Rochester, MN, United States
Rochester, MN, United States

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Engelstad J.K.,Peripheral Neuropathy Research Laboratory | Taylor S.W.,Peripheral Neuropathy Research Laboratory | Witt L.V.,Peripheral Neuropathy Research Laboratory | Hoebing B.J.,Peripheral Neuropathy Research Laboratory | And 6 more authors.
Neurology | Year: 2012

Objectives: Our first objective was to explore the value of estimating 95% confidence intervals (CIs) of epidermal nerve fibers (ENFs)/mm for number of sections to be evaluated and for confidently judging normality or abnormality. Our second objective was to introduce a new continuous measure combining nerve conduction and ENFs/mm. Methods: The 95%CI studieswere performed on 1, 1-2, 1-3 - - - 1-10 serial skip sections of 3-mm punch biopsies of leg and thigh of 67 healthy subjects and 23 patients with diabetes mellitus. Results: Variability of differences of ENFs/mm counts (and 95% CIs) from evaluation of 1, 1-2, 1-3 - - - 1-9 comparedwith1-10 serial skip sections decreased progressively without a break point with increasing numbers of sections evaluated. Estimating 95% CIs as sections are evaluated can be used to judge how many sections are needed for adequate evaluation, i.e., only a fewwhen counts and 95% CIs are well within the range of normality or abnormality and more when values are borderline. Also provided is a methodology to combine results of nerve conduction and ENFs/mm as continuous measures of normality or abnormality. Conclusion: Estimating 95% CIs of ENFs/mm is useful to judge how many sections should be evaluated to confidently declare counts to be normal or abnormal. Also introduced is a continuous measure of both large-fiber (nerve conduction) and small-fiber (ENFs/mm) normal structures/functions spanning the range of normality and abnormality for use in therapeutic trials. © 2012 American Academy of Neurology.


Suanprasert N.,Peripheral Neuropathy Research Laboratory | Berk J.L.,Boston University | Benson M.D.,Indiana University | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory | And 5 more authors.
Journal of the Neurological Sciences | Year: 2014

Protein stabilization and oligonucleotide therapies are being tested in transthyretin amyloid polyneuropathy (TTR FAP) trials. From retrospective analysis of 97 untreated TTR FAP patients, we test the adequacy of Neuropathy Impairment Score + 7 tests (NIS + 7) and modifications to comprehensively score impairments for use in such therapeutic trials. Our data confirms that TTR FAP usually is a sensorimotor polyneuropathy with autonomic features which usually is symmetric, length dependent, lower limb predominant and progressive. NIS + 7 adequately assesses weakness and muscle stretch reflexes without ceiling effects but not sensation loss, autonomic dysfunction or nerve conduction abnormalities. Three modifications of NIS + 7 are suggested: 1) use of Smart Somatotopic Quantitative Sensation Testing (S ST QSTing); 2) choice of new autonomic assessments, e.g., sudomotor testing of distributed anatomical sites; and 3) use of only compound muscle action potential amplitudes (of ulnar, peroneal and tibial nerves) and sensory nerve action potentials of ulnar and sural nerve - than the previously recommended attributes suggested for the sensitive detection of diabetic sensorimotor polyneuropathy. These modifications of NIS + 7 if used in therapeutic trials should improve characterization and quantification of sensation and autonomic impairment in TTR FAP and provide better nerve conduction tests. © 2014 Elsevier B.V.


PubMed | Boston University, Indiana University, Peripheral Neuropathy Research Laboratory and Alnylam Pharmaceuticals
Type: Journal Article | Journal: Journal of the neurological sciences | Year: 2014

Protein stabilization and oligonucleotide therapies are being tested in transthyretin amyloid polyneuropathy (TTR FAP) trials. From retrospective analysis of 97 untreated TTR FAP patients, we test the adequacy of Neuropathy Impairment Score+7 tests (NIS+7) and modifications to comprehensively score impairments for use in such therapeutic trials. Our data confirms that TTR FAP usually is a sensorimotor polyneuropathy with autonomic features which usually is symmetric, length dependent, lower limb predominant and progressive. NIS+7 adequately assesses weakness and muscle stretch reflexes without ceiling effects but not sensation loss, autonomic dysfunction or nerve conduction abnormalities. Three modifications of NIS+7 are suggested: 1) use of Smart Somatotopic Quantitative Sensation Testing (S ST QSTing); 2) choice of new autonomic assessments, e.g., sudomotor testing of distributed anatomical sites; and 3) use of only compound muscle action potential amplitudes (of ulnar, peroneal and tibial nerves) and sensory nerve action potentials of ulnar and sural nerve - than the previously recommended attributes suggested for the sensitive detection of diabetic sensorimotor polyneuropathy. These modifications of NIS+7 if used in therapeutic trials should improve characterization and quantification of sensation and autonomic impairment in TTR FAP and provide better nerve conduction tests.


Kassardjian C.D.,Peripheral Neuropathy Research Laboratory | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory | Davies J.L.,Peripheral Neuropathy Research Laboratory | Carter R.E.,Mayo Medical School | Dyck P.J.,Peripheral Neuropathy Research Laboratory
Journal of the Neurological Sciences | Year: 2015

Background and objectives The association between prediabetes and distal polyneuropathy (DPN) remains controversial. Here we test whether the prevalence of small fiber sensory distal polyneuropathy is increased in prediabetes. Methods Prospectively recruited cohorts of healthy subjects and those with prediabetes from Olmsted County, Minnesota, were assessed for positive neuropathic sensory symptoms, or pain symptoms characteristic of small fiber sensory DPN. Hyperalgesia and hypoalgesia were assessed by "smart" quantitative sensation testing (QST). The prevalence of symptoms and QST abnormalities were compared among the groups. Results There was no significant increase in the prevalence of positive neuropathic sensory or pain symptoms, nor of hyper- or hypoalgesia in the prediabetes group. There was an increased prevalence of hypoalgesia of the foot only in newly diagnosed diabetes. Conclusions Based on positive sensory and pain symptoms and QSTs, we did not find an increase in small fiber sensory DPN in prediabetes. Recognizing that obesity and diabetes mellitus are implicated in macro- and microvessel complications, physicians should encourage healthy living and weight loss in patients with prediabetes. In medical practice, alternate causes should be excluded before concluding that small fiber sensory distal neuropathy is secondary to prediabetes. © 2015 Elsevier B.V. All rights reserved.


Kazamel M.,Mayo Medical School | Dyck P.J.,Peripheral Neuropathy Research Laboratory
Prosthetics and Orthotics International | Year: 2015

Background: Diabetes mellitus is among the most common causes of peripheral neuropathy worldwide. Sensory impairment in diabetics is a major risk factor of plantar ulcers and neurogenic arthropathy (Charcot joints) causing severe morbidity and high health-care costs. Objective: To discuss the different patterns of sensory alterations in diabetic neuropathies and their anatomical basis. Study design: Literature review. Methods: Review of the literature discussing different patterns of sensory impairment in diabetic neuropathies. Results: The different varieties of diabetic neuropathies include typical sensorimotor polyneuropathy (lower extremity predominant, length-dependent, symmetric, sensorimotor polyneuropathy presumably related to chronic hyperglycemic exposure, and related metabolic events), entrapment mononeuropathies, radiculoplexus neuropathies related to immune inflammatory ischemic events, cranial neuropathies, and treatment-related neuropathies (e.g. insulin neuritis). None of these patterns are unique for diabetes, and they can occur in nondiabetics. Sensory alterations are different among these prototypic varieties and are vital in diagnosis, following course, treatment options, and follow-up of treatment effects. Conclusions: Diabetic neuropathies can involve any segment of peripheral nerves from nerve roots to the nerve endings giving different patterns of abnormal sensation. It is the involvement of small fibers that causes positive sensory symptoms like pain early during the course of disease, bringing subjects to physician's care. Copyright © 2014 The International Society for Prosthetics and Orthotics.


Dyck P.J.,Peripheral Neuropathy Research Laboratory | Carter R.E.,Mayo Medical School | Litchy W.J.,Peripheral Neuropathy Research Laboratory
Muscle and Nerve | Year: 2011

Introduction: In this study we aimed to determine which criteria are valid for nerve conduction (NC) diagnosis of typical diabetic sensorimotor polyneuropathy (DSPN). Methods: Eight criteria were assessed from among diabetes databases, the Rochester Diabetic Neuropathy Study (RDNS, N = 456), and in healthy subjects (RDNS-HS, N = 330). Results: In the RDNS, the most frequent abnormal attributes (≤2.5th/≥97.5th percentile) are: fibular motor nerve conduction velocity (MNCV; 26.3%); sural sensory nerve conduction velocity (SNAP; 25.4%); tibial MNCV (24.8%); ulnar MNCV (21.3%); fibular F latency (16.9%); and ulnar F latency (16.0%). Normal deviate (from percentiles) composite scores of NC included: representative of neurophysiological abnormalities; sensitive and specific for diagnosis and useful for epidemiological surveys; randomized trials; and medical practice. By contrast, abnormality of one or more attributes in any nerve or abnormally of two most sensitive attributes performed poorly. Conclusions: Composite sum scores of normal deviates (from percentiles corrected for applicable variables) of sensitive NC attributes and with modifications, RDNS and AAN criteria performed acceptably for diagnosis of DSPN. © 2011 Wiley Periodicals, Inc.


Chahin N.,Peripheral Neuropathy Research Laboratory | Temesgen Z.,Mayo Medical School | Kurtin P.J.,Mayo Medical School | Spinner R.J.,Mayo Medical School | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory
Muscle and Nerve | Year: 2010

Diffuse infiltrative lymphocytosis syndrome (DILS) is a hyperimmune reaction against HIV. It leads to MHC-restricted clonal expansion of CD8 T cells characterized by circulating CD8 hyperlymphocytosis and CD8 T-cell infiltration in organs. Our patient presented with painful lumbosacral radiculo-plexus neuropathy and tested positive for HIV. Nerve biopsy showed large collections of CD8 lymphocytes suspicious for lymphoma. Symptoms, signs, and repeat biopsy improved with antiretroviral treatment. The presentation and treatment response suggest that this case is localized DILS. © 2009 Wiley Periodicals, Inc.


PubMed | Mayo Medical School and Peripheral Neuropathy Research Laboratory
Type: Journal Article | Journal: Journal of the neurological sciences | Year: 2015

The association between prediabetes and distal polyneuropathy (DPN) remains controversial. Here we test whether the prevalence of small fiber sensory distal polyneuropathy is increased in prediabetes.Prospectively recruited cohorts of healthy subjects and those with prediabetes from Olmsted County, Minnesota, were assessed for positive neuropathic sensory symptoms, or pain symptoms characteristic of small fiber sensory DPN. Hyperalgesia and hypoalgesia were assessed by smart quantitative sensation testing (QST). The prevalence of symptoms and QST abnormalities were compared among the groups.There was no significant increase in the prevalence of positive neuropathic sensory or pain symptoms, nor of hyper- or hypoalgesia in the prediabetes group. There was an increased prevalence of hypoalgesia of the foot only in newly diagnosed diabetes.Based on positive sensory and pain symptoms and QSTs, we did not find an increase in small fiber sensory DPN in prediabetes. Recognizing that obesity and diabetes mellitus are implicated in macro- and microvessel complications, physicians should encourage healthy living and weight loss in patients with prediabetes. In medical practice, alternate causes should be excluded before concluding that small fiber sensory distal neuropathy is secondary to prediabetes.


Tracy J.A.,Peripheral Neuropathy Research Laboratory | Dyck P.J.,Peripheral Neuropathy Research Laboratory | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory
Muscle and Nerve | Year: 2010

Peripheral neuropathy in primary (AL) amyloidosis is usually lower-limb predominant, length-dependent, symmetrical, and affects small (pain and autonomic) fibers, as much or more than large fibers. We report a patient with stepwise progressive, multiple upper limb mononeuropathies that were due to nerve biopsy-proven primary amyloidosis (lambda light chain), with no systemic or autonomic features. Recognition that light chain amyloidosis may be the cause of a multiple mononeuropathy pattern adds to the differential diagnosis of this clinical phenotype. © 2010 Wiley Periodicals, Inc.


Tracy J.A.,Peripheral Neuropathy Research Laboratory | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory
Journal of the Peripheral Nervous System | Year: 2011

Twenty-four patients, all of whom were exposed to aerosolized porcine brain tissue through work-place environment (abattoir), developed a syndrome of immune-mediated polyradiculoneuropathy; three also had central nervous system manifestations (transverse myelitis, meningoencephalitis, and aseptic meningitis). Patients had characteristic electrophysiological findings of very distal and proximal conduction slowing (prolonged distal and F-wave latencies, regions where the blood-nerve barrier is the most permeable) and all patients' serum contained a novel IgG immunofluorescence pattern. Nerve pathology, when available, showed mild changes of segmental demyelination, axonal degeneration, and inflammatory changes. Patients had meaningful improvement of symptoms and electrophysiologic findings with immune therapy and with removal of exposure to aerosolized brain tissue. We postulate that this outbreak is an auto-immune polyradiculoneuropathy triggered by occupational exposure to multiple aerosolized porcine neural tissue antigens that result in neural damage where the blood-nerve barrier is the least robust. © 2011 Peripheral Nerve Society.

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