Gregory J. Esper

Acquired Copper Deficiency: A Potentially Serious and Preventable Complication Following Gastric Bypass Surgery

Copper is an essential cofactor in many enzymatic reactions vital to the normal function of the hematologic, vascular, skeletal, antioxidant, and neurologic systems. Copper deficiency in the United States is believed to be relatively rare but has been described in the setting of zinc supplementation, myelodysplastic syndrome, use of parenteral nutrition and chronic tube feeding, and in various malabsorptive syndromes, including following gastrectomy and gastric bypass surgery. Features of copper deficiency include hematologic abnormalities (anemia, neutropenia, and leukopenia) and myeloneuropathy; the latter is a rarer and often unrecognized complication of copper deficiency. We here describe two patients who presented with severe gait abnormalities and anemia combined with neutropenia several years after roux‐en‐Y gastric bypass (RYGB) surgery for obesity who were found to be severely copper deficient. Intravenous copper repletion resulted in the rapid correction of hematologic indices; combined intravenous and oral copper supplementation and eventual oral copper supplements alone normalized serum copper levels in each patient, but resulted in only partial resolution of the neurologic deficits. This report serves to alert physicians of the association between RYGB procedures and subsequent copper deficiency in order to avoid diagnostic delays and to improve treatment outcomes.

Validation of claims‐based diagnostic and procedure codes for cardiovascular and gastrointestinal serious adverse events in a commercially‐insured population

To validate administrative claims codes with medical chart review for myocardial infarction (MI), ischemic stroke, and severe upper gastrointestinal (UGI) bleed events in a large, commercially‐insured US population.

Assessing neuromuscular disease with multifrequency electrical impedance myography

Electrical impedance myography (EIM) is a noninvasive technique for neuromuscular assessment in which low‐intensity alternating current is applied to a muscle and the consequent surface voltage patterns are evaluated. Previous work using a single frequency of 50 kHZ has demonstrated quantitative correlation of EIM parameters with disease status. In this investigation we examined the use of multifrequency EIM, studying a prototypical neurogenic disease (amyotrophic lateral sclerosis, ALS) and myopathic disorder (inflammatory myopathy, IM). Eleven ALS patients, 7 IM patients, and 46 normal subjects participated in the study. Although disease‐specific patterns were not identified such that IM could be differentiated from ALS, impedance vs. frequency patterns for diseased subjects differed substantially from those of the age‐matched normal subjects, with the greatest alterations occurring in the most severe cases. Multifrequency EIM may be well‐suited to serve as an easily applied technique to assess disease severity in a variety of neuromuscular conditions. Muscle Nerve, 2006

Electrical impedance myography in the bedside assessment of inflammatory myopathy

Electrical impedance myography (EIM) is a new technique with potential for the noninvasive bedside assessment of myopathy. EIM was performed on the quadriceps of 10 patients with inflammatory myopathy and 10 normal subjects. The major EIM parameter, the spatially averaged phase, was 35% lower in the myositis patients and correlated with whole-body (r = 0.765, p = 0.01) and quadriceps (r = 0.673, p = 0.03) strength.

Electrical impedance myography in the detection of radiculopathy

Electrical impedance myography (EIM) is a new bioimpedance‐based technique for neuromuscular disease assessment. Past work has focused on EIM in the evaluation of diffuse diseases (such as myopathy). In this study, the methods most basic form, linear‐EIM, was used for the assessment of restricted radiculopathic disease. Ten normal subjects and 10 patients with unilateral cervical or lumbosacral radiculopathy, diagnosed by electromyography and clinical criteria, were enrolled. Linear‐EIM was performed bilaterally on all individuals, and comparisons with the major outcome variable, θavg, were made. In normal subjects, side‐to‐side differences in θavg averaged 0.64% and were no greater than 15.9% in magnitude. In the 10 patients with radiculopathy, θavgwas consistently lower in the affected extremity, with a mean side‐to‐side difference of 15.3%, but ranging as low as 72.3%; there was a tendency for muscles with more prominent chronic neurogenic change to show greater relative reductions in θavg. These findings support the potential utility of EIM in assessment of localized neuromuscular disease. Muscle Nerve, 2005

Effects of age on muscle as measured by electrical impedance myography.

Electrical impedance myography (EIM) is a painless and non-invasive technique for the assessment of muscle which we apply here to the effects of normal aging. The paper presents a cross-sectional analysis of EIM data from the quadriceps and tibialis anterior of 100 healthy subjects (44 men, 56 women, ages 18-90 years). The principal EIM parameter, the spatially averaged phase theta(avg), shows a roughly quadratic reduction with increasing age, declining more steeply beyond 60 years. The correlation was stronger in men (quadriceps: r2 = 0.68 for men, 0.52 for women; tibialis anterior: r2 = 0.74 for men, 0.38 for women; p < 0.001 throughout). Additionally, four subjects (age greater than 75 years) were asked to return for repeat testing several years after their initial assessment. These longitudinal results qualitatively confirm the cross-sectional data, though with greater reductions in theta(avg) at high age. The findings of this study support the potential use of EIM as a simple and effort-independent test of muscle health in the elderly.

Electrical Impedance Myography in the Assessment of Disuse Atrophy

UNLABELLED Tarulli AW, Duggal N, Esper GJ, Garmirian LP, Fogerson PM, Lin CH, Rutkove SB. Electrical impedance myography in the assessment of disuse atrophy. OBJECTIVE To quantify disuse atrophy using electrical impedance myography (EIM), a noninvasive technique that we have used successfully to study neurogenic and myopathic atrophy. DESIGN We performed EIM of the tibialis anterior of subjects with disuse atrophy secondary to cast immobilization and in their contralateral normal leg. Subjects were studied shortly after cast removal and again several weeks to months after the cast was removed and normal mobility was restored. SETTING Outpatient neurology and orthopedic practices at a tertiary care medical center. PARTICIPANTS Otherwise healthy subjects (N=10) with unilateral leg fracture. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Resistance, reactance, and phase measured at 50kHz. RESULTS The main EIM outcome parameter, phase at 50kHz, was lower in the immobilized leg in 9 of 10 cases. Additionally, when normal mobility was restored, the phase of the casted leg increased relative to its initial measurement in all 10 cases, while it increased inconsistently in the contralateral leg. CONCLUSIONS EIM may be a powerful tool for the assessment of disuse atrophy.

Sural and radial sensory responses in healthy adults: Diagnostic implications for polyneuropathy

We prospectively performed sural and radial sensory nerve conduction studies in 92 healthy subjects, aged between 21 and 88 years, both to determine the lower limits of normal (LLN) and to assess the effects of age and body mass index (BMI) on the sural and radial sensory nerve action potential (SNAP) amplitudes and on the sural/radial amplitude ratio (SRAR). Using the nonparametric bootstrap method to calculate 95% confidence intervals, we found that the 5% LLN values for sural and radial SNAPs were 14 μV and 25.5 μV in subjects aged ≤39 years, 7 μV and 17.4 μV in subjects aged 40–59 years, and 3 μV and 12 μV in subjects aged ≥60 years. The 5% LLN for SRAR for all patients was 0.21. Sural and radial SNAP amplitudes but not SRAR were strongly and inversely correlated with age and BMI. These age‐adjusted normal values and revised SRAR will aid in the electrodiagnosis of polyneuropathy. Muscle Nerve, 2005

Health Information Technology and Electronic Health Records in Neurologic Practice

The tipping point for electronic health records (EHR) has been reached and universal adoption in the United States is now inevitable. Neurologists will want to choose their electronic health record prudently. Careful selection, contracting, planning, and training are essential to successful implementation. Neurologists need to examine their workflow carefully and make adjustments to ensure that efficiency is increased. Neurologists will want to achieve a significant return on investment and qualify for all applicable financial incentives from payers, including CMS. EHRs are not just record-keeping tools but play an important role in quality improvement, evidence-based medicine, pay for performance, patient education, bio-surveillance, data warehousing, and data exchange.

Translational Medicine in Neurology: The Time Is Right

P HYSICIANS ARE CONfronting the perfect storm. With a shift from an acute to a chronic disease burden, inundation of scientific data and innovations, and an unsustainable rise in health care spending, we are now tasked with answering the questions: “What works best for our patients, and when and how do we provide it?” Prospective, doubleblind, randomized controlled trials (RCTs) assess the safety and efficacy of treatments and can lead to innovations in patient care. However, because of constraints in study design, RCT results do not always apply to general clinical populations. In addition, RCTs do not provide information on the costeffectiveness of treatments nor on their sustainability in the health care arena. Translational medicine describes a multiphase process by which basic scientific discoveries are ultimately incorporated into clinical care, given differing practice patterns, funding streams for treatment, and patient preferences. The practice of neurology would be well served by creating applicable methods and incorporating more applied clinical research and comparative effectiveness.