Correlation of the patient's reported outcome Inflammatory-RODS with an objective metric in immune-mediated neuropathies.

BACKGROUND AND PURPOSE: There is increasing interest in using patient-reported outcome measures (PROMs) in clinical studies to capture individual changes over time. However, PROMs have also been criticized because they are entirely subjective. Our objective was to examine the relationship between a subjective PROM and an objective outcome tool in patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and gammopathy-related polyneuropathy (MGUSP). METHODS: The Inflammatory Rasch-built Overall Disability Scale (I-RODS©, a multi-item scale that examines functionality) was completed by 137 patients with newly diagnosed (or relapsing) GBS (55), CIDP (59) and MGUSP (23) who were serially examined (GBS/CIDP, T0/T1/T3/T6/T12 months; MGUSP, T0/T3/T12). Possible association between the I-RODS findings and the vigorimeter scores, an objective linear instrument to assess grip strength, was examined. RESULTS: A significant correlating trend was found between the I-RODS and grip strength scores for the overall group and in each illness, independently. CONCLUSION: The objectivity of patients' subjective report on their functional state based on a strong correlation between the I-RODS and grip strength in patients with GBS, CIDP and MGUSP has been demonstrated. These findings provide further support to use the I-RODS and grip strength in future clinical studies in these conditions.

Derivation and validation of diagnostic criteria for chronic inflammatory demyelinating polyneuropathy.

To develop diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), a retrospective series of patients' records diagnosed by sexpert consensus as CIDP or other chronic polyneuropathies were analyzed. Classification and regression tree analysis was applied to 150 patients to derive a classification rule. According to the rule, diagnosis of CIDP required that a patient have a chronic non-genetic polyneuropathy, progressive for at least eight weeks, without a serum paraprotein and either 1) recordable compound muscle action potentials in > or =75% of motor nerves and either abnormal distal latency in >50% of nerves or abnormal motor conduction velocity in >50% of nerves or abnormal F wave latency in >50% of nerves; or 2) symmetrical onset of motor symptoms, symmetrical weakness of four limbs, and proximal weakness in > or =1 limb. When validated in 117 patients, the rule had 83% sensitivity (95% confidence interval 69%-93%) and 97% specificity (95% confidence interval 89%-99%) and performed better than published criteria.

Non-length dependent small fibre neuropathy/ganglionopathy.

OBJECTIVE: To describe the clinical and laboratory features of a painful non-length dependent, small fibre ganglionopathy (SFG). BACKGROUND: The syndrome of generalised SFG with early involvement of the face, trunk or proximal limbs is not well recognised and contrasts with the burning feet syndrome of small fibre neuropathy (SFN) and classical large fibre features of sensory ganglionopathy. METHODS: Retrospective case review including skin biopsies from four neuromuscular centres. Patients with pre-existing diseases associated with ganglionopathies were excluded. RESULTS: 12 men and 11 women, with an average age of 50 years, were studied. Neuropathic pain developed over days in eight and over months in the other patients. The face (n = 12), scalp (n = 10), tongue (n = 6), trunk (n = 15) and acral extremities (n = 21) were involved. Symptoms began in the hands or face before the legs in 10. The pain was characterised as burning (n = 22), prickling (n = 13), shooting (n = 13) or allodynic (n = 11). There was loss of pinprick sensation in affected regions in 19, with minimal or no loss of large fibre sensibility. Laboratory findings included abnormal glucose metabolism in six patients, Sjögren syndrome in three and monoclonal gammopathy, sprue and hepatitis C infection in one each, with the remainder idiopathic. Sensory nerve action potentials were normal in 12 and were reduced in the hands but normal in the legs in six. Skin biopsy in 14 of 17 showed reduced nerve fibre density in the thigh equal to or more prominent than in the calf. Two of seven patients improved with immune therapies, 13 symptomatically with analgesic medications and the remainder had little improvement. Ten considered the pain disabling at the last follow-up (mean 2 years). CONCLUSION: The pattern of symmetric, non-length dependent neuropathic pain with face and trunk involvement suggests a selective disorder of the dorsal ganglia cells subserving small nerve fibres. It can be distinguished from distal SFN. A potential metabolic or immune process was detected in half of the cases and the disorder was often refractory to treatment.

Demyelinating neuropathy and acute lymphocytic leukemia.

We report a 67-year-old man with acute lymphocytic leukemia (ALL) who developed a rapidly progressive areflexic quadriparesis following chemotherapy. Electrophysiologic studies demonstrated an acute demyelinating polyneuropathy. Although peripheral nervous system dysfunction in ALL is often attributed to leukemic infiltration or chemotherapy, a diligent search with electrophysiologic evaluation should be considered and may suggest alternative diagnoses.

Nonpoliovirus poliomyelitis simulating Guillain-Barré syndrome.

BACKGROUND: Paralytic poliomyelitis due to the wild-type poliovirus has been eradicated in the United States because of effective immunization programs. In the postvaccination era, most cases are caused by other RNA viruses, such as coxsackievirus or echovirus. The condition usually begins with a fever and upper respiratory tract or gastrointestinal tract symptoms that progress to a "paralytic" phase characterized by limb weakness, areflexia, and, occasionally, respiratory failure that superficially resemble Guillain-Barré syndrome. OBJECTIVE: To describe 2 patients with nonpoliovirus poliomyelitis and highlight the findings on magnetic resonance imaging of the spinal cord to distinguish these cases from variants of Guillain-Barré syndrome. DESIGN AND SETTING: Case series from an academic medical center. PATIENTS: Following a viral illness, the patients, aged 35 and 50 years, had painless, progressive, asymmetrical weakness in the arms followed by respiratory failure in one patient, and generalized limb weakness in the other patient, reaching a nadir in 1 week. Both patients had fevers but no signs of meningitis at onset. Tendon reflexes were absent or reduced in affected regions. The cerebrospinal fluid findings were as follows: mononuclear leukocyte counts of 100 000 cells/mm(3) and 700 000 cells/mm(3), respectively, and the protein level was above 10 g/dL in both patients. Compound muscle action potential amplitudes were reduced in some nerves with active denervation in clinically affected muscles, and F-responses were absent but there were no other demyelinating features. Magnetic resonance imaging showed discrete T2-weighted signal changes of the ventral horns of the spinal cord, and one had elevated coxsackievirus titers in the serum. There was little recovery and significant atrophy in weak muscles after 3 years. CONCLUSIONS: The poliomyelitis syndrome still occurs in adults in developed countries. It has superficial similarities to a motor axonal variant of Guillain-Barré syndrome but can be distinguished by clinical, cerebrospinal fluid, and, perhaps specifically, magnetic resonance imaging characteristics.

Chronic inflammatory demyelinating polyneuropathy: clinical features and response to treatment in 67 consecutive patients with and without a monoclonal gammopathy.

We report the clinical and EMG details of 67 consecutive patients with strictly defined chronic inflammatory demyelinating polyneuropathy (CIDP) during a 4-year period and compare responses to treatment in patients with idiopathic CIDP (CIDP-I) and CIDP with monoclonal gammopathy of uncertain significance (CIDP-MGUS). Patients were examined an average of 28 months after first symptoms. There were several variant presentations that still conformed to the clinical and electrophysiologic definitions of CIDP, including a pure motor syndrome (10%), sensory ataxic variant (12%), mononeuritis multiplex pattern (9%), paraparetic pattern (4%), and relapsing acute Guillain-Barré syndrome (16%). Pain was more frequent than in previous studies (42%). Conduction block was the commonest EMG abnormality (detected in at least one nerve in 73% of patients), but only 31% had a pure demyelinating neuropathy and the majority had some degree of axonal change. Patients with CIDP-MGUS had less severe weakness, greater imbalance, leg ataxia, vibration loss in the hands, and absent median and ulnar sensory potentials, but were as likely as CIDP-I patients to respond to plasma exchange. Seventeen of 44 patients (39%) with idiopathic CIDP improved for at least 2 months with an initial therapy. Although the response rates among plasma exchange, IVIG, and steroids were similar, functional improvement (Rankin score) was greatest with plasma exchange. Of 26 patients who failed to respond to an initial therapy, 9 (35%) benefited from an alternative treatment, and of the 11 who required a third modality 3 (27%) improved. Overall, 66% responded to one of the three main therapies for CIDP.

Prospective evaluation of MRI lumbosacral nerve root enhancement in acute Guillain-Barré syndrome.

Nerve root enhancement of the cauda equina occurs in Guillain-Barré syndrome (GBS), but the frequency, diagnostic value, and meaning of this finding is unknown. We prospectively obtained gadolinium-enhanced lumbosacral spine MRIs in 24 consecutive patients with acute GBS and blindly rated nerve root enhancement as absent, mild, or prominent. The MRIs were obtained 13 days, mean, after onset of symptoms (range 2 to 42 days). Twenty of 24 patients had cauda equina nerve root enhancement, which was mild in 6 and prominent in 14. Eighteen of 19 with "typical" GBS had enhancement, compared with 2 of 5 with a variant presentation. Sixty percent of patients with prominent enhancement had severe back or leg pain in contrast to 10% of patients with mild or no enhancement. The GBS disability grade (0 to 5 scale) was higher in patients with prominent enhancement, and significantly fewer patients with prominent nerve root enhancement could walk independently by 2 months. There was no relationship between nerve root enhancement and the timing of the MRI, CSF protein, any of several EMG abnormalities, duration of hospitalization, mean disability grade at 2 months, or the time required for patients to improve to grade 2. In two patients, the EMGs at 11 and 20 days, respectively, were normal except for slightly prolonged F-responses and neurogenic recruitment, but there were prominent nerve root enhancement and an elevated CSF protein. Enhancement of the cauda equina nerve roots with gadolinium on lumbosacral MRI is 83% sensitive of acute GBS and was present in 95% of typical cases. This finding may be useful when electrophysiologic abnormalities are equivocal. In addition, conspicuous nerve root enhancement correlates with pain, GBS disability grade, and duration of recovery.

Improvement following interferon-alpha 2A in chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a progressive or relapsing immune-mediated neuropathy usually responsive to plasma exchange, intravenous gammaglobulin or steroids, with some patients being refractory to these conventional therapies. We report a patient with CIDP who had spontaneous improvement after an episode of sepsis, but subsequently relapsed with severe generalized weakness; he was unresponsive to the conventional treatments for CIDP but had dramatic improvement following treatment with interferon-alpha 2A. Nerve conduction studies following treatment showed improved distal compound muscle action potential amplitudes without change in the degree of conduction block. The mechanism of action of interferon-alpha is unknown, but it may modulate proinflammatory cytokines that have a role in immune-mediated demyelination. Interferon-alpha may be an effective alternative therapy in patients with CIDP who relapse or are refractory to conventional treatments.

Treatment of chronic inflammatory demyelinating polyneuropathy with interferon-alpha 2a.

We performed an open-label, prospective, pilot study of interferon (IFN)-alpha 2a treatment for 6 weeks in 16 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). All patients had failed to improve or relapsed after treatment with at least one conventional therapy (steroids, IV gamma globulin, or plasma exchange). Assessment included MRC strength score, leg sensory score, grip dynanometry, Rankin disability score, electrodiagnostic studies, and serum concentration of tumor necrosis factor-alpha. Nine (56%) improved after IFN-alpha therapy. Mean MRC score increased by 4.2 points (p = 0.01), and mean sensory score improved by 2.3 points (p = 0.02). Five patients improved five or more points on the MRC score, nine had slight improvement or were unchanged, and two worsened. We conclude that IFN-alpha may be effective in some patients with CIDP who relapse or fail to respond to conventional immunomodulating therapy.

Stroke with sensory symptoms mimicking myocardial ischemia.

OBJECTIVE: To report five stroke patients with sensory deficits including prominent chest discomfort mimicking angina. BACKGROUND: Chest wall sensory discomfort, as a part of unilateral sensory dysfunction, has seldom been recognized as a potential imitator of cardiac ischemia. METHODS: A retrospective review of stroke patients with sensory symptoms from the New England Medical Center Stroke Registry. RESULTS: As a part of an acute stroke that included unilateral sensory symptoms and signs, five patients had chest pain or discomfort, which prompted cardiac evaluation for potential coronary artery disease. In two patients, the primary presentation was chest discomfort. In the other three, chest discomfort was part of a more extensive stroke syndrome. The symptoms were described as "burning," "hot feeling," "flashes," "tightness," and "cold." In three patients, an MRI or CT scan showed an infarct in the thalamus, corona radiata, or lateral medulla. Cardiac evaluation was negative in all but one patient who had single vessel percutaneous transluminal coronary angioplasty without resolution of sensory symptoms. Chest discomfort fluctuated but persisted for months or years after presentation. CONCLUSION: Chest discomfort mimicking cardiac ischemia may be a prominent sensory symptom in acute stroke.

Rapid infusion of intravenous immune globulin in patients with neuromuscular disorders.

The safety and efficiency of a novel method of rapid-infusion IV immunoglobulin (IVIg) were retrospectively reviewed in 50 patients with neuromuscular disorders. There were 89 adverse events after 341 rapid infusions (26%), 3.5% of which were considered to be major (requiring hospitalization) and 66% minor. All patients recovered without sequelae, and there were no deaths. Fourteen of 17 patients (82%) receiving maintenance therapy preferred rapid IVIg infusion because of its convenience. Rapid-infusion IVIg can be given safely and conveniently in many patients with neuromuscular disorders.

Intramuscular interferon beta-1a in chronic inflammatory demyelinating polyradiculoneuropathy.

OBJECTIVE: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) shares immunologic features with multiple sclerosis (MS). Because IM interferon beta-1a (IM IFNbeta-1a) is an effective and safe treatment for MS, we conducted a dose-ranging efficacy study of IFNbeta-1a in patients with CIDP. METHODS: Adults with IV immunoglobulin (IVIg)-dependent CIDP (n = 67) were enrolled in this 32-week double-blind trial and randomized to IM IFNbeta-1a. Patients received 30 microg once weekly plus placebo (n = 12), IM IFNbeta-1a 60 microg once weekly plus placebo (n = 11), IM IFNbeta-1a 30 microg twice weekly (n = 11), IM IFNbeta-1a 60 microg twice weekly (n = 11), or placebo twice weekly (n = 22). Participants were maintained on IVIg through week 16, when IVIg was discontinued. Patients who worsened were restarted on IVIg. The primary outcome was total IVIg dose (g/kg) administered from week 16 to 32. RESULTS: There was no difference in total IVIg dose administered after week 16 for patients treated with IFNbeta-1a (1.20 g/kg) compared with placebo (1.34 g/kg; p = 0.75). However, exploratory analyses suggested IFNbeta-1a significantly reduced total dose of IVIg compared with placebo for participants who required either high-dose IVIg (>0.95 g/kg per month) or had greater weakness at baseline (Medical Research Council sum score <51). Adverse events included flu-like symptoms, headache, and fatigue in the IFNbeta-1a groups. CONCLUSIONS: Interferon beta-1a (IFNbeta-1a) therapy did not provide significant benefit over IV immunoglobulin (IVIg) therapy alone for patients with chronic inflammatory demyelinating polyradiculoneuropathy. However, IFNbeta-1a might be beneficial for patients with more severe disability or those needing high doses of IVIg. LEVEL OF EVIDENCE: This study was designed to provide Class I evidence for the safety and efficacy of IM IFNbeta-1a in the treatment of CIDP but has been subsequently classified as Class II due to a >20% patient dropout rate. Thus, this randomized, controlled clinical trial provides Class II evidence of no effect on primary and secondary endpoints of 4 dosage regimens of IM IFNbeta-1a added to IVIg in persons with CIDP.

Additional causes for distal sensory polyneuropathy in diabetic patients.

OBJECTIVE: To assess the frequency of additional causes of distal sensory polyneuropathy (DSP) in patients with diabetes mellitus (DM). METHODS: Retrospective review of patients with DM and DSP during a 5 year period. A quantitative sensory score (QSS) was determined at the initial evaluation and extensive laboratory and EMG studies were performed. Patients with one or more potential causes for DSP were compared to those with DM alone. RESULTS: Fifty five patients (53%) had potential additional causes for DSP. These included: neurotoxic medications (seven), alcohol abuse (six), and B12 deficiency and renal disease (four each). The most common laboratory abnormalities were: abnormally low levels of vitamin B6 (11) or B1 (10), monoclonal gammopathy (eight), and hypertriglyceridaemia (eight). Twenty six (25%) subjects had more than one additional cause. Nine (9%) had three or more demyelinating features on EMG. There was a trend toward a lower QSS score (p = 0.05) and reduced mean amplitude of the sensory potentials in those with additional causes. Those with additional causes more often had upper limb sensory symptoms (p = 0.001) and sensory findings (p = 0.003). CONCLUSION: There was a high frequency of additional sources of DSP in patients with DM. These patients more often had sensory symptoms and findings in the hands. Tests that may be useful in the evaluation of DSP in diabetic patients include measures of vitamins B1, B6, B12, serum triglycerides, and immunofixation.

Clinical features, evaluation, and treatment of patients with polyneuropathy associated with monoclonal gammopathy of undetermined significance (MGUS).

A number of common disorders of the peripheral nervous system are closely linked to a monoclonal gammopathy. In a minority of patients, the neuropathy represents the sentinel feature of a malignant plasma cell dyscrasia, such as multiple myeloma or its osteosclerotic variant, Waldenstrom's disease, amyloidosis, cryoglobulinemia or lymphoma; the vast majority have so-called "monoclonal gammopathy of undetermined significance" (MGUS). Sensory symptoms predominate with paresthesias, numbness, imbalance, and gait ataxia. Electrodiagnostic studies show mixed demyelinating and axonal features and often may be indistinguishable from findings in chronic inflammatory demyelinating polyneuropathy. Some have a pure axonal polyneuropathy, and in these patients the relationship to the paraprotein is less certain. With limited success, correlations have been made between the immunoglobulin type (IgM, IgG, or IgA) and the clinical and electromyographic characteristics of the neuropathy. The treatment of MGUS neuropathies poses a considerable challenge. Patients with IgG/IgA-MGUS have improved with corticosteroids or intravenous immune globulin. Only the benefit of plasma exchange has been substantiated in a controlled trial. The IgM neuropathies tend to be more refractory but often improve with similar regimens, particularly if cytotoxic agents are added in doses sufficient to reduce the amount of the M-protein. In addition to plasma exchange, chlorambucil, and cyclophosphamide, interferon-alpha is a novel therapy that holds promise for patients with IgM neuropathies associated with anti-myelin associated antibodies.

Acute respiratory failure neuropathy: a variant of critical illness polyneuropathy.

OBJECTIVE: To describe a severe axonal polyneuropathy that follows acute respiratory failure and, in turn, causes continued ventilator dependence and paralysis after resolution of the primary illness. DESIGN: Retrospective chart review of three patients and prospective analysis of two patients. SETTING: Respiratory and neurologic ICUs of a general hospital. PATIENTS: Five critically ill patients after an episode of acute respiratory failure. Neuromuscular blocking drugs were used in four patients, intermittently in two patients, high doses of corticosteroids were briefly administered in four, four patients had multiple organ failure, three patients had sepsis, but weakness preceded these complications in two patients. INTERVENTIONS: None. MAIN RESULTS: All patients had moderate-to-severe limb weakness with reduced or absent reflexes. Sensation was relatively preserved and the spinal fluid protein concentrations were normal. Electrophysiologic studies showed a severe, acute axonal motor neuropathy in four patients and normal studies in the fifth that later demonstrated denervation. Sensory potentials were mildly or not affected. Two quadriparetic patients died at 2.5 months, one remained weak and ventilator dependent several months after onset, and two patients recovered to walk in 4 to 6 months. CONCLUSIONS: Severe axonal motor neuropathy after acute respiratory failure probably represents a variant of "critical illness polyneuropathy" that can be recognized from the temporal course of a conversion from primarily pulmonary to a pattern of neuromuscular ventilatory failure.

Idiopathic distal small fiber neuropathy.

We describe the clinical details of 20 elderly patients with idiopathic small fiber neuropathy. This neuropathy is ubiquitous in practice but has not been well characterized. The clinical syndrome is relatively stereotyped and appears to be a frequent cause of burning feet in the elderly. The main features were burning, painful paresthesias and dysesthesias in the feet, lancinating pains, moderate to severe distal small fiber sensory loss, absent ankle reflexes, and minimal or no distal foot weakness. All but 2 had mild loss of vibration sense but none had significant proprioceptive loss or sensory ataxia. EMG was normal in 9 while the others had a mild sensorimotor axonal neuropathy. Sural nerve biopsy was normal in 3 and showed axonal loss in 6. Progression was slow, and although pain was a troublesome symptom, no patient became disabled. Symptoms were refractory to most symptomatic therapies but several patients improved with gammaglobulin infusions.

Axonal neuropathy associated with monoclonal gammopathy of undetermined significance.

OBJECTIVE: The neuropathy associated with monoclonal gammopathy of undetermined significance (MGUS) is typically a predominantly demyelinating process that may have additional features of axonal degeneration. Sixteen patients with MGUS and a pure or predominantly axonal neuropathy are reported and compared with 20 consecutive patients with demyelinating neuropathy and MGUS who were seen during the same period. METHODS: Retrospective review of a consecutive series of patients with neuropathy and MGUS evaluated during a five year period. RESULTS: The axonal group had mild, symmetric, slowly progressive, predominantly sensory neuropathy, usually limited to the legs. There were no differences in the age of onset or duration of symptoms at the time of presentation, initial symptoms, or the severity of weakness between the axonal and demyelinating cases. However, the axonal process was associated with less vibration and proprioceptive loss, did not include leg ataxia (present in 55% of patients with demyelinating type), less often had generalised areflexia (19% v 70%), IgM gammopathy (19% v 80%), and anti-MAG antibodies (0% v 40%), and had lower CSF protein concentrations (mean, 49 v 100 mg/dl). The illness was also generally milder with less disability (mean Rankin score 2.1 v 2.8). Fewer patients with axonal neuropathy improved with immunomodulating therapy (27% v 75%). CONCLUSION: There is an axonal neuropathy associated with MGUS that is clinically and electrophysiologically distinct from the more typical demyelinating pattern.

Upper limb predominant, multifocal chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) presents in rare instances with focal or multifocal upper limb involvement. We reviewed the clinical and electromyographic (EMG) characteristics of 10 such patients (UL-CIDP) and compared them with patients with typical generalized CIDP (G-CIDP) and multifocal motor neuropathy (MMN). There were six men and four women, with a mean age of 54 years. Symptoms began in one arm or hand in six patients and in both arms or hands in four and included numbness (n = 10), paresthesias (n = 9), weakness (n = 8), and pain (n = 6). Findings were initially restricted to the ulnar nerve distribution in three patients, and median and axillary nerve in one patient each, and involved multiple nerves in five. Conduction block was detected in the forearm segment of 68% of the median and ulnar motor nerves tested; in contrast to multifocal motor neuropathy, 73% of the sensory nerves tested were abnormal, and none had anti-GM1 antibodies. Aside from a regional onset, there were no clinical or electrophysiological features that distinguished patients with UL-CIDP from those with G-CIDP. However, the magnitude of recovery following treatment was greater in patients with G-CIDP. We conclude that a multifocal variant of CIDP begins with upper extremity sensorimotor symptoms, simulates isolated or multiple mononeuropathies, can be distinguished from MMN, and may have a less favorable response to treatment.

Comparison of IgM-MGUS and IgG-MGUS polyneuropathy.

OBJECTIVE: To compare the clinical and electrodiagnostic features and response to treatment in patients with IgM-MGUS and IgG-MGUS associated polyneuropathy. MATERIAL AND METHODS: Retrospective review of 34 consecutive patients with MGUS associated neuropathy evaluated over 5 years. RESULTS: There were 19 patients with IgM-MGUS and 15 with IgG-MGUS. There were no differences in age, duration of symptoms, or distribution of motor and sensory symptoms or signs. IgM-MGUS patients had prolonged distal latencies of the median and ulnar motor potentials, greater slowing of the peroneal nerve conduction velocity and more often absent ulnar sensory potentials. Half of the patients in both groups improved following immunotherapy. CONCLUSION: IgM-MGUS patients had more severe demyelination on the nerve conduction studies, but there were no clinical features that differentiated the 2 groups. IgM and IgG-MGUS patients improved with plasma exchange and other immune therapies. Anti-MAG antibodies failed to distinguish a subgroup of patients with IgM-MGUS neuropathy.