models were used to assess the relationship between the morphological severity of DSP and various clinical risk factors. RESULTS Glycated hemoglobin (GHb) was significantly related to FD in univariate and multivariate regression analyses. This relationship was present in models in which GHb was handled either as a continuous variable or as a categorical variable with the highest significance level, with a GHb cutoff level of 9%. After dividing patients into groups with optimal to moderate GHb < or = 9%) and suboptimal (GHb >9%) glycemic control, the difference in FD between the two groups ranged between 3,461 and 2,334 per mm2. FD was also significantly related to duration of diabetes and age of the patient. CONCLUSIONS The severity of peripheral DSP expressed by morphological criteria was significantly related to glycemic control in type 1 and type 2 diabetic patients. Inconsistent with previously published electrophysiological data demonstrating a correlation between height and conduction velocity, increasing height is not associated with morphological severity. Based on the results of the present study, it might be hypothesized that improving glycemic control will lessen severity of DSP in terms of FD loss in subjects with diabetes.
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Abstract
OBJECTIVE The utility of rapid and reliable sensory tests appropriate for the diagnosis of neuropathy in the diabetes clinic, rather than as prognostic tools for the prediction of foot complications, has been unclear because of limitations inherent in previous studies. Although clinical practice guidelines recommend annual screening for neuropathy, they are unable to support specific recommendations for screening maneuvers because of a lack of evidence for the validity of screening tests in the medical literature. The objective of this study was to assess the operating characteristics of four simple sensory screening maneuvers as compared with standardized electrophysiological tests in the diagnosis of distal symmetrical polyneuropathy. RESEARCH DESIGN AND METHODS We assessed four simple tests (the 10-g Semmes-Weinstein monofilament examination [SWME], superficial pain sensation, vibration testing by the on-off method, and vibration testing by the timed method) in 478 subjects with independent blinded evaluations compared against the criterion standard of nerve conduction studies. We present receiver-operating characteristic (ROC) curves, positive and negative likelihood ratios, and sensitivity and specificity values for each test. RESULTS The four simple screening maneuvers reveal similar operating characteristics. Cutoff points by ROC curve analyses reveal that a positive or abnormal test is represented by five incorrect responses of eight stimuli applied. A negative or normal test is represented by one or fewer incorrect responses of eight stimuli applied. By these criteria, the point estimates of the positive likelihood ratios for vibration testing by the on-off method, vibration testing by the timed method, the SWME, and superficial pain sensation test are 26.6, 18.5, 10.2, and 9.2, respectively. The point estimates of the negative likelihood ratios are 0.33, 0.51, 0.34, and 0.50, respectively The screening tests showed comparable sensitivity and specificity results. The 10-g SWME, superficial pain test, and vibration testing by the on-off method are rapid, each requiring approximately 60 s to administer. The timed vibration test takes longer, and the interpretation is more complicated. The combination of two simple tests (e.g., the 10-g SWME and vibration testing by the on-off method) does not add value to each individual screening test. CONCLUSIONS Annual screening for diabetic neuropathy should be conducted using superficial pain sensation testing, SWME, or vibration testing by the on-off method. The reported operating characteristics for each sensory modality can be applied to positive findings on the physical examination of individual patients to predict the likelihood of neuropathy.
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Risk M, Bril V, Broadbridge C, Cohen A. Heart rate variability measurement in diabetic neuropathy: review of methods. Diabetes Technol Ther 2001; 3:63-76. [PMID: 11469709 DOI: 10.1089/152091501750220028] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Heart rate variability (HRV) is an important tool to analyze the autonomic function. It therefore has a special interest for early detection and ensuing treatment of autonomic neuropathy in diabetic patients. The aim of this work is to present a brief historical review of HRV, as well as a technical review of the most common methods to measure it. In this work is presented a system that performs three measurements of HRV. An overview of methodologies developed to quantify HRV is presented; this technical review covers the most common time and frequency domain techniques, for short and long periods of time, with comments about clinical utility of these tests. A system performing three standard tests of HRV, Anscore Health Management System, is presented. This system performs metronomic breathing (MT), the Valsalva Test (VT), and the Stand Test (ST). A normal range study with 212 healthy subjects in three centers (ages 20-80 years, with even age distribution, and even male and female distribution) was conducted. A subset of 45 subjects from the total number of subjects was selected for the reproducibility study, consisting of three measurements of each test. The normal range study showed a decrease in all the ratios with age and, for the Valsalva test, a difference among genders; 5th percentiles were calculated. The reproducibility study results, expressed as mean CV%, were 4.30% for the MT, 6.26% for the VT, and 6.66% for the ST. HRV is the most reliable measurement of autonomic function; when controlled maneuvers like MT, VT, and ST are performed, high reproducibility is obtained, with results comparable to that observed for nerve conduction studies. Such reproducibility makes autonomic function testing more feasible as a test component in multicenter studies of different neurological disorders.
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Bril V, Janzen D, Gin H, Ngo M, Bergstrom B. Sensory nerve area measurements in patients with diabetic neuropathy. ELECTROMYOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 2001; 41:59-63. [PMID: 11234569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Sensory nerve potential area measurements may reflect the properties of underlying nerve fibres better than amplitude or conduction velocity measures. The terminal segment of the sensory curve may contain activity of regenerating nerve fibres. The reliability of area measurements of sensory potentials obtained with surface recording techniques is unknown. We scanned sural nerve sensory potential curves and measured the areas under different parts of the curve in 52 reference and 73 diabetic polyneuropathy (DPN) patients. The variability of repeat testing in reference subjects for total area was 12% and for the terminal segmental area (TSA) was 19%. In DPN patients, the total area variability was 17% and TSA variability was 24%. This compares to amplitude variability of 8% in reference subjects and 10% in patients with DPN. These results demonstrate that sensory potential area measurements are feasible, but highly variable. We conclude that current clinical trials do not include sufficient numbers of patients to show change in area measurements, particularly the area under the terminal segment of the curve.
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Bril V, Perkins B. Vibration Perception Thresholds: Comparison Of Case IV And Neurothesiometer Measurements. J Peripher Nerv Syst 2000. [DOI: 10.1046/j.1529-8027.2000.005003180.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
We performed upper- and lower-limb sympathetic skin responses (SSRs) in a series of 337 diabetic patients with and without peripheral polyneuropathy and 38 reference subjects. We did not find any correlations between SSRs and symptoms of pain or autonomic dysfunction. The SSR correlated more strongly with vibration perception threshold (VPT) and sural nerve amplitude than with cooling detection threshold (CDT) or clinical symptoms. We conclude that current limitations inherent in SSR testing preclude its use as a reliable and consistent index of the autonomic dysfunction commonly encountered in diabetic patients.
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Bril V. NIS-LL: the primary measurement scale for clinical trial endpoints in diabetic peripheral neuropathy. Eur Neurol 2000; 41 Suppl 1:8-13. [PMID: 10023123 DOI: 10.1159/000052074] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Regulatory authorities favour the use of clinical endpoints, over surrogate endpoints, to demonstrate the efficacy of therapeutic agents for diabetic peripheral neuropathy (DPN). Progress in the quantification of the severity of DPN has been observed in recent years. The NIS-LL (Neuropathy Impairment Score in the Lower Limbs) is a new scale which quantifies the neurological function in DPN. This scale for determining the neuropathy impairment in DPN optimises the chances of demonstrating clinical change following pharmaceutical intervention in patients with early-stage neuropathy. The use of the NIS-LL in clinical trials, together with other tests measuring nerve function, pain and risk of foot ulcer, provides the best opportunity to evaluate the efficacy of new therapeutic agents for the treatment of DPN.
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Ashworth NL, Zochodne DW, Hahn AF, Pillay N, Chalk C, Benstead T, Bril V, Feasby TE, Bolton CF. Impact of plasma exchange on indices of demyelination in chronic inflammatory demyelinating polyradiculoneuropathy. Muscle Nerve 2000; 23:206-10. [PMID: 10639612 DOI: 10.1002/(sici)1097-4598(200002)23:2<206::aid-mus10>3.0.co;2-k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We studied the impact of plasma exchange (PE) on indices of primary demyelination in patients of the Canadian multicenter trial of PE in chronic inflammatory demyelinating polyneuropathy (CIDP). Individual motor nerves (median, ulnar, peroneal, tibial) were studied: distal motor latencies (DMLs), proximal and distal compound muscle action potential (M-wave) amplitudes, negative peak areas and durations, and motor conduction velocities (CVs). Proximal M-wave amplitudes in individual motor territories, particularly in the ulnar nerve (from below elbow, above elbow, and axillary stimulating sites) demonstrated significant improvement with PE, but not sham exchange. Proximal ulnar M-wave areas also had significant improvement with PE. Trends toward improvement of individual nerve motor CVs, M-wave durations, and DMLs did not achieve statistical significance. Proximal M-wave amplitudes, particularly in the ulnar motor territory, and proximal M-wave areas (providing a measure of conduction block) were the most sensitive indices of improvement conferred by PE in CIDP. In individual patients, these indices may help judge the efficacy of therapy.
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