RESUMEN
INTRODUCTION: Gait impairment is a common presenting symptom in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). However, gait parameters have not previously been evaluated in detail as potential independent outcome measures. METHODS: We prospectively measured changes in spatiotemporal gait parameters of 20 patients with CIDP at baseline and following treatment with intravenous immunoglobulin (IVIG), using GAITRite® a computerized walkway system with embedded sensors. RESULTS: Overall, study patients showed significant improvements in gait velocity, cadence, stride length, double support time, stance phase, and swing phase following IVIG treatment. Mean changes in velocity, stance phase, and swing phase, exhibited the greatest statistical significance among the subgroup that exhibited clinically meaningful improvement in Inflammatory Neuropathy Cause and Treatment disability score, Medical Research Council sum score, and grip strength. CONCLUSIONS: Assessment of gait parameters, in particular velocity, step phase and swing phase, is a potentially sensitive outcome measure for evaluating treatment response in CIDP. Muscle Nerve 56: 732-736, 2017.
Asunto(s)
Marcha/efectos de los fármacos , Inmunoglobulinas Intravenosas/administración & dosificación , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/diagnóstico , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/tratamiento farmacológico , Conducta Espacial/efectos de los fármacos , Administración Intravenosa , Anciano , Femenino , Marcha/fisiología , Humanos , Masculino , Persona de Mediana Edad , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , Estudios Prospectivos , Conducta Espacial/fisiología , Factores de Tiempo , Resultado del TratamientoRESUMEN
INTRODUCTION: European Federation of Neurological Societies/Peripheral Nerve Society electrodiagnostic (EDx) criteria for the definite diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) require the presence of demyelinating findings (DF) in at least 2 nerves. Data are lacking, however, regarding the optimal number of nerves to test. METHODS: We retrospectively reviewed EDx data from 53 patients with CIDP and compared the number of DF found on 2- and 3-limb testing. RESULTS: A median of 3 (range 2-5) DF were found on 2-limb testing compared with 5 (range 4-7) DF when 3 limbs were evaluated. Two-limb EDx studies were sufficient to diagnose definite CIDP in 92.3% of typical, 84.2% of asymmetric, and 66.7% of distal phenotypes. Testing a third limb increased diagnostic certainty in 11 patients (20.8%) to definite CIDP. CONCLUSIONS: Three-limb testing may increase diagnostic sensitivity of definite CIDP, especially in patients with atypical phenotypes. Larger prospective studies are needed to better assess the benefit of performing 3-limb EDx studies.
Asunto(s)
Electrodiagnóstico , Extremidades/fisiopatología , Conducción Nerviosa/fisiología , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/diagnóstico , Potenciales de Acción/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades Desmielinizantes/diagnóstico , Enfermedades Desmielinizantes/fisiopatología , Electrodiagnóstico/métodos , Extremidades/inervación , Humanos , Persona de Mediana Edad , Nervios Periféricos/fisiopatología , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
INTRODUCTION: Electrodiagnostic studies (EDX) are not performed routinely before treatment suspension in CIDP, and no data exist regarding their value in predicting clinical relapse. METHODS: Serial EDX (baseline and after IGIV-C therapy) were analyzed from subjects in the ICE clinical trial who responded to IGIV-C treatment and were subsequently re-randomized to placebo in an extension phase. Comparisons were made between subjects who relapsed and those who did not. RESULTS: A total of 55% (6/11) of the Relapse group had an increase in total number of demyelinating findings (DF) versus 8% (1/13) in the No Relapse group (P = 0.023). In the Relapse group, 100% had ≥ 1 new DF and 73% (8/11) had ≥ 4 new DF versus 60% (8/13) and 8% (1/13), respectively, in the No Relapse group. CONCLUSIONS: An increased total number of DF or the occurrence of ≥ 4 new DF may indicate a higher risk of clinical relapse after treatment cessation in IGIV-C-responsive patients.
Asunto(s)
Inmunoglobulinas Intravenosas/uso terapéutico , Factores Inmunológicos/uso terapéutico , Conducción Nerviosa/efectos de los fármacos , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/terapia , Resultado del Tratamiento , Potenciales de Acción/efectos de los fármacos , Adulto , Anciano , Electrodiagnóstico , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Conducción Nerviosa/fisiología , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , Tiempo de Reacción , RecurrenciaRESUMEN
Peripheral nervous system disease is a common and often debilitating feature of many systemic rheumatologic disorders. Such involvement takes many forms, reflecting the variety of underlying pathophysiology, though most patients present with painful multifocal neuropathy (usually vasculitic) or a distal sensory more than motor peripheral neuropathy (sometimes vasculitic and nearly always axonal). The presence of peripheral nervous system involvement is often an early signal of the generalization of inflammatory disease in blood vessels or extravascular tissues, though peripheral neuropathy is not itself an independent predictor of mortality. Nonetheless, progressive multifocal neuropathy, motor neuropathy, small fiber neuropathy, and sensory neuronopathy should be treated early and aggressively with immunosuppression (or the gluten-free diet in appropriate situations) to limit morbidity. Given the rapidly evolving therapeutic landscape, partnership with a rheumatologist is essential. Treatment is usually sustained for 1 to 2 years, and remission is possible in many cases within 6 to 12 months, with variable rates of relapse and treatment resistance. Patients should be meticulously monitored for relapse with serial laboratory testing, electrodiagnostic studies, and clinical examination. Functional rating scores, such as the neuropathy impairment scale and the total neuropathy score are useful for longitudinal assessment.
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Enfermedad Celíaca/complicaciones , Enfermedades del Sistema Nervioso Periférico/etiología , Enfermedades Reumáticas/complicaciones , Dieta Sin Gluten , HumanosRESUMEN
OBJECTIVES: To determine whether there are gender differences in the clinical presentation or skin biopsy measures of nerve fiber density in patients with small fiber neuropathy (SFN). METHODS: Retrospective chart review of subjects with suspected SFN. RESULTS: Of 218 cases (137 women and 81 men) with suspected SFN, 96 (44%), including 63% of the men and 33% of the women (P < 0.05), had low epidermal nerve fiber density (ENFD) or sweat gland nerve fiber density (SGNFD). There were no differences in the clinical presentation between men and women. In those with abnormal findings, low ENFD alone was more frequent in women than men (51.1% vs. 7.8%, P < 0.05), whereas abnormal SGNFD alone was more frequent in men than women (68.6% vs. 11.1%, P < 0.05). Both SGNFD and ENFD were low in 23.5% of men and 33.3% of women. Skin biopsy findings were independent of clinical presentation or etiology. CONCLUSIONS: The clinical presentation of SFN is similar in men and women. In skin biopsy studies, low ENFD is more common in women and low SGNFD in men.
Asunto(s)
Caracteres Sexuales , Piel/patología , Neuropatía de Fibras Pequeñas/patología , Adulto , Anciano , Biopsia/métodos , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Fibras Nerviosas/patología , Estudios Retrospectivos , Piel/inervación , Adulto JovenRESUMEN
Myelin protein zero (MPZ) mutations cause demyelinating neuropathies that range from severe neonatal to milder adult forms. We report a 65-year-old woman with slowly progressive leg weakness starting at 47. Examination revealed distal weakness and atrophy in all extremities, impaired light touch in both feet and pin perception to proximal calves, absent leg reflexes, and unsteady gait. Electrodiagnostic studies revealed a severe sensorimotor polyneuropathy with conduction velocities of 25 m/s - to normal. The conduction velocities in the upper 20's were seen in lower extremities with severe reduction of the corresponding compound muscle action potential amplitudes. She had a MPZ mutation with A-C transversion (nucleotide: 116, codon: 10, histidine-to-proline). Her sister has an identical mutation, with high arches, distal leg weakness, decreased vibration sensation in toes and ankle areflexia. Nerve conduction studies revealed a moderate-severe sensorimotor polyneuropathy with nerve conduction velocities of 36 m/s - to normal. Their mother had an abnormal gait and conduction velocities of 29-30 m/s. A third sister is clinically and genetically unaffected. One report has previously described four patients with this mutation with similar clinical and electrodiagnostic features. In patients tested for possible CMT, the frequency of MPZ His-Pro codon 10 substitutions was 0.11% (27 of 24,076 alleles).
Asunto(s)
Enfermedad de Charcot-Marie-Tooth/genética , Mutación/genética , Proteína P0 de la Mielina/genética , Anciano , Enfermedad de Charcot-Marie-Tooth/fisiopatología , Salud de la Familia , Femenino , Histidina/genética , Humanos , Persona de Mediana Edad , Conducción Nerviosa/fisiología , Prolina/genéticaRESUMEN
Abnormal concentrations of nutritional factors were found in 24.1% of 187 patients with neuropathy who were newly seen at our academic neuropathy referral center over a 1-year period. All patients presented with sensory axonal or small fiber neuropathy. In 7.3%, they were present in association with at least one other identifiable cause for neuropathy. Elevated levels of pyridoxal phosphate or mercury occurred more frequently than deficiencies in vitamins B1, B12, or B6. The nutritional abnormalities are amenable to correction by dietary intervention.
Asunto(s)
Mercurio/sangre , Enfermedades del Sistema Nervioso Periférico/complicaciones , Fosfato de Piridoxal/sangre , Neuropatía de Fibras Pequeñas/complicaciones , Deficiencia de Vitamina B/complicaciones , Registros Electrónicos de Salud , Humanos , Enfermedades del Sistema Nervioso Periférico/sangre , Neuropatía de Fibras Pequeñas/sangre , Deficiencia de Vitamina B/sangreRESUMEN
BACKGROUND: Celiac disease (CD) is increasingly recognized in North America and is associated with a peripheral neuropathy. OBJECTIVE: To report the clinical characteristics and skin biopsy results in patients with CD and small-fiber neuropathy symptoms. DESIGN: Case series. SETTING: Academic peripheral neuropathy clinic. PATIENTS: Eight patients with CD and neuropathy symptoms. Intervention Three-millimeter punch biopsy using the panaxonal marker protein gene product 9.5 to assess epidermal nerve fiber (ENF) density and a gluten-free diet. MAIN OUTCOME MEASURE: Clinical data and ENF density. RESULTS: All patients had asymmetric numbness and paresthesias. Three had more prominent involvement of hands than feet, and 3 had facial numbness. Celiac disease was diagnosed in 5 after their neuropathy began. The following serum antibody levels were elevated: tissue transglutaminase (n = 6), IgA gliadin (n = 4), and IgG gliadin (n = 7). Results of nerve conduction studies were normal in 7 patients. One patient had mildly reduced sural amplitudes. The ENF density was reduced in 5 patients. The ENF density was at the low limit of the normal range in 3 additional patients, 2 of whom had morphologic changes in axons. Three patients had decreased ENF density at the thigh or forearm, which was more severe than at the distal leg, compatible with a non-length-dependent process. Four reported improvement with a gluten-free diet. One had no improvement after 4 months. Symptoms developed in 2 while receiving a gluten-free diet. CONCLUSIONS: Patients with CD may have a neuropathy involving small fibers, demonstrated by results of skin biopsy. The pattern of symptoms, with frequent facial involvement and a non-length-dependent pattern on skin biopsy findings, suggests a sensory ganglionopathy or an immune-mediated neuropathy. Improvement of symptoms in some patients after initiating a gluten-free diet warrants further study.
Asunto(s)
Enfermedad Celíaca/complicaciones , Epidermis/inervación , Enfermedades del Sistema Nervioso Periférico/etiología , Enfermedad Celíaca/patología , Femenino , Gliadina/sangre , Humanos , Masculino , Conducción Nerviosa , Neuronas/patología , Enfermedades del Sistema Nervioso Periférico/patología , Transglutaminasas/sangreRESUMEN
BACKGROUND: Current electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) are research oriented favoring specificity over sensitivity. Application of such criteria in clinical practice may miss the diagnosis in potentially treatable patients. OBJECTIVES: To analyze the electrophysiologic abnormalities in a cohort of patients with clinically defined CIDP, to compare these data with published electrodiagnostic criteria, and to identify a set of abnormalities that is shared by all patients with CIDP. DESIGN: Retrospective medical record review. SETTING: Academically based neuromuscular clinic. Patients Fifteen patients with clinically diagnosed relapsing sensorimotor CIDP. INTERVENTIONS: Administration of intravenous immunoglobulin or prednisone. MAIN OUTCOME MEASURES: Electrodiagnostic studies. RESULTS: All patients had electrodiagnostic abnormalities in at least 3 nerves with possible partial conduction block or demyelinating range abnormalities in at least 1 nerve. The diagnostic sensitivities of 5 published CIDP criteria were as follows: the Ad Hoc Subcommittee of the American Academy of Neurology AIDS Task Force (40%), Saperstein et al (47%), Nicolas et al (53%), Hughes et al for the Inflammatory Neuropathy Cause and Treatment Group (60%), and Thaisetthawatkul et al (70%). CONCLUSIONS: Current electrodiagnostic criteria for CIDP are insensitive and may fail to diagnose the condition in a substantial number of patients. More inclusive criteria that allow identification of patients in routine clinical practice are needed.
Asunto(s)
Electrodiagnóstico , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/diagnóstico , Potenciales de Acción , Adulto , Anciano , Estudios de Cohortes , Evaluación de la Discapacidad , Femenino , Glucocorticoides/uso terapéutico , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Masculino , Persona de Mediana Edad , Músculo Esquelético/fisiopatología , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/tratamiento farmacológico , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , Prednisona/uso terapéutico , Estudios RetrospectivosRESUMEN
Patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and/or variants who were refractory or intolerant of standard therapies were treated with etanercept, 25 mg twice per week. Ten patients underwent treatment, and manual muscle strength, sensory thresholds and functional abilities were tested prior to and 4-6 months after initiating therapy. Three patients had significant improvement and three others had possible improvement. Based on these preliminary observations, treatment with etanercept may be considered in patients with CIDP, who cannot undergo standard therapies, although its efficacy in CIDP needs to be examined in a double-blinded, controlled clinical trial.
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Antiinflamatorios no Esteroideos/uso terapéutico , Inmunoglobulina G/uso terapéutico , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/tratamiento farmacológico , Receptores del Factor de Necrosis Tumoral/uso terapéutico , Adulto , Anciano , Terapia Combinada , Esquema de Medicación , Etanercept , Femenino , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/fisiopatología , Conducción Nerviosa , Resultado del TratamientoRESUMEN
OBJECTIVE: To determine whether patients with benign fasciculations have evidence for axonal loss in skin biopsies. METHODS: Epidermal sensory and sweat gland nerve fiber densities were quantified in skin biopsies of 11 patients with benign fasciculations and no other known cause for neuropathy. RESULTS: Nine of the 11 patients (82%) had significantly reduced epidermal or sweat gland nerve fiber densities at the calf or thigh, in comparison with control values. CONCLUSIONS: The presence of reduced epidermal and sweat gland nerve fiber density indicates the presence of axonal loss in patients with benign fasciculations.
Asunto(s)
Fasciculación/diagnóstico , Fibras Nerviosas/patología , Piel/patología , Adulto , Biopsia , Electrodiagnóstico , Fasciculación/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Conducción Nerviosa/fisiología , Estudios RetrospectivosRESUMEN
OBJECTIVE: To assess the duration of the distal compound muscle action potential (dCMAP) recording from the tibialis anterior (TA) as a supportive electrodiagnostic feature in chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: We performed peroneal motor conduction studies with recording from the TA in 35 CIDP patients, 30 normal controls, and 21 disease controls. The normal cut-off for the TA dCMAP duration was determined to be 14 ms. RESULTS: Prolonged TA dCMAP durations were detected in 34% of CIDP patients (12/35) and in 33% (2/6) of patients in whom only one demyelinating lesion was identified by conventional motor conduction studies. Prolonged TA dCMAP durations were present in 28% (5/18) of patients with normal duration dCMAPs recorded from the abductor hallucis (AH) and in 42% (5/12) of patients with normal duration dCMAPs recorded from the extensor digitorum brevis (EDB). In patients with AH or EDB dCMAP amplitudes <1 mV, TA dCMAP durations were prolonged in 28% and 23% of patients, respectively. CONCLUSIONS: Determination of TA dCMAP duration appears to be useful for detecting demyelination in CIDP, especially when there is significant coexisting axon loss. SIGNIFICANCE: In patients with potential CIDP and limited electrodiagnostic abnormalities by routine studies, the finding of additional demyelinating findings, such as increased TA dCMAP duration, could allow for improved diagnostic sensitivity.
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Potenciales de Acción/fisiología , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/diagnóstico , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos , Factores de Tiempo , Adulto JovenAsunto(s)
Enfermedad Celíaca/epidemiología , Ataxia Cerebelosa/epidemiología , Adulto , Enfermedad Celíaca/diagnóstico , Enfermedad Celíaca/tratamiento farmacológico , Ataxia Cerebelosa/diagnóstico , Ataxia Cerebelosa/tratamiento farmacológico , Comorbilidad , Femenino , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Terapia de InmunosupresiónRESUMEN
Gene expression analysis previously identified molecular markers that are up-regulated in sural nerve biopsies from patients with chronic inflammatory demyelinating polyneuropathy (CIDP). To determine whether the same or additional genes are also up-regulated in skin, we applied gene microarray profiling and quantitative real-time PCR (qPCR) analysis to skin punch biopsies from patients with CIDP and controls. Five genes, allograft inflammatory factor 1 (AIF-1), lymphatic hyaluronan receptor (LYVE-1/XLKD1), FYN binding protein (FYB), P2RY1 (purinergic receptor P2Y, G-protein-coupled, 1), and MLLT3 (myeloid/lymphoid or mixed-lineage leukemia translocated to, 3), all associated with immune cells or inflammatory processes, were elevated in punch skin biopsies from patients with CIDP as compared to normal subjects or patients with Charcot-Marie-Tooth Type 1 (CMT1). The average fold change of the 5 genes over normal expression, as determined by qPCR, was significantly elevated in skin biopsies from patients with CIDP in comparison to CMT1 or diabetic neuropathy, and similar to that seen in Lyme disease. The findings indicate the presence of inflammatory changes in the skin of patients with CIDP.
Asunto(s)
Regulación de la Expresión Génica/genética , Mediadores de Inflamación/metabolismo , Nervios Periféricos/metabolismo , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/genética , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/metabolismo , Células Receptoras Sensoriales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Adolescente , Adulto , Biomarcadores/análisis , Biomarcadores/metabolismo , Biopsia , Proteínas de Unión al Calcio , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Femenino , Perfilación de la Expresión Génica/métodos , Predisposición Genética a la Enfermedad/genética , Humanos , Inflamación/genética , Inflamación/metabolismo , Inflamación/fisiopatología , Mediadores de Inflamación/análisis , Masculino , Proteínas de Microfilamentos , Persona de Mediana Edad , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nervios Periféricos/patología , Nervios Periféricos/fisiopatología , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/fisiopatología , ARN Mensajero/análisis , ARN Mensajero/metabolismo , Receptores Purinérgicos P2/genética , Receptores Purinérgicos P2/metabolismo , Receptores Purinérgicos P2Y1 , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Receptoras Sensoriales/patología , Piel/inervación , Piel/fisiopatología , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo , Adulto JovenRESUMEN
Infection with hepatitis C virus (HCV) can be associated with demyelinating polyneuropathy that may be responsive to immunomodulatory therapy. In this case report series, we review four patients (all male, ages 47-60 years) with HCV and demyelinating polyneuropathy. Two of the four patients were diagnosed with HCV during the course of initial neuropathy evaluation. All patients had sensory loss, absent/diminished reflexes, lower extremity weakness (except for one patient), and demyelinating electrodiagnostic features. Three patients had polyclonal hypergammaglobulinemia and one patient had IgM monoclonal gammopathy. Intravenous immunoglobulin resulted in improvement in three patients; one patient had no benefit from rituximab therapy, but his symptoms have been stable. Demyelinating neuropathy may develop in patients with HCV unrelated to antiviral therapy. Immunomodulatory therapy may be beneficial in some cases. Testing for HCV should be considered, especially in patients with hypergammaglobulinemia or IgM monoclonal gammopathy.
Asunto(s)
Enfermedades Desmielinizantes/complicaciones , Enfermedades Desmielinizantes/etiología , Hepatitis C/complicaciones , Enfermedades Desmielinizantes/terapia , Enfermedades Desmielinizantes/virología , Hepatitis C/tratamiento farmacológico , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Factores Inmunológicos/uso terapéutico , Masculino , Persona de Mediana Edad , Polineuropatías/complicaciones , Polineuropatías/terapiaRESUMEN
Neuropathy following vaccination has been reported; however, biopsy-confirmed small fiber neuropathy has not been described. We report five patients who developed paresthesias within one day to two months following vaccination for rabies, varicella zoster, or Lyme disease. On examination, there was mild sensory loss in distal extremities, preserved strength, normal or minimally abnormal electrodiagnostic findings, and decreased epidermal nerve fiber densities per skin biopsy. Empiric immunomodulatory therapy was tried in two patients and was ineffective. All patients' symptoms have improved, but persist. We conclude that an acute or subacute, post-vaccination small fiber neuropathy may occur and follow a chronic course.
Asunto(s)
Polineuropatías/etiología , Vacunación/efectos adversos , Adulto , Varicela/prevención & control , Vacuna contra la Varicela/efectos adversos , Femenino , Humanos , Enfermedad de Lyme/prevención & control , Vacunas contra Enfermedad de Lyme/efectos adversos , Masculino , Persona de Mediana Edad , Rabia/prevención & control , Vacunas Antirrábicas/efectos adversosRESUMEN
OBJECTIVE: The objective of this study was to evaluate how the number of demyelinating findings (DF) on nerve conductions affects sensitivity and specificity of electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: Electrodiagnostic findings of 26 consecutive patients with CIDP were compared with amyotrophic lateral sclerosis (ALS) and diabetic polyneuropathy controls. Patients with CIDP were divided into typical and atypical CIDP, as defined elsewhere. RESULTS: Depending on the minimal required number (MRN) of DF on nerve conductions, sensitivities decreased from an arbitrary 100% to 58% and 54%, for an MRN of 1, 2, and 3, respectively, as specificities increased, from 48% to 81% and 95%, respectively. The number of DF per patient was higher in typical CIDP than in atypical CIDP. CONCLUSIONS: The considerable gap between specificity and sensitivity is the reason for controversy regarding the MRN for the diagnosis of CIDP. Requiring 2 or more DFs to identify CIDP increases specificity from 48% to 81% but lowers sensitivity from 100% to 58%. For patients with other potential causes of neuropathy, the requirement of 2 or more DFs could further increase specificity.