Bridget Carey

Laryngeal electromyography for prognosis of vocal fold palsy: A Meta-Analysis

To analyze existing evidence regarding utility of laryngeal electromyography (LEMG) for prognosis in cases of vocal fold palsy (VFP).

A comparison of personality disorder characteristics of patients with nonepileptic psychogenic pseudoseizures with those of patients with epilepsy

We sought to determine the type of personality disorder cluster associated with patients with nonepileptic psychogenic seizures (NES) compared with that of patients with epileptic seizures (ES). Consecutive adult patients admitted for video/EEG monitoring found to have NES were compared with a simultaneously admitted patient with confirmed epilepsy. Personality was assessed using the Structured Clinical Interview for DSM-IV-TR Axis II Personality Disorders. Personality disorders were then divided into personality clusters described in the DSM-IV-TR: A = paranoid, schizotypal, schizoid; B = borderline, histrionic, antisocial, narcissistic; or C = avoidant, dependent, obsessive-compulsive. Thirteen of 16 patients with NES and 12 of 16 patients with ES met criteria for personality disorders. Patients with NES were more likely to meet criteria for a personality disorder in Cluster A or B, compared with patients with ES, who were more likely to have Cluster C personality disorders (chi(2) test, P=0.007). We propose that the personality traits of patients with NES contribute to the development of nonepileptic psychogenic seizures. However, the large proportion of patients with ES with Cluster C personality disorders was unexpected, and further, for the patients with epilepsy, the direction of the association of their personality traits with the development of epilepsy is unknown.

Consensus statement: Using laryngeal electromyography for the diagnosis and treatment of vocal cord paralysis.

Introduction: The purpose of this study was to develop an evidence‐based consensus statement regarding use of laryngeal electromyography (LEMG) for diagnosis and treatment of vocal fold paralysis after recurrent laryngeal neuropathy (RLN). Methods: Two questions regarding LEMG were analyzed: (1) Does LEMG predict recovery in patients with acute unilateral or bilateral vocal fold paralysis? (2) Do LEMG findings change clinical management in these individuals? A systematic review was performed using American Academy of Neurology criteria for rating of diagnostic accuracy. Results: Active voluntary motor unit potential recruitment and presence of polyphasic motor unit potentials within the first 6 months after lesion onset predicted recovery. Positive sharp waves and/or fibrillation potentials did not predict outcome. The presence of electrical synkinesis may decrease the likelihood of recovery, based on 1 published study. LEMG altered clinical management by changing the initial diagnosis from RLN in 48% of cases. Cricoarytenoid fixation and superior laryngeal neuropathy were the most common other diagnoses observed. Conclusions: If prognostic information is required in a patient with vocal fold paralysis that is more than 4 weeks and less than 6 months in duration, then LEMG should be performed. LEMG may be performed to clarify treatment decisions for vocal fold immobility that is presumed to be caused by RLN. Muscle Nerve 53: 850–855, 2016

A novel electrodiagnostic assessment of the laryngeal closure reflex.

Introduction: We describe a novel, clinically applicable conduction study of the laryngeal nerves. Methods: Seventeen normal volunteer subjects were included. Activation of the sensory territory of the superior laryngeal nerve was performed by administration of low level brief electrical stimuli. The laryngeal closure reflex (LCR) evoked by this stimulus was recorded by needle electrodes. Mean minimal latencies were calculated for each response, and proposed values for the upper limit of normal were determined. Results: Uniform, consistent early ipsilateral responses and late bilateral responses, which exhibit greater variation in latency and morphology, were recorded. Significant side‐to‐side differences in latencies were observed, consistent with the length discrepancy between right and left recurrent laryngeal nerves. Conclusions: This technique yields clear, quantifiable data regarding neurologic integrity of laryngeal function, heretofore unobtainable in the clinical setting. This study may yield clinically relevant information regarding severity and prognosis in patients with laryngeal neuropathic injury. Muscle Nerve 47:432‐436, 2013

A novel technique for clinical assessment of laryngeal nerve conduction: Normal and abnormal results

To describe a novel conduction study of the laryngeal nerves, including normal values and abnormal findings.

Abnormal Nutritional Factors in Patients Evaluated at a Neuropathy Center.

Abstract 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.

Elevated Blood Mercury Levels in Idiopathic Axonal Neuropathy

Methods | The electronic records of all patients with neuropathy newly seen by one of the authors (N.L.) at the Weill Cornell Neuropathy Center from July 1, 2013, to June 30, 2014, were reviewed, with Weill Cornell Neuropathy Center institutional review board approval. Patient consent was waived as most patients were referred for a single visit and not available for follow-up. Neuropathies were classified as previously described.2,3 Blood mercury levels, determined at a commercial laboratory by mass spectroscopy, were considered elevated if greater than 10 μg/L in comparison with normal control individuals.1 Findings in patients with IAN or idiopathic small-fiber axonal neuropathy were compared with those with chronic inflammatory demyelinating neuropathy or diabetes mellitus using the χ2 test.

Prolongation of the tibialis anterior CMAP duration in chronic inflammatory demyelinating polyneuropathy

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.

Reply: Comparison of 2‐limb versus 3‐limb electrodiagnostic studies in the evaluation of CIDP

increased the degree of diagnostic certainty, particularly in atypical forms of CIDP. They otherwise state that testing 8 nerves with proximal stimulation is not done routinely in clinical practice. Although this may be the case in many laboratories, this situation is not necessarily appropriate in the attempt to reach a diagnosis. The results of a previous analysis which we conducted showed that with exclusively distal forearm and foreleg studies, diagnostic sensitivity increases by increasing the number of limbs and therefore of nerves tested. In that study, we retrospectively applied different hypothetical electrophysiological protocols of varying extensiveness in patients with clinically suspected CIDP. The results showed that, using what we found at the time to be the most sensitive combination of electrodiagnostic criteria, 4-limb testing of forearm and foreleg nerve segments was considerably more sensitive than unilateral, 2-limb studies (90% vs. 45%). Exclusive upper limb studies with proximal stimulation was also highly sensitive (90%). Vo et al. demonstrate increased level of diagnostic certainty to “definite CIDP” in a cohort of subjects who had all been preselected on the basis of having at least “possible CIDP” as per latest EFNS/PNS electrodiagnostic criteria. This is an important point, as the issue of increasing the level of diagnostic certainty in those with at least 1 demyelinating feature beforehand differs from that of increasing diagnostic sensitivity, per se, i.e., that of the justification for continuing testing when precisely no demyelinating features are found after studying 1, 2, or 3 limbs. Sensitivity may ultimately be what really matters in de novo patients with the suspected diagnosis. Otherwise, the issue of reduced specificity, not raised in this study, deserves mention. It is similarly relevant with more extensive studies, as we have also described. It is interesting that Vo et al. found that 2-limb testing was sufficient to diagnose 12/13 of typical CIDP patients, but it was less sensitive for asymmetrical or distal forms. This may suggest more extensive testing is justified in asymptomatic regions. In another prospective analysis, we found that 50% of demyelinating features are located in asymptomatic regions in CIDP, which highlights the value of extending testing to clinically unaffected territories. In that study, we also found more frequent demyelination in the upper limbs and more axonal loss in the lower limbs, in keeping with the length-dependent axonal loss also reported by others. In contrast, Vo et al. report more frequent demyelinating features in the lower limbs. Another key issue, which may partly explain this discrepancy could be the electrophysiological parameters considered. Prolongation of distal compound muscle action potential duration was included in the last EFNS/ PNS Guidelines with cut-offs derived with low-cut filter settings of 20 Hz. We have since shown in a multicenter European study that these cut-offs were inadequate for low cut filters of 2, 3, or 10 Hz. The authors do not provide their filter settings, but they found this parameter was the second most frequent electrophysiological abnormality in their study. This is of interest, as overdiagnosis may occur as a result of use of the latest EFNS/PNS Guideline cut-offs. Nonetheless, this study is useful and of direct clinical relevance, and the authors should be commended, particularly given the persistent absence of data on optimal electrodiagnostic methodology in the setting of suspected CIDP. Ideally, future studies should be prospective and multicenter but with standardized protocols, and they should analyze treatment-responsive patients.

A novel electrodiagnostic assessment of the laryngeal closure reflex: Laryngeal Nerve Conduction

Introduction: We describe a novel, clinically applicable conduction study of the laryngeal nerves. Methods: Seventeen normal volunteer subjects were included. Activation of the sensory territory of the superior laryngeal nerve was performed by administration of low level brief electrical stimuli. The laryngeal closure reflex (LCR) evoked by this stimulus was recorded by needle electrodes. Mean minimal latencies were calculated for each response, and proposed values for the upper limit of normal were determined. Results: Uniform, consistent early ipsilateral responses and late bilateral responses, which exhibit greater variation in latency and morphology, were recorded. Significant side‐to‐side differences in latencies were observed, consistent with the length discrepancy between right and left recurrent laryngeal nerves. Conclusions: This technique yields clear, quantifiable data regarding neurologic integrity of laryngeal function, heretofore unobtainable in the clinical setting. This study may yield clinically relevant information regarding severity and prognosis in patients with laryngeal neuropathic injury. Muscle Nerve 47:432‐436, 2013