51. Early electrophysiologic findings in neonatal obstetric brachial plexus injury

51. Early electrophysiologic findings in neonatal obstetric brachial plexus injury

Society Proceedings / Clinical Neurophysiology 120 (2009) e89–e126 Conclusion: The study finds that ultrasound is a good diagnostic modality in patien...

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Society Proceedings / Clinical Neurophysiology 120 (2009) e89–e126

Conclusion: The study finds that ultrasound is a good diagnostic modality in patients categorized with moderate CTS by electrophysiological studies then referred to tertiary care centers. In severe cases, ultrasound could be used as a confirmatory procedure to demonstrate nerve atrophy and probable outcomes. Study supported by Deputy of Research Affairs, Zahedan University of Medical Sciences. A. Moghtaderi is a recipient of the 2008 IFCN, North American Chapter Fellowship Award. doi:10.1016/j.clinph.2008.10.067

50. Uniform slowing without conduction block or dispersion in poems syndrome—M.L. Mauermann, G.A. Suarez, E.J. Sorenson, A. Dispenzieri, P.B. Dyck (Rochester, MN, USA) Introduction: Polyneuropathy is required for the diagnosis of POEMS syndrome. ‘‘POEMS represents five common symptoms of the syndrome: peripheral neuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes. Two prior studies (n 12) have reviewed nerve conduction studies (NCSs). Objective: To describe NCSs in a large cohort of patients with POEMS syndrome. Methods: NCS patient information from January 1, 1960, to July 31, 2007, taken from the Dysproteinemia database was reviewed. Study patients met Dispenzieri and colleagues 2003 criteria for the diagnosis of POEMS syndrome. Results: One hundred and thirty-eight patients were identified. Median age was 52 years (range 20–83 years); 90 men, 48 women. There were 551 motor and 364 sensory nerves reviewed. Responses were absent in 48.3% of the motor nerves and in 52.7% of the sensory nerves. Absent responses were found more frequently in lower (motor 71.0%, sensory 82.9%) than in upper (motor 7.1%, sensory 36.2%) limbs. Mean motor and sensory conduction velocities were slowed and distal latencies were prolonged. Terminal latency indices were similar to normal controls. Mean motor F-wave latencies were prolonged compared to F-estimates (mean 5.6 ms). Temporal dispersion (10.6%-11/ 104) and conduction block (6.33%-17/269) were found infrequently. The neuropathy was most often a mixed demyelinating and axonal polyradiculoneuropathy (n = 82), followed by a mixed demyelinating and axonal sensorimotor peripheral neuropathy (n = 49). Conclusions: The author’s cohort of the largest NCS series of POEMS patients demonstrates POEMS neuropathy is best categorized electrophysiologically as a polyradiculoneuropathy with features of uniform demyelination and axonal loss. The lack of temporal dispersion and conduction block with uniform slowing should serve as an important clue in distinguishing POEMS neuropathy from chronic inflammatory polyneuropathy and other acquired neuropathies.

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Methods: Eight full-term neonates (3 girls) aged 2–4 days underwent conventional motor nerve conduction and electromyographical (EMG) investigations. The study protocol included the testing of median, ulnar, and radial motor nerve conduction velocities and M-response amplitudes, as well as conventional EMG studies of proximal muscles of the upper injured limb. Upon clinical examination, flaccid paralysis and an absence of deep tendon reflexes in the affected arm were detected. Results: Nerve conduction studies indicated the absence of compound muscle action potentials in the affected arms of all patients. In addition, conventional needle EMG revealed fibrillation potentials and positive sharp waves. High amplitude, polyphasic potentials and signs of chronic neurogenic lesions were also observed. Conclusions: The data show that in some neonates, early intrauterine injury of brachial plexus may occur long before delivery. Early electrophysiologic investigations should be performed in all neonates with OBPI to detect the potential traumatic cause. D. Chkhartishvili is a recipient of the 2008 IFCN, North American Chapter Fellowship Award. doi:10.1016/j.clinph.2008.10.069

52. Sensory nerve conduction slowing is a specific marker for chronic inflammatory demyelinating polyneuropathy—J. Bragg, M. Benatar (Atlanta, GA, USA) Introduction: Current diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) do not make use of sensory nerve conduction studies (NCSs). Prior studies of sensory NCSs in patients with CIDP had noted a high proportion of nerves with absent responses and a tendency for sensory nerves to demonstrate a somewhat lower degree of conduction velocity (CV) slowing than motor nerves in the same patient. Because of the lower amplitude of the sensory nerve response and the increased susceptibility of sensory nerves to temporal dispersion, many of these studies have required the use of near-nerve recordings. Objectives: To determine if surface sensory NCSs are clinically relevant in differentiating CIDP from axonal polyneuropathy. Methods: A retrospective review of 97 consecutive patients referred to an academic neurophysiology laboratory for electrodiagnostic testing to evaluate for CIDP was completed. The diagnosis of CIDP was based on a combination of the motor NCS and nerve biopsy results. Results: A higher frequency of absent sensory nerve responses was found in patients who met the motor NCS criteria for CIDP than in patients with axonal polyneuropathy (54.9% vs. 35.6%). While rare, CV slowing severe enough to qualify as meeting demyelinating criteria, occurred exclusively in the CIDP cohort, yielding low sensitivity (10.6%) but high specificity (100%). Conclusions: Sensory CV slowing is an insensitive but highly specific marker for differentiating CIDP from axonal polyneuropathy.

doi:10.1016/j.clinph.2008.10.068 doi:10.1016/j.clinph.2008.10.070

51. Early electrophysiologic findings in neonatal obstetric brachial plexus injury—D. Chkhartishvili, G. Natriashvili (Tbilisi, GA, USA) Introduction: Obstetric brachial plexus injury (OBPI) is a common paralysis in the neonatal period and has various traumatic mechanisms. Objectives: To detect electrophysiological abnormalities in OBPI that occurred early in the neonatal period and to illustrate the importance of an immediate electrophysiological investigation.

53. Nerve conduction study and electromyography aids in early identification of west nile infection in the immunosuppressed—P. Kaur, J. Ho, M. Levi, T. Grazia, K.L. Tyler, B. Kleinschmidt-Demasters, D. Quan (Aurora, CO, USA) Introduction: West Nile virus (WNV) infection may result in serious neuromuscular complications in immunocompromised patients. These patients may not demonstrate the anticipated immunological responses, resulting in delayed diagnosis.