The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
M Carvalho - One of the best experts on this subject based on the ideXlab platform.
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Phrenic Nerve studies predict survival in amyotrophic lateral sclerosis
Clinical Neurophysiology, 2012Co-Authors: Susana Pinto, A Pinto, M CarvalhoAbstract:highlights Phrenic Nerve study is an accessible, non-volitional test, to investigate diaphragm motor neuron pool. Phrenic Nerve motor response amplitude is a significant predictor factor of survival for both spinal and bulbar-onset amyotrophic lateral sclerosis (ALS) patients. Phrenic Nerve motor response should be part of the available tools to test respiratory function in ALS patients. abstract Objective: Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease associated with short survival due to respiratory failure. We aimed to test the predictive value of the Phrenic Nerve motor response for survival, in a large population of ALS patients. Methods: We included 254 ALS patients followed in our tertiary centre from 1997 to 2006, in whom phre- nic Nerve stimulation was performed according to the study inclusion and exclusion criteria. ALS was spinal onset in 175 and bulbar onset in 79 patients. The following features were recorded at entry: gen- der, age at presentation, onset region, diagnostic delay, forced vital capacity (FVC), ALS functional rating scale (ALS-FRS) including the respiratory subscore of the reviewed ALS-FRS and mean amplitude of motor responses by Phrenic Nerve stimulation (PhrenAmpl). Results: Survival analysis was evaluated by Kaplan-Meier log-rank test and multivariate Cox propor- tional hazards. Independent factors negatively affecting survival were bulbar onset, short diagnostic delay, FVC and small PhrenAmpl for the total population. Small PhrenAmpl and short diagnostic delay were also independent factors for both spinal and bulbar-onset patients; age at onset and FVC were also independent predictors in bulbar-onset patients. Conclusion: Phrenic Nerve stimulation is a non-volitional test that can be performed quickly in most patients; it is a powerful predictor of survival in ALS. Significance: Phrenic Nerve stimulation should be considered as an additional test for respiratory assess- ment in ALS.
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Phrenic Nerve conduction in amyotrophic lateral sclerosis.
Journal of the neurological sciences, 1995Co-Authors: T Evangelista, M Carvalho, A Pinto, M De L LuísAbstract:Respiratory failure accounts for the majority of deaths in amyotrophic lateral sclerosis (ALS). The main cause of respiratory failure is probably diaphragmatic weakness. In order to test the correlation between respiratory impairment and diaphragmatic function we studied the Phrenic Nerve conduction in 31 ALS patients. Our results showed that patients with respiratory symptoms, and decreased forced vital capacity with arterial PaO2/PaCO2 abnormalities, had more commonly increased Phrenic Nerve latencies or absent response due to severe diaphragm denervation than ALS patients without respiratory complaints. Diaphragmatic paresis commonly occurs during the course of ALS, and its presence and severity can be assessed by Phrenic Nerve studies. It is important to recognize the development of impairment in diaphragmatic function in order to prevent life-threatening complications.
J. P. Camdessanché - One of the best experts on this subject based on the ideXlab platform.
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Phrenic Nerve Conduction in Healthy Subjects.
Muscle & Nerve, 2019Co-Authors: M. Vincent, I. Court-fortune, Frédéric Costes, J. C. Antoine, J. P. CamdessanchéAbstract:INTRODUCTION: Assessment of diaphragm compound muscle action potential by noninvasive Phrenic Nerve stimulation at the neck is well described. However, normal values in a large cohort of healthy subjects are lacking. Our objective was to determine reference values of Phrenic Nerve conduction in healthy subjects. METHODS: We recruited 155 healthy subjects (25-79 years old) and measured mean amplitude (PhrenAmp) and latency (PhrenLat) of motor responses according to Bolton's method. RESULTS: The lower limit for PhrenAmp was 0.28 and 0.25 mV and the upper limit for PhrenLat was 8.41 and 8.56 ms for right and left side, respectively. PhrenLat was correlated with age. PhrenAmp, PhrenLat and area were significantly higher in men. Tolerance to Phrenic Nerve stimulation was excellent. CONCLUSIONS: Our study provides normative values of Phrenic Nerve motor responses in a large cohort of healthy subjects and identifies age and sex as factors of variation. Muscle Nerve 59:451-456, 2019.
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Phrenic Nerve conduction in healthy subjects
Muscle and Nerve, 2019Co-Authors: M. Vincent, I. Court-fortune, Frédéric Costes, J. C. Antoine, J. P. CamdessanchéAbstract:INTRODUCTION: Assessment of diaphragm compound muscle action potential by noninvasive Phrenic Nerve stimulation at the neck is well described. However, normal values in a large cohort of healthy subjects are lacking. Our objective was to determine reference values of Phrenic Nerve conduction in healthy subjects. METHODS: We recruited 155 healthy subjects (25-79 years old) and measured mean amplitude (PhrenAmp) and latency (PhrenLat) of motor responses according to Bolton's method. RESULTS: The lower limit for PhrenAmp was 0.28 and 0.25 mV and the upper limit for PhrenLat was 8.41 and 8.56 ms for right and left side respectively. PhrenLat was correlated with age. PhrenAmp, PhrenLat and area were significantly higher in men. Tolerance to Phrenic Nerve stimulation was excellent. DISCUSSION: Our study provides normative values of Phrenic Nerve motor responses in a large cohort of healthy subjects and identifies age and sex as factors of variation.
M Green - One of the best experts on this subject based on the ideXlab platform.
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unilateral magnetic stimulation of the Phrenic Nerve
Thorax, 1995Co-Authors: G H Mills, D Kyroussis, C H Hamnegard, S Wragg, John Moxham, M GreenAbstract:BACKGROUND--Electrical stimulation of the Phrenic Nerve is a useful non-volitional method of assessing diaphragm contractility. During the assessment of hemidiaphragm contractility with electrical stimulation, low twitch transdiaphragmatic pressures may result from difficulty in locating and stimulating the Phrenic Nerve. Cervical magnetic stimulation overcomes some of these problems, but this technique may not be absolutely specific and does not allow the contractility of one hemidiaphragm to be assessed. This study assesses both the best means of producing supramaximal unilateral magnetic Phrenic stimulation and its reproducibility. This technique is then applied to patients. METHODS--The ability of four different magnetic coils to produce unilateral Phrenic stimulation in five normal subjects was assessed from twitch transdiaphragmatic pressure (TwPDI) measurements and diaphragmatic electromyogram (EMG) recordings. The results from magnetic stimulation were compared with those from electrical stimulation. To determine whether the magnetic field affects the contralateral Phrenic Nerve as well as the intended Phrenic Nerve, EMG recordings from each hemidiaphragm were compared during stimulation on the same side and the opposite side relative to the recording electrodes. The EMG recordings were made from skin surface electrodes in five normal subjects and from needle electrodes placed in the diaphragm during cardiac surgery in six patients. Similarly, the direction of hemidiaphragm movement was evaluated by ultrasonography. To determine the usefulness of the technique in patients the 43 mm mean diameter double coil was used in 54 patients referred for assessment of possible respiratory muscle weakness. These results were compared with unilateral electrical Phrenic stimulation, maximum sniff PDI, and TwPDI during cervical magnetic stimulation. RESULTS--In the five normal subjects supramaximal stimulation was established for eight out of 10 Phrenic Nerves with the 43 mm double coil. Supramaximal unilateral magnetic stimulation produced a higher TwPDI than electrical stimulation (mean (SD) 13.4 (2.5) cm H2O with 35 mm coil; 14.1 (3.8) cm H2O with 43 mm coil; 10.0 (1.7) cm H2O with electrical stimulation). Spread of the magnetic field to the opposite Phrenic Nerve produced a small amplitude contralateral diaphragm EMG measured from skin surface electrodes which reached a mean of 15% of the maximum EMG amplitude produced by ipsilateral stimulation. Similarly, in six patients with EMG activity recorded directly from needle electrodes, the contralateral spread of the magnetic field produced EMG activity up to a mean of 3% and a maximum of 6% of that seen with ipsilateral stimulation. Unilateral magnetic stimulation of the Phrenic Nerve was rapidly achieved and well tolerated. In the 54 patients unilateral magnetic TwPDI was more closely related than unilateral electrical TwPDI to transdiaphragmatic pressure produced during maximum sniffs and cervical magnetic stimulation. Unilateral magnetic stimulation eliminated the problem of producing a falsely low TwPDI because of technical difficulties in locating and adequately stimulating the Nerve. Eight patients with unilateral Phrenic Nerve paresis, as indicated by a unilaterally elevated hemidiaphragm on a chest radiograph and maximum sniff PDI consistent with hemidiaphragm weakness, were all accurately identified by unilateral magnetic stimulation. CONCLUSIONS--Unilateral magnetic Phrenic Nerve stimulation is easy to apply and is a reproducible technique in the assessment of hemidiaphragm contractility. It is well tolerated and allows hemidiaphragm contractility to be rapidly and reliably assessed because precise positioning of the coils is not necessary. This may be particularly useful in patients. In addition, the anterolateral positioning of the coil allows the use of the magnet in the supine patient such as in the operating theatre or intensive care unit.
M K - One of the best experts on this subject based on the ideXlab platform.
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use of the Phrenic Nerve for brachial plexus reconstruction
Clinical Orthopaedics and Related Research, 1996Co-Authors: Y D Gu, M KAbstract:: To examine the clinical effectiveness and safety of Phrenic Nerve neurotization for brachial plexus reconstruction, the authors retrospectively analyzed the surgically treated cases within the period between August 1970 and March 1990. There was a total of 180 patients who sustained brachial plexus injuries and had Phrenic Nerve transfer. The Phrenic Nerve was identified and traced distally to give the longest possible length and sectioned. The proximal stump was coapted to the distal segment of the musculocutaneous Nerve, either directly or through a Nerve graft. Sixty-five patients who were seen in followup for >2 years were studied. The time taken for the return of a muscle power rating of 3 (M3) in the biceps muscle ranged from 3 to 30 months; the average time was 9.5 months. Of the patients, 84.6% regained biceps power to M3 and greater strength. Only 1 patient had a transient respiratory problem after surgery. Pulmonary function tests showed decreased pulmonary capacities within 1 year of operation, improving toward 2 years. Thus, it is concluded that Phrenic Nerve neurotization can be accepted as a sound option for the restoration of biceps function in brachial plexus injury.
David W Brown - One of the best experts on this subject based on the ideXlab platform.
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functional restoration of diaphragmatic paralysis an evaluation of Phrenic Nerve reconstruction
The Annals of Thoracic Surgery, 2014Co-Authors: Matthew R Kaufman, Andrew I Elkwood, Alan R Colicchio, John Cece, Reza Jarrahy, Lourens J Willekes, Michael I Rose, David W BrownAbstract:Background Unilateral diaphragmatic paralysis causes respiratory deficits and can occur after iatrogenic or traumatic Phrenic Nerve injury in the neck or chest. Patients are evaluated using spirometry and imaging studies; however, Phrenic Nerve conduction studies and electromyography are not widely available or considered; thus, the degree of dysfunction is often unknown. Treatment has been limited to diaphragmatic plication. Phrenic Nerve operations to restore diaphragmatic function may broaden therapeutic options. Methods An interventional study of 92 patients with symptomatic diaphragmatic paralysis assigned 68 (based on their clinical condition) to Phrenic Nerve surgical intervention (PS), 24 to nonsurgical (NS) care, and evaluated a third group of 68 patients (derived from literature review) treated with diaphragmatic plication (DP). Variables for assessment included spirometry, the Short-Form 36-Item survey, electrodiagnostics, and complications. Results In the PS group, there was an average 13% improvement in forced expiratory volume in 1 second ( p p p p p p p Conclusions Phrenic Nerve operations for functional restoration of the paralyzed diaphragm should be part of the standard treatment algorithm in the management of symptomatic patients with this condition. Assessment of neuromuscular dysfunction can aid in determining the most effective therapy.
