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Biomedical subjects

M B Bromberg

Publications and source records attributed to M B Bromberg.

At least 37 records · Page 2Linked to original sources
PubMed1998

Electrodiagnostic studies in clinical trials for motor neuron disease.

Motor neuron disease (MND) is a group of neurodegenerative disorders characterized by death of upper motor neurons (UMN) and lower motor neurons (LMN). Clinical study of UMN loss is limited, but electrodiagnostic studies can be used readily to assess the functional state of LMN. Electrodiagnostic studies are regularly used in making the diagnosis of amyotrophic lateral sclerosis (ALS) and other forms of MND. They can also be used to follow disease progression and serve as end point measures in drug trials. In this role, electrodiagnostic studies can provide specific information not readily available from measurement of muscle strength or clinical functional scales. This article emphasizes the primary pathologic and secondary physiologic changes that take place after LMN loss and how they can be assessed by electrodiagnostic studies. It reviews the uses of routine electrodiagnostic studies for the diagnosis of MND but focuses on how special electrodiagnostic studies can be used as end point measures in drug trials.

Amyotrophic Lateral Sclerosis↗
PubMed1998

Calciphylaxis mimicking dermatomyositis: ischemic myopathy complicating renal failure.

BACKGROUND: Among the complications of chronic renal failure is a syndrome of medial calcification of small- to medium-sized arteries associated with ischemic necrosis of the skin and other organ systems, leading to gangrene and a poor prognosis. The syndrome has been reviewed in the renal, dermatologic, and surgical literature under the term calciphylaxis, which describes a postulated pathogenetic mechanism whereby sensitization to an endogenous or exogenous substance (such as parathyroid hormone) predisposes to calcium deposition after exposure to a challenging agent. Myopathy has rarely been reported as the presenting feature, and the syndrome has not been discussed in the neurologic literature. METHODS: We report two patients with renal failure and systemic calciphylaxis who presented to our hospital with myopathic complaints and signs suggesting dermatomyositis. We also discuss possible disease mechanisms and treatment. CONCLUSIONS: Because early treatment (including aggressively lowering the calcium and phosphate levels and parathyroidectomy) may improve the outcome, early recognition of the syndrome of calciphylaxis is essential.

Adult↗
PubMed1997

Peripheral neuropathy in the nondiabetic patient.

The differential diagnosis includes an array of acquired and hereditary disorders. The history often offers the richest source of information, which can then direct the physical examination and electrodiagnostic testing. Further studies may include nerve biopsy and, most recently, blood testing for genetic disorders. Some neuropathies may respond to treatment; indeed, the response to treatment may be diagnostic.

Adult↗
PubMed1997

Randomized trial of azathioprine or prednisone for initial immunosuppressive treatment of myasthenia gravis.

Ten patients with myasthenia gravis were randomized to azathioprine or prednisone as the initial immunomodulating drug and followed for over one year. Of five patients randomized to azathioprine, two had idiosyncratic reactions and were immediately crossed over to prednisone. Two patients completed one year on azathioprine with little or no change in level of function and were crossed over to prednisone and showed greater improvement. The fifth patient on azathioprine had a satisfactory improvement and continued on it during the second year. All patients initially randomized to prednisone improved, but the degree varied among patients. The side effects of azathioprine were idiosyncratic reactions. The side effects of prednisone were manageable.

Adult↗
PubMed1997

The influence of active electrode placement on CMAP amplitude.

The compound muscle action potential (CMAP) is a measure of the number of axons in a nerve. Placement of the active recording electrode over the motor point of a muscle is thought to give the maximal response, but there is considerable variation in amplitude among initially negative CMAP wave forms. Ten examiners of varied training backgrounds and experience placed the active electrode as they usually do over the thenar, hypothenar, abductor hallucis, and extensor digitorum brevis muscles in the same normal subject. There was variability of the CMAP amplitude recorded over each muscle; the lowest value recorded from a muscle was 57% of the maximum value, and the lowest median value was 77%. There was no relation between examiner background or level of training and recording the maximal response. Higher amplitude CMAPs were associated with steeper wave form slopes, but the range of correlations between amplitude and slope was 0.42 to 0.92. We conclude that when it is important to record the maximal CMAP response, empirical assessment by moving the active electrode is necessary.

Action Potentials↗
PubMed1997

A self report measure of affective lability.

OBJECTIVES: The development and validation of the Center for Neurologic Study-Lability Scale (CNS-LS), the first self report measure of affective lability in patients with amyotrophic lateral sclerosis (ALS). METHODS: Potential questionnaire items were identified through interviews with patients and families and expert review. Potential items, as well as measures of affect intensity, affective lability in psychopathology, and depression were administered to 99 patients with ALS for item selection and the examination of factor structure and construct validity. Test-retest reliability was examined using an additional sample of 31 patients with ALS, and criterion related validity was examined by comparing CNS-LS scores with physicians' diagnoses of affective lability in a sample of 77 patients with ALS. RESULTS: A seven item questionnaire emerged, composed of two subscales measuring labile laughter (four items) and labile tearfulness (three items). The CNS-LS showed a pattern of associations with affect intensity, affective lability in psychopathology, and depression consistent with a scale measuring affective lability. The CNS-LS also showed good test-retest reliability and internal consistency, and successfully predicted physicians' diagnoses of affective lability. An auxiliary subscale measuring labile frustration, anger, and impatience also emerged. CONCLUSIONS: The CNS-LS is a short, easily administered, and psychometrically sound measure of affective lability for use with patients with ALS. It has potential applications as both a clinical screening device and a research tool. The need for future research into the relation of depression as well as labile frustration, anger, and impatience to the syndrome of affective lability in neurological disorders is discussed.

Affect↗
PubMed1996

Dysphagia in elderly men with myasthenia gravis.

Eight elderly men whose primary symptoms of myasthenia gravis were decreased speech and swallowing ability were seen for speech pathology evaluations and videofluoroscopic swallow studies. All patients had fatigable flaccid dysarthria and greater than expected pharyngeal phase dysphagia on videofluoroscopy; eight had decreased pharyngeal motility as demonstrated by residual material in the valleculae and pyriform sinuses bilaterally; seven had episodes of laryngeal penetration secondary to overflow of residual material; and five experienced silent aspiration despite gag reflexes and the ability to cough to command. Five patients required feeding tubes because their dysphagia responded poorly to treatment. Videofluoroscopic swallow studies revealed a common swallowing profile with pharyngeal phase dysphagia greater than expected from patient symptoms. Dysphagia did not improve at the same rate as other manifestations of myasthenia gravis.

Aged↗
PubMed1996

Relationships between motor-unit number estimates and isometric strength in distal muscles in ALS/MND.

Measurement of progression in amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) is useful for charting the natural history and assessing efficacy in drug trials. Common measures are maximal voluntary isometric contraction (MVIC) which mainly focuses on-proximal muscles, and electrophysiologic measures of the compound muscle action potential (CMAP) and motor-unit number estimation (MUNE) which focus on distal muscles. We have undertaken a study to compare the relationships between MVIC, CMAP and MUNE recorded in intrinsic hand muscles of 10 subjects with ALS/MND. Grip and pinch (between the first and fifth digits) MVIC were recorded. The CMAP and MUNE (determined by the multipoint stimulation technique) were recorded from thenar and hypothenar muscle groups. To facilitate comparisons between strength and electrophysiologic measures, the MUNE values and the CMAP values from the thenar and hypothenar muscle groups were each summed. Test-retest correlations were high for all measures (r = 0.75-0.99). Pinch and grip MVIC were highly correlated (r = 0.83). However, MVIC measures showed weaker correlations with summed MUNE values (pinch r = 0.56, grip r = 0.64) and summed CMAP values (pinch r = 0.58 and grip r = 0.65). The weak correlations between MVIC and electrophysiologic measures are due to two factors. First, grip and pinch MVIC are correlated through co-activation of agonist muscle groups, for we recorded strong concomitant muscle activity from forearm flexor muscles during pinch. In contrast, CMAP and MUNE reflect measurement from isolated muscle groups in the hand. Second, MVIC and the CMAP are affected by collateral reinnervation and only indirectly assess motor-unit loss, while MUNE is uninfluenced by reinnervation and directly addresses the degree of motor-unit loss. These factors determine the information available from endpoint measures. We offer guidelines for choosing useful measures based upon the goals of a given study.

Action Potentials↗
PubMed1996

Vest restraint palsy.

OBJECTIVE: Evaluate by electrophysiologic methods the cause of arm weakness and numbness in an agitated patient who struggled against a vest restraint garment. CASE PRESENTATION: An agitated patient with encephalitis required vest restraint and developed bilateral numbness of hands and weakness of distal upper extremity muscles. He was of thin stature and had abrasions in the axilla from the restraint straps. Routine nerve conduction and needle electromyographic needle studies were used to document bilateral conduction block of ulnar and median nerves between the elbow and Erb's point with minimal denervation. INTERVENTION: After identification of the vest restraint as the cause of neuropraxic palsies, adjustments were made to the vest straps. RESULTS: The symptoms and clinical signs began to resolve with adjustment of the vest restraint straps and completely resolved after the patient was no longer encephalopathic and was discharged from the hospital. CONCLUSIONS: Compressive nerve lesions in the axilla should be recognized as a potential complication of vest restraint, especially in combative patients.

Adult↗
PubMed1996

A controlled trial of amino acid therapy in amyotrophic lateral sclerosis: I. Clinical, functional, and maximum isometric torque data.

We conducted a two center, double-blind, placebo-controlled treatment trial with oral branched chain amino acids (BCAA) (L-leucine 12 g, L-isoleucine 8 g, and L-valine 6.4 g daily) or L-threonine (4 g daily) with pyridoxal phosphate (160 mg daily) for six months in patients with amyotrophic lateral sclerosis (ALS). The effect of treatment on disease progression was estimated every two months by recording clinical muscle strength, maximum isometric muscle torque in selected muscles, forced vital capacity (FVC), activities of daily living pertaining to the upper and lower limbs, and timed tasks. Ninety-five patients were randomized to receive BCAA (n = 31), L-threonine (n = 32), or placebo (n = 32), of whom 77 (81%) completed the trial. Mean weight loss in the placebo group was 1.1 kg and in the L-threonine group was 3.2 kg; the BCAA group gained 0.2 kg (p = 0.04). The estimated decline in FVC was about 2.5 times greater in the BCAA and L-threonine groups as compared to placebo (p = 0.03). Otherwise, no significant differences were found in the changes observed in clinical, functional, timed, or maximum torque measures among treatment groups. The amino acids were well tolerated. The results of our study failed to show a beneficial effect of BCAA or L-threonine treatment for six months on the disease course in ALS. The higher rate of loss of pulmonary function in patients treated with BCAA or L-threonine may have been due to chance, but an adverse effect of these amino acids cannot be ruled out.

Adult↗
PubMed1996

Placebo-controlled trial of gabapentin in patients with amyotrophic lateral sclerosis. WALS Study Group. Western Amyotrophic Lateral Sclerosis Study Group.

We designed a phase II trial to evaluate the efficacy of gabapentin in slowing the rate of decline in muscle strength of patients with amyotrophic lateral sclerosis (ALS) and to assess safety and tolerability. Gabapentin (800 mg) or placebo was administered t.i.d. in a randomized, double-blinded, placebo-controlled, trial for 6 months. We enrolled 152 patients at eight sites in the United States. The primary outcome measure was the slope of the arm megascore, the average maximum voluntary isometric strength from eight arm muscles standardized against a reference ALS population. A secondary outcome measure was forced vital capacity. Slopes of arm megascores for patients on gabapentin were compared with slopes of those taking placebo using a two-way ANOVA. We observed a nonstatistically significant trend (p = 0.057-0.08) toward slower decline of arm strength in patients taking gabapentin compared with those taking placebo (mean difference 24%, median 37%). We observed no treatment effect on forced vital capacity. Gabapentin was well tolerated by patients with ALS. These results suggest that further studies of gabapentin in ALS are warranted.

Acetates↗
PubMed1996

Pattern of denervation in clinically uninvolved limbs in patients with prior poliomyelitis.

In most cases of poliomyelitis, motor neuron death is extensive. In mild cases primarily involving one limb, the pattern of neuron death has not been fully determined. Nine mildly affected patients were studied systematically for electrophysiologic evidence of denervation by sampling one muscle in each limb. Fiber density was found to be increased in all but one muscle. Needle electromyography and turns and amplitude plots of the interference pattern were abnormal in all muscles in weak limbs and the majority of muscles in unaffected limbs. Turns: amplitude ratios were lower in muscles in weak limbs and greater in muscles in unaffected limbs in a pattern suggesting a horizontal gradation of motor neuron death across the spinal cord. This may be attributed to axonal transport of the virus. The horizontal pattern of sub clinical involvement in mild cases of poliomyelitis was compared and found to be similar to reported patterns of progression of limb weakness in amyotrophic lateral sclerosis type motor neuron disease.

Adult↗
PubMed1995

Sources of error in the spike-triggered averaging method of motor unit number estimation (MUNE).

Motor unit number estimation (MUNE) is an electrophysical technique to estimate the number of motor units innervating a muscle or muscle group. MUNE may be useful as a measure of progression of lower motor neuron loss in amyotrophic lateral sclerosis (ALS). Several methods of MUNE have been developed. The spike-triggered averaging method can be readily performed on EMG machines with signal averaging capabilities and is suitable for estimating the number of motor neurons innervating proximal muscles. We have used MUNE as a measure of disease state in a drug efficacy trial for ALS. From our experience with this method we have identified sources of error which can affect MUNE accuracy. We have investigated these sources and report their effect on MUNE.

Action Potentials↗
PubMed1995

Individuals with amyotrophic lateral sclerosis are in caloric balance despite losses in mass.

The purpose of this study was to quantify body composition changes during amyotrophic lateral sclerosis (ALS) progression and to determine whether these subjects were losing or maintaining the energy stored in their bodies. The body composition of 12 males in the early stages of ALS and 6 age-matched controls was measured twice over a 6-month period using dual X-ray absorptiometry. During the study period the control group did not change. The ALS group lost an average of 2 kg of lean mass while gaining 0.55 kg of fat mass, resulting in a 1.45 kg loss in total body mass. When the changes in mass were converted to their energy equivalents, the ALS subjects lost an average of 1800 kcal of energy stored in lean mass but gained 4900 kcal in fat mass, resulting in a net increase of 3100 kcal stored. In conclusion, a small increase in fat mass can successfully compensate for the energy lost in lean mass from disease progression. Therefore, it is possible to preserve the amount of energy stored in the body of ALS patients, even when there are significant losses in lean and overall body mass. Consequently, a moderate loss of body mass should be expected and even encouraged among this patient population.

Absorptiometry, Photon↗
PubMed1995

Long-term follow-up of patients with chronic inflammatory demyelinating polyradiculoneuropathy, without and with monoclonal gammopathy.

We previously demonstrated differences in presentation and initial clinical course between patients with idiopathic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP-I) and those in whom CIDP was associated with a monoclonal gammopathy of undetermined significance (CIDP-MGUS). We now report the long-term follow-up of 69 patients with CIDP-I and 25 patients with CIDP-MGUS. (i) The clinical course was progressive in most of the CIDP-MGUS patients. CIDP-I patients were more likely to have a monophasic or relapsing course. (ii) Impairment developed more slowly in CIDP-MGUS than CIDP-I patients, with a longer time from onset of deterioration to peak impairment for each episode. (iii) Patients with CIDP-MGUS experienced less severe functional impairment and a lesser degree of measured weakness during their worst episode than did patients with CIDP-I. The primary source of functional impairment in many CIDP-MGUS patients was sensory. In contrast, the deficits in most patients with CIDP-I were primarily motor. (iv) CIDP-MGUS patients experienced a smaller degree of improvement to a poorer functional level after each episode than did patients with CIDP-I. (v) Most patients had a good outcome. However, the strength and functional scores at the time of last follow-up were significantly poorer in CIDP-MGUS than in CIDP-I patients. (vi) The disease was reclassified in seven patients; some patients with CIDP-I developed an MGUS, while some with CIDP-I or CIDP-MGUS developed multiple myeloma or a related malignant lymphoproliferative disease. These findings have implications for patient counselling and long-term prognosis, and underscore the need for long-term clinical and immunological monitoring.

Adolescent↗
PubMed1994

X-linked bulbospinomuscular atrophy (Kennedy's disease) masquerading as lead neuropathy.

A 43-year-old male was referred by a veterinarian who evaluated his dog for a seizure and suspected a toxic lead exposure for both. He refurbished houses, removing old paint, and complained of decreased cognition, fatigue, and muscle cramps. He had a depressed affect, postural tremor, right arm weakness with partial denervation on EMG, and borderline-low sensory nerve action potential (SNAP) amplitudes. A mild anemia and elevated serum and urine lead levels supported a diagnosis of lead neuropathy. Chelation therapy increased urine lead excretion without symptomatic improvement. His brother worked part-time with him and developed similar findings, but also had difficulty chewing, dysphagia, perioral twitching, gynecomastia, and multifocal denervation of extremity and facial muscles. His lead levels were not elevated, but an androgen receptor mutation identified on the X chromosome for both brothers confirmed the diagnosis of X-linked bulbospinomuscular atrophy (Kennedy's disease).

Action Potentials↗